NGC3372 - The Keyhole Neb

[pmrid (Peter)]

This is really a test image. I had my first opportunity last night to test an Optec Lepus .63 reducer. The scope is my EdgeHD 1400 but with the Lepus, it's at a FL of about 2450. In the absence of a reducer from Celestron, this is the ony one that claims to be designed for HD optics. The results were dissapointing - serious coma re-introduced into the flatfield the HD optics produce but reasonable in the centre. So the attached image is a crop of the centre. It is 6 x 5 minute subs - a bit of levels and curves applied later.
Peter

[renormalised (Carl)]

Nice shot Peter

I don't think any of the reducers/field flatteners work in these types of scopes. You usually go from just barely passable (like yours) to what looks like you've just jumped to warp8 (stick Meade's .33 one in their ACF scopes, you'll see what I mean).

[pmrid (Peter)]

Originally Posted by renormalised

Nice shot Peter

I don't think any of the reducers/field flatteners work in these types of scopes. You usually go from just barely passable (like yours) to what looks like you've just jumped to warp8 (stick Meade's .33 one in their ACF scopes, you'll see what I mean).

The Meade can't be any worse than this - have a look at the full frame.
Peter

[allan gould]

Peter
Great detail but you must be disappointed in the flattener/reducer. I read somewhere that there is a reducer for the HD comming out soon. You would think that making a reducer just for the ACF and HD scopes would be a real must by now. Any thoughts on the GSO reducer for their GSO RC scopes?

[pmrid (Peter)]

Originally Posted by allan gould

Peter
Great detail but you must be disappointed in the flattener/reducer. I read somewhere that there is a reducer for the HD comming out soon. You would think that making a reducer just for the ACF and HD scopes would be a real must by now. Any thoughts on the GSO reducer for their GSO RC scopes?

Hi Allan,
I haven't been following the discussions about the RC reducers - I sold mine. If anyone has one I could borrow for a few days, I wouldn't mind giving it a tryout.
Peter

[gregbradley]

Wow, an Edge HD1400 - that should hold a lot of promise.

As far as reducers go - apart from a factory designed one for that specific scope you may have luck with the AP67 flattener that is used on RCOS scopes for smaller chip (up to ST10) sized cameras.

You certainly got some nice close up image scale going there. The reducer is clearly not working. Same with my TEC180 - my Tak reducer setup kind of works but leaves stars a bit wonky in the corners of the image.

Probably the more expensive Tak reducer - would work for me. You are in the same boat - a bit of trial and error. I am sure one will work.

My best guess is the AP67 2.7 inch reducer.


Greg.

[ozstronomer (Geoff)]

Peter

Nice image..shame about the reducer not working out. I hope you can find something to suit as the center FOV is great. I've PM'd you

Geoff

[Germ]

Do you have the correct spacing from reducer to image plane this is critical. Optec make very good quality equipment.

Cheers

[pmrid (Peter)]

Originally Posted by Germ

Do you have the correct spacing from reducer to image plane this is critical. Optec make very good quality equipment.

Cheers

Yep. Using a purpose-made 82mm adapter made by Optec themselves for the specific CCD I'm using. The problem seems to be with the interrelationship between the flattener in the rear of the baffle tube and the reducer itself. According to Jeff Dickerson, the manufacturer, the only effect of having a mismatched camera adapter is some vignetting as it can still produce an image down to 22mm. So whatever the problem is, it's in front of the reducer, not behind it.
Peter

[multiweb (Marc)]

I'd keep the corrector at a set/recommended distance that you choose first in relation to the CCD. Then I'd move the whole [camera assembly/corrector] up and down the visual back and compensate with the primary translation to focus. Go one way or the other then see if it gets better or worse. You're bound to hit the sweet spot soon or later. On axis is excellent so you're nearly there.

[pmrid (Peter)]

Originally Posted by multiweb

I'd keep the corrector at a set/recommended distance that you choose first in relation to the CCD. Then I'd move the whole [camera assembly/corrector] up and down the visual back and compensate with the primary translation to focus. Go one way or the other then see if it gets better or worse. You're bound to hit the sweet spot soon or later. On axis is excellent so you're nearly there.

Thanks Marc.
I've been exchanging emails with Jeff Dickerson at Optec and have to say he has been really receptive and actively helping me sort this out. I'm more than a little impressed.
Peter