I could really use some help here. For the past several years, I've been trying to get some momentum going in doing visual variable star observing, but I keep running into brick walls.
I know I have an interest in it. I found the Nova in Delphinus last year fascinating and I enjoy star-hopping and looking at star fields. However, my variable star program has been basically just a series of false starts and frustrations.
It has been a few months since my last effort and I've recently begun to think long and hard about what has been going wrong, which actually wasn't all that difficult in hindsight.
I started out using an SCT on a goto mount. This seemed like the most efficient way to get measurements. However, the field of view was always too narrow; I never could identify the fields. Plus, the goto was just tedious and boring. It automated me right out of the hobby. It wasn't fun.
So, next I tried the AAVSO Binocular Program, which is wonderfully and thoughtfully put together. It seemed like a logical place to start for a beginner. Yet, I didn't enjoy it much either. Even with my 10x50s, the shakes were distracting and the constantly reacquiring the field was exceptionally tedious. I tried several tripods and binocular mounts, but those proved annoying unwieldy. So that wasn't much fun either.
So, I'm trying a different approach. I have thought long and hard about given my limited weeknight observing time, what equipment would be the most enjoyable to use that has the greatest usefulness in visual variable star observing.
I have settled on this: I have a 66 mm ED f/6 refractor on a lightweight but sturdy alt-az mount. The scope is exquisitely comfortable to use -- the eyepiece is always at a convenient height while seated. I can pick the entire thing up easily and move around the yard to avoid trees and lights. My wide-field eyepiece gives a 3.3 degree field of view and with my amici prism diagonal, the view matches any star chart.
So here is where I need some help. I've searched, but I'm in information overload. There sure are a lot of stars in the sky. What are three-to-five variable stars in the late Spring sky in the northern hemisphere that are relatively easy to find and estimate and in the range of my scope would be good to start with? (NELM is about 4.5) Well-observed stars are just fine. I want to practice first. And, of course, a star with a relatively short period would be nice, just for fun.
R Leo is a good one for this time of the year.
Although an LPV, it should still have a nice variation the following weeks. It's also dim enough now so that all usefull comparison stars will fit the TFOV of 3 degrees, but not too dim as to be invisible in your scope, at least for the time being.
I've found that a cheap "chaise lounge" works very well for observing with binoculars. A small table (or TV tray) with charts and red flashlight next to it can make a very nice night.
I'm in Dickinson, Texas....about 30 miles southeast of Galveston.
For the binoculars, I've tried the standard photographic tripod and homebrewed parallelogram mount. I found the tripod mount to be a pain in the neck (literally) for anything above 40 degrees. The parallelogram mount was just big bulky and heavy. It also had some backlash issues. It really just became more trouble than it was worth. At the end of the day, I found that looking down into an eyepiece was far more comfortable than looking up into binoculars.
And thanks for the suggestion on R Leonis. I had forgotten about that star. If I remember right from my reading, that was David Levy's first variable star many decades ago.
Although you are correct that R Leonis might have been my first one (or one of my first) many decades ago, I believe you meant that it was Leslie Peltier's first variable star even more decades ago! My current favourite variable star is TV Corvi, or Clyde Tombaugh;s star.
The best suiggestion I can offer is keep trying, and never give up. Variable stars are truly an inspiring field.
David H. Levy (LVY)
Well, unless them Mira types are in their inner sanctum, they will show variations from one week to the other, so they're a safe bet. Same goes for cepheids.
Eclipsing binaries can be tough - if the components are well detached then you really need to wait for an eclipse to occur. Systems like beta Lyrae though are nice, they will also provide change on an almost daily basis.
With your scope, I think you can go ahead and pick a few stars from the binoculars program - miras, cepheids being the more obvious choices.
Your GO TO mounted SCT should be no sweat . Give it another try. Are you aligning correctly? Check through the instruction procedure. Make sure the tripod is level, too!
If you've an 8 inch scope you can maximise the field of view with a focal reducer, taking you to F/6.3, and a 32mm Plossl eyepiece will give you a nice 78' field. That's plenty. Now, about your finder: make sure its set up to give a mirror image, like the scope, by employing a diagonal mirror. An 8x50 finder should give a 5° field. Scope field should be nested in the centre of the finder field; check with a terrestrial target. Now you're in business!
Next; check your aligning correctly with a bright star or planet and that the two fields coincide, as above. OK?
Your finder charts must be mirror image too! Use a B chart to relate the view to your finder. Then, with a D chart, go in deep with the main scope. The comparison stars will all be there, I assure you. If you cant see your variable...it's just too faint at the time. Try a higher power, then move on.
If your still having problems, my E mail is firstname.lastname@example.org.
Don't give up! Variable star observing can be most rewarding. I have a goto (12" Meade LX200) but I find the stars using the handbox (manually) starhopping and just use the drive to keep the stars in the FOV.
The first obstacle is finding the variables and I use VSP to produce Finder Charts. I use 900 arc minutes (15° FOV) but you can go up to 1200, and you can set the magnitude to whatever you like. I suggest mag 9 for these charts. This is a really wide FOV and should enable you to find most stars. Then I might use a 180 arc minutes at mag 11-12, and a 30 arc minutes (mag 13-14). Using progressively narrower FOVs and fainter mags makes it relatively easy to find the variables. And as mentioned above, you need to flip charts (ie East on the right -- in the Southern Hemisphere for me anyway -- which is an option in VSP).
If you follow this link you will find the LPV Legacy Stars and you could select from there. There are plenty that come within the rnage of your 8"
I would suggest you pick one or two stars and follow them until you are totally familiar with them.
R Leo was suggested as a good one to follow. I concur. Right now it's dimming. When it is brighter you can switch to the finder and use that.
Which brings me to a point that causes a lot of new people frustration. The charts. You need to select the charts to match your own need. For myself I have made sets of the standard a thru e scales. For the most part this covers what I need. But you also need to make sure your charts match your orientation. Pick a bright star like Eps Aur or Beta Lyr and try the various chart configurations. You may do the a and b scale for your finder and the c ,d, and e orientation for the main scope.
I prefer the standard scale charts because I can instantly relate them to my instruments' fields of view.
The main thing is to pick targets and charts that work for you. As much as I am fascinated by the Z Cam types they just don't work for me. Miras do.
We have all felt your frustration when we started but stay with it. This science has its unique rewards.
There really is no substitute for learning your way around the sky. I have never used any sort of Goto mount (don't need to) and wouldn't accept one as a gift. A dobsonian is ideal for variables - the eyepiece is nearly always in a comfortable position, and there's little 'technology' to get in the way.
As a sample of stars you could observe (all Miras or SRa type):
S, T and possibly RS UMa (all near to each other)
V and R Boo
W, RS and SY Her (with W Her you also get an excuse to look at M13! SY has quite a short period so you see a good amount of change.)
R LMi and possible U LMi not far away
X and RR Cam (circumpolar)
Of course, there are loads of other Miras when you can catch them near maximum, but you did say you wanted a bare bones list!
Thanks everyone for the encouragement and for the suggestions of stars. I'm definately not going to give up...just need to get some experience going here.
And someone brought up the charts....this may be part of the source of my troubles. I am having trouble "guessing" what an appropriate field of view and other settings should be for each chart at each level (A, B, etc). Often I find myself with a field of view with no comparison stars.
Since at the moment you appear to be concentrating on the brighter stars, most of the time I think a (b) chart will be OK. These show an area of about 9 square degrees (I think!) so often there will be at least one naked-eye star that you can star-hop from. If I just go through some of the stars I mentioned:-
V Boo - very near gamma Boo. Use the (b) chart.
R Boo - near epsilon Boo. b chart again, or maybe d when you're familiar with the field.
RS Her - use delta Her to starhop to 73 Her, which will be on the b chart
SY Her - use delta again to starhop to a bright (5-6m) star near SY. Maybe get the b and d charts.
If you find some charts are a bit too cluttered for you, you can use simple image software such as 'paint' to erase some of the unwanted stuff. For instance, I've just taken a look at the 13300BHM chart for RS Her. There are two duplicates there - two stars labelled 94 and two stars labelled 99, and the 94 star is close to a 93 star. Really, all you want is the 93 and one of the 99's, so just paint over the labels for the 94 stars! (save the chart with another name so you still have the original). Again, looking at that chart, there are 103, 105 and 107. A great choice, but for 'decluttering' purposes you can get rid of the 105 label, since a gap of 0.4m (from 103 to 107) is still a very usable one. I'll post a 'before and after' pair of examples.
I have not removed any labels but I have plotted DSO's or label an easy to find star on the "a" chart as a reference. My visual instrument is a an intelliscope and I use the Object Finder to target a nearby DSO and starhop from there.
Whatever works to keep us obserbving!
Clear skies and Dark-
Well, it looks like this dreary winter weather pattern may slowly be finally abating. So, taking yall's advice, I've picked some stars to start with for this Spring. I will probably just concentrate on the first three, but if I have trouble finding them, I'll move on to the latter three (the latter are also in my area of worst light pollution):
- R Leo
- V Boo
- R Boo
(I like the position of the stars in Bootes, very easy to start hop from it seems.)
- S UMa
- T UMa
- RS UMa
But first, I'm going to do something that I should have done long ago. I am going to try to detect the brightness variation of a Cepheid. It is somewhat embarrasing that during all of my false starts, I have yet to have that experience of "hey, this star seems just a bit brighter/fainter than when I last saw it."
In the past, I discounted observing Cepheids as they are so well understood. Where is the interest in observing a star when you have a high degree of understanding of what it is going to do next? Obviously, I was getting way ahead of myself. I need to observe some Cepheids preciesely because they are predictable. I need to get good at being accurate before moving on to the more "interesting" variables.
So, after looking around, I see that Zeta Geminorum is Cepheid with a relative short period. It's also naked eye, althought not with a large amplitude. It's also decently placed in the sky for the next month or so.
I'm going to try to observe it every clear night in April and compare it with Lambda Gem and Nu Gem (the two stars suggested by the Variable Star of the Season article ( http://www.aavso.org/vsots_zetagem). Hopefully, I can keep myself from checking out the light curve to avoid biasing myself. I wonder how I'll do?
(And if there are some other bright Cepheids I might want to look at, please let me know!)
Well, while I did get to see the first bightness drop with R Leo, I did my "variable star observing school" on another well known variable: beta Lyrae.
The components of this eclipsing binary are deformed, so you get a pretty much continuous variation, with maximums at aprox. m=3.4 and main minimum going towards 4.1. With a period of around two weeks, is pretty good for naked eye observing; a bit difficult this time of year (requires waking up at 2 - 3 AM), but worth observing during summer and autumn.
Still, if you have a dog that needs his/her night walk out, you can try it also in the spring.
I cut my teeth- or eyes rather- on Algol, Beta Lyr, and Del Cep as well as R Leo. With Algol it is best to look up a predicted minimum and make hourly measurements. Beta Lyr and Del Cep are nightly and R Leo weekly.
Some time in the future consider R CrB. Right now it is too dim for my 12" dob but there are some very distinctive star patterns that make it easy to find.
Incidentally- last year at one our monthly star parties I was showing R CrB to some of Dr. Russ Genet's students. One of the freshman students made her first ever variable star observation and the magnitude estimate she came up with seemed too dim to me ( I had last checked on it the previous week). When I made my estimate I verified she was right. After I got home and checked I discovered the star had begun another fade less than two days previously. Russ let her know she was one of the first to see its latest fade. So just because the behavior is well known does not mean you should not observe them.
>>> I'm going to try to observe it every clear night in April and compare it with Lambda Gem and Nu Gem (the two stars suggested by the Variable Star of the Season article
using only two comparison stars will limit your accuracy.
I would add iota Gem (V= 3.79; B-V= 1.03) to the comp star sequence.
The visual range of zeta Gem is V= 3.62 - 4.13 (there is a close companion that is not resolved when making naked eye observations). So the other two are okay, lambda Gem has V= 3.58; B-V= 0.11 and nu Gem has V= 4.12 and B-V= -0.12 (it is a combined triple with a BCEP primary but the range is only 4.10-4.13).
I am happy to report that I made my first ever telescopic (all previous ones were binoculars or naked eye) measurement of a variable star tonight.
I "warmed up" by making a naked eye measurement of Zeta Geminorum. I then turned my refractor towards Leo. I started off at Subra, the 3.5 mag star just west of Regulus. I then found what I thought were 18 and 19 Leonis; however, the distinctive triangle formed (at least on my charts) of the two 9th magnitude stars and R Leonis was just not visible. I became quite disappointed -- was it just too faint?....until I realized that none of the other stars in the field matched up around 18 and 19. In other words, I wasn't looking at 18 and 19 Leonis!
Indeed, I hadn't gone east enough and had simple stopped at the first pair of stars that looked like they were the right orientation. From what I understand this is a fairly common beginner issue -- not being able to match one's field of view with the field of view on the chart. Once I went about a field east after carefully looking at my chart again, I found 18 and 19 Leonis for real and the triangle came into view, but only barely.
I was doing this from my driveway and there are two streetlights nearby. Realizing this was going to get annoying fast, I went inside and got a towel. Draping it over my head I spent a few moments just exploring the field while my dark adaption increased. Within only a little bit of time, the R Leonis triangle became very easy to see.
This was a pretty good moment for me. I had identified R Leonis -- the star the Leslie Peltier and David Levy talk about! It is a little like becoming a member of some exclusive club. But on to the matter at hand -- estimating it.
This is where the 66 mm f/6 refractor really comes into play. The field is fairly wide (I was at 30x and 1.6 degrees of field) and the mounts slow motion controls made it very easy to move comparison stars to the center of the field of view and then back to the variable.
It was while doing this that I noticed that R Leo actually appeared to be a bit on the red side. It was then that I remembered the Purkinje effect and the caution to only take short glimpses of a red star when trying to estimate it. After a time, I finally settled on a value. (I totally felt like I was at the optometrist's office....fainter than star 1...or star 2? Star 1? Or Star 2?)
Another cool thing is that as one of the comparison stars is magnitude 9.8, I know that with the 66 mm I can get down to essentially magnitude 10 near zenith on a transparent night, even with my light pollution.
So there is the story of my first successful telescopic variable star measurement....and I thank everyone for the encouragement!
I think this was already mentioned in this topic: chart orientation plays a major role in how easy one finds a certain star field. The people that wrote the Visual Observing Manual ( http://www.aavso.org/visual-observing-manual ) definitely had his in mind. Pages 15 and 16 definitely come in my mind. So, be careful on the map orientation: as the earth rotates, the N-S and E-W directions take different angles against the horizontal line.
Naked eye and binocular observations play their role, not just while learning to make estimates. Nova Del 2013 was a very good binoculars target in the first month. Each instrument has its own limiting magnitude and maximum field of view, so each can be used to its own strenght.
Congrats on R Leo! Yep, it's definitely a red star, like all Miras. While adding some challenge to estimating it, it also makes it stand out in the field, so I'm quite certain next time you'll find it fairly easy. Keep observing it and your selection of naked eyes variables - one of these days one of them will raise the hair on the back of your neck when you'll find it quite different from how you left it after your last observation.
This is a very inspiring and encouraging discussion for me as I have tried several attempts at observing variables during the past few years and felt discouraged in that I felt I would never be capable of accurately recording the magnitudes of variable stars.
However after reading the comments and the suggestions posted I realized I was trying to progress too fast and expected to be proficient too soon. So I'm going to restart observing and try to observe on as many clear nights as possible. The time is right in that the weather is starting to be less cold (it's been a long harsh winter here in Canada) and spring generally is a good time - nights not too short and no humidity or bugs to deal with!
I have been following the discussion and have found it to be very informative. I have been very interested in variable stars and have been observing them for a number of years; however I have only recently started to report my observations. I too had started with a very ambitious observing program and thought that was easy to make magnitude estimations. I was wrong as I did not yet have the skill set to easily find the stars and to make magnitude estimations. I think that I am now at that point and I am slowly expanding my list of stars and I cannot wait for better weather conditions. We have had a beautiful New England Winter with bitter cold nights.
Two stars ,that will soon start to rise at a decent hour, that I spent a lot of time viewing last year are Beta Lyr and XY Lyr. One would think that they would be easy stars as they are fairly bright; however there are not many comparison stars. I have made, what I consider, some decent estimates in the past and hope to continue with them in the future. I got out late last night, with my telescope, and went searching for R Leo. It turned out to be easily found. I did not not make a magnitude estimate as the observing conditions were deteriorating; however this star will become part of my observing program.
Cheers and clear skies,
I just finished a very enjoyable estimate of Z UMa! I am actually rather pleasantly surprised at how enjoyable it was!
I used my 66 mm refractor and the A chart to star-hop to it. The moon didn't have as much effect as I thought it would have. I was elated to identify Z UMa and, using a B chart as a guide, used the slow motion controls of my mount to bring the comparison stars to the center of the field of view. After several times going back and forth, I finally settled on an estimate. I love making little asterisms to navigate my way around.
I don't think I've been this satisfied after viewing just a single object in a night than I have in a long while. That really was fun....and I think much of it has to do with the interactivity, if you will, of the endeavor. Not only am I star hopping to the star, I'm also having to engage with it and its friends to determine its brightness.
It is quite a bit refreshing from the let's-log-the-ten-billionth-elliptical-galaxy "observation."
In any case, I felt relaxed and refreshed and....to some extent felt like I accomplished something somewhat challenging. Z UMa is should be visible for quite a while. I'm going to try to observe it every two weeks. I wonder when I'll first notice a change?
Tomorrow I'm going to try for two of its friends, S and T UMa.
[quote=mdrapp] Z UMa is should be visible for quite a while. I'm going to try to observe it every two weeks. I wonder when I'll first notice a change?[/quote]
Not sure about Z UMa, I don't have it on my list. I do have a few other SRs though, and for most of the time they don't do anything, they just idle at their minimum. Then all of the sudden they start to brighten up, then go back down. And it's back to idle for the next weeks/months. SRs can really test one man's patience :), so I like to label them as "aquired taste".
What I found to be a good compromise is to observe one or two SRBs and one or two stars that are more likely to show variations (miras, beta Lyrae). So that when the SRBs are staying idle, I get my "brightness-has-changed" fix from other stars.
The thing with a lot of SR stars is their usually slow speed of variation. I find once a month is enough for most of them - but there are so many that you can observe several different ones per night. You do need to look at the subtype with SRs - the SRa and SRd types are definitely less irregular than the SRb/SRc (which I believe form the vast majority). In fact you can think of SRa stars as 'mini-miras' insofar as they show a definite periodicity and really differ from Miras only in their smaller amplitudes. One of my favourite stars is AV Cyg, an SRd star with a short period. It's in a really pretty field not far from albireo. Estimate it once a week and you might end up with an equally pretty lightcurve.
Excellent! If I remember rightly, Z UMa is in a little x-shaped asterism. S UMa is embarrassingly easy to find, right near a bright star with an arc of stars close by. T is a bit more of a challenge, especially if it's not near maximum.
If you want to experiment with a slightly different type of variable (I think you have the wind in your sails now, so you might be up for it!) give SS Gem a try. It's an RV Tauri type variable, which stars have a double maximum - so there is a bright minimum (in between the two maxima) and a faint minimum (in between each pair of max-min-max above). Miras, because of their long periods, only need observing once a fortnight or so, though personally, I think once a month is OK for most of them. The RVT stars have shorter periods so observe them once a week. With SS Gem - it never gets very faint, and a 'b' chart is fine - you also get to look at the beautiful open cluster M35 close by!
Keep on observin'!
Thanks, Michael, for the SS Gem suggestion! I'll add that one to my list. Just printed a few charts for it and I think I can find this one. :)
I am still enjoying visual variable star astronomy. Quite frankly, this has restored weeknight astronomy for me. It is something I can do fairly quickly, which is very important on a weeknight, and doesn't require the critical cool-down and steady seeing needed for planets and double stars, the traditional objects for city viewing.
I also enjoy how interactive it is. Of course, there is the star-hopping, but it doesn't end there. Once one had found the variable, one must compare it to the companion stars. In any case, for whatever reason, I seem to feel more satisfied after making a variable star estimate than I have recently tracking down a faint elliptical galaxy.
I'm slowly developing a set of program stars, taking cues from the LPV lists of the AAVSO. With my NELM being around 4, I'm also, at the moment at least, choosing stars that are relatively near (within 10 degrees of a Mag 4 or brighter star). So far, my stars are R Leo, Z UMa, S UMa, T UMa, RS UMa, SS Gem, Zeta Gem, R Boo, and V Boo. Some of these are too faint for me to see the star yet. I wonder what I'll feel when a star -- from my perspective -- suddenly is present where none was before.
I've also switched scopes. I initially chose my ZenithStar 66 SD for portability. It also has a wide field of view (388 mm fl) and is its own finder. However, I tried my 8" Dob, which actually is about as portable as the ZenithStar and can go quite a bit deeper. It has a RACI finder and this setup works well, as long as I remember to print my A charts with correct-image settings, and my B charts rotated 180 degrees.
All in all, for twenty years I wondered what the allure of variable star observing was....what was so interesting about looking at dots in the sky? I seem to have finally found out. :)
This is a heartwarming story about discovering the joy of variable star observing. I remember 20 years ago, a similar "epiphany". I never looked back.
BTW: Are you aware that we are having a meeting in June, in Ontario California, of AAVSO? Details on the web page. Probably about 70 variable star observers and another 50 amateur observers giving papers and exchanging experiences and information. You might find it very rewarding.
I'll be there at Ontario, CA! It will be nice to see Dr. Arne before he retires. I also want to nail down Photometric Transformations before the meeting is over. I'm in LA so the venue to the Ontario Airport Hotel is realtively closeby at 35 miles away from home.
look at the section easy to observe variables. I got started in photometry with a DSLR camera, you might look into that...a good used Canon 450D will only run about $450. Here is section on the easy to observe variables. Also do the 10 star tutorial , if you have not already do it..