celestron 80ed feild flattener

[Pete Presland]

i would quite like switch to using my celestron 80ED instead of my 200PDS. but using it the other week i had horrible vignetting and poor star shapes away from the center of the field of view. on the plus side the amount of room i suddenly had in the obsy was superb!

having done a little research about flatteners it seems that to use a flattener you have to ensure that the camera sensor has to be a quite accurate distance from the flattner. also not all flatteners are suitable for all refractors, you have to match the flattener to the F ratio.

anybody got any experience of using this scope with a field flattener? i believe the scope is identiclal to the orion ed80.

[Earl]

The sky watcher one for the 80ed pro will work for you.

[Pete Presland]

thanks for the suggestion but i think i might go for the orion as the scopes are meant to be identical

[Beardy Bob]

Let us know how you get on with this, I have the same scope and would be interested in how effective your flattener is.

[dugpatrick]

The are a couple of flatteners I would recommend for a ED80...

If you just want a flattener, without any reduction, then the Orion Field Flattener for Short Refractors is a good value.  Here's a sample image using the flattener:

http://www.flickr.com/photos/62714751@N05/8392878761/

For reduction and flattening, the Skywatcher (or Orion or Celestron) 0.85x Field Flattener / Field Reducer is a perfect match for the scope.  Here's a sample using the 0.85x:

http://www.flickr.com/photos/62714751@N05/10879269464/

Doug

[Pete Presland]

a couple cracking images the orion flattner looks like its doing a fine job!

[Beardy Bob]

I'm glad it worked well. It looks like the ED80 is right at the top end of the stated f-ratio range for it. Let me now if you post a 'before and after using the flattener' comparison, I'd love to see it.

I hadn't seen the Orion version before you mentioned it. Where did you get it from?

[Pete Presland]

after a bit of research finally settled on the Orion field flattener. managed to purchase one from a nice chap in South Africa at a decent price.  

this is just a single image to test the vignetting and flatness of the image. i got a little excited and forgot to check the focus properly  also there is no calibration frame so quite a few hot pixels!

the image is the Garnet star and what looks like a little IC1396 showing as well. fairly pleased with the overall appearance of the image, it certainly looks like the flattener is doing its job.

all coments obviously welcome

[Beardy Bob]

That looks good. It looks like some of the stars are slightly off-round, especially up the left hand side, but I guess that's due to the correction. It's definitely better closer to the edges that a non-corrected C80, and miles better than the usual 'warp' effect!

Was it the plain flattener you got or was it a reducer too?

This one?

http://www.scsastro.co.uk/catalogue/orion-field-flattener-for-short-refractors.htm

[Pete Presland]

it was the plain flattener no reducer, hopefully got some better on M81/82 on Thursday.