Quote:
Originally Posted by LewisM
I "got around" the need for aperture by using a fast refractor - the FSQ-106. If f/5 isn't fast enough, you can go to f/3.65 with the reducer (and still maintain perfect field flatness).
All that goes soon, as I traded my FSQ-106ED for an FSQ-106N, so will be "stuck" at f/5, but I am not particularly upset. f/5 to me is a nice balance between depth and FOV. f/3.65 is a little too wide for my aesthetic tastes.
Anyway, if you want a QUALITY imaging Newt that requires absolutely minimal fiddling and holds collimation for a VERY long time, consider the f/4 Vixen R200SS. Only downside to it is the thick spider vanes (which is how it maintains secondary collimation so well) but these can be milled down.
The Skywatcher Quattro's seem to be almost clones of the R200SS, though somewhat cheaper. Heard OK reports on them, but holding collimation is NOT as good as the R200SS. GSO "generic" imaging newts need SERIOUS DIY work - mirror springs, secondary pinching, focuser etc. If you are willing to fiddle, then they are a good cheap beginning.
I did own 3 R200SS, and I can wholeheartedly recommend them. The figure on the mirror is superb. Also has a proprietary flattener that seems to work as well as the Baader MPCC.
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Thanks for the info Lewis, much appreciated. That Vixen looks very nice!
Yeah those FSQs are the way to go fast but I'm pretty happy with the FL on my TSA120 - just wish it was 8"!!
Quote:
Originally Posted by rustigsmed
G'day Hugh,
Nice to be hoovering up the photons at break neck speed!
I'd recommend the baader RCCi coma corrector http://www.teleskop-express.de/shop/...-distance.html
setback is around 94mm to go longer I think you will need to go exotic. (The MPCC is only 55mm)
But then again will you need the AO in a shorter focal length scope? If finding a CC more than 100mm it might get expensive.
I think you will be pretty safe with a CF model in terms of worrying about tube formation.
Collimation at f4 does take longer but nothing to worry too much about really.
The focuser upgrade is a must (but this is true of most scopes) - secondary mirror collimation screws replaced with bob's knobs (so you can adjust by hand) and you're on your way.
yep I don't know why more people don't use them, throw a barlow in and you've got good FL too for close ups.
Cheers
Russ
ps if considering gso you will need to replace secondary springs as well. |
Thanks Russ.
I'm pretty keen to keep using the AO, life has been immeasurably easier since I got it. I'll calculate exact distances and see what I can find.