I thought i would try the nine year old C8 on my new EQ6 Pro mount with the guide scope being a W/o Petzvall 66. I wanted to try the go to capabilities of this mount. I selected M16 and the scope slewed to what looked like the right direction. No adjustments from me. This is the location of M16 in the field of view. 9 X 5 Min lights and 5 X 5 Min darks ISO 800 DSS and processed both using DSS and GIMP. Very happy with the mount and the image. I also have included our first M16 through an ED80 to show the difference in aperture. Any advice on processing welcome.
May I ask how you went with autoguiding such a long focal length (C8) with the comparatively short FL of the Petzvall 66? the image I suppose speaks for itself in that regard, as the stars are brilliantly round and sharp..
Im about to start imaging in much the same way, and have got mixed opinions about guiding 2800mm Focal length with a 400mm or 700mm...
Once the scope was on M16 I just found a guide star in the 66 using an illuminated reticle and then replaced the eyepiece with a Phillips Toucam 840 and used PHD guiding. The EQ6 Pro mount has worked a treat with no problems of guiding over about 1 1/2 hours. To focus I used a free program called focus assist which downloads the image straight to the computer screen and then I also use a magnifier program to look at individual stars at say 10x so I can focus them almost to pixel size. Once this is done I just started taking photos and as always kept my fingers crossed that PHD would not make that horrible DONG sound indicating its lost the guide star. I have not had this issue with this mount unlike our schools HEQ5 that did this regularly. I don't know any theory in relation to focal lengths and guide scope length. I just gave it a go and it seemed to work. Hope that helps.
