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M13...my first DSO

jonifive

By jonifive
in Imaging - Deep Sky

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jonifive

jonifive

Posted
Posted

Hi

After the fantastic support I received after my first dodgy astropic, I took up the challenge and had a go at the ring.......could I find it......not a hope! So I moved on to Hercules and the lovely M13 for my first DSO.

877_thumbnail.png

(click to enlarge)

One widefield shot with my Nikon D40 at ISO 400 for thirty seconds, prime focus in my little WO 66 Petzval. I know it is slightly out of focus, I am having real problems with this as even through my new ebay focus adapter my eyesight is so poor I am struggling to tell what is in focus and what is not. It was also a bit cloudy and I kept losing it whilst the clouds passed!

Anyway, ta for looking, and criticism is absolutely expected as its the only way I'll learn!

Jonathen

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GazOC

GazOC

Posted
Posted

I just re-read your first post...sorry :(. I'm not 100% its focus thats the main problem....the aberation seems to get worse towards the edges and always towards the edge of field? Poor focusing should give rounder, bloated stars, not stars with such pronounced tails. One for experts methinks... :)

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geppetto

geppetto

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Posted

The Petzval does have coma round the edges which gets better the further back the focuser is.

There is a mod (bodge) to slightly change the distance between the front lens assy and the rear

(in the focuser) lens assy which I might try on mine sometime.

Anyhoo, apart from that, your out of focus JF which makes it look worse than it is...

Whilst Jupiter is about, set your focus up on that so that the moons pop into view and make a

note of the position on the focuser scale of your scope...

Also, did you twist the barrell of the right angle camera finder to adjust it for your eyesight before you started

using it?

Set it so that the three squares in the camera viewfinder are crisp in focus first then tweak the

scope focus to the object your looking at :(

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jonifive

jonifive

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Thanks Phil.

It was already dark when I set up and I never thought about setting up with Jupiter!!! My main problem is that to get focus I am always at the very end of the focusers travel. It is as if I need more infocus. No problem with EP's, but when I attach the D40 it is problematic.

My set up is as follows

D40 - t ring - SW Barlow lens with lens removed - 30mm extender - WO 66

Any suggestions!

JV

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Cloudwatcher

Cloudwatcher

Posted
Posted

Hi

................ criticism is absolutely expected as its the only way I'll learn!

Jonathen

An evil chuckle was heard as he rub his palms together in anticipation of the depths to which he could sink in responding to such an innocent expectation..........

Seriously though JV there is an extraordinary amount of data present in the image. It would be well worth your while giving it a thorough 'going over' in PS. I did a quick ten minute job on the centre section just now and can already see the 'propeller' emerging.....course it ruined your original but never mind, a?

CW

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barkis

barkis

Posted
Posted

Have you got a diagonal for the scope Jon.? If you are having to rack the focuser right out to get the focus almost on the chip, I say almost, because that is how it looks. Trying a diagonal should allow you more leeway I would think. A diagonal should have a longer light path than the device you are using, and therefore focus point should be more accessible to you.

Just a suggestion you know old boy. :(

Ron. :)

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