Mike it was an 80ED that had a shortened tube to take an AstroPhysics 2.7 inch focuser with an AP focal reducer that I bought just for the AP focuser andFR. I have now put these on the 100ED that I cut the tube off to get the correct length.
I replaced the focuser on the 80ED with a ScopeStuff Crayford focuser. It needs a 2" tube extender to get focus without a FR. But it is handy for focal reducer experiments as a FR needs IN focus.
My aim was to design an 80mm F5 APO astrograph with a flat field for C size sensors that anyone could afford. It does work. I have lent the modded 80ED to Andrew. I am putting together a FR as we speak as the experimental one was not suitable for prolonged use (too flimsy). I will send it to Andrew to see how it performs.
That's a great image that feels like we are looking a long way away into the Solar System. Great to have another comet discovered by an Aussie, lets hope it brightens even more.
I would also like to add that Andrew only received the scope last friday and he produces a great images of Comet Lovejoy on Saturday morning. I am very envious as all I can get is images of cloud at the moment.
Were the comet images taken with the FR Andrew?
If they were then the 80ED with FR was 344mm focal length at f/4.3 !
Is that the AP 67CCD reducer Bert? I have one, and used it for a while in the FC100, but am wondering about using it with the ED80/840 Zeiss. I also wondered about using it with a newly finished 8" f5 newt, but the coma is severe enough at f5 so may go to Plan B instead? Haven't worked what Plan B is yet tho.
Gary
Yes Bert, that was with the Focal reducer, I didnt get a chance to try it without it. Like you, we got clouded out. I think I cropped the images too to remove the coma.
Gary it is this one http://www.buytelescopes.com/product...=&pid=5598&m=5
It screws into the AP 2.7" focuser.
For a Newtonian an MPPC is the way to go.
I think you have to go to specially designed expensive FR's for Newts for wide flat fields.
Any decent doublet will work as a FR with an APO. It is just a matter of working out optimum distances for placement.
To keep the thread relevant. That is great Andrew that you got Comet Lovejoy centered. Did you realize you had a 344mm at F4.3?
The 'new' FR should give about F5 at 400mm focal length.
