Charts, Charts, Charts...
Every few years or so, the dining room table in my house becomes “AAVSO Variable Star Charts Central”. The centerpiece, placemats and silverware are put away, and in their place are three ring binders, plastic page protectors and stacks of paper charts. The printer in my office gets a workout, and I become a regular at the office supply store, buying ink, paper and other supplies as the project progresses.
This is the fifth time in ten years I have performed this major renovation project, so I’ve got it down to a science now. I’ve kept most of the charts that have been replaced, so it has become a sort of archival history project too.
When I first started observing, I started with all the stars in David Levy’s book A Guide to Variable Stars. I used everything I could lay my hands on. Old "micro-dot" charts, preliminary charts, and a few new format charts that I would have to hold upside-down and shine a flashlight through to match the view in the eyepiece. In 1998, not everything in the chart catalog was online yet, and only a small percentage of the charts were available as reversed charts for use with a Schmidt-Cassegrain. It wasn’t long before my observing program became all the stars with available reverse charts. That was a lot easier than using the flashlight trick or trying to flip them in your head.
I realized immediately that I would need to organize all these charts into binders to keep them protected from the dew, frost, and wind. My system evolved quickly, and it hasn’t changed much over the years. I printed wide field finder charts from planetarium software with a limiting magnitude of about 9 that had a circle indicating the size of my finder scope field of view, and a little arrow pointing to my ‘jumping off star’. This was the star I would aim for when dialing in the setting circles or star-hopping to the next target. The same star would be indicated on the variable star chart so when I got to the eyepiece I could find my way to the variable star by star-hopping from there.
In the binder, the finder chart was on the left and the variable star chart on the right. Simple for most CVs, I usually only needed one comparison chart. Each time I flip the page I'm on a new star. Mira stars with large amplitudes usually require additional charts. Typically, B charts for maxima above 9th mag, which I observe using the finder scope, D charts for 10-13th mag and E charts for fainter than 13th mag or to relieve crowding on some D charts. Some Milky Way fields require F charts to relieve the crowding of comp star labels or to show 15th magnitude comps.
The second generation of charts began with me printing reversed star fields from planetarium software and hand labeling the magnitudes, but I always hated the messy look of my handwriting on these charts and they were limited by the contents of the Guide Star Catalog, so they didn’t last long. Once the complete AAVSO chart catalog became available online, I started downloading all the charts and flipping the fields and labels around in an art program. I think that was when the true chart madness set in. I couldn't decide what to observe, so I decided to observe everything! I made hundreds and hundreds of charts in various scales and orientations.
My CV binders stayed more or less unchanged for a long time once I had maximized the order for speed. That was an interesting project. I took day-glow stickers and labeled them with the names of all my CVs then placed them on their respective pages of Sky Atlas 2000 so I could figure out the most efficient order to observe them in. I recently read a paper on ACP Scheduler and was pleased to see I had followed the same logic as the software in assigning the observing order. I just did it the old-fashioned analog way. The same way I was observing.
Using those binders I was able to observe 100+ CVs on a decent night. I did over 250 in a night a few times. It’s easy when all you are doing is reporting, “it isn’t in outburst”. But I have to admit 250 is just insane.
In 2003, I began coordinating chart production at AAVSO and we started the last major overhaul of the chart catalog before VSP came online. By 2005, I had replaced all my previous charts with the new ones we were making using Henden and ASAS photometry. Until recently, I still preferred these charts to anything the chart plotter could produce. They were beautifully crafted, hand labeled and thoroughly checked before being released to the public. But there was no way we could continue that practice and keep up with the pace of new discoveries or the demand for more and better charts.
By 2009, we had revised a significant percentage of the sequences with newer, better photometry and it was time to bring the binders back indoors from the observatory for another update. Not only that, but now I had a CCD on another telescope in a new roll off and I needed a whole different set of charts for those program stars!
With the latest round of improvements to VSP most of my previous objections to the charts it produces have been eliminated. First among these were the ridiculous huge star dots it used to plot for many variables! I have hated those blobs for years. So here we are again, updating all the chart binders and revising the observing programs again.
My visual program is now going to concentrate on AAVSO Legacy and Program LPVs. I want to observe stars I can make positive estimates of 99% of the time. I have tens of thousands of “fainter than” observations in the AID and I don’t find them that much fun to make any more. So I have several binders with all new LPV charts for the eyepiece.
My CV program will just be the prototypes, legacy CVs, bright active stars and a few favorites I will observe forever just because I like them. I’m pretty sure I will never sit out all night under the stars and report “I didn’t see it” 100 times ever again. Let someone else discover the next outburst of PQ And. I want to make observations you can plot on a light curve.
I have another binder for the CCD scope. That program is Z CamPaign stars, northern RCB, recurrent novae and some quirky favorites. I affectionately call them my ‘oddball' program stars.
Well, time to go. The printer has grown quiet, so I either have another batch of charts to organize, or I’m out of paper. Until next time…
Submitted by SXN on Mon, 03/07/2011 - 12:34