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My first deep-sky object!

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#1 joelimite

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Posted 08 July 2013 - 10:12 PM

After two years of dabbling in lunar and planetary imaging, I imaged my first-ever deep-sky object, M13, last night using my TMB92L and brand new Canon T3i.

This shot consists of 14 light frames and 5 darks, each consisting of a 30-second exposure at ISO 800.

Deep-sky imaging is certainly a different beast compared with planetary imaging. I'm excited to try again, next time with more light frames.

Posted Image

Full-size here: http://www.flickr.co...in/photostream/

#2 shrevestan

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Posted 08 July 2013 - 10:33 PM

That's a nice M13! Good job!

#3 Erskin71

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Posted 08 July 2013 - 11:15 PM

great job.

I think the core looks great.

#4 CounterWeight

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Posted 09 July 2013 - 12:01 AM

For a first DSO image this is very well done, in fact it's well done for any night with the gear! congrat's! :) I'd call that a keeper.

#5 Wouter D'hoye

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Posted 09 July 2013 - 12:16 AM

I can only agree with what's said above. A nice image.

Thanks for sharing.

Wouter.

#6 Darren1968

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Posted 09 July 2013 - 05:48 AM

Great 1st DSO.
Very well framed and processed.
I am looking forward to your 2nd DSO.

Darren

#7 Madratter

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Posted 09 July 2013 - 09:37 AM

Very nice effort.

#8 TimN

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Posted 09 July 2013 - 09:39 AM

That's a very good image Joel. Having a first DSO that good makes it harder to show improvement. :D

#9 Jeff2011

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Posted 09 July 2013 - 09:44 AM

Good first DSO Joel. :waytogo: Yes DSO AP is quite a beast, but very addictive. As your exposures get longer, you might want to take more darks and add some flats and dark flats. Some people take biases, but I just take dark flats instead. Good luck and look forward to seeing some more.

#10 proteus5

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Posted 09 July 2013 - 10:10 AM

Very Very nice M13!!!

#11 joelimite

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Posted 09 July 2013 - 04:48 PM

Thanks for the kind words, everyone! I'm glad I dabbled in planetary/lunar imaging first; I've got a decent hang of polar alignment and processing already, which eliminates some of the frustration.

I'm going to need to read up on taking flats and bias frames. As far as the number of dark frames to take, is there a ratio to shoot for, say, one dark frame for every two light frames or something like that?

#12 Madratter

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Posted 09 July 2013 - 05:37 PM

Not a ratio. Even if you take only one light frame you would want to take a large number of dark frames. Commonly you will see numbers of at least 12-20. Personally, I shoot for at least 20. The benefit goes up as the square root of the number shot. So if you double the number you take, the noise goes down by about 1.4. So 20 will have about 1.29 times less noise than 12.

If you do darks wrong (wrong temperature, incorrect time, etc.) you could actually introduce more noise than you got rid of.

#13 joelimite

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Posted 10 July 2013 - 08:19 AM

Thanks for the info, Madratter. I'll definitely try more darks next time.

I'm using an unmodded camera, so I imagine I'll have the best luck with clusters and galaxies, huh? Still, I should be able to take decent shots of brighter nebula such as M27, right?

#14 Madratter

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Posted 10 July 2013 - 09:54 AM

For the really bright emission nebula like M42 you will get pleasing shots even with an unmodded camera. You won't capture the dimmest parts but you'll still have something that looks good. For dimmer ones, you will still be able to capture something but it won't be very good. Here is an example of the Helix I shot with an unmodded Canon 50d.

Rosette Unmodded

Furthermore I was using short subs (60s) since I was unguided at the time. So it isn't all together hopeless. It just depends on what level of quality you are willing to live with.

The more natural targets for an unmodded camera are as you mentioned galaxies and clusters, both open and globular. Reflection Nebula like the Merope Nebula in M45 will be fine too.

#15 CounterWeight

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Posted 10 July 2013 - 11:35 AM

I think that Helix link is pointing to your Rosette image.

#16 Madratter

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Posted 10 July 2013 - 12:00 PM

I think that Helix link is pointing to your Rosette image.


Doh. You're correct. I meant Rosette. I have changed the post.

#17 Tyranthrax

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Posted 10 July 2013 - 01:56 PM

I've been trying to get this with a video cam that I use to get most of my shots. I can't get it near that crisp and I've ben tring lots of diffret things. This gives me a model to shoot for and to referance! Well done!

#18 joelimite

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Posted 12 July 2013 - 12:57 PM

Maddratter, your unmodded photos look terrific!






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