Thu, 10/27/2016 - 22:28
Hello! I may be the discover of some variable stars. I plotted the initial lightcurves in which I saw the variations with C-Muniwin.
I have some questions which will help me for reporting them:
1. How can I measure the magnitude range?
2.How can I measure the period?
3.How can I determine the type of variable star?
Thanks in advice !
Andrei
Andrei,
I'm not familiar with C-Muniwin but have used a simple program called PERSEA. It was freeware written by Gracjan Maciejewski but no longer appear to be available online. I can email it to you if you would like.
The PERSEA output window gives a periodogram, the best-fit period, an estimate of the error in this, a phase plot using that period, the magnitude range, etc. Attached is a brief description and an example of the output window. (W UMa data is provided with the program as an example.)
You can use AAVSO contact form to reach me via email (as this is an openly available website I won't post it here).
Tex
Hi,
Items 1, 2 and 3 are not usually derived by one single person, since all sorts of outside factors (bias, substandard comparison stars etc) can be manifested. Try looking at an AAVSO light curve for a known variable (say something like S UMa) and notice how many observers contributed to it, the spread of magnitudes on any given date, the uncertainty of establishing exactly when a maximum or mininum took place and so on.
What are the stars you have been following?
Andrei,
Agree with Michael's post about using AAVSO lightcurve generator if you are using data from multiple sources in AAVSO database. If you have a dataset from your own measurements, then another option is the program PERANSO which can be downloaded from: http://www.peranso.com/
I have not used this program but it seems similar to PERSEA which I mentioned in my previous post. Again, happy to send you PERSEA via email if you wish but this new program has a users manual while PERSEA doesn't.
Tex
Hello! Sorry for the late response, and thanks for your answers. Meanwhile from the monent that I made the topic, I discovered 2 variable stars:
Both of them are EW. I think that I am one of the yougest variable star discoverer at the age of 16.
Thanks !
Andrei
Andrei, all
If you want a free multi-platform, supported tool, you could try VStar: https://www.aavso.org/vstar-overview
It supports period search: DCDFT and AoV (ANOVA based).
David
Hello!
Thanks David! Is there any method to get the magnitude range with VStar?
Andrei
I should write a plug-in to summarise mag ranges by band.
You can currently do this manually by selecting just the series (band) of interest in the plot control dialog then selecting observations at the top and bottom of the plot.
Or, in the observation list, observations can be sorted by magnitude, reading min and max.
Or, extrema can be determined using a polynomial fit and looking at the Extrema tab of the Models dialog.
Does this help?
David