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Old 14-02-2012, 10:52 PM
DJ N
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First Light William Optics New Flattener III

I have been looking for a suitable reducer/flattener for the ED120 to "speed" up my imaging. Recently I have been using the Hotech Field Flattener and this has been working very well. However it is only a flattener.

In the mean time, I recently was perusing the William Optics website and I noticed they have recently updated their flattener III, specifically for f7 to f7.5 systems. I ordered it on Saturday and it arrived Wednesday....not bad...... especially with the current exchange rate and free shipping.

With this new 0.8x reducer/flattener, this should speed up the ED120 and ED80 to f6 (from f7.5). This therefore should enable 1.5625x quicker imaging!!!

Well, finally did a bunch of testing last night. Initially set up the 56mm spacing between the flattener and QHY8L as specified per the William Optics website, and I could not bring either the ED80 or ED120 to focus. Not enough "in focus". I then proceeded to play around with reducing the spacing between the flattener and CCD. To make a long story short..... with a 20mm spacer in place, I am getting round stars in the corners of the frame with both the ED120 and the ED80. Very strange result considering the WO spec, however, very pleased with the final result.

I have attached a couple of images to indicate its performance (so ignore the processing ).....obviously all images are of Eta Carina

i. ED120 and QHY8L with the WO 0.8x Flattener III (6x 5min)
ii ED80 and QHY8L with the WO 0.8x Flattener III (4x 5min)
iii ED120 and QHY8L with the Hotech Flattener (5x 10min)

iv. Top RH corner ED120 with WO III
v. Top RH corner ED80 with WO III

Thanks for looking!!

Cheers,

Daniel
Attached Thumbnails
Click for full-size image (Eta Carina 13Feb12 ED120 QHY8L WO Flattener III  6x5min.jpg)
123.0 KB117 views
Click for full-size image (Eta Carina 13Feb12 ED80 QHY8L WO Flattener III 4x5min.jpg)
127.9 KB114 views
Click for full-size image (Eta Carina 21Jan12 ED120 QHY8L Hotech 5x10m.jpg)
124.8 KB97 views
Click for full-size image (ED120 Top RH.jpg)
79.4 KB115 views
Click for full-size image (ED80 Top RH.jpg)
73.1 KB110 views
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  #2  
Old 15-02-2012, 07:17 PM
garymck (Gary)
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keep in mind tjhat if you are not using the spacing as designed, you won't be getting the full f ratio reduction. You may be getting far less than you expect if you have significantly reduced the spacing. Curious as to why you didn't buy the Skywatcher reducer corrector? I have one for an ed80 and it works superbly.

cheers
gary
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Old 15-02-2012, 09:35 PM
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Rigel003 (Graeme)
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Actually I was a bit dubious about the amount of reduction compared to the Hotech too, but I measured the distance between the two brightest stars on the first and third images and the ratio is about 0.8. Nice photos and the edge stars are looking good. That'll be a useful addition to your gear.
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Old 15-02-2012, 10:34 PM
DJ N
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Quote:
Originally Posted by garymck View Post
keep in mind tjhat if you are not using the spacing as designed, you won't be getting the full f ratio reduction. You may be getting far less than you expect if you have significantly reduced the spacing. Curious as to why you didn't buy the Skywatcher reducer corrector? I have one for an ed80 and it works superbly.

cheers
gary
Hi Gary,

Thanks for that. I was intending to get the Skywatcher reducer for the ED120, however I have replaced the original focuser with a Moonlite. As a result, I would be unable to thread the reducer on. I do believe that First Light Optics in the UK sell an adapter which would allow it to fit into a 2 inch focuser, but to be honest, I could not be bothered. Especially that I would also need to purchase a reducer for the ED80. In addition, I was under the impression that on the camera side of the reducer, I would need an adapter for M48 thread to T2 thread to enable the CCD to be attached.

Thanks,

Daniel
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Old 15-02-2012, 10:35 PM
DJ N
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Quote:
Originally Posted by Rigel003 View Post
Actually I was a bit dubious about the amount of reduction compared to the Hotech too, but I measured the distance between the two brightest stars on the first and third images and the ratio is about 0.8. Nice photos and the edge stars are looking good. That'll be a useful addition to your gear.
Thanks for that Graeme..... quite happy with the purchase.


Cheers,

Daniel
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  #6  
Old 16-02-2012, 07:45 AM
garymck (Gary)
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Hi Daniel,

I got one of the adapters from First light optics as the ED80 I use has a GSO focuser. You are right about needing an M48 to t2 adapter as well. I'm not actually sure if the ed80 and ed120 reducers are actually different in any way other than the label. Both scopes are f7.5 and have the same recommended spacing......Never been able to find anyone who could verify if they are different or not.....Enjoy your new purchase!!!

cheers
Gary

PS anyone in Melbourne with an ED120 who would be willing to try the ED80 reduce on it one night???
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