Scope = TEC 140 mm f7.0 apochromat.
Field Flattener = Astro Tech AT2FF for APS C chips and TEC large format field flattener for full frame DSLR chips (24 x 36 mm).
Tele Extender = TAK Extender TOA-1.6x aka TOA 130EX.
Focusing with Bahtinov Mask.
Mount = Astro Physics Mach1GTO.
Cameras = Hutech modified Canon 400D, Griffin modified Canon 600D, Hutech Canon 6D, Hutech cooled Canon 6D.
Guide Scope = Hutech Mini Borg 50 mm Achromat, f5.
Guider = Starlight Express Lodestar.
Guider Software = Stark Labs PHD Guiding; PHD2 now.
Field laptop = X61s Thinkpad, Thinkpad T430s.
Flats = 7" Alnitak Flat-Man.
Capture, Focus, and Processing Software = Image Plus by ML Unsold.
Post Processing = Picture Window by Digital Light and Color.
Before 2011 autoguiding was done with an SBIG STV and efinder.
And before that I looked at illuminated cross hairs; but I could never do that for more than 15 min at a time.
Older mounts include Losmandy GM-8
Newer mounts include iOptron iEQ30
AP1100 Mount (TAK 250 CRS on top. Note the photographer reflected in the primary mirror :) Cables have been run through the mount; no dangle, dangle ---)
TAK 250 CRS
(A 10" CDK reduced to f/7.3 and 1825 mm focal length. I think this
starts as an f/12 system which is reduced and flattened to f/10
internally, then an external TAK 0.73 reducer is added bringing the
system to F/7.3 and 1825 mm f.l.)
* The image circle is listed by TAK at 35 mm and a full frame DSLR chip (24 x 36 mm) has a 43 mm diagonal. Thus the system yields heavy vignetting on the far edges and corners of a full frame DSLR. The image quality, on the other hand, holds up fairly well.
* Note the use of a second set of rings to hold the guide camera. This greatly reduces the chance of differential flexure. These rings carry almost no weight. I am successfully guiding an 1825 mm f.l. astrograph with a 250 mm f.l. guide scope.
Cooled Hutech Canon
6D full frame camera on above system.
* Camera operated by BackYard EOS.
* Focusing with BY-EOS FWHM readout. Seems remarkably stable (well filtered/damped) with seeing twinkle. On initial outing, the FWHM readout was more useful than Bahtinov mask focusing.
* Flat fielding using a 'Spike-a Flat Fielder'; 12" square.
Works well unguided for short to medium focal length lenses (to 180 mm). Can be autoguided in RA and I have used up to 300mm fl.
Prime Focus: 85 mm Dia, 450 mm FL, f 5.3
Reducer: Tak 0.73X > 328 mm at f 3.86
Extender: Tak 1.5X > 680 mm at f 8
EF 15 mm f2.8 Fisheye
50 mm f1.8 AIS manual focus Nikkor
85 mm f1.4 AIS manual focus Nikkor
Sigma 300 mm f4.0 manual focus Apo
500 mm f4.0 AIS manual focus Nikkor