This Week Only: White House Star Party and LCROSS Impact

As a 1 year long event, IYA2009 has worked hard to provide a steady stream of events. That said, some weeks are more interesting than others, and this week is shaping up to be one of those more interesting weeks. On October 7, Mr and Mrs Obama will host a star party at the US White House, and on the night of October 8/morning of October 9, the LCROSS mission will impact the Moon.

White House Star Party
There aren’t a lot of details, but here’s what I know. According to the White House Press Secratary, “the President and First Lady will host an event at the White
House for middle-school students to highlight the President’s commitment to science,
engineering and math education as the foundation of this nation’s global
technological and economic leadership and to express his support for astronomy in
particular – for its capacity to promote a greater awareness of our place in the
universe, expand human knowledge, and inspire the next generation by showing
them the beauty and mysteries of the night sky.” From what I’ve heard, around 200 middle school kids are going to be invited to participate. Helping these kids and the Obama’s celebrate the International Year of Astronomy will be a group of professional and amateur astronomers from all over the United States. According to the event organizer, “more than 20 telescopes [will be] set up on the White House lawn focused on Jupiter, the Moon and select stars; interactive dome presentations, and hands on activities including scale models of the Solar System, impact cratering, and investigating meteorites and Moon rocks.” An opening address and hopefully general coverage will be streamed on whitehouse.gov and on NASA TV.

LCROSS Impact
At about 4:30am Pacific time on October 9 NASA is going to drop an empty rocket segment into the Cabeus A crater near the moon’s south pole. Hot on the heels of this large chunk of metal will be the LCROSS space craft and its cameras. The rocket section should throw a large plume of material into space that LCROSS will fly through and (before itself crashing into the moon) probe for water. The impact is timed to allow it to sorta be dark across most of the US (or at least everyone west of the Mississippi), and most importantly, to allow the telescopes in Hawaii to see all the details about what’s going on. Want to watch it yourself? To see anything interesting, you’ll really need a telescope of some girth – 12″ at a minimum, and really 16″ or larger is probably a better bet. You can find everything you need here. Better yet, check out streamed video live from the Exploratorium.

Three Dreamers

I know a set of men who had a dream. They wanted to see every child in the world have access to a high-quality low-cost telescope. They wanted something that would show the rings of Saturn, survive a tumble down the stairs, and just keep revealing the sky night after night after night. This is a good dream; a dream inspired by the one laptop per child project. It is a dream that could be a reality, but it needs help. These men need you to dream with them and help their dream become a reality.

Moon thru a Galileoscope (by Andreas O. Jaunsen)

The Concept is Born
The Galileoscope project was launched about the time everyone realized the 2009 International Year of Astronomy idea was about to become a UN endorsed reality. Lead by Doug Arion, Rick Fienberg, and Steve Pompea, the Galileoscope telescope team gave themselves a goal of $10 per scope and set out to design. Like the original One Laptop Per Child goal of $100 per computer, they overshot a little bit. In this case, they came in at $20 per scope + shipping (or $15 to donate). Still not bad. See that image to the right? That was taken through a Galileoscope. These are systems with excellent optics.

The Problem
There is only 1 problem with the Galileoscope: No one can get one in a timely fashion unless, well, you go bid on this or this auction. Here’s the reason for the problem: No one ever provided the start up money needed to produce that first batch of Galileoscopes. We are literally collecting money until we have enough to run a batch out of the factories, producing and shipping that batch, and collecting money for the next batch. At a minimum, we just needed one rich soul to come forward with $200k to turn the factories on and start producing scopes while we collected a round of orders. Ideally, we need just $500k to get a stock pile of scopes we can sell with 24-hour shipping, while incoming money goes to the next round of orders. But that large donation never came. That donor, that sponsor, that dreamer never stepped forward. So these men with a dream, they put in their own money to get this started, and they asked the world – Will you buy a scope? We’re sorry, but it could take 6-months to get it. But will you buy a scope please?

Looking in the box

Originally, we’d all imagined millions of orders – both personal purchases and donations for kids everywhere in the world. Just like the original One Laptop Per Child, we have the option to Buy-One-Give-One. These scopes are the price of a double-CD. Why not think they’d sell like the latest top 40 hit? With orders like that, we projected we could turn on more assembly lines, speed up the rate of production, and keep maybe not ahead, but at least keep up. But those millions of orders never came. Everyone it seemed was waiting to see one, touch one, and play with one (or to at least have overnight delivery). But without those millions, that one touchable one never came to the vast majority of people who were thinking “Maybe I’d buy one. I just want to see one first.” They are coming to those who order, one by one a few hundred thousand scattered across the world at a time. They are coming. You may have yours (comment if you do?), and I know mine are coming soon.

A Solution
The one thing this project needs to overcome the delivery problem is funding. Galileoscope itself isn’t a non-profit company (simply because they didn’t spend all the extra money to become a not-for-profit. It costs almost $1000 in fees to set up a not-for-profit for something like Galileoscope!), so they either need help from other organizations or help from someone who doesn’t care about tax deductions. Bottom line – they need finacial help, and while I haven’t found that couple hundred thousand dollar donor, I’m hoping to find maybe a couple thousand dollars of help.

Felicia Day

This is where you, the casts of Battlestar Galactica and Ghost Hunters International, as well as the wonderful Felicia Day and the new non-profit Astrosphere New Media all come into play. At Dragon*Con in Atlanta on Labor Day weekend, I got pictures of a few famous people (and a few cool costumes) with a Galileoscope. When (thanks to the great Phil Plait!) I asked Felicia Day for her photo, she just signed the box. w00t! An idea was born! We’d get signatures and give someone the chance to have the ultimate geek gift of SyFy geekery. Our wonderful volunteer Laura S. took a box, and I took a box, and between us we cornered the cast of Ghost Hunters International and Battlestar Galactica. Two Galileoscopes. Two sets of different signatures. Two possibilities to make scopes for kids a reality.  The proceeds from this scope will buy scopes for needy kids, and with each scope purchased we are a little closer to a production run.

An eBay Auction
Right now on eBay we have (through Astrosphere New Media Association) two charity auctions. All proceeds are tax deductible and Astrosphere will use the proceeds to buy scopes for needy kids. The auctions are open until October 1st around 7am Pacific / 10am Eastern / 3pm London. You now have the chance to have your own scope, your own geek signatures, and to do a good thing all at once.

Now, I know there is the potential for the winning bid to not be divisible evenly by the $15 a scope costs, so I’m going to step forward and say I’ll personally round the bid amount up to buy that last telescope (I’m just a state university professor, so I can’t do anything cool like match the winning bids, but I would if I could, and if you can, would you please?) Right now, the two scopes are at

• 

  Felicia Day + Battlestar Galactica Cast signed Galileoscope

  Scope 1: Signed by Felicia Day, Michael Hogan, Kandyse McClure, Alessandro Juliani, Mary McDonnell, Michael Trucco, Kate Vernon, Luciano Carro, Richard Hatch, and the BSG Science Advisor Kevin Grazier (see picture). Current Bid: $152!

• 

  Ghost Hunters Galileoscope

  Scope 2: Signed by Ghost Hunters International Joe Chin, JC Howell, Dustin Pari, Dave Tango, and 2 more (see picture). Current Bid: $66!

This means if the bidding ended right now there would be 15 scopes for kids who may never have seen the sky with anything other than their eyes. That’s awesome.

But can’t we do better?

Here is my challenge: Fandoms – Ghost Hunter Fans, The Guild / Dr Horrible Fans + Battlestar Galactica Fans – which of you can get the most scopes into the hands of the most kids? Show your fandom colors by bidding high and lending a helping hand.

Please?

We have 9 days left. Spread the word. Spread this post. Help gets scopes for kids. Help a dream.

Kate Vernon (Ellen Tigh) Cool Costumed People Adam Savage and Phil Plait Gil Gerard (Buck Rogers) Galiloscope in Surly Amy's Scientific Jewelry Richard Hatch (The ORIGINAL Apollo) Steam Punk Boba Fett

Remember: The Universe is Yours to Discover.

Station Fire with JPL in Foreground, by mbtrama

This has not been a good August for the hearts of observational astronomers around the globe. A few weeks ago, smoke filled the Canary Islands as fires swept toward – but not quite to – Roque de Los Muchacho, home of the 4.2-m William Herschel Telescope . Now, the Station Fire is threatening both the Jet Propulsion Lab and Mt Wilson Observatory (Emily Lakdawalla has a story here).  For the next day or so I suspect much of the space sciences community will be holding its collective breath as we wait to see if these two facilities survey the flames. And while we wait, our hearts go out the scientists, engineers, and staff of these two facilities who have lost their homes to the fire. Fire is a part of astronomy. We didn’t exactly design the system to work this way, but the best places to put observatories are remote mountain tops, and desert air is good for astronomy – water effectively blocks many infrared wavelengths of light. Mix dryness with vast expanses of unpopulated woods and you have the perfect mix for fire. (JPL’s situation is different – it simply suffers from being in California – state prone to setting itself on fire.) Long-term observers from Kitt Peak National Observatory and McDonald Observatory all have their own version of “and then there was fire.” While I’ve never experienced flames closer than half a mile away, I did lose a couple weeks of observing back in 2002 to smoke clouds, and even suffered the complete destruction of a very nice I-band interference filter after it got coated in ash and I tried to clean it with alcohol (there is a reason I should have taken chemistry). While I and my dissertation suffered from that particular fire, I was lucky. Just a few months later,in January 2003, Australia’s Mount Stromlo Observatory was destroyed by fire. That southern summer, fire swept through the regions all around Canberra. On January 19th, the fire burned so hot and so fast across the historic Mount Stromlo causing some of the mirrors to melt as structures crumpled. While  the observatory has re-opened, the memorial there stands as a reminder that astronomy is a dangerous science played in high stakes environments, and we can loose everything in minutes if the wrong summer hits. As I write, JPL and Mt Wilson are both still standing. I hope when I wake they will still be there.

The phrase “Eclipse of the Century” sounds a bit pretentious, but with this summer’s eclipse that phrase actually applied. This eclipse had the longest totality time that will occur during this century thanks to the lucky combination of the moon being about as close as it gets to the Earth and Sun being about as far as it gets from the earth. This meant the Sun appeared (if measured very carefully) especially small, while the moon (if measured very carefully) appeared especially large, allowing for a longer then normal period of totality. This eclipse also had the potential to be seen by more people than any other eclipse in recent memory. Starting over India and ending just shy of South America, this eclipse passed over India, China, the ocean just south of Japan, and continued to the Marshall and Gilbert Islands.

I was part of the “Eclipse of the Century” tour as one of their lecturers. Our boat was going to try and be on the center line somewhere around 130 degrees E, on our way traveling from Japan to Shanghai. It was a risk – weather was slatted to be bad everywhere and we were slatted to be at the place with the best statistical chance of good weather (something like 50% chance of good weather).

Can I just say that I hate probabilities?

The day of the eclipse I took a look out the portal a few minutes before sunrise and decided I could sleep a bit longer. The sky was solid gray. These were not the type of clouds that bring beautiful sunrises. These were the type that bring gross mornings best spent in bed with a large dog. Failing to have a dog, I just slept a bit more. Getting up an hour later, I grabbed coffee and headed to the deck.

I have never seen a sorrier group of damp individuals as I saw that morning. We tried a ran dance (mostly to amuse our wet beleaguered crowd). We tried cursing. We tried laughing. I don’t think there was any actual crying. But…. well… Let the pictures tell the story. (Not all mine.)

[IMAGES COMING - I'm on a connection that doesn't let me get images uploaded]

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Please go to http://www.starstryder.com/the-list/astro-tweaters/

Basic Rules:

• Don’t buy cheap filters or off brand filters. All because the Sun may not hurt to look at, you can’t know that it isn’t damaging your human optics until it is too late.
• If you are using a Cassegrain telescope of some type (A reflector with a front end corrector lens and rear eyepiece), you must must must use an aperture filter to prevent melting of necessary plastic bits within your optical tube assembly.
• Remember: When in doubt, project the image and look at the Sun on a screen instead of through the eyepiece

It sounds simply, but quite a few folks have lost an eye or two to the sun.

They are wrong. Anyone with a penchant for details and a love of science can do spectroscopy with a telescope (12inch works, bigger is better). Currently I’m listening to a talk showing amatuer measurements of the Recurrent Novae RS Cyg (I think I got that right), Nova Cyg08 and other systems using a LHIRES III diffraction grating, and in the later case with a DSLR camera as a camera. They also have completely usable spectra of SN2004DJ (mag 12) and SN207AF (no mag given on overhead). It is very easy with these systems to be first one on field identifying the type of Nova and Supernova that has just gone off. It was even possible to see that yes, Var Cas 06 was a remarkably improbable microlensing event.

Beyond identifying things, they are also measuring the velocities of components in binary star systems (allowing masses to be measured). They are reproducing measurements within 3-8 km/s for objects with 219 km/s velocity differences.

Be Stars are also a prime target for these systems. To get a solid understanding of these annoyingly confusion objects, night after night of constant observations are required to sort out the complicated behaviors. No pro who doesn’t have a dedicated campus telescope is going to be able to get this type of time (I couldn’t do this work, for instance). An amateur, however, can partner with a pro, get all the data and collaborate on the analysis, allowing hard questions to be answered more readily. Not all of them are using the HIRISE grating mentioned above. All sorts of systems – some home built – are used across the field.

While spectroscopic work hasn’t taken off among amateurs in the US, there is a small and vibrant community of observers in England, France, and Germany. This is a brave new frontier of amateur equipment that is opening the last of the closed doors between what pros do with university equipment and what amateurs do in their backyards.

Interested in getting a spectroscope and trying a new type of science? Want some help? There are upcoming campaigns on WR140 (also see: this link, and on Eps Aur . Join in and the campaign teams will help you learn while giving your observations a scientific purpose.

If someone tells you that you need a PhD to observe anything from the ground. Smile and tell them they are wrong – the tech is coming and what can’t be done today (like high redshift studies), will probably be doable in some future tomorrow.

My personal way of handling this empty space in my life that a telescope could fit into is to find skilled amateurs to take data for me and to thief (or at least legally download) data from the Sloan Digital Sky Survey. When I’m lucky, I get to look through other peoples scopes.

There are other options though, and a very humorous presenter, Martin Nicholson,  is giving a great presentation on his use of Global Rent a Scope. It costs roughly $20 per imaging hour (less is you build a team and buy time and work together). They have 6 Telescopes in New Mexico U.S.A., 1 in Isreal, and 3 in Australia. Scope time is given on a first come first served basis (and you can book in advance or get time on the fly), and for people awake on a British schedule, there is pretty much always at least 1 scope available.

Martin has no financial stake in the company, and is presenting strictly as a happy customer.

Pros: Can observe all night during the day by choosing a telescope halfway around the globe, and you don’t have to worry about maintenance, you don’t freeze in the control room, and you can use better optics then you can probably buy without annoying your significant other.

Cons: The telescope you prefer to use may not be available when you want it (but you can book ahead to increase the odds). You also don’t have the romantic thrill of standing in the cold slewing across the sky.

I’m going to see if I can get trial to use with my class next week. I’ll let you know how it goes.

Global Rent-a-Scope isn’t the only game on the internet. It’s just the only one being talked about. Anyone have experience with other systems?

No matter what form they take, binaries that are lined up with one star in front of the other on the sky have variations in brightness that can be observed easily, in some cases even with the unaided eye. This means you, no matter who you are, if you can read this page with your eyes, you can observe variable stars and contribute to our understanding of the universe.

Here’s how it works: As two stars line up side by side, we are able to see the light from both. If they are close enough together (which is most of them), their light blends together and we see them as a single bright object.  When they line up, one in front of the other, we only see the light from one of the stars, and if the bigger and brighter one is in front, the system appears fainter but not necessarily a lot fainter. Now, when the smaller star goes in front, the system appears a lot fainted because the smaller star blocks the brighter light (think of a large van with it’s headlights on parked in front of a larger spot light announcing a mall opening. The van is emitting light, but it blocks more then it gives off). As we watch the light of these stars change, we see a flat bright line when the stars are side by side, and then two different sized dips as the pass in front of each other.

Looking at this, we can somewhat understand the geometry of the system based on how long the dips – the eclipses – take, and how much time there is between eclipses. If you have two systems that each consist of identical pairs of stars, you might get short eclipses that are equally spaced (bright bright deep-dip bright bright little-dip) as the stars go round round in a circular orbit that is at a slightly angle, such that the little star grazes across the bottom of the star on the front and dips across the top of the star as it passes behind. At the same time, you might see, from identical stars in a different system, long eclipses that are closely spaced in time, followed by long gaps (l-i-t-t-l-e-d-i-p, brgt, b-i-g-d-i-p, bright, bright, bright, bright) if it is an elliptical system with the smaller star crossing directly in front of the middle of the bigger star (wider area to cross) and directly behind the middle of the bigger star. We also use a bunch of math and theory to measure stellar masses based on this data combined with spectra (a topic for another time).

Today, several people are showing their light curves of various binary systems, ranging from white dwarfs stripping mass of their companions, to fairly close, fairly fast orbiting regular stars. Everyone is asking for help. For instance, the stars DW UMa and SW Sex (for Sextantis) both are looking for people to help them observe in detail. These two white dwarf binary systems have changing orbits and it is only possible to understand them if we hand the stars off from observer to observer around the world around the year. Interested? You can actually find out more about the DW UMa program (they’d love it if you had a CCD camera and filters), through their google group. My initial attempt to quickly copy their group URL failed, but I’ll try and get a URL later today.

Want to get involved in general, check out The AAVSO Mentoring program to find mentor to walk you through your first steps of celestial exploration.

There were roughly 20 scopes of all types and sizes spread out with knowledgeable owners eager to explain their gear and point at a suggested object. I got to see a couple new systems I hadn’t met in person before, and I saw an open cluster I hadn’t seen before as well. I also had the pleasure of confusing some people who thought I was a local student (I was in an Astronomy Cast T-Shirt with my hair in a pony tail). I love getting mistaken for a student now and then. And it was in those moments when they thought I was a student that many members of the club proved themselves to be really good with the public. They offered to let me try their telescope controls, explained to me how I could use averted eyes to see fainter objects, and made sure I saw all 5 of Saturn’s moons. This was the nice, friendly, “just taking care of you” type of mentoring that I always hope to see.

What was particularly cool was the plethora of small running children that scampered in all directions at high velocities. It was reported that one kid actually went through the legs of a tripod as he hurled him self from eyepiece A to eyepiece B. Over the course of the evening, several 100 members of their public – children and teens making up a large fraction – filtered through the parking lot of scopes. At one point, the line from a large telescope stretched at least 100 ft, as people waited to peer through the retractor at Saturn.

As things quieted, I had a chance to sit back and talk with many of the club members. They are involved in the Night Sky Network. They are thinking about the International Year of Astronomy. One of their members took the time to talk to me at length about his experience working with the Columbia Disaster investigation (and I plan to do a interview with him to get more information).

Meeting with and talking with these people was a wonderful experience. If any of you are in the San Antonio area, check out their program of events and go out and look up.

Epilogue:
Sunday I slept in, got a last wonderful taste of sushi and then headed to the airport. The flight home was a bit eventful – They had to remove part of the wing on my flight to DFW, and they initially planned to just leave that piece off! They ended up replacing it instead, which was better then leaving it off, but still. Eek!

Now that I’m home, I’m working my way through a backlog of 100+ emails that need responses and I’m trying to complete a bunch or paperwork to prepare for the St Louis AAS meeting May 31 – June 4. There is a weekend workshop open to the educators, amateur astronomers, and other people interested in doing astronomy EPO. If you are free those days, please consider attending!

This week I’m going to work to keep getting out new LPSC results and audio. I hope to be done by Sunday. Thanks everyone for coming along for the ride.

The GLOBE at Night:  Starting Monday February 25, the GLOBE at Night program is asking everyone in the world (which would include you) to go out, look up, match how many stars they see in Orion with comparison charts available online, and then report their observations through their website.   This data will be used to map the severity of light pollution around the globe.

Lunar and Planetary Society Conferene: Interested in Solar System Science? Are you a Houston are Educator (formal or informal?) March 10-14 the 34th LPSC conference will be taking place in League City, TX (just outside of Houston) and on March 9 they will hold an pre-conference EPO Meeting at the Lunar and Planetary Institute. Rebecca and I will both be going and we will have a very informal get together Tuesday March 11 at 8pm. I am leaning toward the bar at San Lorenzo’s Mexican Cafe on Marina Bay Drive. If anyone has a better idea, please pipe up.

Saturn Night Live: March 15 I’ll be in San Antonio with some friends from BAUT Forum at Scobee Planetarium. Join us to look up and enjoy Saturn, the moon and other bright celestial objects.

2nd International Sidewalk Astronomy Day: April 12 (I’ll remind you ) will be a day of guerrilla astronomy. Do you own a telescope? Well, get it out and set it up in a public place and plan to assault random people with the stars! If I’m not in Europe (and I’ll let you know as soon as I know if I’m going), I’ll be at Annie’s Frozen Custard with local astronomers.

I have to admit it: It was blisteringly cold and there were intermittent clouds and I missed the lunar eclipse.

But, I still got to see it thanks to John S Gianforte of Blue Sky Observatory. He caught the images above (click for larger versions) using a Meade 127ED refractor at f/9 with a Canon 20Da DSLR.

The sequence above was taken by Richard Drumm. Rich said the image was taken with a “Nikon D-70 at prime focus of an Orion Atlas 10 reflector. Totality image is a stack of 2 images (stacked by hand in PhotoShop). The little star (HIP 50370/TYC 840-1499-1 mag 8.5, 1,124 LY, non-variable binary >10″ sep, 3.6 solar radii) in the totality image had to be stacked separately from the Moon as the Moon had moved slightly between images. The 2 totality images were taken at ISO 1600 and 1/4 sec exposure. The white balance setting was set for “sunny”. 10:28:48 & 10:28:54 were the time of the 2 exposures according to the camera’s internal clock. I suspect the images were actually taken closer to 10:22. The Moon had moved perceptibly (a couple pixels anyway) in only 6 seconds!”

Have some images of your own? Email them to me at pamela at starstyder dot com and I’ll post them here or leave a link to your site in the comments below. I’d love to see the different colors the moon may have appeared from different locations.

Giant hat type to Derek C Breit who posted this on the AAVSO-Photometry listserv.

While having my birthday and finals align themselves has been a fairly constant source of annoyance, having my Birthday and a meteor shower align is kind of cool. (Of course, that whole “finals week” thing makes it often hard to actually enjoy them, but what’s life without dichotomy?)

The Geminids are consistently one of the more active meteor showers. This may be due to the 1.5 year period of the parent object, 3200 Phaethon. This strange object refreshes the meteor stream every other year, keeping the source of the storm fresh. This year — TODAY, Dec 10 — this object actually passes within 47 lunar distances of Earth, making for a particularly fresh storm.

Most meteor showers come from comets, but Phaethon looks a lot like an asteroid. We think we have some understanding of the mystery involved. It’s thought Phaethon is a former comet ran out of surface volatiles – the pockets of material that can turn into gas and produce a tail. It has also built up a thick crust of interplanetary dust grains – bits and pieces of left over stuff from the solar system’s creation, knocked off of asteroids, planets and other objects during collisions, or spewed into space by particularly spectacular volcanoes. This combination means that Pantheon is in many ways the equivalent of a snowball rolled around in dirt until it looks like a mud ball. As that mud ball rolls around the sun, it leaves behind a trail of dirt, ice, and other stuff that is aligned just right for the Earth to smack into them once a year.

Meteor showers are really nothing more than the Earth smacking through a column of dust and ice left behind by some comet or comet like object. When these objects hit our atmosphere, like bugs hitting a windshield, they give off tremendous amounts off light as they burn up in the atmosphere. A lot of scientists encourage people to go out and report their observations (although I have to admit I can’t find anywhere to report this shower online – anyone know anywhere?) so that we can get better measurements of the paths of the parent object. As the Earth passes through this years tail and the tail from 1.5 years again and from 3 years ago, etc, etc, we get separate peaks in the number of meteors we see each hour. It takes a whole globe of people looking up to measure where our atmosphere is hitting how many objects per hour. Imagine driving down the road with a clean wind shield and crossing a stream of gnats. You can measure the distribution of the gnat stream by counting how many dead gnats you end up with on different parts of your wind shield.

In general, just like the gnats won’t harm your windshield, the its and pieces of comet-like-thing that cause the meteor shower won’t harm the Earth. That said, there is a probability that someday in the future we will cross the comet instead of the comet’s stream. There is no concern for anytime in the next several 1000 years for any of the known objects, but …. there is a neat possible history of a possible past collision between the Earth and a fragment of Comet Enke (the parent of the Taurid Meteor Shower) that may (may may may – the data is week) have aided in the end of the bronze era.

So, you’re safe today. 3200 Phaethon is a little bit close (and landed on the Potentially Hazardous Asteroid List (scroll down)) but no possible harm will actually come. Instead, go out, look up, and catch yourself a look at a falling star falling comet dust.

I paniced (and hopefully hid it well), rebooted, and my computer decide it was going to do a split screen display with the projector as the primary monitor (EEK), and fixed it, all while going through the “pictures aren’t required” intro part of my talk (EEK EEK). When I opened PowerPoint I totally missed that it opened a recovered file instead of the correct file (ACK!), and half way through my talk I ceased to slides (breath breath breath), so I closed the recovered file, opened the correct file, and made it through, somehow, only going maybe a minute over.

That was by far the worst talk I have given. Ever. Ever. I did better as an 8th grader.

I’m now sitting in the corner of the room, blogging my quickly beating heart out.

Okay. Breath.

I will never again try and give a talk without rebooting my CPU right before hand. I knew better, but it is a new CPU with 4GB of memory, so I thought it would be okay. I was so totally wrong.

Anyway…

I gave a talk on AH Leo, my favorite pet star. The basic results are summed up in the graph below.

(The really large Preliminary means I still need to finish my error analysis, to make sure I didn’t go to a ludicrous number of decimals anywhere. )

So, what does all this mean. Well, first go read this if you didn’t go read it above.

After that article was written, I requested an observing campaign from the AAVSO and they supplied me with several thousand wonderful data points. Before I could finish the analysis, AH Leo rose for the 2007 observing season, so I got one more season of data before settling down for analysis.

The way the data is analyzed is pretty straight forward. Imagine that you are looking at an EKG of someones heart. It should repeat over and over exactly the same. Now imagine you have a loose wire, and every part of a second, you loose signal. In this case (hopefully) the heart is doing the same thing over and over, but you don’t see the whole shape. To see the entire shape, you can cut up the EKG plot into one heart beat junks, and line up the data. Mathematically, you are taking the (Time of measurements / length of time for heartbeat) = Phase. What we plot is phase versus signal from heart.
For stars, instead of loose wires, our data suffers from daylight, clouds, and moonlight preventing data from being acquired. But, if we observe enough nights, we can get the whole cycle (although stars with ~1 day pulsation periods are really annoying).

To make it easier to see the transition between cycles, it’s customary to take the phase diagram and add 1 to it (or subtract 1), and create side by side, identical phase diagrams on the same plot. That’s what is in the image above.

This particular star has a 0.466321 d period. That I believe within 0.000005 d (I think), but I want to work more on my error analysis so I can put on better error bars.

This star (as you read) is weird and its brightness at maximum light varies. Thanks 4 years of hard observing, I think the period to vary is 41.49 d (error may be >0.1 day though, so don’t use this number until I get my error analysis complete and get a paper through peer review. Caveat Caveat) To get this number, I fit each night of data that showed the inflection point at maximum light and made a table of the fit time and brightness for maximum. It’s really ugly:

But, despite the ugliness, it is possible to see the shape of the curve.

It was a long route to get here, and I’m not done yet. But I’m 90% of the way there.

More after dinner…

Hi there. Have a good time?

No one quite knows what happened. This normally bland, boring, not visible without a fairly large telescope comet suddenly decided to flare into something that can be seen from big cities.

Personally, I can’t wait to see the science on this one.  One of the best collections of data I’ve seen so far is here. There is an annulus of material (from an outburst? from a tail seen face on? from both?), jets, and evidence of molecular carbon in the tail. Why? No idea.

Go look again   Will discuss this more when the science papers start coming out.

For those of you not wanting to get into the special details of photometry, rest assured tomorrow I’ll have a special online treat

Now onto the the nitty-gritty data analysis details…

There are several different ways to obtain astronomical data. Perhaps the three most common forms of data are contour plots, spectra, and photometry. In each case the data has to be calibrated in a different way. While (IMHO) spectral data are perhaps the hardest to process and analyze, calibration often requires nothing more than looking at a flux standard and imaging a lamp or a series of lamps. At the other end of the spectra, photometric data is relatively easy to reduce and analyze, but calibration is a long and tedious project. This document attempts to explain the best way to make it through this long and tedious process, called All-Sky Photometry

I Why suffer?
No two data sets from two different telescopes can be assumed to be identical. Two diferent processes work against observers, changing measured values non-standard ways.

Airmass: The first problem is airmass. When an observer looks at an object straight overhead, the light they are observing passes through what is called 1 airmass of atmosphere. Along the way, that light will get thinned out by the atmosphere as photons are scattered through interactions with gas atoms/molecules. This process, called Raleigh Scattering, is responsible preferentially effects light (photons) with short wavelengths. In this way, sunlight passing through the atmosphere has its blue photons absorbed. those photons are then emitted in random directions (and perhaps re-absorbed and re-emitted multiple times). This process of absorption and re-emission is called scattering, and it leads to our sky being blue (which should give you a sense of how far across the atmosphere sideways a photon may end up going before it gets scattered toward an Earth-bound observer).

As an observer looks at objects lower and lower in the sky, they are viewing light that has had to travel through progressively more atmosphere. The more atmosphere the light from a source has to go through, the higher the probability the blue light (and maybe even the green and yellow light) from the object will be scattered out. This effect explains why the sky becomes more and more red as the Sun gets closer to the horizon. Scientifically, we refer to the amount of atmosphere the light must travel through as air mass, and mathematically, airmass =

(A good airmass calculator is here: AAVSO calculator)

In general, you don’t want to take data below an airmass of 1.2 (more than X degrees away from Zenith) because you’re fighting the atmosphere. Even within this window, however, airmass effects can alter the measured magnitude of an object by a few tenths of a magnitude. To determine how to correct for this loss of blue light, it is necessary to measure how the observed magnitude of known objects changes as a function of airmass. (More on this below.) Since stars of different colors will have their overall black body curve mutated in different ways (with blue stars getting more of their light knocked out than red stars), it is necessary to take calibration images in more than 1 filter.

Optical throughput: The second problem effecting photometric data is the variation in throughput of optical systems as a function of wavelength. Different mirror coatings, different lens coatings, and different glasses all reflect and transmit light in different ways at different wavelengths. For instance, check out this discussion on Silver versus Aluminum mirror coatings. By the time the light (or at least what’s left of it) reaches the detector, different chunks of the electromagnetic spectrum have been removed in part or in whole (this link shows you the curves for the Canada-France-Hawaii Telescope). Different detectors then do their own part to remove light, with CCDs being general less efficient detectors in the blue than in the red (see this discussion on back illuminated CCDs). This effect essentially acts like an additionally filter, and causes your telescope to respond in a non-standard way. To figure out how to correct for this problem, it is necessary to take images of objects spanning a wide range of colors and measure how the difference in published magnitude and measured magnitude deviates as a function of color. As with airmass, it is necessary to obtain calibration images in at least 2 filters.

II Observing Strategy
When trying to calibrate a scientific field it is necessary to set aside one photometric night (which ever one turns out to have the absolute cleanest skies), and spend an evening doing calibration images. A photometric night is defined as one in which the sky’s transparency is the same in all directions (typically, this means there are no clouds anywhere – it does not mean the seeing is good. It is alright to use a night with ok but not great seeing to do all sky photometry).

A list of papers containing primary standards and secondary standards (created using the primaries) is provided below. These objects have been selected to be non-variable and generally free of too-close neighbors. Primary standards can be thought of as the kilogram mass locked up in France from which the kilogram has been defined, and secondary standards can be thought of as uber expensive laboratory masses that have their masses defined using that kilogram mass in France.

In selecting standard fields, you want to choose fields that bracket your objects in airmass and containing objects that bracket your objects in color. In other words, If your object starts the evening with an airmass of 1.2, select comp fields that have airmasses of 1.4 and 1.0, as well as near 1.2. If your object has a B-V of between 0.2 and 1.2, your comparison objects you range from 0 to 1.4 (with a lot of colors in between). By extending the data you have for your comparison fields beyond your actual object, you can help guarantee the corrections you solve for are legitimate and eliminate the need for extrapolation. It is also useful to try and find standards close in magnitude to your science fields. The fainter you go, the harder this will be. As the exposure times of objects get longer, the variation in airmass from beginning to end of the exposure will increase. This isn’t a problem for similiar exposure tines, but things get messy when you are apply airmass term solved for using 5 second exposures to a 5 minute exposure.

My personal all sky photometry strategy is to sort my objects by RA and make a table of the time when the rise to an airmass of 1.2, the time they set through an airmass of 1.2 and what their minimum airmass is. I then add in standard fields that rise before my first object, set after my lasts object and fill in all the spaces in between. I will then observe on a rotation that allows me to follow my objects through the sky. (See example below).

There a couple important caveat: 1) Keep your standard fields as close to your science fields as possible, 2) Sometimes there just won’t be a standard field that reaches as high an airmass as your science field (this is because the standard fields are grouped around the equator and your objects probably aren’t. If you are observing near either pole, fields may not be available.)

It is more important than ever to obtain good bias, dark and flat exposures on the night you do all-sky photometry. Don’t forget that you’ll need darks (if your CCD requires them) for all the exposure times you use. If you have any concern that your CCD temperature is varying, take biases and darks throughout the night, interleaved with your observations. It is also good to take flats at the beginning and end of the night, to make sure no changes took place.

III Reduction Overview
This is not meant to teach data reduction. If you want to learn data reduction, go read this or this.

That said, here’s the “Quick Start” version.
1) Combine you bias exposures into a master bias using median combine
2) Subtract your master bias from everything
3) Examine your darks by exposure length. If they vary through the night, don’t combine exposures taken from different batches (but do median combine those from the same batch if you took more than.
4) Carefully subtract the master darks (or individual darks) from the images (flats and science frames) with the same exposure time taken at the same time of night.
5) Average combine your flats from the beginning and end of the night. Try subtracting 1 from the other. If you get a nice flat nothing, try combining average combining the flats from the beginning and end of the night.
6) Divide your science images by the master flats. If you have non-identical flats for the beginning and end of the night, you’ll have to do a bit of trial and error to figure out when the conditions changed.
7) Do NOT co-add anything.
Back up everything

IV Photometry
This can be done in many many different software packages. In general, you want to choose an aperture that is 4-6 times your average full width half max for the entire night. In general, a good way to determine the correct aperture for your image is to make a plot (for stars of many magnitudes) of (Magnitude / Magnitude with 1 pixel aperture) versus aperture for apertures ranging from 1 pixel to 8 x FWHM. The point where all the slopes go ~flat is a good aperture.

You will want to use the same aperture for all stars in all images. You may be tempted to not do this. Do not give into temptation! The FWHM of a star (not a galaxy / QSO / Planet / etc) is determined strictly by the atmospheric conditions. If you have a steady, photometric night, all stars of all magnitudes will have the same FWHM (within error). If this isn’t the case, your night isn’t suited for all-sky calibration photometry.

Once you have your data, organize it into columns along these lines:

(Example File here)

V Solving Transformations
So, now you have your data. That means it is time for math.

The generic equation for a transformation is:

where, m_B = instrumental magnitude in B, B = published apparent magnitude in filter B, x_1B = zero-point offset (the baseline difference between instrumental and published magnitudes, (x_2B) = airmass correction in Filter B, X_B is that observations airmass, (x_3B) = colour-term correction, and BR = B-R color.

If you have three filters, and the data for each filter has three unknowns, then you have three equations and 9 unknowns. You can’t solve that algebraically with just one observation! Instead, you have to fit a plane to the data using fancy statistical software (or IRAF), or you solve things iteratively using excel.

Here’s how. (I apologize for the graphics of the math).

At some point in your life someone probably taught you that the equation for a line is y=mx+b, where y=what you plot on the vertical axis, x=what you plot on the horizontal axis, m is the slop of the line through the data, and b is where that line intersects the vertical axis. Excel is capable of solving for the line that best fits a data set that has been plotted. (Just right click on data and select “Add Trendline”)

We’re going to start by assuming the colour term is close to zero and solve for the airmass term. Start by adding the published magnitudes to your spread sheet (as in the example), and creating a column for instrumental – published magnitude. Now plot (instrumental – published) versus airmass. The slope of this line is your first draft of the value for the airmass correction term (x2_F1). You can then use that value in the transformation equation to fit a line to the color term.

To solve for the color term, you want to now want to create a column in your table for (instrumental_F1 – actual_F1 – (x2F1)(airmass in F1) and plot it against the color (F1-F2). The slop of this line is now the colour term and the Y-intercept is a second draft of the zero-point offset.

You can now solve for the airmass term more accurately by making a new plot.

You cannot iterate a couple times between solving for the colour term and refining the airmass term.

To check your solutions, you need to invert the equations above to solve for the actual magnitudes using the instrumental magnitudes and coefficients. This is ugly if you try and solve for, say, B and R directly, but solving for R and BR is fairly straightforward. Take the equations for m_B and m_R and subtract them from one another and solve for BR first.

You should stop iterating your solution when the difference between the published BR & R and your calculated BR & R values stop improving.

VI Applying Transformations

Having checked your values for the standard stars against the published values, you now know your transformation works (and the stdev between calculated-published gives you your error). Now you can you the same inverted equations to solve for the values of your science targets and the secondary standards you use in your field (e.g. the comp stars in differential photometry).

Once you have good solutions for a variety of standards in your field, it is possible to use those secondary standards to determine the zero point offsets for future images taken on imperfect nights.

Standard Star Papers

• - Landolt, (1983) UBVRI photometric standard stars around the celestial equator
• - Landolt, (1992) UBVRI photometric standard stars in the magnitude range 11.5-16.0 around the celestial equator
• - Christian et al. (1985) Video camera/CCD standard stars (KPNO video camera/CCD standards consortium)
• - Odewahn et al. (1992) Improved CCD standard fields”

This is a single data point from a single telescope.

But it’s kinda cool.

One of the problems with astronomy is you can’t look at the whole sky the whole time, so rare events are rarely seen. If a galaxy has 1 supernova every 100 years, than if you look at 100 galaxies you’ll see 1 supernova a year.

But it is hard to watch that many objects for that long continuously.

Astronomers on this project, lead by Duncan Lorimer, note that 100s of these events could be going off somewhere in the sky each day, but because this object only gave off light for 5 millisecond (and it took a 210-ft telescope to see this first one), our chances of looking at the right place at the right instance with a big enough telescope… Well, clearly the probability isn’t zero, but it is very very low.

But this all assumes this was a real event.

And we don’t exactly know where to look to try and find the same event.

Was it real?

The best way to find out if it is real is to re-analyze all the old data that is out there and see if we captured a previous burst at some point in time. Maybe, if we search hard enough, we’ll find a second burst, from hopefully a second telescope (so the perfect electrically glitch can be ruled out). And if we have two, the theoriests can really get going. So far, 1 point has generated 1 press release containing 2 theories.

It’s not every day that something totally new gets noted. If this was an evaporating black hole, the next generation of more sensitive radio telescopes may be able to detect these things popping off all over the sky and this first burst could be remembered in the same way we remember the first gamma ray burst.

But then again – it could have been nothing.

It should be noted this data point was found by an undergrad who was doing the boring re-analysis of the data. Searching for more data points is a perfect undergrad task. This could be one of those neat moments when a great discovery comes from the efforts of someone who is still daily asking, “So why do I have to learn calculas?” Imagine being able to put on your graduate school application, “I discovered evaporating black holes…” The student on this project, WVU undergraduate David Narkevi, just might get that opportunity.

For those of you who aren’t quite sure what causes a lunar eclipse, let me step back a second (everyone else, skip this paragraph). Every 29.53 days the Moon completes one orbit around the Earth relative to the Sun. Kevin Lee has created a neat applet of the moon’s orbit if you want to see things in action. The gist of it is simple. If the moon is between us and the Sun, we can’t see any of the part of the Moon that is being illuminated, so we have a new moon. In order for us to see a full Moon, we need to get out in front of the Moon (between and the Sun), and keep our own shadow out of the way in the process. The tilt of the moon’s orbit generally does this for us. As the moon goes around the Earth its orbit carries it North and South of the ecliptic – the line the Sun follows in the sky. The tilt of the moon’s orbit, like the tilt of the Earth, maintains a fairly constant orientation relative to the stars, which means the high end of the orbit only points toward the Sun once a year, and the low end of the orbit only points toward the Sun once a year. There are two mid-points, where the orbit crosses the Sun’s path, and these each also get their shot at pointing toward the Sun. When the moon is new and this intersection of orbit and Sun’s path on the sky occurs, we get a partial or full solar eclipse, and when the Moon is full, we get a lunar eclipse. (I tried really hard to find a copy-right free image to explain this and failed. If enough people ask for a graphic, I’ll create one). Anyway, we are about to have one of these twice a year alignments where the Earth gets directly between the moon and the Sun.

This Tuesday night (for my time zone – check here for more general times a lunar eclipse will begin at about 2:30 am and continue on into the dawn. This is not a user friendly time for me and my 9am meetings. It is admittedly even worth for those on the East Coast, and not at all visible for Europe.

However, if you are in South East Australia, New Zealand, or Indonesia, this is totally the total lunar eclipse for you. It will start just after Sunset and continue through the early evening. It will be high in the sky for those just north of the equator. This is a nice temperate time of year, and you really can’t ask for better.

Those of us on the other side of the world are just going to have to pout this one out.

Oh, what a wonderful Google world we live in. Today, Google unveiled a new feature in Google Earth, the Sky. That’s right, along side your house, your office, and that mutant strange thing you created in Google Sketchup, you can also look at the stars, galaxies, and planets in Google Earth. In collaboration with ESA and NASA, Google now includes sky maps complete with links to Hubble imagery and all sorts of neat factoids.

I’m sure you’ve already heard a bunch a bloggers praise Google (and if you haven’t here’s Phil’s take). Now, while it is uber cool, and is certain to waste many many man and woman hours, my first thought was, “This is gonna make teaching so much easier.”

Here’s how:

1) If there is a star party coming up, I can open up Google Earth from any computer I can install an ap on – no fees – and find out interactively what is out there. Up until now, I’ve been using Sky and Telescope’s Interactive Sky Map. I love and respect the work S&T is doing, but will now turn to a new tool when planning my star parties.

2) The zoom feature let’s me zoom in to a binocular sized viewing area. This is a great way to practice star hopping with soft ware! Star hopping is how you get from a bright star that you can see with your eyes to a faint object you can only see with the aid of binoculars or a telescope that you are manually operating. For instance, when I’m looking at Andromeda, I often get there by star hopping from one of the legs in Pegasus, from the star nu Andromeda.

3) I can easily show students around the sky, and after I turn off all the labels, it is just as confusing as the real sky. These means we can practice using outdoor star maps, like planispheres, inside on Google Earth.

4) Did I mention how easy this is going to make planning star parties?

5) This will also allow us, when we have remote connections, to figure out what the heck we accidentally discovered while lost in the sky. If you ever wander around Sagittarius with a pair of binoculars you’ll very quickly understand what I mean. That particular region of the sky is chock full of nebulae, star clusters, and all sorts of combinations of these objects.

I had previously uninstalled Google Earth because there was nothing it did that I needed that I couldn’t do with Google Maps (my computer only has 40GB of memory, so choices have to be made). This new functionality won me over, and Google now has acreage on my hard drive and a place in my curriculum.