A kind of widefield in M11 area

[Yoddha]

This is my first attempt to image with the little friend WO ZS-66SD. So far I used as a finder, widefield and travel scope, hope soon the get is main assignment - guide scope. Few months ago I cut a Bahtinov mask for it, which was very challenging, but so far in the field I always was in favor of its bigger brother ZS-110

Last time I was in the nearby mountain the weather was not good at all and decided to point the small one to that part of the sky which was free of clouds. Luckily it was my back-up target for the night - M11. Looks like I will start a quest for WO FF-II because FF-III can't manage all the curvature.

So here are M11, NGC6704, most of the dark nebula Barnard 104 (the L-shape one) and a portion of Milky Way



A bigger version can be found at : http://www.ideiki.com/astro/astroima...contrast_t.jpg

[David Fitz-Henr]

Nice wide field image Ivo - Barnard 104 stands out quite well! It may be worth varying the spacing between the FF-III and the imaging chip to see if you can reduce the field curvature before buying an FF-II. I achieved very good results doing this with a Televue Paracorr.

[Yoddha]

Thank you David! How long spacer you use?

[David Fitz-Henr]

Well, I added about 3mm extra distance to the recommended value of 55mm (giving 58mm total) - however, the optical properties of the Paracorr may be different to the WO FF-III. The problem may be that you might need to reduce the space between the FF-III and the chip. Looking at the distortion in the corners I suspect that this may be the case (which may not be so easy).

[Yoddha]

Thanks again! Will search the net for more info about the distortions. BTW FFII are so rare that there is no hurry