AAVSO Extended format: Check and comp star magnitudes
Based on the T-C-K example (present and previous) I have been submitting observations with standardized instrumental magnitudes for the comp and check stars. However, I noticed in Deick Szabo's AAVSO report application that it is populating these fields with raw instrumental magnitudes (negative numbers).
It occurred to me that submitting the raw instrumental magnitudes in these fields allows AAVSO to extract "pseudo zero points" (Zpt -k'X) and also makes it possible to assess sky conditions for sets of data with more than a few observations more easily by detecting non-systematic variation in the comp or check raw magnitudes. With standardized magnitudes flux variations in the comp and check tend to offset each other and reduce the effect of variations in sky quality which makes assessing sky quality for a set of observattions more difficult. On the otherhand, if sky quality variations don't show up in the scatter of check star standardized magnitudes, it may not matter unless the separation between comp and check is significantly smaller than the separation between comp and target.
Which values does AAVSO prefer in these two fields, standardized instrumental magnitudes or raw instrumental magnitudes?
Brad Walter, WBY
From the extended file format page:
2. A little more information:
#TYPE=EXTENDED #OBSCODE=TST01 #SOFTWARE=GCX 2.0 #DELIM=, #DATE=JD #OBSTYPE=CCD #NAME,DATE,MAG,MERR,FILT,TRANS,MTYPE,CNAME,CMAG,KNAME,KMAG,AMASS,GROUP,CHART,NOTES SS CYG,2450702.1234,11.235,0.003,B,NO,STD,105,10.593,110,11.090,1.561,1,070613,na SS CYG,2450702.1254,11.135,0.003,V,NO,STD,105,10.594,110,10.994,1.563,1,070613,na SS CYG,2450702.1274,11.035,0.003,R,NO,STD,105,10.594,110,10.896,1.564,1,070613,na SS CYG,2450702.1294,10.935,0.003,I,NO,STD,105,10.592,110,10.793,1.567,1,070613,na