Comparison stars magnitude not available in SR- and SI-band

Technology VPhot
1

Hi, I am using AAVSOnet to monitor several variable stars. I receive images from MPO61u and OC61 which have filter sets B,V,R,SI and B,V,SR,SI respectively. I use Vphot for the analysis and all available comparison stars in the field of view have magnitudes available in B,V,R,I bands. So I am not able to determine magnitudes in SR- and SI-band. Any advice on how to solve this? For example, can I request SR- and SI-magnitudes for these reference stars using CHET?

Thanks!
Roel

2

#DATE=JD
#OBSTYPE=CCD
#NAME,DATE,MAG,MERR,FILT,TRANS,MTYPE,CNAME,CMAG,KNAME,KMAG,AMASS,GROUP,CHART,NOTES

TransformApplier, V2.71

desc: TG - Version 6.6, Telescope= OC61, Time created (UT) = 2021_02_23_23:30:47

OC61 has SR and SI filters. These coefficients transform these filters to R and I magnitudes.

#Tbv= 0.9180, +/- 0.0130
#Tbr= 0.9870, +/- 0.0210
#Tbi= 0.9840, +/- 0.0280
#Tvr= 1.1250