LRGB Processing Help

[04Stefan07]

Been imaging for a number of years but I am new to LRGB with a monochrome camera! This is my shot of NGC2070. I think I know why it hasn't come out the best but I was hoping to get some peoples opinions too.

- My exposure was only 2 mins and made up of 5 images per LRGB channel. As I was experimenting and wanted to get some images before the night was up I only had time for 40 minutes. I think this nebula needs a lot longer than 2 mins
- I completely forgot to take Darks and Flats which is probably why I have a bit of noise
-  My focus wasn't 100% as I didn't have the electric focuser attached. Recently got one and need to attach it so  my next images should turn out sharper

I am puzzled why my image is lacking colour. There is no L channel on it, Is this due to exposure maybe or something else? Also there are some red dots, hot pixels maybe?

I have attached an image of the result.

Thanks,

Stefan,

[ollypenrice]

How did you combine the colour channels?

Once you've combined them you'll need to balance them. As a rule of thumb the top left hand side of the histogram peak should lie the same distance from the left in each colour.

Olly

[04Stefan07]

22 hours ago, ollypenrice said:

How did you combine the colour channels?

Once you've combined them you'll need to balance them. As a rule of thumb the top left hand side of the histogram peak should lie the same distance from the left in each colour.

Olly

Hey Olly.

I just had a play around and got a much better result. The only thing I am confused about are the red dots. Possibly they are hot pixels??

[wimvb]

That looks a lot better already.

Calibration frames are a must in this hobby of ours. The noise that you mentioned is not due to the lack of calibration frames, but the lack of data. Noise (ie, the random pixel to pixel variation) in the final master images decreases with total integration time. Calibration frames help remove hot/cold pixels, amp glow, vignetting and dust bunnies. Stacking further helps to reduce faulty pixels, and average out noise.

The red dots in your latest version look like stars to me (I'm viewing the image on my mobile phone). Hot pixels are only one pixel wide, and occur in all masters. The intense red is a combination of colour saturation during processing, and the stars being photographed through a cloud of red glowing Ha gas.

What camera, scope and software did you use?

The brighter corner upper right, can probably be fixed with dbe in PixInsight.

[ollypenrice]

49 minutes ago, 04Stefan07 said:

Hey Olly.

I just had a play around and got a much better result. The only thing I am confused about are the red dots. Possibly they are hot pixels??

Looking better! At this scale I can't see the red dots but if they are hot pixels a quick Photoshop fix involves using the Colour Select tool to pick them up and the Median filter (in the Noise menu) to zap them.

Olly

[04Stefan07]

@ollypenrice thank you!

@wimvb I totally forgot about the dark, bias and flat frames! That should make a difference. I was thinking maybe the GradientXTerminator might fix the bright corners (did crop them a bit). I am using a ZWO ASI178MM-Cooled with an Explore Scientific 102mm APO Triplet.

 

[wimvb]

5 hours ago, 04Stefan07 said:

I am using a ZWO ASI178MM-Cooled

That explains the brighter corner: amp glow. The best way to remove it is calibration with darks. The second best way is fiddling with DBE in PixInsight.

With an APO with 3 lenses that is properly focused, you should get an even focus for the entire spectrum. In theory. But if focus was off, that may very well be the cause of halos around stars.

[04Stefan07]

7 hours ago, wimvb said:

That explains the brighter corner: amp glow. The best way to remove it is calibration with darks. The second best way is fiddling with DBE in PixInsight.

With an APO with 3 lenses that is properly focused, you should get an even focus for the entire spectrum. In theory. But if focus was off, that may very well be the cause of halos around stars.

I purchased an electronic focuser for the scope but didn't have time to install it as I need to design a custom bracket for it. It will be controlled from the computer too. I think once I put that on and get a finer focus it will look more sharp!