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M57 using Lodestar Live


RobertI

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Hi all,

Had a quick session last night under severely light polluted skies.  Enjoyed looking at M57 using the C8 + F3.3 reducer, the following images of 15 second exposure using 'mean' stacking:

post-17401-0-40959900-1408364742.png

Same exposure and stacking, but image adjusted 'on the fly' to reveal (just) the spiral structure of IC1296 a barred spiral of mag 14.8 lying at 221 million light years:

post-17401-0-22220600-1408364752.png

Working at F3.3 is proving an education!! Every change of object requires significant refocussing due, I imagine to mirror flop. The vignetting is still unresolved, despite trying various lens to sensor distances, and I am beginning to think I have one of the rumoured 'duff' Meade F3.3 reducers which are talked about on the various forums.

I notice the vignetting is slightly 'off centre' and centred at about 8 o'clock, roughly where M57 is. Is this likely to be a result of scope being out of collimation?

I'll try M57 using the F6.3 reducer as a comparison.

Cheers

Rob

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I rather like the 'warp drive' effect - it took me ages to get that right! But seriously, I have been trying to eliminate the coma - I have tried a variety of distances with very little effect. I understand the sensor to lens distance is supposed to be 59mm and I have tried this but no joy. Have tried moving in, moving out, shaking it all about, but no solution yet. :)

Perhaps I should ask the bloke who sold it to me whether he had any more luck.

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I'd defiantly check the collimation, and also that the Lodestar and focal reducer are orthogonal to the image plane. Hefty focal reduction puts heavy demands on collimation and focus - I have found that to be try with my 0.5x reducer on the AA6RC.

Still a great result though - you got the dim central star of M57 and the galaxy was an extra bonus. Tweaking around the levels during observing is a great way of finding things like that - it can be amazing what is buried in the data!

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Hi Rob,

I'm with Paul on the collimation and focus being critical in this situation. As far as making sure that the sensor is square with the optical train, just make sure you're using a good quality holder with compression rings and at least two thumb screws. I assume you have the FR screwed directly to the back of the SCT and are then using some kind of extension ring to space the camera.

Also, if you have an F6.3 reducer, try that on M57. It will give you a better FOV for that size object. If you get coma with that, it's probably not the FR. I did a search to find if there were any bad F3.3 reducers, and couldn't find anything. Some say the ones made in China are bad, but that's what I have, and I haven't had the problems you're having.

Here's M57 I recently got using the F6.3 with my 8" Meade SCT. It was taken the night after the full super moon.

post-36930-0-46976900-1408517286.jpg

You're still making excellent progress. Hope my suggestions help.

Don

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Thanks for the advice and encouragement Don. You are right, I am screwing the FR directly to the back of the SCT and then using the Baader SCT to 2" adaptor with a 2" to 1.25" adaptor. They are all compression fitting and it all seems very solid. I will try my F6.3 and compare to what you have and let you know . Nice clear pic by the way, excellent detail.

Rob

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