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