The Prosper Project

During the last year, observers could follow sometimes heavy discussions about usefulness of visual observations. The conclusion is simple: photoelectric and CCD observations are preferred, but visual observations of all types of variable stars are truly useful! However, a care should be taken with selecting of target stars and methodology of taking observations. Observing slowly variable stars with small amplitude is appropriate only for a small number of observers. Well, let’s assume I have suitable variable star with suitable maximum and minimum brightness. I calculate prediction or find it in summary available on the Internet. If the star exhibits minimum in the given night, I can start with observations. Knowing the accurate time of minimum is not always desirable as observers who are not psychically resistant are going to see the star dimmer and dimmer as it approaches the predicted time of minimum even if it is not real.

However, there is always second option. Just to go observing without knowing any prediction of the minimum of a star. So I can only observe stars of W UMa or beta Lyrae type. These stars have usually smaller amplitude than Algol stars, though. Or I can select more than one star for a night a just write down when to start observing and how often to estimate the variable to get at least 15 estimates per minimum. But there is even another possibility – I can follow only stars that should be short period eclipsers without known ephemeris. Stars with known ephemeris could be found in the BRKA catalogue, basic version. For such stars there are already calculated predictions and for a lot of them there are also finding charts. But what shall I do with the stars without ephemeris?

These stars are tabulated in the BRKA catalogue, Prospektor version. The group of observers has included some other stars and has selected a smaller subset. Finding charts for visual and CCD observers has been created for the selected stars by the courtesy of D. Motl. They can be found at http://prosper.ssph-brno.org/download.en.php. For each season we will make publicly available a set of two or three stars together with a detailed info on each star and of course with finding charts accompanied. The style of observations should be (at least from the beginning) similar to the style of observations of semiregular and irregular variables. A few observations or just a single observation per night should suffice. If there are enough observations during the season and we are lucky, we should be able to determine preliminary ephemeris. After that, observers with CCDs or PEPs will acquire some measurements at least around the minimum. This is a result which can be published e.g. in Information Bulletin on Variable Stars. All visual observers will be, of course, co-authors of such a paper. A working scheme like this is very successful in other groups of observers.

All observers who contribute to this project will be continuously informed about results. More detailed information, questions and comments should be directed to above addresses. All information about observing programme can be found also at http://prosper.ssph-brno.org/.

Be successful at the telescope!

David Motl and Miloslav Zejda