Good morning,
I use version 1.2.5 and I would like to try to extract the magnitude of a variable star from a single image.
I have seen from various tutorials that it is possible to create a light curve from a sequence of images, but I would like to use a single image. Once I open the single photo it is recognized and the WCS information is active. The coordinate grids, the cardinal point arrows and the names of the recognized stars appear. I click on the PSF aperture photometry icon and I can choose a star. But at this point I have no other options…
I would like to choose the variable star, then the comparison stars and at this point have the magnitude of the variable. Is this function possible in the program?
Thanks for those who can tell me the steps I have to do for this measurement, if it is possible.
Hello and welcome!
In Siril 1.2.5, only having a single comparison star is possible. This is possible using the commad setmag : Commands — Siril 1.2.5 documentation
It’s simply a matter of setting the correct offset to the computed magnitude. Using a single star is not great because of noise. We may improve that in the future to use more images, but I don’t know when.
Thanks for the reply Vincent.
I tried it and it works.
Surely with two or more comparison stars the measurement of the variable star would be more accurate, but I’m already happy.
We can use more comparison stars for measurement, for example for light curve. What Vincent said is that we cannot use more than one star to compute the true magnitude.
Ok.
in fact I wonder how I can indicate the comparison stars.
I would be grateful if you could show me the steps to be able to set the comparison stars on an image, so as to have the magnitude of the variable star.
Thank you very much.
I had already seen this tutorial, but to tell the truth I was not able to estimate the variable star…
I did not understand how to tell the program which are the comparison stars. I have a bit of a hard head.
Now I have seen how to set the true magnitude of the stars in the image, thanks to Vincent.
Now I do not have time, as soon as I can I will do some tests with Siril.
