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What is the "p" bandpass?

btschumy
Affiliation
American Association of Variable Star Observers (AAVSO)
Fri, 09/02/2022 - 15:17

In the AAVSO Target Tool, there are often stars that have values like:

17.0 p  12.5 p

for the min and max magnitude.  What does "p" mean in this context?  I can't find it in any of the standard photometric systems.

Sebastian__Otero
Affiliation
American Association of Variable Star Observers (AAVSO)
Fri, 09/02/2022 - 15:42
Photographic

Hi Bill,

p stands for "photographic".
These values usually come from old photographic plates and are close to the Johnson's B passband.
Then you will find that these ranges are usually a couple of magnitudes fainter than visual for red variables.

Cheers,
Sebastian