I am currently processing photometric data for research analysis on the exoplanet TrES-5b, and there are two issues I am encountering when processing this data, one of which impedes directly with the data, and the other can be avoided but can become a hassle.
Lack of selection of photometric filter when creating a comparison stars file - In previous versions of Siril and tutorials online showed that there was a selection for the photometric filter, but now I can’t seem to find this selection box, and it impacts both the comparison stars the program is selecting and the outputted data, as the magnitude of the star is calibrated against stars in Vmag, whereas the data was collected under an R filter. Is there any way to directly call for the comparison stars file to only look for comparison stars that are under different photometric bands?
When queuing the comparison stars file to look for stars, when I input the designation TrES-5, it cannot find any photometric data on either cataloge, unless I use the 2MASS designation, for which it only pulls the Vmag data.
Hi Maxfield
It’s nice you perform photometric analysis with siril.
To answer your questions:
1-Siril doesn’t deal with photometric filters. When I designed the comparison stars feature, only the Vmag was computed.
However, If you have a look here (https://youtu.be/k03EJzAE15M), you can find a more advanced version dealing with photometric filters and so on.
2-you are right, TrES-5 doesn’t return any photometric value. And this is a big deal to cross-find the right data in all catalogues from only one designation.
So, for this particular case:
-the Exoclock page teaches us the mother star has also other names according to Simbad/Gaia/2Mass (https://www.exoclock.space/database/planets/TrES-5b/)
-by trying in Simbad with the designation GSC 03949-00967, one can see magr’= 13.520 [0.004] magR 13.517 [0.06]
Just remind that siril deals with stars, not planets, and TrES-5 is the companion planet of GSC 03949-00967
-so now, try with this same designation in siril
PS: the user-DSO shows an entry as:
with the mag=13.58, which is magV from Simbad.
You can check in the file comparison stars file (.csv), the line labeled “target”. The last figure should be the magnitude of the target in the according band (rounded to 13.52 in R-band)
Thank you for your reply! So in the video that was linked, I noted that the version of Siril here is 1.3.5, was the photometric band drop-down a part of this version, or are they using a self-modified version of Siril to obtain this?
The purpose of this is to ensure that when the comparison stars file feature is run, that it will choose stars that are of a similar type than that of the target, and if it’s primarily selecting stars that are comparable based on their photometric profile in V, it could potentially throw off the comparison stars values, and therefore the output of the light curve.
Would it be possible to integrate a drop-down like this, where the comparison stars file creation, when it queries for stars, to also check for photometric band, or possibly adding an additional variable in a script to account for the filter?
Also, I did try your suggestion on using the GSC designation for TrES-5, and while it did return information, it still only used V photometric data for gathering comparison stars.
I guess what I want to know now: Is it possible to add this feature, so that when an automated light curve is produced, it can properly read out the Rmag of the star, as well as find comparison stars that are of similar type?
Hi Maxfield
You are right, at the time when I developped this feature, siril was still in 1.3.5. Till then, other photometric features were added. If you want to try, have a look at the description of the video.
For the time being, their integration into Siril is not planned.
My suggestion was for use with XPhoto.
Could you please send 1-2 images of the sequence, to try?