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 Post subject: My first... blob?
PostPosted: Tue Nov 25, 2008 9:26 pm 
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Another clear night, so another chance to get my scope out.

For whatever reason, I couldn't get the auto-align working tonight. I gave up after the 3rd attempt and just manually pointed it up somewhere around where the Andromeda galaxy is supposed to be. Pegasus was easily visible and served as a good guide. I looked around the area, and caught a faint fuzzy blob. I could barely see it even using the tricks of not using the middle of the eye and moving around it for motion detection. I looked at and around it for a while, but couldn't see anything else interesting in the immediate area. So I thought I'd see if a long exposure could bring it out.

As it was so high in the sky, I couldn't mount the camera on the rear port so had to use an eyepiece adapter. I dropped my camera in and... blank. Oh, it's also a bit of a shock to see how bright "black" is on the screen. I knew the focus would be out, but I couldn't see anything to focus on. So I moved the scope to the brightest thing I could see (probably Capella) and used that to focus the camera in live view x10 mode. I swung it back to where I saw the blob and managed to find it again in the viewfinder. With a remote release I tried some manual shots. Blank. Erm, maybe up the ISO a bit? 3200... nothing. 12800. That's better. Took about 10 seconds to see anything half brightly, but the motion was leaving a trail at that duration. And as I didn't get the alignment working, I didn't have any tracking at all. So I went to the last resort - 1 second exposures on continuous, and worry about combining them later. Idea is this is short enough not to significantly trail, while hopefully getting some data I can extract later.

After a but of tinkering in Paint Shop Pro 7 and Photoshop Elements 7, following is the result:

Image
1325mm f/13 ISO12800, Ten 1s exposures manually aligned and added. Greyscale created from green channel only to reduce the glow from light pollution in the red channel. Slight crop then resize.

I'm a long way from Greg's works, but still, it's a first. I think I need to do two things to get much better with what I have: I need to go somewhere darker so I can see much of anything. Then I need to get that alignment working with wedge.

I have been pointed at a public accessible location on top of a hill, with car park, about 30 mins drive from where I am. Apparently it's far enough out to not suffer too much from light pollution too. Think I'm going to have to try there next.

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
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 Post subject:
PostPosted: Tue Nov 25, 2008 11:36 pm 
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Hi popo,

Regarding the light pollution issues, one solution is a dedicated filter but, unfortunately, they aren't cheap. For the 50D the filter costs $259 (LPS-P2-FF1 from Hutech). The filter fits into the camera body just behind the rear element of any lens (if fitted) as can be seen here.

My guess is that you won't need one of these until your total exposure times are rather longer than they are now, but you might want to bookmark the site for future reference.

Bob.

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OM-D E-M5, H-PS14042E, Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
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 Post subject:
PostPosted: Tue Nov 25, 2008 11:49 pm 
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Thanks, and that's the site I was thinking of regarding the dust filter thread elsewhere... so that's why I couldn't find them. They're not primarily dust filters, and do have limits on lens compatibility.

I have an eyepiece light pollution filter, and as I'm using an eyepiece adapter I can put it in place with the camera. By eye it does reduce the local street lamps a lot, but I haven't seriously tested it with a camera yet. I need to work on setting up the mount correctly before I can get seriously long exposures.

On my todo list, I still need to match up the stars near that blob so I can confirm it's identity.

I was wondering if I should have maybe used the 100-400L instead. It's a lot brighter than the scope and would get more field of view. Maybe next time...

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.


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 Post subject:
PostPosted: Thu Nov 27, 2008 8:33 am 
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Nice blob. Not to dissimilar to my blob a couple of weeks back. It certanly opens your eyes more seeing this and, for me, it spurs me on the improve and find out more of what out there.

Keep at :-)

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 Post subject:
PostPosted: Thu Nov 27, 2008 12:38 pm 
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Still trying... I definitely need to get the mount sorted, which means moving to a clear location, which means more planning... so it goes on :p

I think I might have to play about by eye more before going back to imiaging. Looking at a wider angle eyepiece now to increase FOV.

Also, not been able to identify my blob yet. As said, it was in vicinity of where Andromeda was, and there's others in the area I might have hit instead.

Oh, while shopping, I found this. Nice to know expensive Zeiss isn't limited to the photo world :p

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.


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 Post subject:
PostPosted: Thu Nov 27, 2008 5:43 pm 
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Tell me about it, the planning that goes into it is quite precise.

Isnt it M31 that you have caught?

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 Post subject:
PostPosted: Thu Nov 27, 2008 6:29 pm 
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I just had another look, and yes, I can now confirm it is M31 a.k.a. Andromeda galaxy. I had trouble trying to line up the stars around it to make the confirmation.

Although it was most likely as the brightest blob in the area, there was still a small chance it might have been M32 or M110 and I somehow managed to miss M31 totally. I'm still not used to the sense of scale when viewing.

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.


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