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burb scope
member
Reged: 04/18/08
Posts: 55
Loc: Canton, MI
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Aren't focal reducers also "field flatteners"? Are they built to be applied to SCT optics? If the LT-6 ACF optics are already "flat", then would a focal reducer undo that advantage? Is there a special focal reducer for ACF optics?
The LT-6 appeals to me more than the LS, and I am considering what accessories I would like.
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brianb11213
Carpal Tunnel
Reged: 02/25/09
Posts: 2076
Loc: 55.215N 6.554W
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Quote:
Is there a special focal reducer for ACF optics?
Not that I'm aware of, but you can get screw-in threaded 0.5x (nominal) field reducers in 1.25" and 2" eyepiece threaded fittings which don't have the field flattening function of the 0.63x SCT focal reducer. The 0.33x SCT focal reducer doesn't have field flattening characteristics either, but that's intended only for imaging with small chip cameras and will not be effective for "wide field" visual use.
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rmollise
Post Laureate
Reged: 07/06/07
Posts: 4555
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Quote:
Aren't focal reducers also "field flatteners"? Are they built to be applied to SCT optics? If the LT-6 ACF optics are already "flat", then would a focal reducer undo that advantage? Is there a special focal reducer for ACF optics?
The LT-6 appeals to me more than the LS, and I am considering what accessories I would like.
They aren't flat. The design Meade is using reduces coma, but leaves field curavature as is.
Some are, some aren't, and those that are really need to be designed for the particular optics in use to be completely effective. The standard 6.3 (get a Celestron) may work OK...I have not tried it with this scope. And indeed haven't SEEN one of these scopes yet.
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Uncle Rod
Rod's New Book:
Choosing and Using a New CAT
Available now!
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nytecam
Postmaster
Reged: 08/20/05
Posts: 5742
Loc: London UK
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Quote:
My experience as a visual observer is that there is so very little difference between the standard optics and the ACF optics it honestly is a non issue... (Note I said as a visual observer)...
In all the years of visual I've always centred the object of interest so the extreme edge was largely a non-issue for me - so good SCT is more than adequate and for small CCDs too. The lower cost LT [SCT] with proven h/ware+s/ware is good news  That said I'd never buy an AltAZ scope with little or no imaging potential 
Might have to eat my words with Warren's ETX-LS pics here.
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Nytecam 51N 0.1W
Meade 30cm LX200+ETX-70+e-finder+C8+Ha+CaK PSTs SBIG SGS+homebuilt spectrographs
Starlight SXVF_M9+Lodestar CCDs/Canon 300D DSLR/Fuji E550
My observatory build-ETX-70 imaging-my videos
Edited by nytecam (11/09/09 03:17 AM)
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