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Dob DSO photography.


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I have one question:

Can you photograph even "bright" DSO's (M42) practally with an iPhone and a 8-10in non-GoTo dob? I know you can, (ive got camera glimpses with a 3.5 in) but is it practical? And what about the brighter galaxies/planetary nebulas? (M27, M57, Virgo Supercluster?)

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My profile pic (M42) was done by putting my Google Pixel XL up to my eyepiece. I have a 12" dob with 1500mm focal length and the eyepiece was an 14mm ES 82. The exposure was only 0.6 seconds and the ISO was 3200. It's certainly doable. Practicality is another issue. It's fun to try, but you're never going to get super great photographs out of it. Even if my focus had been a bit better, I was still limited on exposure. My phone won't do more than 0.6 seconds. an iPhone may.

Edited by Buzzard75
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5 hours ago, Buzzard75 said:

My profile pic (M42) was done by putting my Google Pixel XL up to my eyepiece. I have a 12" dob with 1500mm focal length and the eyepiece was an 14mm ES 82. The exposure was only 0.6 seconds and the ISO was 3200. It's certainly doable. Practicality is another issue. It's fun to try, but you're never going to get super great photographs out of it. Even if my focus had been a bit better, I was still limited on exposure. My phone won't do more than 0.6 seconds. an iPhone may.

How did that compare to visual? Looking at the full size version of your pic, I think I get slightly more brightness/extent and a bit more detail in my 12", but not much - it's very close!

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12 minutes ago, alan potts said:

Well furry socks,

I have an 18 inch Dob and you can't see that red colour with that scope, at least not with my eyes, so I would say that ia a result. I can see colour in M42 but not to that degree.

Alan

Ah... I did, in fact mean shape, extent, variation, etc... everything but colour. ;)

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I guess what I was getting at was, if a 0.6s handheld phone shot is "comparable" to the eye, give or take, then with a digi-clamp or similar then even on an untracked Dob, afocally, "better-than-the-eye" should be within reach.

I found this post - https://www.cloudynights.com/topic/592172-afocal-eaa/#entry8112140.

It relates eyepiece exit pupil and AFOV to the camera being used. With the small sensors found on camera phones, guide scopes, webcams, etc... I imagine the gain in focal reduction for increased true field of view, afocally, should mean longer exposures than the same camera at prime focus - and live-stacking or post processing with SharpCap or similar may again give more.

An old subject no doubt... recently, I tried an un-tracked, prime-focus, live-stack of M33 in a ST102 with a Datyson T7M...

blob.png.6e43e70db8fec29f38f597c7b7c145b7.png

Very difficult, a very narrow field of view, but fun and definitely better-than-the-eye. Practical? I vowed never to do it again...

 

Out of nearly 3K replies, there might be some afocal dob DSO images in here...

 

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2 hours ago, furrysocks2 said:

How did that compare to visual? Looking at the full size version of your pic, I think I get slightly more brightness/extent and a bit more detail in my 12", but not much - it's very close!

You certainly don't get the colors with your naked eye. It's hard to describe and I don't have a sketch, but the images in Turn Left at Orion of M42 are pretty darn accurate. I found this image from the Cambridge University Press, which is also extremely accurate to what I could see with my own eye. I could see a bright swath of white along the edge of the nebula. It was extremely bright compared to other nebula and I was blown away at how well I could see it. It was the first time I'd ever seen it and I really wanted to have a memory from the moment, hence the picture. Which in and of itself was amazing to me to see those colors.

 

 

M42invertedDob.jpg

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  • 2 weeks later...

If you stand the dob on an Eq Platform you can take slightly longer exposures, but I wouldn’t  buy one just for imaging. http://www.equatorial-platforms-uk.co.uk/photogrpahy-with-a-platform

And as @mystyco says with a video camera you can get much better results but I haven’t tried that.

Its fun trying, I took this image of the cats eye with my 16” on my eq platform with my canon. From memory Inthink it was about a 10 second exposure.

8901780B-D182-4A29-9B50-D1A16A2005E9.jpeg.874cf1001c6b7209006fa87d770b840c.jpeg

 

And M82

DE0D66E1-2BBB-4C6C-AA24-C78DADFA8AED.thumb.jpeg.e06a0d3f547ccb41f426b62ac493bd1d.jpeg

 

Edited by Scooot
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