Repro Ha images

[bluescope]

Hi All

I decided to re process my Ha images of M8 and Eta because I really wasn't happy with the first attempt.

This time I extracted only the red channel from the exposures and loaded them into DSS ... hey presto I got 6 frame one hour stacks.

With better data to work with I did a slight post processing in PS and here are the results.

Still not sure if I'm doing this right but I'm happier with these versions anyway.


:thumbsup:

[AlexN]

They look great Steve, Awesome contrast as is to be expected with Ha imaging..

Normally when I used to Ha image with my QHY8, I would stack all the colour subs in DSS, then when I open the saved TIFF in photoshop, I would take the final red channel out, and process that as the Ha image.. Your method of achieving this would have a very similar result, but may be a little more time consuming.

[bluescope]

It's actually very quick and simple extracting the red channel in CCDOPS Alex just one more click in my normal processing routine.

I shot the images with 2x2 binning ... hence the small size of the image 800x600 pixels .... I'm not really sure about binning but I know it's recommended when doing Ha images with a OSC camera like my ST2000XCM.

DSS wouldn't stack the original 3 channel binned fit images so I had to extract the red channel for it to work :shrug: I'm just happy I got it to stack the files to increase SNR.

Glad you like the shots mate !

:thumbsup:

[AlexN]

Yeah binning 2x2 is recommended when Ha imaging with an OSC camera, as it definitely increases your SNR, which is always a good thing... I usually tried to avoid it through taking 20+ minute subs Bin 1x1, however some nights I did use binning to speed things up a bit... (20+ min subs bin 2x2 are usually awesome if your guiding will hold up) Are you using your self guiding through the 13nm filter or are you using an external guiding setup?

[Bassnut]

Looking very nice Steve

Perhaps the 3 channel fits files wouldnt stack because they were RGB, converting to mono 1st might work. How did the G and B channels look, was there any signal there at all?, would be interesting if there was. If not, then extracting red only is obvious anyway.

OIII is smack in the middle of the green/blue filter crossover zone on a DSLR (ie poor response, depending on the curve steepness and gap between green and blue), would be interesting to see how that goes too.

[bluescope]

Self guiding through the 7nm filter Alex ... just had to take longer guiding shots i.e. 2.5sec instead of my normal 0.5 sec - 1 sec ... seems to have worked ok ... gets slightly bigger guiding errors to correct ... also still getting smoke here from those fire mad farmers :mad2:

:thumbsup:



Hi Fred

Virtually nothing in the Green and Blue channels ... I don't have an OIII filter ... maybe in the future but I'll stick with Ha for now. Glad you like the pics.

:thumbsup:

[multiweb]

Nice pics Steve. :thumbsup: I just use the channels that the data ends up in so I bin 1x1. Usually I keep red for Ha and Sii, Green and blue for Oiii. I stack all the HaRed, SiiRed, OiiiBlue and OiiiGreen separately and do a data rejection. Then I stack the Oiii Green and Blue into one Oiii. All the rest is noise so I don't use it at all.

I haven't tried binning but I assume that if you bin 2x2 you'd collect all this noise together in one monochrome picture that has half the resolution.

[bluescope]

Thanks Marc !

Apparently you get less noise but you do get less resolution .... 6 of one a half a dozen of the other ;)

Here's a link to some info on binning ............

http://www.starrywonders.com/binning.html

:thumbsup:

[tornado33]

Good images there with plenty of detail.
I process the full RGB images in Iris, but once aligned and stacked, I remove the green and blue channels, by going to "colour balance" and putting green and blue sliders to zero, leaving only red. Then I change that to monochrome by reducing saturation slider to zero, leaving only the red channel displayed in monochrome. That seems to work best for me anyways.
Cheers
Scott

[bluescope]

Thanks for looking and sharing your method Scott.

:thumbsup:

[multiweb]

Cool! :thumbsup: I'll try that then.