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V Filter Question

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Jupe's picture
V Filter Question

I recently started using MPO Canopus and am a bit confused about transformed magnitudes.

I have a photometric V filter and when submitting observations to AAVSO, a question is: Is the magnitude  "Transformed?"

Can a submission be transformed when only a V filter has been used? Or must one have two filters?

Thank you,


CBLA's picture

I'm going to give you the short answer and I'm sure there'll be more detailed replies to come:

1.  No, if you just make a measurement from a V filtered image it is not transformed.

2.  No, a measurement cannot be transformed with only the V filter.

Basically, even though you are using a V filter, there are differences between filters that cause create differences between measurements.  Transformation coefficients are a way to standardize the results between observers using different kinds of filters.  You take measurements of the same star field with different filters and compare the results.  You are then left with an assortment of transformation coefficents that can be applied to your measurements to give you a standardized result.

For more information see the following thread:


Jupe's picture
Re: V Filter

Thanks Blake,

I assumed that was the case.

It seemed too easy.


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