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Outside is a dark clear sky but high wind and a very bright half moon that lightens the whole sky. I tried this and that and did a serious first test of the K3ii with an Omegon 12nm Ha filter on the Flaming Star Nebula. Up to now I only had one H-alpha sub of the bright Orion Nebula which is not a heavy target.

The moon was only a few degrees away and glows into the ímage. Also the mount shook from wind gusts and the image is just from 16 subs x 5 minutes @ ISO 1600. Also I did just a 2 minute rough processing.But what came out is worth mentioning and worth showing at least here, where most of us are hanging around with unmodified sensors. The say, we can't capture H-alpha:



I'll do a meridian flip now and get some more subs. I will do a more serious processing if I get some more good subs (the wind will get harder and stay over the weekend).

Pete

Continue pushing the envelope Pete. Great work.

Nice result..I've given thought to trying my 2" Baader HA filter on either the K5ii-or-K3ii, have yet to do so...focusing with a broadband filter is a challenge.

Yeah, hard work . I use Sirius, Rigel or comparable bright stars with a bahtinov mask to get into focus with a 10 s ISO 6400 shot and iterative adjustment.

Finally I did not get more than 26 subs because the wind gusts were too strong (+4Bft). Here is what I got out of this:


It is certailnly far from being a masterpiece but it prooves two things for me:


1) the Pentax K3ii sensor can catch a reasonable amount of Ha-light in acceptable exposure time!
2) it makes sense to go for another testing.


Because there is a lot of noise in the red channell I think that it takes more than 50 subs to get a clean image (I had to do a heavy noise reduction and the result is too smooth). But - if I compare it with my old full spectrum image I see al lot of different structures between the two versions. So it could really make sense to do a Ha-RGB combination.

What do you guys think about this all?

Pete

Can't hurt to try...(till max frustration sets in)... :-)

I am interested in seeing you combine it. I want to find a reasonably priced Ha filter myself.

Using a broadband Ha filter is useful for the unmodified cameras. I was able to get decent Ha signal with using a Baader 30 nm Ha filter on an unmodified K-10D.

Once the camera is modified, however, you'll find that the signal to noise ration skyrockets. It's worth getting an older body and having it converted.

Also, don't forget that running at 1600 ISO just clips the data from the brighter stars. So long as you're getting signal (skyglow, stars, nebulosity) above the noise floor, you don't need to saturate.

I don't think I'll go that direction. I'd prefer to invest into dedicated astrocamera if some day I have the feeling that I want to change the camera.

I know, you are right. Normally I don't use that long exposures at ISO 1600. But before that test I had no idea if there would come in enough Ha at all. So I coosed the "brighter" settings.

Did you already do Ha-RGBs? I am not sure how to deal with the stars. I think I would eliminate the stars in the Ha-version and use the RGB stars in the final image combination. Or do you see a better way to deal with the stars to get natural loking stars?

Pete, I was using the Nb RGB combine script in Pixinsight. It assumed that you had an RGB image that was already well-balanced, and it automasks to add the Ha data.

This is an example of a picture I did with the script: NGC 281 HaRGB | NGC 281 HaRGB in Menlo Park, CA Sept 2013 Th? | Flickr