Affiliation
British Astronomical Association, Variable Star Section (BAA-VSS)
Sat, 08/17/2024 - 20:29
I found the key from the last post but there is a CV filter explained as
Unfiltered with V Zeropoint
Please can I have an explanation of this term Zeropoint
Kevin,
Since no-one else has replied, the following is my understanding. Disclaimer: I don't use unfiltered observations.
Unfiltered with V Zeropoint implies the use of a number to correct or transform an unfiltered instrumental magnitude to the V magnitude of a target.
Here is a link to a paper.
https://www.aavso.org/apps/jaavso/article/3194/
Roy
The AAVSO Extended File Format explains this... and other codes.
https://www.aavso.org/aavso-extended-file-format
Generally the following text of the explanation applies to almost everyone, ...
"CV: Clear (unfiltered) using V-band comp star magnitudes..."
This means you observed with a clear or no filter and formed your variable magnitude estimate using the comparison stars listed V catalog magnitudes.
Jim (DEY)
This is different from the question posed by Kevin.
The Extended File Format filter definition for CV makes no reference to a V zeropoint.
Roy