Quote:
Originally Posted by madbadgalaxyman
Peter,
this might be a very luminous supernova, as the total B-band (blue) apparent magnitude of the entire host galaxy is around 10.8 and the total V-band (visual) apparent magnitude of the entire galaxy is close to 10.0
(but I wouldn't bet that these magnitude figures are very accurate)
What wavelength-band is the estimate of magnitude 11.5?
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Can I assume that this supernova peaked at V (visual) apparent magnitude 11.5 ?
I
seem to recall that the AAVSO variable star comparison atlas used V magnitudes for comparison stars around a variable (though I have not used these charts for years!) so I suppose that some approximation of visual magnitude, and/or the Johnson V photometric band, is a sort of de facto standard for magnitude estimation.
Another thing I clearly remember from my "very long ago" 12 months stretch of time when I was doing visual magnitude estimation (every clear night) using just the naked eye or binos together with charts, is how
inaccurate some of the other observers' magnitude estimates were when compared to photometric measurements. A small number of visual observers consistently achieved an excellent accuracy of 0.2 (or even 0.1) magnitude, while a lot of others achieved an accuracy that was 3-5 times worse than this!!
My impression is that an accuracy of +/- 0.2 magnitudes is good going for visual estimates of the apparent magnitude of a stellar source, though perhaps some variable star observers can shed some more light on this.
cheers, Robert