I had my telescope out again last week.

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AZ Maverick

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I got four days of imaging in without clouds or Moon!
I imaged IC405 (The Flaming Star Nebula) in narrowband SHO.
IC405 is both an emission and a reflection nebula and is located about 1500 light years from Earth.
I used my ED127-FCD100 telescope with a .7 focal reducer at a 666mm focal length at f/5.25.
I did 7.75 exposure hours on the Hydrogen Alpha filter, 10.1 hours on the Sulphur 2 filter, and 11.9 hours on the Oxygen 3 filter - exposures were all 5 minutes each.

Tscope.jpg
 
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I got four days of imaging in without clouds or Moon!
I imaged IC405 (The Flaming Star Nebula) in narrowband SHO.
IC405 is both an emission and a reflection nebula and is located about 1500 light years from Earth.
I used my ED127-FCD100 telescope with a .7 focal reducer at a 666mm focal length at f/5.25.
I did 7.75 exposure hours on the Hydrogen Alpha filter, 10.1 hours on the Sulphur 2 filter, and 11.9 hours on the Oxygen 3 filter - exposures were all 5 minutes each.

View attachment 751485
So, did you stack the images? Is that what I see there?
 
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AZ Maverick

AZ Maverick

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So, did you stack the images? Is that what I see there?
Yes.
I took 356 images each exposure was 5 minutes in length - all of those images were mono (black & white) images.
92 images through the Ha (hydrogen alpha) filter
122 images through the Sll (sulphur 2) filter
143 images through the Olll (oxygen 3) filter.
Each of the images through each filter were stacked to create one single filter image for each of the three filters.
Then each of those three images were integrated into the separate red/green/blue channels to create a false color image from the mono black and white images.
This is a technique known as the Hubble Pallet, as it is the most prevalent way that the Hubble Space Telescope presents its images.
 
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Yes.
I took 356 images each exposure was 5 minutes in length - all of those images were mono (black & white) images.
92 images through the Ha (hydrogen alpha) filter
122 images through the Sll (sulphur 2) filter
143 images through the Olll (oxygen 3) filter.
Each of the images through each filter were stacked to create one single filter image for each of the three filters.
Then each of those three images were integrated into the separate red/green/blue channels to create a false color image from the mono black and white images.
This is a technique known as the Hubble Pallet, as it is the most prevalent way that the Hubble Space Telescope presents its images.
Can you post a photo from each of the 3 filters? I'm interested in how much each contributed.
 
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AZ Maverick

AZ Maverick

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Can you post a photo from each of the 3 filters? I'm interested in how much each contributed.
Sure, no problem.
Here are the final stacked images from each filter, these are still pretty much raw images without much processing done to them (star reduction, noise removal, deconvolution, etc..).
The final image is mapped in SHO (Sll image mapped to the Red channel, Ha (hydrogen alpha) image mapped to the Green channel, Olll image mapped to the Blue channel), this is called the Hubble Palette as it is the most prevalent way that the Hubble Space Telescope presents its images.
Unlike wide band Red/Green/Blue imaging where each channel is about 100nm wide, these images are narrow band and only 7nm wide, this shows the emission line of each element.

Ha (Hydrogen Alpha)
Ha_small.jpg


Sll (Sulphur ll)
Sll_small.jpg


Olll (Oxygen lll)
Olll_small.jpg
 

SaltNeck

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Wow, those are some great exposures!

Do you do this from an area near your home or from your backyard?

Not knowing much about telescopes and photography would it help to be in a darker area (i.e. one without light pollution)?

Also, what software do you use to stack the images? How are the pixels combined bitwise (xor, or, and)?

In Search of the Darkest Skies (pbswisconsin.org)
 

Deadalus

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Awesome!

That's really cool, I didn't know color channels(?) were mapped that way. Each night you used a different filter then? (You mentioned four nights.) Sounds like putting the three filters together is a weighted sum/average. Would you happen to know how the varying night sky conditions are subtracted out/standardized? I'm guessing maybe there is some reference against which they are measured maybe or perhaps certain conditions are measured and entered?

Once or twice I have opened that space station thread...
 
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AZ Maverick

AZ Maverick

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Wow, those are some great exposures!

Do you do this from an area near your home or from your backyard?

Not knowing much about telescopes and photography would it help to be in a darker area (i.e. one without light pollution)?

Also, what software do you use to stack the images? How are the pixels combined bitwise (xor, or, and)?

In Search of the Darkest Skies (pbswisconsin.org)
I do this from my back yard.
Yes, trying to image with a lot of light pollution really makes things more difficult.
My back yard is in a Bortle high 4 to low 5 area - so not terribly bad but not the best either, a lot of people have it much worse than me.
I currently use software designed specifically for astrophotography, Pixinsight (which is the best but most complicated) and Astro Pixel Processor.
I also use Photoshop to make edits that, while possible in the Pixinsight, it easier to do in Photoshop.
There are other ways and programs that can stack and process images that I have used (and are free), but Pixinsight and Astro Pixel Processor are the ones I have settled on that give me the most flexibility in processing - not that the other programs didn't work.
 
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AZ Maverick

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Awesome!

That's really cool, I didn't know color channels(?) were mapped that way. Each night you used a different filter then? (You mentioned four nights.) Sounds like putting the three filters together is a weighted sum/average. Would you happen to know how the varying night sky conditions are subtracted out/standardized? I'm guessing maybe there is some reference against which they are measured maybe or perhaps certain conditions are measured and entered?

Once or twice I have opened that space station thread...
Yes, I have an automated filter wheel that is mounted right in front of the camera (which is a dedicated cooled astro camera ASI 1600MM PRO) it contains a set of filters that I can choose from (Clear,Red,Green,Blue,Ha,Sll,Olll).
The imaging camera is a mono black and white camera that is TEC cooled to -20°C to reduce background sensor noise.
I will usually rotate through each filter that an image requires through the night so that each filter is subject to the same sky conditions from night to night.
Stacking and processing software measures sky conditions and does the best it can to equalize backgrounds, remove satellite/plane trails, weight the individual frames for quality and stacking contribution.
The best quality frame is used as the reference and the rest of the weighted frames are registered to that frame when they are stacked.
 

Deadalus

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Yes, I have an automated filter wheel that is mounted right in front of the camera (which is a dedicated cooled astro camera ASI 1600MM PRO) it contains a set of filters that I can choose from (Clear,Red,Green,Blue,Ha,Sll,Olll).
The imaging camera is a mono black and white camera that is TEC cooled to -20°C to reduce background sensor noise.
I will usually rotate through each filter that an image requires through the night so that each filter is subject to the same sky conditions from night to night.
Stacking and processing software measures sky conditions and does the best it can to equalize backgrounds, remove satellite/plane trails, weight the individual frames for quality and stacking contribution.
The best quality frame is used as the reference and the rest of the weighted frames are registered to that frame when they are stacked.
Aha I was going to ask that, whether you rotated them through during the same night or even sequentially. I did see the sort of View-master disk housing on the end but I wasn't sure since there were differences in the total number between filters.

Thanks! Brought a bit of cheer to the morning when I saw it!
 

MaxStout

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I suppose Prescott is still close enough to Phoenix that you get some light pollution, plus Prescott itself. Despite that, you pulled in some awesome images!
 
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AZ Maverick

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I suppose Prescott is still close enough to Phoenix that you get some light pollution, plus Prescott itself. Despite that, you pulled in some awesome images!
Actually, not much LP coming from PHX (I would hate trying to image in PHX!).
The worst in PRC is downtown at Bortle 5, my backyard is Bortle 4.
Light pollution map

LP.JPG
 

hout17

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As mentioned nice pics. I live north of Denver and went from bottle 4 to bortle 6 in about 2 years. One of our most precious resources that nobody really cares about is the night sky and unfortunate light pollution as population centers explode because nobody really thinks about it and steps to mitigate.
 
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Actually, not much LP coming from PHX (I would hate trying to image in PHX!).
The worst in PRC is downtown at Bortle 5, my backyard is Bortle 4.
Light pollution map

View attachment 751538
I took a look at that map. Seeing a VERY hot spot near Keene, North Dakota, I suspected it was not reliable. There is no city nearby. But it seems there are a LOT of oil wells there - enough to light up the sky significantly. I learned plenty about the North Dakota oil boom.

1638925165100.png


1638925396903.png
 
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AZ Maverick

AZ Maverick

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AZ Maverick

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There are many different light pollution filters available for astrophotography.
They are not polarizing, they are bandpass/bandstop filters and sometimes both in one.
I actually have a couple of them myself from back when I was imaging with my DSLR.
What is the Best Light Pollution Filter For Astrophotography?
Several years ago, I set up my DSLR to track one of my telescopes as it tracked a target across the night sky.
You can see the fluctuations in the light pollution and the satellite/aircraft traffic.


 
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