Triad Filter and dualband filter questions

[TheButcher]

Has anyone tried a Triad or a Dualband STC filter on thier ZWO 294MC- P? Alaso has anyone tried using a 1.25" filter with the adapter on the 294mc pro?

I was thinking of doing it but not sure how it would work with my setup. "I plan to get the 1.25" and mounting it on the camera adapter flush to the sensor but curious if it would work ok (if the filter fully covered the 294's sensor). Now I also recently purchased an Astronomic CLS-CCD-2" filter which I like a lot and with this in mind.........Would I still need to have the Astronomik Filter to view galaxies and and such?

Or would the Triad cover the the narrow band channels that i am looking for I know the STC Dualband only has 2 bands so could capture narrow with that. Also could you combine two different sets of exposures taken at the same rate and stacking them in DSS. For example I take 4 hours exposure with the Triad filter or STC Dualband, then take another 4 hours of the Astronomik CLS-CCD with seperate imaging sessions and not combining one filter on the top of the other with 1 imaging session since I know the CLS filter would be useless stacked with them. But could benificial capturing other light frames to get rmoe data.

Sorry if I sound confusing and if it odes, that's because I am.

Thanks in advanced

[STEVE333]

Hi "Butcher" - First off, I have used both filters and like them both. They are intended primarily for imaging nebulae. The nebulae tend to emit light primarily (in varying degrees) in the Ha, Oiii and Sii spectral bands. The two filters you have mentioned pass the Ha and Oiii radiation. The Triad filter passses a bit wider spectral band around the Oiii so it also captures the H-beta emission. Aside from that difference, they both block all other light, so, broadband sources like galaxies are better captured using your CLS-CCD filter.

The diagonal width of your sensor, corner to corner, is 1.12" which would tell me that a 1.25" filter would cause significant vignetting especially toward the corners of your image. I use the 2" filter (of course it is more expensive) with my Canon DSLR and vignetting hasn't been a problem.

The two narrowband filters you mention act as exceptional LP filters. I'm able to take 9 min exposures with either the Triad or STC Duo-Narrowband filter, and could even take longer exposures. With my normal IDAS LPS-D1 filter (which blocks only the Na and Hg emission lines) I'm limited to about 3 min exposures.

Hope this helps.

Steve

[TheButcher]

Thanks Steve for the very informative response. That helps my decision. It could to know that I should opt for the 2' then be stuck with the 1.25".