Skip to main content

Utility of DSLR B measurements

4 posts / 0 new
Last post
SFS
Utility of DSLR B measurements

I apologize in advance for asking this, as I'm sure it must have come up before.  If only there was a search tool for the forum posts!

I'm doing DSLR photometry, almost entirely of RR Lyrae and DCEP stars, and that is the context in which I ask my question.  Is it of any scientific value for me to report transformed B magnitudes as well as transformed V magnitudes?  I am using Mark's intermediate spreadsheet, AIP4WIN, and ensembles of 6 comparison stars in addition to the target and check star.

A "Yes" answer would suffice, but if the answer is "No", I'd like some information as to why.  Thanks in advance!

CS,

Stephen

NEVER MIND!  I figured it out.  But I couldn't figure out how to delete the post...  (Yet another project for the web team?)

Mark Blackford
Mark Blackford's picture
Utility of DSLR B measurements

Hi Stephen,

I'm no expert on these types of variables (or any type for that matter) but I understand RR Lyr and DCEP stars show colour changes throughout their pulsation cycles and time offsets of the maxima at different wavelengths as well. So obvservations in B would provide useful information.

As you learnt in the course stars with significant emission lines or absorption bands are not suitable for transformed DSLR photometry, but I think RR Lyr and DCEP stars should be fine. If anyone knows differently please chime in here. Cheers,

Mark

SGEO
SGEO's picture
DSLR B mags: report them if they are part of a transform.

If you are transforming your DSLR TG data to V you should report the TB transformed to B data that you used in the transform. Transformed data should be "grouped" with the group field in the AAVSO Extended Format record. (ie, the two records, TG and TB, used in the transform should have a common group id). You should always report complete groups.

George

SFS
Utility of DSLR B Measurements

Thanks, Mark and George!  I will henceforth report both V and B for RR Lyr and DCEPs.  I understand why DSLR V should never be reported for variables having significant H beta or higher order emission lines.

Log in to post comments
AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484