This is my first post here, as i've just started with VSO. Not writing about anything in particular but sharing my first experience uploading data to AAVSO and my first "technical" issues and doubts. Any comment to those are very welcome, both from more experienced observers and from other newbies alike.
I've commited myself to a modest observing program for 2020 comprising the stars in the 10-star tutorial and those at the "easy stars" list, summing up 37 stars. Each month i'm selecting those easily visible ("easily" coming from my instrumentation limitations: Binoculars on a tripod, difficult to see at cenit, and time window limitations also... a paralelogram mount is coming soon). This is 10 of them for december. I started the other day making a pair of estimations which didn't upload, just for practice and confidence building. Yesterday the sky was clear, went to a close place to escape a bit from the city lights, and started the program.
Fist of all, sensations: This is very fun and addictive!!! And builds up my star hoping skills.
Now the stars: I were able to do just 5 of them in about 2 hours, taking into account setup and that i've got company to show constellations and such from time to time... I think at my actual level i can do 5-7/hour more or less.
- R Lyr: Too much moon to find naked-eye comparisons, so i used my 10x50. To compare i needed to go back and forth between star fields (~1.5-2 FOVs). I found two close 44 comparison stars (eta and theta lyrae, chart X25764AOJ) handy and not too far. First surprise was perceiving them a bit brighter than the variable at a first glimpse, given that the variation range goes down as much as 4.4 exactly. So i ended up unfocusing a bit and taking only one of the paired comparison stars in field (on one side of the FOV) and comparing just that one with the variable (offseting it to the same position in its FOV as the comparison star). When done this way, difference seemed to evaporate. Questions here: Isn't taking a look at variable range before estimation lying a bit? Is my sensation of two similar stars versus one appearing brighter than one at a time just my sensation or common issue? How do you deal with?
- Gamma Cas and Algol (Beta Persei): Those were obviously naked-eye. After submitting my observations i read https://www.aavso.org/thought-about-visual-observing in this same forum. I'm keeping them for learn purposes, but as stated there those visual light curves are too sparse to see any pattern. May i keep submitting my observations or just keep them for myself? About Algol: It was 30º appart from the moon, comparison stars about 40º... I assumed that to be a non-issue, but what do you do in that conditions? skip it? have you got some kind of rule saying e.g. "If ratio between comparison-variable separation and variable-moon separation goes up 20% i'm not observing it tonight"?
- General doubt about submitting: I planned (not needed with yesterday's stars) to make several estimations with different comparison stars if available and average them. The form to submit visual observations just allows room for one comparison star and optionally one "confirmation" star. Does this mean i should not be averaging? Otherwise, how do you submit that? What time do you assign to the observation if spread over 5 minutes?
- Are "fainter than" estimations useful at all? I did that with the two Miras selected for yesterday (Khi and R Cyg). A pity, because looking at the light curves they might be visible from my place with my 20x80s if not that low and if not moon.
I dropped the other stars assigned for yesterday because of the moon position and lack of time.
Well, so those are my doubts and sensations after a first contact... I think i'm becoming a member and finding a mentor soon, in the meanwhile (december) i'll keep going and gaining skills.
Hello! And welcome!
A great group and very supportive.
As to your questions, I'll defer to those who do more visual observing. Best regards.
Welcome to visual variable star observing. I agree, it is a lot of fun. For me, I find it relaxing and a way to do astronomy on a weeknight from my driveway.
You're off to a great start.
I am 99% a binocular observer. (I have a pair of 10x50s on a mount.) Do check out the binocular program: https://www.aavso.org/aavso-binocular-program It's a great deal of fun.
Let me try to answer some of your questions.
I try my best not to look at the range of a star that is printed on the chart before I observe the star. When I do look at it, it does greatly bias me. Yes, not looking at the range, means you will end up trying to find stars that are below the capabilities of your instrument. (Some of the stars on the binocular program when they are near their minimum are invisible to my binoculars.) But as you said, star hopping is fun and great practice. Invisible stars also helps one to really identify star fields with accuracy.
As far as "fainter thans," I don't report these. If I were using a 20" scope, that might be different. :D
Also, don't average your estimates. Find the variable, compare it to the companion stars, and make your best guess. :) There will always be uncertainty, especially if you have situation in which, say, your nearest comparison stars are 7.1 and 8.0. Is the variable exactly between those two in brightness, or slightly closer to one or the other? This can be challenging, although accuracy increases with experience. The statistical truth emerges when many of us submit our estimates.
Moon interference is an issue, of course. I generally don't do much variable star measurements from gibbious phase to gibbious phase (so for about a week out of the month). For me, the problem is that the moon washes out the stars I am using to star hop from. :) (On a transparent moonless night, my naked-eye limiting magnitude at zenith is about 4-4.3.)
As far as number of variables per night.....for me it really varies. On some pleasant spring nights I might do twenty. On a sultry humid night filled with mosquitos, I may do just one! The most important thing for me is that it is fun. Never let science get in the way of a good hobby. ;)
Let us know if we may help further!
--Michael in Houston (RMW)
Thank you for your replies and hello. Thank you mdrapp, helped a lot!
I've also been suggested to find stars with more variation than some of the ones i posted the other day, so i'll review my list and exchange those by some in the binocular program.
I find this a good astronomic occupation for a weeknight too. Weather here is almost always cloudy from october to may, so one has to take every chance. Could also happen that you find the day is cloudless, you get everything into the car, go to your place... just to discover you left your aavso charts at home (happened to me just a pair of hours ago :-)))
Ah! I was also advised (email) to keep out of red stars on moon nights... I'm sharing that one as i don't remember reading about that in the manuals.
One problem many beginners struggle with (including me when I first started) is to over-observe - especially stars typed as 'irregular'. Take Betelgeuse. Yes, it's irregular but it's a 'slow' irregular. Basically, if a variable is red (like Betelgeuse) you only need to observe it once a month because the variations - if any - are slow. Many of these red stars go through long stretches of not varying at all! When I observed with binoculars there were a couple of stars on my programme that I never saw vary at all (KK Per and OP Her). If you want to see variation in a reasonably short spce of time I'd say go for some bright members of the RV tauri class. AC Her is a really good one! CH Cyg is a really important star on lots of levels, and it's nearly always visible with binocs. AB Aur is a young star that occasionally undergoes unpredictable fades, and even these fades are visible with binoculars.
"Fainter thans" - I'd say don't bother if all you have is binoculars. It's a fair bet that even though (say) Mira is too faint for you, lots of folks with bigger scopes will be able to see it.