actionhac
professor emeritus
Reged: 08/09/08
Posts: 732
Loc: WA
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If you had to choose, which one would you pick? and why?
Used, close in price.
Same aperture, same focal length.
RV-6 has a small secondary obstruction.
C6-R will have some CA on bright objects.
Robert
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Bonco
Carpal Tunnel
Reged: 04/17/06
Posts: 2297
Loc: Florida
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I see your question is not getting much of a response. So I'll offer what I can. I don't know what a C6-R 6"f8 is. But because you said it would have CA I guess it must be a achro refractor. If so the refractor will be heavier and need a robust mount. The RV6's optically are typically excellent. The factory mount is nothing to be proud of but it's adequate for visual use. I've compared the RV6 side by side with a 6 inch f8 older version AP triplet and the RV6 won hands down optically. That old AP refractor I've seen recently selling for over $5000. The venerable RV6 is often offered at very reasonable prices on the internet. Not sure I answered your question but maybe this will help to get some discussion on your thread. Good luck.
Bill
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RV6
Meade 2045
6 inch f/4 RFT R. Fagin Optics
TV Genesis
2.4 inch Lafayette Equitorial
3 inch Polarex/Unitron Equitorial
10 inch Zhumell
PST 40mm Solar scope
4 inch F/15 Antares
2.4 inch Unitron Equitorial
Tasco 10K 80mm/1200mm
Towa 339 Restored
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actionhac
professor emeritus
Reged: 08/09/08
Posts: 732
Loc: WA
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Thanks Bill.
The Celestron C6-R is a made by Synta in China 6"f8 achromat that seems to be very popular and somewhat inexpensive for this size of refractor.
I remember the RV-6 having a reputation for excellent optics and I think you partially answered my question with the AP 6" comparison.
We classic scope users just take high optical quality for granted. Just wondering how what is almost a modern equivalent to the RV-6 a general purpose scope for the masses stacks up against the old standard.
Robert
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tim53
Pooh-Bah
Reged: 12/17/04
Posts: 1439
Loc: Highland Park, CA
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Hi Robert:
RV-6 by a landslide. The Synta refractor will be full of CA, not just a little bit. At low power, it will be fine, but at high power it will be annoying. My 6" f/10 Jaegers is fine for resolving subtle detail on Jupiter, but I can't shoot in color, because Jupiter is green with purple belts even with a Baader contrast booster.
My 6" f/10 Newt (Clearvue Optics primary/secondary) resolves finer detail than my excellent orange tube C-8.
-Tim.
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"We`re just waiting looking skyward as the days come down.
Someone promised there`d be answers, if we stayed around."
-Orchestral Maneuvers in the Dark, "The Romance of the Telescope"
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charles genovese
super member
Reged: 02/04/06
Posts: 132
Loc: Madisonville Louisiana
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I have both. The RV6 eats the refractor on everything but one- the widest field of view with a stock RV6 with a 32mm 50 deg eyepiece is 1.3 degrees. But wirh a 40mm 70deg eyepiece the 6" f8 refractor will get you 30X with a field of view of 2.3 degrees. one could modify the RV6 with a bigger diagonal and change to a 2" low profile focuser but I wouldn't do it.
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actionhac
professor emeritus
Reged: 08/09/08
Posts: 732
Loc: WA
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Looks like the old RV-6 is still hard to beat. I had a feeling this might be the case and not just my rose tinted glasses.
Robert
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Darenwh
Pooh-Bah
Reged: 05/11/06
Posts: 1221
Loc: Covington, GA
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With the quality of the RV-6 optics I would say it would be better for most objects. There are just too many variables with the celestron yard cannon. Put that RV-6 on a modern mount and give it a good focuser and you would have an amazing scope. I would still try to keep the origional mount in good shape and maybe even the origional focuser but I would not use them with it.
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Daren
Covington, GA
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rmollise
Post Laureate
Reged: 07/06/07
Posts: 4564
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Quote:
If you had to choose, which one would you pick? and why?
Used, close in price.
Same aperture, same focal length.
RV-6 has a small secondary obstruction.
C6-R will have some CA on bright objects.
Robert
The RV-6, unless you are into the Color Purple and enjoy fixing balance problems. 
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Uncle Rod
Rod's New Book:
Choosing and Using a New CAT
Available now!
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Mr Magoo
scholastic sledgehammer
Reged: 11/05/05
Posts: 999
Loc: Franklin, Indiana
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Ken
Franklin, IN
Member, Indiana Astronomical Society
B.S.A. Astronomy Merit Badge Counselor
6" f/10 Dob
Vintage Sears Discoverer 4-6305A 60mm
Vintage Manon 60mm (The Marsha Scope)
Criterion RV-6
My CN Photo Gallery
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mattyfatz
Pooh-Bah
Reged: 12/27/06
Posts: 1293
Loc: Boise Idaho
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I'm what you
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**Matty**
Stimulating the economy, one piece of equipment at a time.   
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mattyfatz
Pooh-Bah
Reged: 12/27/06
Posts: 1293
Loc: Boise Idaho
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I'm what you'd call a NEWTIST, so obviously I'm going with the RV-6. The Newts eyepiece is always at a convenient hieght. The view from an RV-6 is crisp and color correct. Oh yeah and the best part...
MADE IN THE U S A WHOOHOO!
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**Matty**
Stimulating the economy, one piece of equipment at a time.
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mikey cee
Post Laureate
Reged: 01/18/07
Posts: 3512
Loc: bellevue ne.
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Thanks guys. If I were an owner of a Synta product I'd feel like tossin' it in the trash. You helped make my day. 
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7x35 and 10x50 sears tower binocs, 3" f/10 edmunds reflector, 2.4" f/11.7 manon refractor, 6" f/8 jaegers refractor, "The 8 Ball" 8" f/13.3 brandt refractor, 3" f/15.8 sans&streiffe refractor, 3.1" f/15 selsi refractor(towa 339), 2.4" f/15 sears refractor, selsi 30x30mm spyglass, criterion 5-draw 25x45x75x spyglass(1957), 4.25" f/14.8 tasco 20te.
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Doug76
Postmaster
Reged: 12/05/07
Posts: 5541
Loc: SE Louisiana, future Texan
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Have to against the grain here, at least somewhat. I can say nothing about the RV-6, having never used one. But I'll assume it is excellent.
The C6R, on the other hand, I do own.
Contrary to popular belief, it is not overloaded with CA. Yes, it is there, but it leans toward the upper end of the violet, an almost blacklight effect. Very easy to ignore. And it doesn't increase much with power. I use mine in the 240x range constantly. And if you really can't put up with the CA at all, Baader makes a filter called the Semi-Apo which will effectively remove most of the CA present, without altering the color balance. And it is a great scope otherwise optically. It does have the balance problem, being nose heavy, and it is a fairly heavy and long OTA. But it does allow use of 2" ep's. Overall a killer deal for a large achro.
I bought mine nearly two years ago, and have no complaints about it's optics.
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Doug
Truckstop Astronomer
The Universe, the light of God, in all it's majesty
6 achro refractors 50mm-150mm
1 apo refractor 90mm
1 SCT 8inch
UO Abbe Volcano Tops
Faworski Ortho's
Panoptic 24mm
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