[vsnet-chat 4057] Visual Magnitude Estimates

["Andrew Pearce" <arpearce@ozemail.com.au>]

Further to Seabastian's original enquiry, I thought I would outline my observing
methodology.  Being primarily a visual comet observer (variables take more of a
priority when there are not many comets around!), I like to make magnitude
estimates by defocusing stars that are bright enough in the 16" reflector.
Typically this limit is around 12th magnitude.  All variables brighter than
this, I use this method.  Generally if there is any colour, which normally is
only in Miras or SR stars anyway (which I don't observe much), by defocusing,
this tends to reduce the effect and then you can either use direct or averted
vision without a great deal of difference.

Fainter than this, I find it easier to observe and make magnitude estimates
using averted vision.  I just find it easy with my eyes, I must admit to not
having thought much about its relative value.  However there is a degree of
consistency there.

As an aside, I must admit, that I have been interested in the discussion about
whether visual observers can report magnitudes to greater than 0.1 mag accuracy.
I generally find that for many variables, the comparison star magnitudes are
either not that internally consistent between themselves in the same sequence or
there is not a good spread of them to be confident of a greater accuracy.

Regards
Andrew Pearce
W.Australia

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