Teams / The Mark I Eyeball Team / Wanted: well-observed southern Miras or other variables

Wanted: well-observed southern Miras or other variables

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Hi,I'd like to query the observers among us to see if anyone can quickly recommend one or more Mira or other variable stars that match thefollowing criteria: - southern, so it has good ASAS coverage - fits well within the good quality ASAS range (perhaps V=8.5 to 13) - has an excellent visual sequence, and has had for a long time - is very well observed visually, and - isn't too red (i.e. not a carbon star).What I'm looking for are stars with lots of visual data that can becompared with ASAS (or another photometric data set with reasonablywell-defined bandpass). It will be a bit tedious to go through all ofthe AAVSO/RASNZ lightcurves and compare them to ASAS, so if anyoneknows any good ones off the top of their heads, please post a reply.The reason I'm asking is the following: the brute-force (and naive) way ofmaking presentable visual light curves is to do a straight averaging of all visual data without regard to how many (or which) observers happento be observing; we just create 10-day averages or 7-day averages or whatever. I'm playing with a few ideas to see whetherthere are more statistically rigorous ways of creating mean lightcurves. One obvious way is to go observer-by-observer and compare eachone to disentangle physiological and perceptive differences betweenthem. Another is to make sure that each averaged point has a sufficientnumber of observers in it to yield a meaningful statistical measure of the uncertainty.And I'd also like to study individuals who contributed to the light curveand see how their data changes over time, whether their data gets better(more experience) or worse (degraded vision) over time.If anyone can suggest good visual light curves to look at please do. Matthew

While you're at it...

This project could conveniently study an additional topic that I have wondered about, but have been unable to find any previous research: If the eye's sensitivity to different levels of light is sufficiently nonlinear (or non-log-linear) (as several charts in Chapter 2 of Roger Clark's "Visual Astronomy of the Deep Sky" would suggest, though they do not directly address that particular question), then the apparent brightness of a target star relative to a brighter comp and a fainter comp could depend somewhat on the aperture used. For instance, a 7.2 target mightappear midway between 7.0 and 7.4 comps when viewed through 7x35 binoculars but might appear closer to the 7.4 comp (or to the 7.0 comp) when viewed with 10x50 or larger. Indeed, I have found some such effects myself when viewing the same target through different optics. Therefore, the new project might also request participating observers to report the aperture used for each program observation, and later the team can analyze whether the aperture is correlated with any systematic biases. Similarly, magnification could also be requested and analyzed, as it will affect the darkness of the background sky and thus potentially affect the apparentbrightnessrelationship between the target star and fainter comps. (The relevant variable for the study could be the exit pupil of the optics.)

bright Southern Hemisphere Variables

Hello Matthew, I just happened to see your post and wondered if you might have information or sources that can help my team, Southern Gems. We are a group of about 6 who are trying to identify bright variables that are visible in the Southern Hemisphere that could be used to create a Southern Hemisphere 10 Star Tutorial similar to the one on Citizen Sky for the Northern Hemisphere. If you have any information, sources, or people that you think could help us, please email me at I am the manager of Southern Gems, but I am the only member of the team who lives in the Northern Hemisphere. Thanks very much. Cheers, Joan Chamberlin

southern variables

Joan, I think one of the best people to ask is Sebastian Otero. He's a member of the Mark 1 eyeball team. He probably knows all the good bright southern variables personally. Cheers, Mike

Southern Variables - A list

As Mike said, that's my field!I love bright Southern variables. I made a list in the Southern Gems Group:

I hope to observe some of these stars in person with some of you in the Argentina AAVSO"Spring"Meeting!



southern variables

Mike, Thanks. I'll email him. Joan

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