Back to 350 D - M 42

[jsmoraes (Jorge)]

My 3350D hasn't IR filter. I try to test about the noise in red channel. My 1100D is present much noise.

Without the IR filter I have less noise, but I loose some green and blue color. (I am wondering if atmosphere and IR filter are causing this amount of noise)

photo 1: final result
photo 2: the RAW crop
photo 3: the DSS result crop
photo 4: Halfa red channel only.

note: the result of DSS is very red. I will try to stack again with no Bias. I can not see the reason to this reddish appearance.

oh, I forgot: it was only test of camera and BackyardEos remote control. Only 6 x 1 min ISO 400 RGB Skyglow filter and 10 x 3 min ISO 400 Halfa filter.

[jsmoraes (Jorge)]

And a reprocess. Tree versions.
The fourth photo is a crop of the weird white spot noise in red channel of Halfa capture. They are strong only in the region with strong signal. At black background they are present, but with the same amount but with less intensity.

http://www.astrobin.com/145643/

http://www.astrobin.com/145646/

[cometcatcher (Kevin)]

I like 3 the best I think. Don't think I've seen that white spot noise before.

[LightningNZ (Cam)]

The white spots look like heat noise to me.

[jsmoraes (Jorge)]

Humm! Maybe Cam. But, why only in the red channel ? Thermal noise should appear in all channels. It is an internal noise from sensor.

I am thinking on the possibility to be problem with my Halfa filter. A bad one, for example. Those dots aren't a normal noise, understanding normal noise as the noise I saw in red channel with skyglow filter or without filter.

Note that this white spot noise appears in 1100D and 350D. More strong in unmodificated 1100D (it has IR filter). I have no other Halfa filter for test, and I haven't no mate near to ask for one to test.

[John K]

Jorge,

I find, particularly for a modified DSLR, Deep Sky Stacker does a terrible job of the colour balance.

Play with the settings in DSS in RGB levels to get the balance right before you save.

Same with the Luminance and Saturation levels.

I crank up the saturation levels up to 17% to 21% and then adjust accordingly RGB and Luminance before I save.

It's best to get the image as good as you can out of DSS before processing in other software.

Your data looks good - it's about getting the colour balance and saturation levels correct.

Also, you can save a lower Luminosity image to use as your core - so save 2 versions in DSS.

Here is an example with my modified 400D and 12.5" f/5 at ISO1600 200 second exposures and 5 seconds and 30 seconds for the core:

https://www.flickr.com/photos/johnka...ream/lightbox/