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My attempt on Orion Nebula

rigellim

By rigellim
in Getting Started With Imaging

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rigellim

rigellim

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post-34971-0-90794800-1393427334_thumb.j

Greetings all,

My first decent AP shot using SW 200PDS as prime focus, and Nikon D90 camera.

9 x 30secs iso 800 shots. Stacked with DSS and post-processed with PS.

The initial shots were very low in contrast because of heavy light pollution, but still DSS is able to bring out a lot of details and tonal range.

The details however are not very sharp, maybe I did too much post-process on it.

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rigellim

rigellim

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Lovely shot, better than my first attempt last night.

DSLR on the back of an ST80 and camera tripod. Too much field rotation even with just 6 seconds.

Your ST80 is on an Alt/Az mount? Is that the reason to have field rotation?

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malc-c

malc-c

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For me it's bee over processed, and the colours look too false, especially the turquoise and purple, the star in the bottom left is a prime example - Just my opinion

Also looking at the star in the bottom your scope seems to be suffering with the same issue I did, where the minor axis of the secondary mirror is not fully coated and gives additional diffraction spikes.

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hobsey

hobsey

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Your ST80 is on an Alt/Az mount? Is that the reason to have field rotation?

No, its on a camera tripod.

Its was more of a mess around moment to pass a couple of minutes just to see if I could actually capture any detail in orion as I've never tried before.

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Stargazer33

Stargazer33

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Very nice for a first attempt.

Post processing skills will develop alongside your photography skills and at least you can practice the processing on those all too often cloudy nights!

Something else you could try is taking some shorter exposures to get the stars in the trapezium. You can then blend the centre of the nebula into the outer areas, so having both exposed correctly instead of burning out the trapezium cluster which happens all too often when trying to capture as much of the nebulosity as possible.

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Langy

Langy

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Colour being correct or not that is a great image to look at.

As I read in the Capture Every Photon book recently, it doesn't matter if what you end up producing is correct, it is your interpretation of the object.

With the blue rather than red that we usually see does make a nice image.

Well done, I'd be happy to get anything near to that detail.

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Russe

Russe

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Congrats on your first decent shot. Keep going!

Postprocessing will be the more difficult skill to learn IMHO. For the actual act of AP, it only needs the right equipment (EQ mount with guide scope, DSLR/CCD/webcam, scope achieving/holding focus).

Once you mastered polar alignment, focussing (Bahtinov), finding your object spot on, PHD guiding - you'll be waiting for clear nights only for data acquisition. Postprocessing skills development will take you back to your old data time and again. Never throw away a sub or a callibration frame!!

Good luck!

PS. I'd agree on the colour being off, and the trapezium being overexposed, but hey... Look up photoshop tutorials on YouTube!! Yes, I'd get into learning a picture editing program properly. After working a sweat to capture this data, you'd not want to muck about with a program that can't give you best possible results...

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rigellim

rigellim

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For me it's bee over processed, and the colours look too false, especially the turquoise and purple, the star in the bottom left is a prime example - Just my opinion

Also looking at the star in the bottom your scope seems to be suffering with the same issue I did, where the minor axis of the secondary mirror is not fully coated and gives additional diffraction spikes.

Yeah, you have a point, if I compared my shot with others, my shot seems too saturated. About this additional diffraction spikes issue, how do you deal with it?

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rigellim

rigellim

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Colour being correct or not that is a great image to look at.

As I read in the Capture Every Photon book recently, it doesn't matter if what you end up producing is correct, it is your interpretation of the object.

With the blue rather than red that we usually see does make a nice image.

Well done, I'd be happy to get anything near to that detail.

you have a point as well, nowadays surreal photos created by post-processing are more eye-catching than the actual scene.

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malc-c

malc-c

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 About this additional diffraction spikes issue, how do you deal with it?

If you have an hour or so you are welcome to have a read of this thread ( http://stargazerslounge.com/topic/159748-200p-colimation-or-poor-optics/ )

In a nutshell, I ended up fitting an oversized secondary from Orion Optics which resolved the issue straight away.  But you have a PDS version which as it already has the oversized mirror compared to the normal 200P, so I'm a bit perplexed.  Unless it too has an uncoated edge causing the light to defract.

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Christopher Davenport

Christopher Davenport

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+1 on a lower iso to capture trap in center.

I always try to layer my capture, my run last night at F7.5 on 80ed of Orion was:

ISO100 500s on trap.

ISO400 300s on core.

ISO800 300s on surrounding nebulosity.

ISO3200 180s for luminous.

Total integration of 6000 seconds.

Now to process, DSS, PS5 layers, curves and starmask.

Agree with Russ this is the hard part and it is easy to over egg it.

Something I am learning fast is to push till it looks good then pull back by 25%. Just cause I am eager!

Keep up good work.

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Russe

Russe

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+1 on a lower iso to capture trap in center.

I always try to layer my capture, my run last night at F7.5 on 80ed of Orion was:

ISO100 500s on trap.

ISO400 300s on core.

ISO800 300s on surrounding nebulosity.

ISO3200 180s for luminous.

Total integration of 6000 seconds.

Now to process, DSS, PS5 layers, curves and starmask.

Agree with Russ this is the hard part and it is easy to over egg it.

Something I am learning fast is to push till it looks good then pull back by 25%. Just cause I am eager!

Keep up good work.

Interesting! But why would you change the ISO?

http://www.blackwaterskies.co.uk/2014/01/do-high-isos-make-dslrs-more-sensitive.html?m=1

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Christopher Davenport

Christopher Davenport

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Thanks for the link it has made me think about my approach.

I am just copying what others who produce amazing pictures do. 

http://www.astropix.com/HTML/SHOW_DIG/M45_The_Pleiades.HTM

But some people just vary the exposure time not the ISO.

http://www.flickr.com/photos/astro-tanja/10276522704/

Not sure what the right answer is, but different ISO works for me.

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Langy

Langy

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Just to add that most DSLRs are configured to give their best results between 200 - 400 ISO. I heard Canon tend to be around 400, so by going lower you make capturing harder to produce a less optimal capture.

Just something to think about.

Sent from my Windows Phone 8X by HTC using Tapatalk

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