Skywatcher ED100 as imaging scope

[Benjamin (Ben)]

Just wanted thoughts on whether the Skywatcher 0.85x FF/FR is a must with the Skywatcher f9 ED100? The focal reducer make sense but wonder how flat the field is natively without the flattener. The reason I ask is that I have been gifted a TOAG that, as it is, would work fine without the FF/FR, but with the FF/FR I'd need to track down a few extra bits and pieces (TOAG Canon bayonet adapter, M48 to T2 adapter). Guiding fine with my finderguider but keen to try an OAG given I now have one :-) Advice appreciated as always.

[cometcatcher (Kevin)]

Hi Ben. The F9 ED100 is fine as an imaging scope without correction, although it does have a bit of a center bright spot. Flats get rid of it.

[jenchris (Jennifer)]

I haven't noticed any coma or distortion at the edge of mine.

[Benjamin (Ben)]

Thanks for that :-) Are there specific objects you image with the ED100 as opposed to the other scope/scopes? Kevin do you always use the .8x focal reducer with it? Do you use the Orion FR so you can use 2" filters with it or are the filters you use elsewhere in the image train? Loved the image of the comet and the Rosette by the way! Sorry for the many questions. Getting out under dark skies to try things is less of an option for a few months.

[cometcatcher (Kevin)]

After the ED100 I bought an 8" F4 / 10" F4 and that pretty much retired the ED100 from deep sky, except for some comet work with the focal reducer. But I find Moon shots are still excellent with the refractor.

I played around with the spacing of the Orion focal reducer also and found I could get the F9 ED100 down to about F7.2.

Yes I screw the 48mm filters in the end of the flattener / reducer normally. (Or coma corrector for the reflectors)

I really find the ED100 a joy to use. It's so easy to focus and never needs collimation. Reflectors are a pain. At least the F4 ones are. But man they are fast.