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Re: BVR transformation and instrumental magnitude

Posted by chrismlt on May 03, 2024; 3:34pm
URL: http://astroimagej.170.s1.nabble.com/BVR-transformation-and-instrumental-magnitude-tp2430p2436.html

Thanx Karen for the suggestions/advices.

To perform the transformation of the BVRI data obtained in my system (which include the camera, optic and filters) to the standard BVRI system, I will need to image a standard field, when it transits at meridian, so as not to include atmospheric deviances. The airmass will be constant.
The idea was about getting some 20 one-minute exposures, and to get the mean value of thoses 20 individual images, before computing the instrumental magnitudes.

The AAVSO provides some maps and UBVRI mags for a large number of stars in all standard fields :
(E.g.)

https://app.aavso.org/vsd/stdfields  (link provided in a previous mail)

https://app.aavso.org/vsp/chart/?title=Melotte%20111&ra=186.125&dec=25.858333&fov=180&maglimit=14.5&special=std_field&all=on&north=up&east=left
(map)

https://app.aavso.org/vsp/photometry/?title=Melotte+111&ra=186.125&dec=25.858333&fov=180&maglimit=14.5&special=std_field&all=on&north=up&east=left
(photometry table)

Clear Skies,
Christophe