Quadband filter vs L in RGB

[billhinge]

I have  a Quadband filter which I purchased before ordering a mono CCD (still waiting so I can't test it) - I  was looking for a QHY268 OSC  earlier in the year but no stock

Before I decide  whether to sell it, would a Quadband filter be useful in  LRGB since  it would reduce light pollution elements?

I'm thinking  Quad + Red, Quad plus Blue, Quad  plus Green together and Quad by itself for L

RGB  are 31mm  in  an 8 slot wheel and Quad is  2"  so  could  go in focuser etc

I have Ha, SII and OIII already

from  blurb

Quad Band - combines Sii AND Ha into a red zone, and H-beta + Oiii into a green/blue zone. (Recommended for moderate light pollution).

1st band, CWL495nm FWHM35nm
2nd band, CWL 660nm FWHM 35nm
1mm thick optical glass with 30 arc sec parallelism.
UVIR Block and Anti-Reflection Coating.

Edited September 9, 2020 by billhinge

[DaveS]

From reading the description of This crazy-expensive quad band filter I think the best use would be as a Luminance filter in NB. If your LP is so bad that you need some kind of a filter for LRGB imaging, then something like an IDAS D2 might be a better bet.

[billhinge]

Thanks, in my suburban/country area they turn  the street  lights off  at  about  11, its  mainly the odd light from gardens,  bedrooms and distant buildings on the southern  horizon

I  did use one of the clip  in eos  filters  previously for dslrs

[ollypenrice]

On 09/09/2020 at 17:11, DaveS said:

From reading the description of This crazy-expensive quad band filter I think the best use would be as a Luminance filter in NB. If your LP is so bad that you need some kind of a filter for LRGB imaging, then something like an IDAS D2 might be a better bet.

That makes sense.

The problem with the filter as luminance for LRGB is that it will pass very little blue from reflection nebulae, just those wavelengths which happen to coincide with H beta and OIII. (OIII only passes the longest of the blue wavelengths anyway.) My limited experience of processing OSC CMOS data s that it is already thin on blue even with no filter.

Olly

Edited September 11, 2020 by ollypenrice
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