My RV-6 Restoration Project
Last updated : 07/27/2008
Back when I was still young, my parents decided to surprise me with an Criterion 6" RV-6 Newtonian Reflector for a present. Before then, I had been using an Edmund 3" Reflector and then "moved" up to the ubiquitous 4.5" Tasco Newtonian Reflector (which surprisingly is still being made today!). Needless to say, the Criterion was a "real" telescope to me, large optics, clock driven equatorial mounting, it had it all! Back in the early 70's, a 6" telescope was considered a moderate size telescope. Now here in the new century, anything less then a 16" is considered small with the 18" to 25" ones being a moderate size telescope!
The RV-6 that I had was a splendid telescope, it had excellent optics and I enjoyed it every chance I had to use it. However, that was short lived when less then 2 years later, it was stolen on Christmas Eve 1975. I decided not to replace it until I moved to my own house. That was 20 years ago. Since then I've had several 8" telescopes (Newtonians and Schmidt-Cassegrains), built an observatory and finally got a 10" LX200 a few years ago which I use for CCD work.
But, like your first love or your first car, I kept remembering that old RV-6 and I vowed one day to get another. Well, fortune finally smiled on me and I ended up buying one in Oct. 2000. I waited until my birthday in Nov. to open it up (my own special birthday present!). Based on the information garnered on the Dynascope web site, with a serial plate ID of M-RV6, this points to this telescope being a pre-1963 RV-6 (actual date unknown) which does make it a collector's classic.To my dismay however, the mount had been damaged in shipment. The saddle plate had been broken off.
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I was very disappointed because that night had promised to be a very clear night with Jupiter and Saturn high in the sky and I wanted to test the optics out to make sure they were okay. Well, I figured I could still mount it on the saddle plate as long as I was careful, so I tried it and I was glad I did! |
Even though the mirror coating was real thin (almost like looking through a window), the optics are superb! Typical of the Criterion mirrors of the late 50's and early 60's. I don't remember having better views of Jupiter and Saturn in years. Needless to say, this one is a keeper and deserves to be restored to like new or better then new condition.
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The clock drive showed all of it's 30 years and will require a fair amount of effort to restore. |
Restoration Objectives
Where required, restore
the RV-6 to like new or better condition for visual use only.
Mirrors should be
recoated with enhanced coatings.
Install Digital Setting Circles (this might prove difficult). Try to keep the RA encoder assembly contained within the RA clock drive case.
Darken and/or baffle the
tube to reduce reflections and enhance contrast.
Replace the power cord
with a grounded (3 plug) cord.
Replace the 6X30mm finder with an 8X50mm.
Test the effect of a fan ventilator to reduce tube currents.
Try to keep the total cost under $600.00! (This is going to prove not likely, since after I finish all the upgrades it'll probably be closer to $800.00)
Chronological Events ((Click on the thumbnails to see larger images)
November 5, 2000 - Telescope unpacked, discovered the saddle plate had been broken. General condition of the tube assembly was good though the mount was only fair with some surface rust on the exposed surfaces and in bad need of refinishing. Mirror cleaned and inspected. It had a very thin coat with many sleeks in the surface (but no scratches).
November 8, 2000 - Found a local welder that TIG welded the saddle plate back together again. Started claims process with UPS.
November 11, 2000 - Tore the clock drive assembly apart for inspection and cleaning. All the old grease had turned into a hard lacquer material, the cork clutch material was non-existent, most of the screws and bolts had rusted, the motor was very dirty internally and required a good cleaning. The worm gear showed signs of being forced at one time with several teeth bent. It was obvious that the mount had been caught out in the rain at least once in it's lifetime, probably more. I took the gear assembly apart and my friend Larry cleaned it all up and repaired the obvious damage.
November 18, 2000 - Mirrors packed up and shipped off to Spectrum Coatings for a 96% reflectivity coating. We started to take the mount apart for a through inspection and cleaning and have run into problems with frozen Allen screws.
November 25, 2000 - Larry and I finally got the RA axis disassembled. We ended up having to drill out several of the Allen screws. Some light corrosion was on the RA axis but not on the bearing surfaces. Overall, the condition of the bearings and shims seemed pretty good, so hopefully cleaning up the surface rust won't be too difficult.
November 28, 2000 - Picked up the materials to remove the old paint and refinish the mount. Started the stripping process but it will take some elbow grease and sandpaper to clean it up.
December 13, 2000 - Received the check for reimbursement for the incurred shipping damages.
March 23, 2001 - Well, a lot has transpired since the last entry. The mirrors came back from being recoated and I tested the primary mirror on my Foucault tester. The mirror is good to nearly 1/18 wave which confirmed the visual test I made when I got it. The mount was completely stripped down, the old paint removed, the clock drive repaired and the mount repainted. I only need to add some set screws to the collars and setting circles, install the circle pointers, replace the two plug AC cord with a three wire grounded one and the mount will be finished.
The tube was stripped down and repainted using Krylon Ultra-Flat black on the interior and epoxy white on the outside. The mirror cell and spider assembly was also painted with the Ultra-Flat black so they need to be re-installed and the basic scope will be ready to go again! I hope to get that accomplished over the Messier Marathon weekend and just might have it ready in time for that event (didn't make it).
March 25, 2001 - Repainting the tube is turning out to be a real challenge. It's all been painted except for a small area around the eyepiece focuser. Every time I try to paint that area, the paint crazes up. I suspect that the paint/tube/air in the garage is still too cold but I wonder why the rest of tube didn't do that?
April 5, 2001 - Tried to reinstall the spider assembly and found out I couldn't adjust the secondary mirror because the set screws had basically frozen in place. I ended up having to remove it (again) and strip it completely down using vise grips to remove the screws. My friend Larry tapped the adjustment screw holes to accept a slightly larger and longer screw and now it works fine. I also replaced the main mirror cell hardware with new brass screws and nuts and used some nice knurled knobs for the adjustment screws. I center dotted the main mirror and re-installed it and proceeded to collimate it. Using the knurled knobs made the job a lot easier to perform (no tools). In order to lock the declination axis, I tried to use a regular thumb screw, but found that it didn't give enough "grip" to be able to turn it down to lock the axis, so I welded a small piece of steel rod to the thumbscrew to make a lever and that worked fine.
April 6, 2001 - Except for some minor adjustments and clean up work, the RV-6 is READY! Except for the tube, the scope looks better then new. Now, to wait for some clear weather to give it a finally collimation and a real star test.
I've decided to hold off on installing the digital setting circles and the other modifications. I want to use if for awhile first!
April 19, 2001 - I didn't like how the secondary mirror adjustment worked, so I added tension springs to the adjusting screws. Now I don't have to worry about the "loosen one, tighten one" method of adjustment. Just turn the necessary screw the necessary way.
November 10, 2001 - I finally got tired of fighting with the original focuser and went ahead and purchased and install a JMI RCF-1 focuser. It went on with just a little work and makes a world of difference compared to the old one I'd certainly recommend one to anyone who uses an RV-6.
Using the RV-6
Performance wise the RV-6 doesn't leave much to be desired optically. Just the other night (11/07/01) I was observing Saturn with it and it looked just like a painting or a picture from a spacecraft. Detail was visible within the planets belts and the ring system was simply spectacular. The Crepe ring and Cassini's division was easy and Encke's division was visible when the air became very steady.
Lunar observing is equally enjoyable. When conditions permit, I routinely push the scope up past 350X (the highest I can go) without image breakdown and the amount of detail visible is astounding. I'm looking forward to viewing Jupiter this coming winter. The few views I've had of it this year was when it was low in the sky and not much was seen other then half a dozen belts though I could easily detect that Jupiter's Galilean moons are different sizes.
Deepsky observing with the RV-6 can be disappointing if you don't have dark skies and of course it doesn't gather nearly the amount of light that my 14.25" Dob does but the images through the RV-6 are pinpoint sharp with a dark and contrasty field of view.
Mechanically my RV-6 is typical of the "bargain priced" 6" f/8 Telescopes of it's period. The mount is usable, but I've had problems trying to get the clock drive adjusted to track properly but will continue working on it until it's working the way it should. It is kind of nice to be able to pick the entire scope up and move it around to another place in the yard as needed, something I can't easily do with the 10" SCT or 14.25" Dob so the RV-6 has become my "quick look" scope.
For those who have the opportunity to view through a restored RV-6.... DO IT!!!
And if you are fortunate to be able to own one I'm sure you won't be disappointed in how it performs.
Click on the following images to see them full size.
Clock Drive East side Equatorial Head West side Equatorial Head Tube and Clamps Serial Plate
Mirror Cell Adjusting Back in Service Equatorial Head JMI RCF-1 Focuser
Screws
Photography with the RV-6
While the RV-6 wasn't designed for long exposure photography (and really can't in it's original configuration) with the availability of inexpensive web cameras, taking photographs of the brighter solar system objects is well within it's capabilities. Just to see how it would do, I coupled the RV-6 with the Meade LPI camera to take some images of the Moon and Jupiter and for initial efforts came out I think very well. Click on the following images to see them full size.
For Christmas 2004, I received an Apogee GE Mount (clone of a CG-5) as a gift (well, I did ask for it!) so that I could mount a variety of different telescope OTA's on it, one of which was the RV-6. Shortly afterward I ordered the dual-axis controller from Orion which happened to fit perfectly. Overall I'm very pleased with the mount but have noticed a bit of a vibration damping problem which I suspect is related to the square aluminum tripod legs and I'll research that a bit further in the future but having the RV-6 OTA on a dual-axis controlled mount is real nice.
RV-6 on Apogee First image w/LPI M3 M57
Mount using the Apogee mount
Now after a further bit of research I came across the "Roboscope" site which is a nice web page and Yahoo group dedicated to adding the Meade© Autostar system to Vixen SP/GP and CG-5 clone mounts. After getting the parts, I'm going to see about retro-fitting a Meade© DS/Autostar controller to the mount for goto capability.
Autostar Update - April 7, 2005
Well, got all the parts put together and son of a gun....it actually works! Below are some pictures of the Autostar motors on the RA and Dec axis and a computer screen shot of the the telescope tracking on M13 (actually, it was in my basement and the telescope THINKS it's tracking M13, but good enough for the simulation!) I haven't taken the hybrid RV-6 out to a dark sky site yet, but in testing out the Autostar combination in my light polluted front yard with just about every light in the neighborhood on, it was nice to be able to have the telescope slew to what I wanted to see as opposed to me trying to star hop when the faintest star you can see is around 3rd to 4th magnitude. On the first night out with it (March 30, 2005), I managed to observe about a dozen Messier objects in less then an hour, some of which were right at the limit of visibility (I wasn't really dark adapted either) so it's nice to know I'll be maximizing my time looking at things rather then looking for them!
RA drive motor Dec drive motor Autostar tracking
April 18, 2005
I've had two opportunities to take the hybrid RV-6 out to observe, once at a regional star party and once for Astronomy day. At the star party, the telescope garnered a lot of interest because many people recognized the RV-6 tube assembly but did a double take at the mount. This was the first time I could take the telescope out in its new configuration to a reasonably dark sky site and it performed very well. Once I got that mount polar aligned and the Autostar system powered up, I spent the next 6 hours just going all over the sky and was pleased to see the telescope put every object I selected well within my 24mm Konig eyepiece FOV. During the course of the evening, I had several people stop by to take a look through the telescope (Saturn being the favorite) and had a couple of observers come by asking me to have the telescope point to some object they were having problems finding in their big dobs! We had a pretty good night to observe, and one of my favorite accomplishments was spotting the E and F stars in M42 with the RV-6. The best compliment I got though was from a friend of mine (who is also an award winner for the optical and special categories at Stellafane and an RV-6 owner himself) pronounce the RV-6/Apogee/Autostar combination "sweet" and "a winner" and stating that it compared very favorably to someone's AstroPhysics 6" refractor that was at the star party. Dave even wanted me to see if the RV-6 could split Sirius with it! We tried, but it was a little too low in the sky for us to succeed so that might have to wait until next winter. Shortly after 1:00 AM however, the dew won (my secondary dewed up) and I had to pack it up but it sure was fun while it lasted!
At my club's 2005 Astronomy Day event, again the RV-6 gathered a lot of interest, from the general public as well as my fellow club members that hadn't seen it yet. The first quarter Moon and Saturn were the two highlights of the evening for the public viewing Just for grins, I hooked up my Palm Pilot to the Autostar system and it was fun to have someone point at an object on the screen and have the telescope slew to it. Most people were impressed that the setup didn't cost thousands and thousands of dollars and wanted to know where they could get one like it. Overall, I'm very pleased with how the system functions and would recommend it to other RV-6 owners that wish to expand their systems fine optical performance to include modern technologies. For the RV-6 purists though, I have kept all the original components also so that maybe on nostalgia day I can put it all back together!
While any good 6" reflector is like any other, having a restored classic telescope is kind of special and even in this day and age the 6" f/8 Newtonian can still show you a lot of what's up in the sky and is very versatile for many types of observing interests. Having a telescope that's nearly as old as me connects me to the history of that telescope, wondering who else has shared the pleasure of looking through it over the years and did they aspire to bigger (if not necessarily better) telescopes and did they themselves enjoy it as a lifetime hobby? I also wonder how many other lives this particular telescope will touch in the future and hope that it continues to do so for a long long time. The saga continues.....
August 30, 2005
II decided to take the RV-6/Apogee/Autostar combination up to Stellafane, VT with me both to show it off and to have the chance to observe under darker skies then I normally see near my home. After the 11 hour trip up there, I decided not to set up at the Stellafane site but instead elected to set it up in the playground area of the camp ground I was staying at. While it was still hot and humid and hence the skies never got black dark, it was still enjoyable to see the Milky Way extend from horizon to horizon and make me wonder what it must be like on a GOOD night there. I set the RV-6 up and hooked up the Autostar to my laptop and spent the better part of 18 observing hours just exploring everything I could find in my planner (I use a software package called "Astroplanner" to plan and control my telescope. Very nice software, very reasonable price).
Overall I observed nearly 200 objects, mostly new ones I had never seen before but of course did stop by and see many of my favorites. I was reaching a little past 12th magnitude so limited my observing list to objects at that magnitude or brighter. Of course having a telescope set up in an open field like that did garner quite a bit of interest and in the course of the week I had several people stop by (some several times on different nights) to take a look through the telescope and most were suitably impressed with how the system operated but did cut into the observing time but it's enjoyable for me to be able to share the night sky with anyone interested.
So, overall the RV-6 performed very well as usual (except for the damn diagonal dewing up again and again...got to work on that) and it turned out to be a most enjoyable trip and experience.
Restoration Cost - Total to date
RV-6 Purchase $330.00
Shipping Costs $71.48
Welding Costs $50.00
Mirror recoating $109.20
Refinishing supplies $30.45
Refund for shipping damages -$63.09
Misc. hardware $5.48
JMI RCF-1 Focuser $66.00
Apogee GEM mount $160.00
Orion dual-axis drive motors $110.00 <----- (Sold these)
Meade Autostar Motors $35.00
Custom made motor brackets $182.00 <------(OUCH! But they are nicely made fitted brackets)
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Total to date : $1,086.52
Orion Motors -$80.00
Adjusted Total $1,006.52
Well, so much for keeping it under $600 but I'm not THAT far over my projected $800 costs and seeing how it averages out to a little over $200 per year, that's not all bad! However, I'm afraid I'm still not finished yet. The RV-6 has such a nice optical system, I'm sure it'll be interesting to see how it works as a photographic platform....now, what do I need to do next?
