Vereniging Voor Sterrenkunde, Werkgroep Veranderlijke Sterren (Belgium) (VVS)
Thu, 03/17/2011 - 15:32


I planning to observe the binocular program I have found on the LPV section.

How often may I observe these stars? A lot of them are semi-regular. Is there also a 7 day rule like the mira stars?

Clear skies, Hubert

American Association of Variable Star Observers (AAVSO)
Frequency of observations

I think a good rule of thumb is to obtain 50 points per cycle. If the star has a period of 50-100 days, you could observe it every clear night.

A star with a 400 day period you might choose to observe once per week or less often.

If it is an unpredictable star, like an RCB or NR, you can observe it every night.


American Association of Variable Star Observers (AAVSO)
How Often


Periodically this generates a lot of talk in the general discussion group and I think we burn entirely too much hydrogen over it. As a general rule don't get caught up being agonized over precise intervals- not with visual estimates. Relative to photometric techniques visual estimates are low-resolution data.

I'd stay with theĀ recommended intervals in the visual manuals. These were derived by decades worth of observations and are picked to be long enough to show changes but not long enough to miss them. It would be silly to disregard a century's worth of experience simply because I think I'm smarter or more experienced than Leslie Peltier was! (btw-I don't even come close!)

Sometimes a researcher will request a more intense series of observations built around their scheduled observatory and/or satellite time and they will generally specify their needs in the AAVSO notices and alerts. (Read about the U Sco and T Pyx campaigns for good examples of Pro/Am collaboration)

You do need to be careful of star colors -especially with very red ones like R Leo-which is always neat to look at.

Dave (MDAV)

Magyar Csillagaszati Egyesulet, Valtozocsillag Szakcsoport (Hungary) (MCSE)
I agree with Dave. In most

I agree with Dave. In most cases one per week is enough for binocular variables (mostly SR). Maybe in case of some fast SR variables every 5 days can be useful, but I'd stay with once per week. Some RV Tauri stars with short period can be observer more frequently (eg. AC Her) even visually, but it is an exception I think.