Vmagnitude for comp star

Wed, 02/28/2024 - 17:22

Hi all,

Just a question by the way.

When doing photometry extraction, and assigning a V mag for the comp star, should we use preferably the V mag found in the photometry chart accompagning the chart in the variable star plotter : V = 4.830 from tycho 2, or a V mag = 4.819 from the same catalogue, found on Simbad.

I suppose there are multiple versions of that old catalogue. Which one is the best ?


Thanks in advance,


American Association of Variable Star Observers (AAVSO)
Photometry sources

The magnitude in VSP comes from the Bright Star Catalogue, BSC (source 22), not from Tycho-2 (source 1).
You can see the source codes at the bottom of the photometry table.

Always use the values provided in the photometry table, this helps in obtaining measurements consistent with those from the other observers.