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Criterion RV6

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#1 criterion

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Posted 21 July 2006 - 08:58 PM

I have a Criterion RV6 in great shape, bought back in 1980 or 1979, back before B&L bought Criterion out. I'm currently fixing the motor on it and cleaning it up.

I'm thinking about putting it on a new mount, and wondering if anyone had any experiences or opinions as to what will work.

If the cost is not prohibitive, I'd love to get it on a mount with a computer full of objects loaded in, and with a much better more sturdy tripod. The factory delivered pier is really a pain in the rear to cart around and move around the corners of the house!

If a new (or used) mount is too costly (over $350), what do you think would be a fair price? I have 4 eyepieces, The original 18mm, 9mm, a 6 mm, and a great Televue 26mm Plossl, as well as a "nebula filter. Any idea on what a fair price for all this would be? I see them on Ebay going around $400+.

I would hate to sell it, its still in great shape and the mirror is in great shape and the tube is as original.

Thanks for the help!

#2 tbourg

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Posted 22 July 2006 - 08:37 AM

Hello,

You are very lucky, the RV-6 is one of my favorites. I use one quite often at the local observatory. The optics are very good.

Most of the RV-6's I've seen for sale on Astromart go for about $300+shipping.

At that price, I'd keep the scope. There is no way that you can get a comparable scope nowadays for anywhere near $300.

You might get $75-$150 total for the eyepieces. They are collector's items. I had a set that was stolen and I still wish I had them. The same goes for the eyepieces as for the scope, IMO. If you are not in dire straights financially, I suggest you keep them. If my memory is correct, they are pretty good eyepieces.

An Orion Skyview Pro or larger mount will work, although the eyepiece height of the RV-6 will be somewhat higher.

Good luck and clear skies.

Tom B.

#3 criterion

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Posted 22 July 2006 - 01:58 PM

I'm going to see how it goes with the new motor put in it and such. As for stability of the mount, I meant to say something lighter and easier to move in and out of the house. The RV6 has those large metal legs and heavy tube, it makes transportation not much fun!

#4 FAB

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Posted 22 July 2006 - 04:01 PM

I had an RV6 I purchased in the midsixties new. I gave it to my youngest son about fifteen years ago. Now I get to watch him use what is probably the finest instrument for anywhere near the 199.95 I paid for it I've ever seen. Oh! I also get to wish I had it back. My suggestion is, keep your RV6.
FAB

#5 Bonco

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Posted 22 July 2006 - 05:04 PM

I have my original purchase 1961 RV-6. I love it but agree that the scope deserves a better mount. I mount mine on my Super Polaris mount and it tracks and points beautifully. These mounts are frequently for sale used for around $300.
I'd suggest keeping the scope. Typically the optics are superb and the bakelite tube is lightweight but strong.
Bonco

#6 Jon Isaacs

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Posted 22 July 2006 - 06:19 PM

Hi:

I have a couple of RV-6's.... I like em.

Some thoughts and comments..

Finding a full GOTO mount capable of handling the RV-6 for under $350 is unlikely, probably a Meade LX-55 is the only choice, those were quite problematic, something of a gamble. If you are happy with a standard EQ mount, I think a Sky View Pro or a CG-5 with the 2 inch stainless legs would handle the RV-6 very nicely. These often are available on Astromart. For around $450 you can probably find a CG-5 ASGT used which is a solid computerized mount.

Personally I enjoy using the original mount. There is some slop in the drive but the viewing positions are much more comfortable, tripods tend to tangle with the scope but more importantly with my legs and/or my chair.

Here's a webpage about replacing the clock drive on an RV-6. With a bit of handy work, you can replace the drive for about $25.

http://www.dynascope...ive_replacement

Also there is an active Criterion RV-6 Yahoo group, it is worth looking at...

Whatever you do, keep the scope and mount together and if you don't have some modern eyepieces, get some. Inexpensive Chinese Plossls are a whole lot better what folks were using with RV-6's back in the day.

Jon

#7 Jon Isaacs

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Posted 22 July 2006 - 06:26 PM

>>>Oh! I also get to wish I had it back. My suggestion is, keep your RV6.
FAB
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Floie:

Must be pretty hot in Blythe right now... I hope all is well.

Are you serious about want an RV-6??

Jon

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#8 Jon Isaacs

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Posted 22 July 2006 - 06:26 PM

>>>Oh! I also get to wish I had it back. My suggestion is, keep your RV6.
FAB
----

Floie:

Must be pretty hot in Blythe right now... I hope all is well.

Are you serious about want an RV-6??

Jon

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#9 criterion

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Posted 22 July 2006 - 06:42 PM

Blythe is the artic, try living in Phoenix.

118 was the high yesterday.

#10 Jon Isaacs

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Posted 22 July 2006 - 07:02 PM

>>>Blythe is the artic, try living in Phoenix.

118 was the high yesterday.
----

Not quite the artic, a quick check of the San Diego paper shows that it was 118F in Blythe yesterday...

San Diego, well, we are sweating it out in the 80's... If it gets any hotter we just might have to turn on the air conditioning...

Jon

#11 Bonco

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Posted 22 July 2006 - 07:48 PM

tripods tend to tangle with the scope but more importantly with my legs and/or my chair.

Jon


Tis true. For observations close to the zenith/meridian the tube will hit the tripod legs on my Super Polaris mount and tripod. When I first tried it I was disappointed. However I found that I could move the scope way up in the rings and the SP was able to handle the imbalance. I really enjoy my RV-6 on a steady mount with elec slo-mo controls. But hey I have had decades of enjoyment with it on it's original mount.
Cheers, Bonco

#12 Jon Isaacs

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Posted 23 July 2006 - 09:14 AM

>>Tis true. For observations close to the zenith/meridian the tube will hit the tripod legs on my Super Polaris mount and tripod. When I first tried it I was disappointed. However I found that I could move the scope way up in the rings and the SP was able to handle the imbalance. I really enjoy my RV-6 on a steady mount with elec slo-mo controls. But hey I have had decades of enjoyment with it on it's original mount.
Cheers, Bonco
----

One of these days I will buy another dovetail and drill it out so I can use an RV-6 with my CG-5 ASGT mount. I like the ASGT because it is super solid with those 2 inch Stainless tripod legs and the motors are strong and responsive, slewing is not a matter of waiting around like it was with my old CG-5 and the slewing speed has a broad range...

Jon

#13 Achernar

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Posted 23 July 2006 - 11:59 AM

Definitely keep that scope. They as a rule have extremely good optics, which is more critical than many people think for looking at planets and double stars. You could get a new german equatorial mount on a tripod, but one that can carry the load could cost you more than buying many 8 and even 10-inch Dobs. The tube will weigh as much as 20 pounds, and that would require a sturdy mount, like Celestrons's CG-5, which certainly can handle your scope, but the eyepiece height may be a problem. It can be bought if I'm not mistaken with the DSC's built in, in short a true GOTO mount. I've seen them in action, and they work very well and can cope with a surprisingly heavy load.

What might be better would be to modify your current mount to make it easier to load and transport. I had the same sort of mount you did on my 6-inch, so I know what you mean about the pier being a pain to move. Knobs to make removing and attaching the legs without tools will help, and the same will work well on taking the head off the pier. You can buy DSC's that will work on equatorial mounts.

An alternative is to make a Dobsonian mount for it, then put DSC's on that. I turned my equatorially mounted 6-inch into a Dob, and I quickly found that kind of mount to be much easier to use. I don't really miss the tracking much, I find the lack of it a minor drawback compared to the steadiness of the mounting plus the ease of using DSC's in it.

Taras

#14 twhite

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Posted 25 July 2006 - 04:54 PM

There is a guy in our club that has an RV-6 OTA on a SkyView Pro mount instead of the original mount. It works extremely well, and he's quite happy with it. I owned that scope for a while, and it was a fantastic instrument, and he's enjoying it thoroughly now on a better mount. :)

#15 criterion

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Posted 25 July 2006 - 06:48 PM

That SkyView looks like a good mount. How often do you see those going up used?

I'm getting my new motor today and will take the whole thing to a shop tomorrow, I just didn't have the ability to install the drive shaft from the old motor to the new one, and the shop will do all that plus give it all a good once over.

#16 tbourg

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Posted 25 July 2006 - 07:26 PM

Hello,

I've got a couple of Skyview Pro's. They are great for a 5" mak, okay for an 8" F5. The 8" is pushing that mount to the very limit, IMO.

It should be fine with an RV-6.

Clear skies.

Tom B.

#17 criterion

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Posted 10 August 2006 - 08:06 PM

I just got the scope back today (actually the mount) and am dying to test out the motor and see how well its tracking and whether I am any good at balancing it and getting it just right....(you know the story from here)

Monsoon storm! Clouds, wind, rain, dust, lightning and all that!

Life in Phoenix in August!

Anyone know any good places to get my mirror re-silvered and get some good coatings for it? Preferably somewhere in the South West?

Thanks!

#18 Jon Isaacs

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Posted 11 August 2006 - 01:43 PM

L&L Optical in Orange County seems quite good and has reasonable prices.

www.llopt.com ???

jon

#19 Joel F.

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Posted 11 August 2006 - 08:07 PM

If you think the RV-6 is heavy you have tried one of the DeLux scopes! I had aan 8" Delux and it weigh 160 pounds which included a 45 pound cast iron pier. However, inside the pier they also had a wood tripod; thus reducing the weight I had to move around to 115 pounds. I could just manage this.

The views were great and I wish I still had the scope!

Therefore, I suggest you keep the scope!!

#20 criterion

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Posted 12 August 2006 - 12:49 AM

I'm having trouble with the motor tracking, I don't think the clutch is engaging and I can hear it sound like its slipping.

The motor works well, and I pulled it out and the gears are not stripped (I can't turn the shaft coming out of the motor, just a bit of a wiggle). I have tightened and loosened the clutch tension screws. I'm wondering if its the clutch lining, what killed the old motor is that some water got inside and rusted things up, and I think the clutch lining may have been shot which is why its not engaging. The guy who fixed it said the motor was turning the worm, but this was without the OTA and without the mount being on the pier. The scope moves well manually on both RA and Dec.


I only had a very brief shot tonite at Jupiter, and I had a very crisp view, so the scope is still in great shape, just having problems with the clock drive.

#21 Jon Isaacs

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Posted 12 August 2006 - 07:20 AM

>>>>The motor works well, and I pulled it out and the gears are not stripped (I can't turn the shaft coming out of the motor, just a bit of a wiggle). I have tightened and loosened the clutch tension screws. I'm wondering if its the clutch lining, what killed the old motor is that some water got inside and rusted things up, and I think the clutch lining may have been shot which is why its not engaging. The guy who fixed it said the motor was turning the worm, but this was without the OTA and without the mount being on the pier. The scope moves well manually on both RA and Dec.
----

A few thoughts...

1. There are probably 10 or more pairs of gears inside that box, the fact that you can't turn it does not mean it is not stripped, it can be stripped, it can have one bad place on one gear, that it all it takes.

2. It is possible the clutch is gone. I replaced mine with some cork from an art store it works.

3. You can test the mount durng the day to see if it actually works. Put it in, set the RA to zero and come back 30 minutes later and see if it has moved. Just don't forget it.


4. These mounts often have a bit of slop in them, waiting a moment or two for things to catch up, moving the scope into position from the correct direction help minimize this.

5. There is a good site for the RV-6's

http://home.wmis.net/~rv6/

6. Motors can be replaced inexpensively...

http://home.wmis.net...place_kens.html

http://www.herbach.c...=Synchron - RPH


jon

#22 criterion

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Posted 12 August 2006 - 08:24 PM

I'm gonna pull the motor and the worm gear assembly out and see if its moving correctly. (Note, I removed the worm from the gear and ran it, and the worm is turning, just fine)

I think that the clutch is not engaging, or is trying. I can hear it slip every 30 seconds or so. I tightened the worm assembly and it still did the same thing, but it made the scope move much less easily.

As for the clutch lining, I've seen pictures of it being fixed, I assume I just need to buy corkboard about an eight inch thick and glue it to the inside plate of the gear.

#23 Jon Isaacs

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Posted 13 August 2006 - 09:43 AM

Hi:

I am not sure you need to glue the cork to the gear, if I am not mistaken (I could be mistaken) it just rests between the two plates.

You can see if the clutch is slipping just by trying to move the scope with the motor drive cover off.

Also, how well balanced is the OTA, if it is not balanced top to bottom you will have problems...

Jon

#24 criterion

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Posted 13 August 2006 - 11:26 AM

I better go return the cork I bought, it has a self adhesive.

As for balancing, what is the procedure for that?

Thanks for all the help.

#25 Jon Isaacs

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Posted 14 August 2006 - 12:10 PM

>>>I better go return the cork I bought, it has a self adhesive.
-----

I wouldn't do that until you verify whether or not I am right... Just going on memory.

>>>As for balancing, what is the procedure for that?
----

There are two things you need to balance, one is the counter weight and the other is the tube itself end for end.

The counter weight balances the RA axis so that the force required to move the scope is small. The best way to do this is with the clutch loose and then position the counter balance it balances the scope. IF the scope is not reasonably well balanced, the clutch can slip.

Balancing the tube end for end is done by releasing the DEC wing screw and then moving the tube in the rings until it is balanced.

Hope this helps

jon


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