When I sold my much loved RC10 - it was simply getting too much of a handful for my ageing 82 year old body, I knew I would still want a similar focal length telescope for imaging smaller deep sky objects, and of course planets. Before the RC10 I had used a Meade ACF which had a good flat field, but unfortunately they had by this time gone out of business! The only sensible alternative which would be light enough to handle was a Celestron Edge HD. I was tempted by the 9.25", but it was very expensive and still quite chunky, so I settled for the 8" version, f10, 2032 mm focal length, which duly arrived on 21st October 2025 courtesy of First Light Optics. It had a Losmandy style dovetail fitted which was too big for both my Observatory and EQ6 'Star Party' mounts, but rather than fit a slimmer dovetail which might have compromised stability I was able to use the strong solid Vixen style dovetail which had been on my RC10 with Losmandy clamps fitted to it (click on the thumbnail for a larger image)

The Edge HD design has an inbuilt field flattener, and requires that for astrophotography the camera is fitted at the correct distance from the telescope. I had a manual camera rotator which I made several years ago, but no longer needed for my other telescopes - they all have rotators built in to the focuser. But the Edge is focused internally, and I thought it would be useful to have the rotator as part of the camera attachment. I had to shorten it somewhat to get the correct distance, but all seemed well on my first light test on NGC 7331. I had binned the camera 2x2 for that image, and the stars appeared to be ok. But I next tried it on an open cluster in a field of Milky Way stars, and it was immediately apparent that something was not right as can be seen in this full size corner crop from a single frame.

So I re-measured and found I had to shorten the rotator by around 4 mm. While doing that I also ensured that the assembly was as orthogonal (square on to the telescope) as possible. I again tested it on the same target, open cluster NGC 7039 in Cygnus, and this time all was well. Here are full size corner crops:

Round stars right into the corners. Most satisfactory! The original image is here in my QSI section.

And here is the telescope on my Observatory mount with also a clear view of the rotator arrangement. As before, click on the thumbnail for a larger image. Much lighter and easier to handle than the RC10, and will of course happily ride on my EQ6 mount at Star Parties.

Waiting for photograph!