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RV-6 Opinions, Please

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#1 trainsktg

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Posted 18 November 2005 - 01:50 PM

Well,

The time has come for adding a collectable equ. reflector to my collection and I'm considering a Criterion RV-6, preferably with clock drive on pedastal mount (classic!). From what little I can find, I've read nothing but good reviews from owners...things such as the scopes being provided with only two kinds of mirrors, 'good' and 'great', etc.

Recommendations, anyone?

Keith

#2 bsmart

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Posted 18 November 2005 - 02:21 PM

I'd highly recommend the RV-6. The mount and the focuser are, however, not that great. No slow motion control on either axis and lots of slop and play in both axis. The optics are great. I store mine on it's original mount but when I use it I put a dovetail on it and mount it on an HEQ-5 mount. Saturn is fantastic, it looks etched into the eyepiece. I've had excellent detail at 480X. I got mine for $142.50 from Portland Community College in 2003. I also have an RV-8 which I pull out when there's no wind. It's a monster and, like it's little brother, has wonderful optics. I've replaced the focuser on it, I hate it when eyepieces fall out, with a helical focuser and use it on the HEQ5 mount as well.

#3 FAB

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Posted 18 November 2005 - 02:44 PM

I owned an RV6 for about thirty years. I bought it new in the early sixties for 199.95. I gave it to one of my sons in the early 90s. Now it and an antique Tasco (yes, Tasco made decent scopes in those days), also from the early 1960s, are his scopes of choice even though he owns a 10" on a GEM. The RV6 has the original mirrors with the original surfaces. The original clock drive still works. The post above is accurate. It has no slow motions, but I never really missed them. Perhaps I would now. I found nothing objectionable relating to the mount. Sure, it could have been heavier and more sturdy, but it was adequate. I did not use it for astrophotography except afocal shots of the moon and planets. I note now that RV6s are selling for twice their original cost or more. Giving it away, even to a beloved son, was a mistake. I wish I had mine back. I could have willed it to him. Hey, maybe some night after my son is asleep I could slip into his backyard and . . . no I guess not.
FAB ;)

#4 Jon Isaacs

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Posted 18 November 2005 - 02:47 PM

Well,

The time has come for adding a collectable equ. reflector to my collection and I'm considering a Criterion RV-6, preferably with clock drive on pedastal mount (classic!). From what little I can find, I've read nothing but good reviews from owners...things such as the scopes being provided with only two kinds of mirrors, 'good' and 'great', etc.

Recommendations, anyone?

Keith
----

Keith:

I am not really a collector of classic scopes, rather I just pick anything up that comes along at a decent price. Earlier this year I saw a "6 inch newtonian, EQ mount, clock drive" advertised in the local paper for $175. Finally after a week or two of ignoring it, the "clock drive" got the best of me and I gave the seller a call.
Of course it turned out to be an RV-6, I made the guy an offer and I was the owner of another telescope.

I have enjoyed using this scope, I just cleaned the mirrors, they are not in the best condition, dusted off the OTA and have been using pretty regularly. It does provide very sharp images, it seems to do a nice job on double stars and planets. The scope cools nicely so one sees nice diffraction rings around stars.

OTA is nice and light,about 8lbs, some sort of composite, the mirror cell is aluminum, adequate and provides for good cooling. The finder's field of view is limited, I currently use a 6x30 Celestron that fits right in. The 1.25 inch focuser is a weak point, it does work but it has no retaining screws and it is somewhat crude.


The mount is interesting and adequate, certainly old style, the RA has a slip clutch so you just move it like a DOB. The large polished aluminum tube rings make the scope quite attractive, and better yet, the scope turns easily in the rings, unlike modern asian scopes. The RA motor is unavailable so that is a problem.

Overall, this is my opinion:

I have owned a few older scopes, recently I bought and sold a Sears 76mm F16 refractor. The mount was nice looking, lots of brass, chrome and a nice wood mount. It did provide some nice views but in the end, the shaky mount and the 0.965 inch eyepieces and that long OTA gave me great appreciation of what it was like using one of these scopes. I much preferred the Celestron 80mm F11.3 on a CG-3 mount, just easier to use and a better all around package. Not as attractive but easier to use.

In contrast, I think the RV-6 holds its own against today's scopes. When I am using it, I am not constantly thinking, "This is a 30 year old scope and it is amazing how much easier it is to use today's scopes."

Rather I am thinking, "this is a pretty amazing scope, it gives some amazing sharp images and it is easy to use, too bad they still don't make em." So while it is a classic and a scope to be admired, it is a very practical scope that is a pleasure to use.

Bottom line: This scope was first introduced about 45 years ago. It has stood the test of time like few others.

I say go for it...

Jon

#5 trainsktg

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Posted 18 November 2005 - 04:21 PM

Hi Everyone,

The reviews so far back up what I've been reading. Sounds like a winner. One thing consistently mentioned was the substandard focuser...is this the type with no EP set screw, but rather a spring loaded bearing on the inside tube that exerts pressure on the EP when inserted? I have a similar one on my Vernonscope.

Thanks.

Keith

#6 bsmart

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Posted 21 November 2005 - 12:24 AM

Yes this focuser has no set EP setscrew. The end of the tube has four slots cut in it allowing the sections to be bent inward providing spring tension to hold the EP.

#7 trainsktg

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Posted 21 November 2005 - 03:05 AM

I guess the supply house was out of drill and tap kits when they came up with that one...

Keith

#8 bsmart

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Posted 21 November 2005 - 07:10 PM

I found one for sale by a guy I can vouch for as being reputable as I've dealt with him before.

Huge ugly web link

#9 Averted

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Posted 21 November 2005 - 11:24 PM

Keith,

I love my RV-6. Focuser is the weak point, but after a little lube job, it performs adequately. Just keep the focuser pointing up! (easy to do).

I agree with Jon. I just foret its a "vintage" scope when I use it.

The only other thing that may take some getting used to (at least for me) is the equatorial without gears. In many old ones the cork clutch goes bad and you end up with slop in the drive. Finding one without needing some attention might be a challenge.

Here is a link you should check out.

dynascope@yahoogroups.com

A very active group.

#10 Jon Isaacs

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Posted 22 November 2005 - 01:41 PM

The only other thing that may take some getting used to (at least for me) is the equatorial without gears. In many old ones the cork clutch goes bad and you end up with slop in the drive. Finding one without needing some attention might be a challenge.
----

The second RV-6 I bought ($40, how could I resist) had problems with the cork clutch. I bought some cork at an artist supply store and replaced it and so far so good. If the drive motor itself is faulty, then things get a bit more complicated.

jon

#11 Averted

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Posted 23 November 2005 - 04:34 PM

$40 for an RV-6? If only I could be so lucky!

#12 Jon Isaacs

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Posted 23 November 2005 - 06:43 PM

>>>$40 for an RV-6? If only I could be so lucky!
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It was a deal to be sure, they were cleaning out a home in the high priced district and wanted it out of there fast. Of course, since I already have one, it just means I spent $40 because one way or the other, it will be a gift to someone.

It gets expensive saving money...

jon

#13 jarhead

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Posted 06 December 2005 - 08:49 PM

I have owned an RV-6 for about 20 years. Still has original optics, motor drive, focuser(not very good) and EQ mount. It is reasonably stable. I have completely refurbished the outside of OTA and all of the EQ pedestal. It now has high polished aluminum rings with new felt, Polished aluminum legs on the base and hammered paint job on the pipe for the EQ mount. The optics and never been re-coated, but I'm sure it would help. GREAT views of Saturn, Orion Nebula, Moon, and many Globular Clusters. Even saw the Faint image of the Dumbbell Nebulae on a good dark night. I would recommend this scope for anyone. It is simple and offers great views. I even have the original set of Criterion eyepieces including an Eferle wide.
If I new how to attach an image, I would take some pictures to share with everyone.
My grandkids names will be painted on the OTA. I doubt I will ever sell it.

#14 Bob Pasken

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Posted 07 December 2005 - 01:42 PM

If the motor is a cramer clock motor then you get a replacement motor from Bristol Motors. The address is

Bristol Motors
Div. of Vocaline Co. of America
Old Saybrook, Conn. U.S.A.

IIRC it is a 1 rpm motor

#15 Jon Isaacs

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Posted 07 December 2005 - 01:45 PM

If the motor is a cramer clock motor then you get a replacement motor from Bristol Motors. The address is

Bristol Motors
Div. of Vocaline Co. of America
Old Saybrook, Conn. U.S.A.

IIRC it is a 1 rpm motor
-----

When I looked into this, what I found was that Bristol no longer had any replacements and that if one wanted a motor it would have to be custom made. I would be interested in knowing if you have recently been able to secure replacement motors from Bristol.


Jon

#16 Bob Pasken

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Posted 08 December 2005 - 12:38 PM

Jon I got the address from a friend who is restoring a Cave and needed a new RA motor. He was able to get the 1 rpm motor.
If Bristol is out of business now, several people on the Cave group have said tha a Hurst motor Series A, AB Geared Synchronous Motor would work with some work in the mounting holes..

#17 jarhead

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Posted 09 December 2005 - 12:46 PM

I have included a site link for the motor replacement for an RV-6 if anyone is in need of it. http://www.dynascope...ive_replacement
I have not checked to see how current the info is, but you may be able to find other information about parts etc. there.

#18 jarhead

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Posted 09 December 2005 - 12:52 PM

Sorry for the repetitive responses, but I just found another site that says it has 6 rph (criterion uses 6 rph) motors in stock. About $18.00 if anyone needs one.
http://www.herbach.c...=Synchron - RPH
They are recommended by the Dynascope group also for motor replacement.

#19 Jon Isaacs

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Posted 09 December 2005 - 01:18 PM

Bob and "Jarhead":

Thanks for the information. I really enjoy using my RV-6's but I have been reluctant to take them to dark skies and run them over inverters because the motor is slightly noisier and I did not want to risk damaging an otherwise irreplaceable motor.

But for $18 plus shipping, it seems like buying one just to have around would be a good move.

Thanks

jon

#20 Bob Pasken

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Posted 09 December 2005 - 08:57 PM

It would not be keeping the RV-6 in pristine shape, but have you considered getting a stepper motor of the correct size and using one of $10 stepper motor driver kits? I built one of these cheap kits for a scope I built that had an odd sized number of teeth on the worm wheel. I simply used the supplied variable resistor to adjust the speed until a star stayed centered on the cross hairs. You could replace the AC motor with the stepper until you're ready to put the scope in a museum

#21 Jon Isaacs

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Posted 10 December 2005 - 06:10 AM

It would not be keeping the RV-6 in pristine shape, but have you considered getting a stepper motor of the correct size and using one of $10 stepper motor driver kits? I built one of these cheap kits for a scope I built that had an odd sized number of teeth on the worm wheel. I simply used the supplied variable resistor to adjust the speed until a star stayed centered on the cross hairs. You could replace the AC motor with the stepper until you're ready to put the scope in a museum.
-----

Bob:

What I had considered was using an EQ-2 drive. I happen to have a spare EQ-2 drive and it has speed control with a wide range, I think it would work. But being the lazy fellow that I am, I like the idea of running it off an inverter and the 12 volt 17 am jump starter I have.

Jon


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