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FORUMS Photo Sharing & Visual Enjoyment Astronomy & Celestial 
Thread started 15 Jan 2018 (Monday) 03:32
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M42 - M81, M82, and NGC 3077

 
Roy ­ A. ­ Rust
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Jan 15, 2018 03:32 |  #1

Tonight looks like the last clear night for a while around here, so I set up my Orion Sky View Pro with my Tamron 150-600mm lens out back to take a lot of pictures of the Great Nebula of Orion (M42), and try to get some better shots of Bode's Nebula (M81) and the Cigar Galaxy (M82), while I had the chance.

Someday, I hope to figure out how to avoid blowing out the trapezium in Orion's nebula, or to fix it in post processing. But in the meantime, this is the best I've come up with, so far. I also need to make another trip to a darker site than my back yard - then I could probably get by with less than 151 exposures! Although, the more the better.

I stacked 151 images of M42, and 98 of Bode's Nebula with the Cigar Galaxy toward the bottom, and NGC 3077 as a tiny fuzzy object toward the upper right.


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Celestron
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Post edited 7 months ago by Celestron.
     
Jan 15, 2018 10:02 |  #2

Roy, nice job on the captures especially m42 . The secret tho to keep from having a blownout center on m42 us taking multiple short exposures from 5-15 sec exposures just to capture the trapizium . Then with the image you have above you can either add those during stacking or you can stack the exposures of the trap and then do a copy/paste of the trap on to the anove image . However when you do a copy/paste which can be done in PS , you can use the magic wand around the finished trap then right click and choose feather approx 2-4 pix then do copy and then paste on the original image . Feathering keeps the lines from showing up when pasting . It really is a simple technique and works wonders ! Look up Jerry Lodriguss and his website did have explanations how to do so easily .

Here's a link to the process above I told you about . Works very well !
http://www.astropix.co​m/html/j_digit/comp2.h​tml (external link)




  
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Roy ­ A. ­ Rust
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Jan 15, 2018 12:22 |  #3

Celestron wrote in post #18541315 (external link)
Roy, nice job on the captures especially m42 . The secret tho to keep from having a blownout center on m42 us taking multiple short exposures from 5-15 sec exposures just to capture the trapizium . Then with the image you have above you can either add those during stacking or you can stack the exposures of the trap and then do a copy/paste of the trap on to the anove image . However when you do a copy/paste which can be done in PS , you can use the magic wand around the finished trap then right click and choose feather approx 2-4 pix then do copy and then paste on the original image . Feathering keeps the lines from showing up when pasting . It really is a simple technique and works wonders ! Look up Jerry Lodriguss and his website did have explanations how to do so easily .

Here's a link to the process above I told you about . Works very well !
http://www.astropix.co​m/html/j_digit/comp2.h​tml (external link)

Thanks for the info... I'll certainly give it a few tries and see if I can master it... or at least novice it. ;-)a




  
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Pagman
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Jan 15, 2018 21:35 |  #4

I was wondering the same regarding the blown out look I get of the center of Orion, no matter what I do in post, I can not bring it down, I just came to the conclusion it must be a lassive area of intense bright light.

P.


Some stuff.

  
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Celestron
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Post edited 7 months ago by Celestron.
     
Jan 16, 2018 08:22 as a reply to  @ Pagman's post |  #5

There are 4 stars in the center that create alot of brightness throughout the nebulaes heart section , which causes blowout with long exposures . Short exposures of just a few section capture the stars but not alot of neb data . Therefore 30 or more captures of the center stars stacked will make a nice trap shot which then can be composited with the overall image . Just make sure when copy/pasting you paste the trap image ontop of the original image then adjust accordingly with PP . Look up M42 Trapizium only images and that will help you understand why you need seperate captures .

https://apod.nasa.gov/​apod/ap050710.html (external link)




  
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MalVeauX
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Jan 16, 2018 08:39 |  #6

Nice grab! Composition helps too. You have the raw data in there, so you can practice processing it over time to try different things.

M42 is a very bright DSO, and is everyone's most common target usually because it's big, bright and easy to capture to an extent. But, it has a lot of dynamic range involved, from the very bright core (trapezium) to the wispy dust lanes surrounding it. To capture it all in a single exposure value, currently doesn't happen, due to dynamic range limitations (the difference of capturing the dust vs the trapezium is huge and overwhelming to the sensor, hence oversaturation occurring and clipping out all the data).

I used a similar approach that is described already, two sets of data, one for the core, one for the rest, and simply overlay the core and blend it in with masks, making a composite, but keeping all the data.

For mine, I used 30 x 180 seconds for my light subs for the nebula, dust and everything else (F6 ISO 800).
And I used 31 x 10 second subs for the core (F6 ISO 800).

The exposure difference is huge. 10 seconds for the core is all it took for me. And 180 seconds for the nebula and dust. That's almost 5 stops exposure difference (and each stop is a doubling of the exposure).

You can inspect how I blended my core & nebula here: https://flic.kr/p/Srjm​E2 (external link)

Very best,


My Flickr (external link) :: My Astrobin (external link)

  
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richardsjacob27
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Aug 09, 2018 08:36 |  #7

I'm really sorry to necropost, but I just got the 150-600mm Tamron for my D750 and I love it. I've always wanted to try something bigger on my Ioptron and I was curious what mount and setup you used to make your Tamron work for you? I've been able to use my 200mm on the Skytracker, but never thought of attempting the 600mm beast.

Great work!

Jake




  
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Roy ­ A. ­ Rust
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Aug 09, 2018 20:43 |  #8

richardsjacob27 wrote in post #18680728 (external link)
I'm really sorry to necropost, but I just got the 150-600mm Tamron for my D750 and I love it. I've always wanted to try something bigger on my Ioptron and I was curious what mount and setup you used to make your Tamron work for you? I've been able to use my 200mm on the Skytracker, but never thought of attempting the 600mm beast.

Great work!

Jake

Please don't apologize for 'necroposting'. I appreciate any comments or questions, no matter how long ago I posted the images.

I'm not sure which mount I used for the images of Orion's nebula, but probably used my Orion Sky View Pro mount. But, I often use my iOptron Sky Tracker, even with the Tamron 150-600 lens on my camera. It's just so simple to set up and use. Much quicker and easier than the Orion. I'm always careful about positioning the big lens on the iOptron, though. I try to get the weight slightly off-center to the west, to avoid straining anything in the iOptron. The main problem with using it is focusing... the ball-head is the weak link to rigidity, and it allows the slightest touch on the lens while focusing to wiggle the image all over the place in live-view. However, once I've gotten the best focus I can, the iOptron seems to be able to keep the image steady for the few seconds required to take a picture, and keep the object in place for multiple exposures. I don't remember taking any really long exposures with it, though... usually just use it for shots of the moon and planets. But, I wouldn't expect to have any problems with 10 or 20 second exposures.

One other thing about my setup... I have the iOptron mounted on a heavy-duty video tripod... no center column to bend and sway when the weight shifts due to the tracking movement. I don't think a standard camera tripod, with center column, will be rigid enough to hold things steady for long exposures with the big lens on it. However, I think it would manage to keep brighter objects, like the moon and planets in the frame while you take multiple shots. That's mostly why I use it - just to avoid having to keep repositioning the camera/lens to follow the object.

Give it a try. You don't have anything to lose, except a little time. Just try to position the camera/lens so it puts the least load on the iOptron's motor/gear train.




  
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M42 - M81, M82, and NGC 3077
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