New SBIG Spectrogrtaph

[Olivier GARDE]

Latest announcement from SBIG, A new spectrograph for the ST-i CCD :

http://www.sbig.com/blog/st-i-spectrograph/

[Robin Leadbeater]

Hello Olivier,

The intended application seems strange. I read the linked article and I still do not understand what the connection is between flat fielding and the light pollution spectrum. As far as I can see flat fielding and sky background removal are totally different issues in astrophotography as they are in spectroscopy. The need to make sure reflections are eliminated, particularly when imaging in IR are obvious and the need to use finishes which are broad band non reflective is important, particularly for when used in our spectrographs but the effects are not limited to the skyglow and in any case don't astrophotography luminance filters normally have IR blocks? I don't understand issues raised concerning narrow band imaging or photometry either. Surely all astro imagers and photometrists take flats with the filters in place don't they?

Cheers
Robin

[Olivier GARDE]

Hi Robbin,

Yes it's strange...

I don't understand the usefulness of this spectro ?
He talk about flat, light polution, but nothing about stelare spectrum.

The bandwidth ranging from 430 to 1050nm seem to be important, (and go up in the near infrared)
Nothing about the price too ?

[Mike Potter]

What I gathered from the article was that the new spectrograph would be useful to determine the appropriate color to use to create flat fields. I've run into that sort of problem myself - doing flat fields with twilight flats, though my skies are green/yellow from sodium lamps (I'm very near the center of Baltimore). Using an appropriate color flat field device (and they seem to be thinking a mix of colored LEDs) should help level and smooth the background for pretty pictures and improve differential photometry - most particularly in bright urban skies.