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mrnumpty

Should i be able to see M13

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I was looking at well-resolved stars in M13 the other night through a 70mm f6 scope in light-polluted inner London.

If you'd asked me a week ago if that was possible, I'd have said no. But that was before I set up a Mintron frame-integrating camera with a little 7" black and white monitor.

Quite how the physics works, I don't know - how can a CCTV camera overcome the usual rules about the resolving power of a given aperture?

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From my garden which is a reasonably dark site by UK standards (although still light polluted with ghastly Na D), my 5" Mak and 4" refractor will both show the "diamond dust" effect mentioned above as the seeing comes and goes, and occasionally some individual stars, and quite a strong impression of structure. There is a good description given by Mallas and Kreimer (Messier Album) for a 4" frac which I would say matches my own impressions exactly.

Chris

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I was looking at well-resolved stars in M13 the other night through a 70mm f6 scope in light-polluted inner London. If you'd asked me a week ago if that was possible, I'd have said no. But that was before I set up a Mintron frame-integrating camera with a little 7" black and white monitor. Quite how the physics works, I don't know - how can a CCTV camera overcome the usual rules about the resolving power of a given aperture?

My little ETX-70 resolves M13 in a short camera exposure too but a fuzzy blur when eyeballed through an EP! Although the eye is a supreme detector it's lousy at 'integration' as it runs at ~25fps - it doesn't take many seconds exposure through a less efficient cam to trump the eye - here's 1sec exp and 30s exp on M13 via my 30cm LX200 :Envy:

http://www.cloudynig...0622x1smgcn.jpg

http://www.cloudynig... june11lode.jpg

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Thanks for that confirmation nytecam - I was kind of assuming that the frame integration was only able to increase the amount of light gathered but didn't think that it could make such a difference on resolution.

Edited by Ludd

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Thanks for that confirmation nytecam - I was kind of assuming that the frame integration was only able to increase the amount of light gathered but didn't think that it could make such a difference on resolution.

I suspect the 'resolution' in both cases is similar only that the eye @ 25fps receives insufficient light to kick-start the eye's individual photosensitive cells :Envy:

Strange hobby stargazing - you stare at an object @ 25fps and it's not going to change much in the next 1000 years :evil:

Edited by nytecam

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i have decided M13 is going to be my 1st messier to try and spot simply as vega and arctucus are right in my garden view, contradicting information as to if you will be able to see it or not lol i have a SW 130p some are saying you wont see it with this some saying you will lol i will see for myself as soon as i get a clear sky, i hope i can see more then a fuzzy blob :( if i do will have to break out the dslr for some long exposure's and stacks to see if i can spot the amazing M13 :D

http://www.themcdonalds.net/richard/index.php?title=Finding_M13

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you will definitely see it with a 130mm scope - it's obvious even in my 50mm finder and is bordering on naked eye at dark sites.

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it cleared up a treat late last night so I popped out with my new 8x40 Aspheric Bino's, got a lovely view of M13 as a smudgy ball very pleased considering 40mm of aperture per eye! also M31 was the best I've seen through bins, great to have a treat after all the cloud:)

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Picked up M13 with 1-inch aperture last night eg 10x25 binos but only as a tiny fuzzy patch :cool:

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I am still waiting for a view of m13 in which I can resolve stars. I found it a few weeks back with my 15x70s but it only showed itself as a blurry smudge. I was unable to locate it night before last in my 8" dob, mainly because I got lost near the zenith!

Last night I found it again in the bins but was the blurry smudge again. I guess that the light nights do not help in resolving. Although it was neary an hour past sunset when I was out last night, it was still light enough to read without too much strain. Living in the centre of a largish town won't help either.

I'm hoping for some darker skies when on holiday in late August. I should have a 70mm travelscope for then We are staying here www.palefarmcottages.co.uk which I'm hoping will be darker than home!

Ikorodu

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From my experience around 5inch should be able to resolve M13 to diamond dust with some structure, the effect is similar to viewing M45 with the naked eye on a nice dark night, just many more tiny stars twinkle with the atmospheres turbulence, my 127 mak does it reasonably well.

However, when you get to 8inch and beyond, that is where globs just leave you breathless and you can begin diving into them with higher mags.

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If it makes you feel any better, I have never resolved stars in my 5 inch scope. Some granulation at over 130x , but not much more. In my 10 inch dob, I have to get my focus absolutely spot on to see any stars. The focus really is crucial and I find that aspect quite tough, as a tiny tap on the focuser can make all the difference.

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