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Visually the nova is a lot fainter than your estimate. I got it at 12.6 on Feb 11.05UT and the latest CCD V observation gave 13.0 . Both determinations are based on the AAVSO sequences for the star.BrooksObs

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Do I detect a hint of disapproval? I must admit I was more interested in recording the object to show on various fora than providing a V mag which mine is not as unfiltered and perhaps closer to R mag - amended above.

I did consider taking a spectrum but it was too much hassle last night. I'd already seen a 100 l/mm [probably Staranalyser] lo-res spectrum on the internet that shows the radiation was dominantly in near-IR from strong H-alpha peak and completely invisible to you eyes - hence the discrepancy perhaps. I won't blinker my camera to conform to 'visual'

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Visually the nova is a lot fainter than your estimate. I got it at 12.6 on Feb 11.05UT and the latest CCD V observation gave 13.0 . Both determinations are based on the AAVSO sequences for the star.BrooksObs

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Do I detect a hint of disapproval? I must admit I was more interested in recording the object to show on various fora than providing a V mag which mine is not as unfiltered and perhaps closer to R mag - amended above.

I did consider taking a spectrum but it was too much hassle last night. I'd already seen a 100 l/mm [probably Staranalyser] lo-res spectrum on the internet that shows the radiation was dominantly in near-IR from strong H-alpha peak and completely invisible to you eyes - hence the discrepancy perhaps. I won't blinker my camera to conform to 'visual'

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Hardly critical of such an observation, but the situation does point out the need for qualifying the nature of any posted magnitudes from CCD camera images (i.e. image mags are "unfiltered with an R bias").

As it stood, any less experienced visual observer looking for the nova with a modest scope after seeing the image would almost surely miss it at an actual "v" magnitude of 13.0 (as opposed to the mid 11's). As you've subsequently noted, novae often show a very strong H-alpha emission making them appear strongly red shortly after maximum, although looking white in your image, and thus appearing far brighter in unfilted CCD images than they do visually.

BrooksObs

Edited by BrooksObs (02/15/13 08:45 AM)

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...novae often show a very strong H-alpha emission making them appear strongly red shortly after maximum, although looking white in your image, and thus appearing far brighter in unfilted CCD images than they do visually.
BrooksObs

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Thanks - for your possible interest below are a couple of colour spectra of V4743 Sgr = Nova Sgr 2002 No.3 from my webpage - diffraction grating spectra are essentially linear with half the spectra [right of red H-alpha] recorded colourless as this invisible radiation can't have colour! Thus a dominantly near-IR object can appear white in an unfiltered colour image.

Of course spectra of Miras etc are almost entirely in near-IR even at apparent visual minimum a strong spectrum is record so the star only dramatically fades visually - spectra are great fun

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