Quote:
Originally Posted by sjastro
Thanks Rolf, Mike, John, John and Ross for your kind comments.
I think the near infrared filter will do a good job on obscured objects that emit a continuous spectrum such as galaxies and globular clusters.
The same story can't be said for obscured emission nebulae.
I've tried the filter on the emission nebula RCW71 which is heavily obscured by the Coalsack. I'd estimate you would need to increase the exposure time by a factor of 10 or more to get a similar exposure to a clear luminance filter.
Clear skies
Steven
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I think this is correct. There are emission lines in the NIR but not as bright as the Ha lines. Take a look at my spectra of M8 here
http://www.iceinspace.com.au/forum/a...e.php?a=120697
There are weak lines longer than 700nm but not very many. I actually imaged it out to ~900nm and there isn't much there.