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Equipment Discussions >> Classic Telescopes

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe
      #5637116 - 01/22/13 03:07 PM Attachment (81 downloads)

Taunting me for the past couple years has been this little Cave 8" sitting by the entrance of my favorite used telescope shop, Stellar Visions, in downtown Tucson. It kept saying "Take me home! Buy Me!" every time I visited. So, since lately, it's been kind of dry for any kind of Classic around here, I made up my mind Saturday to make a deal and go get it.

Once at the shop, we rolled it on out from behind a bunch of other scopes to pull the mirror and have a look. I wanted to be sure it was a Cave mirror before I bought it. Turns out it was made in 1972, with a 35 1/4" FL - f/4.4. For a long time, I thought this was an f/5 scope, but this is actually the Cave 8" f/4.5 RFT Lightweight Deluxe model as advertised in the early 70's catalog. It was also advertised as a Dual Capability scope - an RFT at f/4.5 and f/14 with a barlow. The only eyepieces or accessories that came with this one was an older Japan Teleview 40mm Plossl.

The 38" long fiberglass OTA sits on a Lightweight Deluxe mount with Clock Drive, 1" shafts and rotating rings. The scope is painted the grey and wrinkle black scheme. There are no Cave Labels on the OTA or mount and no signs that there every were any.


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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5637124 - 01/22/13 03:09 PM Attachment (38 downloads)

The Focuser is actually pretty nice, a 1 1/4" Carle II Photo/Visual that has a push/pull adjustment as well as fine focus. With a 32mm Brandon, the focus point is out far enough that I think the in-focus travel will allow a camera to be used. I have not tried a camera on it yet.

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5637129 - 01/22/13 03:10 PM Attachment (26 downloads)

The Finder is an unbranded 50mm with a 1 1/4" diagonal, but no eyepiece.

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5637131 - 01/22/13 03:11 PM Attachment (29 downloads)

The Tube End Rings are the thicker type from that time period. The Secondary is somewhere between 2.1" and 2.4" - I haven't taken it out to see what the size really is. The inside of the tube is really dirty and coated with dust, just like the rest of the scope.

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5637132 - 01/22/13 03:12 PM Attachment (34 downloads)

Nice 4" Magnusson aluminum setting circles with aluminum block pointers.

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5637133 - 01/22/13 03:12 PM Attachment (26 downloads)

On the top of the rotating rings are what look like mount holes for guidescope rings.

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5637134 - 01/22/13 03:13 PM Attachment (23 downloads)

The Pier Cap has 4 set screws (2 on either side) to keep the latitude adjustment in place. I've seen this on the heavier mounts before, but not on a Lightweight.

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5637136 - 01/22/13 03:14 PM Attachment (44 downloads)

The mirror was coated in dust. Since it was already removed at the store, I went ahead and cleaned it up before re-installing it, but as you can see, the coating is nearly gone! The good news is that I found a place in Tucson, Composite Mirror Applications, that coats smaller mirrors with about a 1 week turnaround time!

This is a photo of the mirror surface after cleaning - that's not dust, that's light passing through!


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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5637141 - 01/22/13 03:17 PM

The next day, I started to collimate it (it was way off), but the secondary would not budge! So, I zoomed up to Ace Hardware, got some fasteners and stuff and did my non-destructive collimation screws mod with it as well as replaced the 5/16" threaded rod and re-installed it. Then, rolled it out of the garage and plugged in the Clock Drive. But, no motor sound! So, I pulled the Clock Drive cover off and sure enough, it's a dead motor that I'll have to deal with later. But I was able to get a nice sharp view of the moon from center to edge, even though probably more than 1/2 the light was passing through the bad coat on the primary.

I plan to start overhauling this one soon, keeping the original paint scheme and hopefully repair the motor since replacements are hard to find. The OTA can always be set on my 8" f/7 Lightweight Deluxe mount for photography. At low power, with about a 2-degree FOV, a Clock Drive is nice, but not mandatory for wide-field observing.


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Dave M
Postmaster
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Reged: 08/03/04

Loc: Ohio
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5637164 - 01/22/13 03:30 PM

Nice scope, Congrats!

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mdowns
Pooh-Bah
*****

Reged: 06/12/10

Loc: Englewood,FL
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Dave M]
      #5637262 - 01/22/13 04:18 PM

How much did you give for this one? I'm jealous!

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mustgobigger
Postmaster
*****

Reged: 06/12/07

Loc: Michigan
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: mdowns]
      #5637452 - 01/22/13 05:56 PM

nice dan,
i didn't know cave made mirrors that fast.
learn somthing new...


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droid
rocketman
*****

Reged: 08/29/04

Loc: Conneaut, Ohio
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: mustgobigger]
      #5637514 - 01/22/13 06:35 PM

Given that you said it was focuser made for photo visual, is it usable for visual work???

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: mdowns]
      #5637607 - 01/22/13 07:38 PM

Quote:

How much did you give for this one? I'm jealous!




Well, kind of close to Retail But, not really because I traded in a Meade ETX90 and Tripod to get the cash side of it down. Of course any time I get a scope, my wife must get something too, so it's hard to say how much I had to give


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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: droid]
      #5637631 - 01/22/13 07:59 PM Attachment (23 downloads)

Quote:

Given that you said it was focuser made for photo visual, is it usable for visual work???




It works for both. Since it's not ready for photography yet because of balance, I pointed it horizontally towards the Santa Rita mountains, about 20 miles from here to get an idea of eyepiece and camera focus travel. Overall, the out-focus is a little over 4" and in focus is 7/8". In the picture, you can see where focus is for visual and photo. There's about a 1/2" to spare with the camera. I will run the tube layout through the Newt program soon to get an idea of any vignetting that might be going on.


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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: mustgobigger]
      #5637638 - 01/22/13 08:01 PM

Quote:

nice dan,
i didn't know cave made mirrors that fast.
learn somthing new...




Thanks Brian The catalogs show a whole lineup of f/4.5 scopes, but I have know idea how may they made.


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gelkin
Pooh-Bah
*****

Reged: 09/22/10

Loc: Western, MD.
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5637677 - 01/22/13 08:28 PM

Looks like a great Cave project. Congrats Cave master. Love the Magnusson circles. Wish my lightweight had them. Interesting how there are 2 counter weights. Are they smaller than the usual one weight on most?

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PiSigma
Carpal Tunnel
*****

Reged: 10/14/09

Loc: North Carolina
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5637744 - 01/22/13 08:58 PM

Sweet Dan.

Take a look at the April 1972 S&T Cave ad. It shows this OTA on a heavy duty mount (and even with the 360 degree dec drive). It also shows a guide scope on very high mounts on the rotating rings.

My Lightweight Deluxe doesn't have any set screws to hold the latitude adjustment. It actually holds just on the clamping force between the pier cap and RA shaft housing.

I'm curious about the paint scheme. I thought when they went to the grey and black scheme it was actually a sort of pewter silver and black like my '74 Model B and not the earlier equipment grey. This is the first one I've seen that is equipment grey and black.


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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: gelkin]
      #5637754 - 01/22/13 09:02 PM

Quote:

Looks like a great Cave project. Congrats Cave master. Love the Magnusson circles. Wish my lightweight had them. Interesting how there are 2 counter weights. Are they smaller than the usual one weight on most?




The OTA weighs in at about 28lbs and each of the counterweights are about 14lbs. With the short Dec Shaft, I guess the extra weight is needed to counterbalance the missing guidescope and it would also work with a camera. Normally, a longer shaft with less weight would be better since that adds up to less weight overall. Remember the weight X distance = weight X distance thing. If there's not a lot of distance on the Dec Shaft for counterweight travel, then more weight is needed for less of a distance to counterbalance the OTA and what's on it.


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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: PiSigma]
      #5637861 - 01/22/13 10:09 PM

Quote:

Sweet Dan.

Take a look at the April 1972 S&T Cave ad. It shows this OTA on a heavy duty mount (and even with the 360 degree dec drive). It also shows a guide scope on very high mounts on the rotating rings.

My Lightweight Deluxe doesn't have any set screws to hold the latitude adjustment. It actually holds just on the clamping force between the pier cap and RA shaft housing.

I'm curious about the paint scheme. I thought when they went to the grey and black scheme it was actually a sort of pewter silver and black like my '74 Model B and not the earlier equipment grey. This is the first one I've seen that is equipment grey and black.




I took a look at the April 72 S&T ad - noted that the Finder rings are painted that grey color instead of black. I think the guidescope rings were higher so they could clear the obstructions from the Finder and Focuser. It doesn't look right to me, and with the guidescope that far away from the center of gravity, it would require more weight on the Dec shaft for balance. Also, in the ad, the Guide Scope rings are black. Looks like it's just barely fitting in there too! From my experience with a 60mm f/15 guidescope and film photography and what looks like a 50mm f/10 or so guidescope in the ad, that would have been really hard to work with - finding a guide star near the object to photograph, centering it under high power and doing a long exposure would have taken a good 30 mins or so to setup! Ah, the old days!

When I bought my 75 Lightweight Deluxe, I thought I was getting what was in the catalog photo - grey and black with 4" circles, but much to my surprise, it was the pewter and black scheme and 6" circles instead - the newer design. That was alright by me


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turk123
Pooh-Bah
*****

Reged: 07/09/10

Loc: N.E. Ohio
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5637891 - 01/22/13 10:29 PM

Wow! Outstanding Dan. Perfectly balanced size for a large scope. You have too many scopes, want to sell it????

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Rich (RLTYS)Moderator
Post Laureate
*****

Reged: 12/18/04

Loc: New York (Long Island)
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5638281 - 01/23/13 06:14 AM

Quote:

The 38" long fiberglass OTA sits on a Lightweight Deluxe mount with Clock Drive, 1" shafts and rotating rings. The scope is painted the grey and wrinkle black scheme. There are no Cave Labels on the OTA or mount and no signs that there every were any.




Beautiful scope. I still have the tube assembly for mine (sold the mount years ago, dumb, dumb me ) which measures 40" in length. I guess a slightly longer focal length. I also remember only a single counter weight. Good luck with yours.

Rich (RLTYS)


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Grava T
Pooh-Bah
*****

Reged: 06/18/08

Loc: Quebec, Canada
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Rich (RLTYS)]
      #5638426 - 01/23/13 08:50 AM

Nice telescope Dan. You should be able to get some nice widefield views with that baby.

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Grava T]
      #5639805 - 01/23/13 11:53 PM

I talked with the owner of Composite Mirror Applications in Tucson and am setting up to have this mirror as well as my 8" f/7 and the Horsetrail Cave mirror stripped and recoated there next week. It costs a wee bit more but the turnaround is 1-2 weeks and there's no risk of damage from shipping.

It'll be kind of interesting to bring in these old school 40 year old mirrors to a high tech composite mirror/telescope making place. I'll bring a camera and try to get them to let me take a peak at the scopes they are making. Take a look at their website, it's pretty cool stuff!


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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5673221 - 02/10/13 10:40 PM Attachment (11 downloads)

It was bright and sunny today here in Tucson, a little cold, but I managed the 50 degree temps okay So, I commenced to take the scope apart and get the mirror ready to go for recoating at Composite Mirror Applications later this week.

Jon had mentioned earlier that the color scheme was unusual, and he was right, the mount used to be pewter and wrinkle black at one time and somebody painted over with a grey color.

As you can see, they did a mask-n-paint instead of taking all the mount apart and painting it. Surprisingly, they did not even remove the Dec Pointer, which would have been easy. Here you can see the original paint beneath the pointer. (I sure do like my Canon 3Ti)


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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5673228 - 02/10/13 10:43 PM Attachment (11 downloads)

More evidence on the RA Shaft Housing Flange. This part was a bear to remove - it was gouged up by the set screws and fit very tight in the Pier Cap. You can see the Pewter Paint on the edge of the flange and the obvious grey paint line ending above the center hole.

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5673233 - 02/10/13 10:47 PM Attachment (10 downloads)

The inside of the Pier Column also had some Pewter Paint over spray, and a little rust. Thankfully, none of the fasteners gave me a hard time due to too much corrosion - the legs came off quite easily. Other parts? More on that later!

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5673244 - 02/10/13 10:51 PM Attachment (10 downloads)

This is the Dec Shaft Lock Knob. As you can see, the underside has its original Black Paint while the exposed sides are painted grey.

This part was difficult to remove because, in the past, the knob had been over tightened and the softer brass mushroomed out against the steel Dec Shaft. It would not easily unscrew from the drilled and tapped 1/2 or so set screw that it screws in to. But, with a little persuasion it eventually came out.

Now, this is supposedly a 1972 model. The threaded rod is all brass and 1/4" diameter. Later models are 3/8" steel with a bras tip. Hmmm.

Edited by Datapanic (02/10/13 11:13 PM)


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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5673249 - 02/10/13 10:55 PM Attachment (12 downloads)

I thought for sure that I would find Pewter Paint on the outside of the Clock Drive Housing Backplate, however when I pulled it off, I found the machinist blue stuff instead! It also seems that there is only one coat of grey paint and I didn't find any evidence of Pewter Paint on this piece anywhere.

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5673261 - 02/10/13 10:59 PM Attachment (13 downloads)

What really got me going on this Paint Scheme was the Rotating Rings. First, the adjusting set screws are 3/8-24 (fine thread). The newer models are 3/8-16 (coarse thread). Also, the outer edges of the outer rings are not as beveled as the later model rings.

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5673266 - 02/10/13 11:03 PM Attachment (8 downloads)

I thought for sure that on the inner side of the Outer Rotating Rings that I would find some Pewter Paint, judging by the rest of the paint job, but the paint there is grey! It gets kind of confusing because the tapped holes for the missing Guide Scope Rings go all the way through, which means when they were tapped, the rings had to have been removed in order for the tap to thread the holes all the way through. But, no Pewter Paint and, based on the Dirt Factor, no indication that the scope was every taken apart before - lots of metal filings were found.

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5673273 - 02/10/13 11:11 PM

So to me, it doesn't make sense. If whoever painted over the Pewter Paint didn't take anything apart to paint it, why are the inside of the Rotating Rings grey? Surely if they didn't want to remove the single bolt holding the Dec Circle Pointer they would not have wanted to take the Rotating Rings apart!

I have a theory. Two part, actually.

First, this telescope was assembled on a Friday Afternoon.

Second, this telescope was built very near the time when Cave switched their color scheme from the Grey/Black to the Pewter/Black combinations. I think the OTA was originally grey and the Mount was originally (or mostly) pewter.

So the question that will never be answered, did the mount get painted at Cave to quickly get it out the door in matching colors or did the original owner receive it and paint it himself afterwards. This scope came from consignment from the original owner; I'll try and find out.

As it is now, the entire scope is all apart, ready for cleanup and painting. Not sure what color though! The mirror will be back from coating in a couple weeks. I need to inventory all the fasteners and order stainless versions for replacements. -- note that I always save the originals.

Edited by Datapanic (02/10/13 11:14 PM)


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dgreyson
professor emeritus
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Reged: 11/06/12

Loc: South Carolina
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5673351 - 02/11/13 12:17 AM

When I stripped the paint on my 12" F4.5 cave the mount had originally been flat black it seemed, the rings were grey, dunno what the support color used to be.

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PiSigma
Carpal Tunnel
*****

Reged: 10/14/09

Loc: North Carolina
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5674791 - 02/11/13 08:57 PM

Hi Dan,

I don't know about the Friday afternoon thing but I agree about the second part of your theory. This scope was made right at the time Cave was switching from the all grey scheme to the pewter/black. There certainly could have been a few 'hybrid' paint schemes going out the door at this time. Who did the overpaint on the pewter parts? Good question. It will be interesting if you can find out anything from the original owner.

What is also unusual about the rotating rings is that your inner rings are black where on the grey scheme they are usually the same grey as the outers. All of my Caves have 3/8-24 thread on the adjusting screws except my '74 Model B, which is 3/8-16.

BTW, my '70 Lightweight Deluxe also has a 1/4" diameter threaded brass screw on the dec lock while my 1974 Model B Deluxe is 3/8". Perhaps the 1/4" is only on a Lightweight?


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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: PiSigma]
      #5674837 - 02/11/13 09:32 PM

My 75 Lightweight Deluxe has a 3/8" Dec Lock...

I also think they stopped making the 4" Magnussen Setting Circles around that time.

I sent an email off to Frank at Stellar Visions to get in contact with the original owner and get the scoop on the paint job.


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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5676765 - 02/12/13 11:06 PM

Today I brought (avoid the word DROPPED) the mirror off at Composite Mirror Associates to be recoated. Originally, I was going to bring this mirror, my 75 8" f/7 and the Horsetrail Cave mirror all in for recoating at the same time, but fear moved in - all three of my Cave mirrors in for that work all at the same time!? No way! Bob Romeo, the CEO there told me that it would be about a week, I told him that's fine since I need to order new fasteners and repaint everything anyway. It was a cool place to visit, I'll post more here on the other Cloudy Nights Thread: The Future Today Part II: CF MIrrors

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5689470 - 02/19/13 06:47 PM Attachment (11 downloads)

And 1 week later - the mirror was ready! So I picked it up and got to see it on the their optical test bench, which was pretty cool!

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5689474 - 02/19/13 06:49 PM Attachment (12 downloads)

It has a good figure but not sure how to read the Wavefront data from the Imagine Optic Haso 3 program. Maybe someone here does?

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Datapanic
Carpal Tunnel
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5689481 - 02/19/13 06:54 PM Attachment (10 downloads)

The Ronchi Diagram showed a good figure as well.

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Jeff Phinney
super member


Reged: 02/20/13

Loc: CA
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5691029 - 02/20/13 02:37 PM

Nice classic!

I'm not sure(which is to say, I don't recall) what motors Cave used on those mounts, but maybe you might find a suitable replacement here.

http://www.hansen-motor.com/ac-synchronous-motors.php?mm_campaign=e860a03aaeb...


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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Jeff Phinney]
      #5691519 - 02/20/13 06:46 PM

Quote:

Nice classic!

I'm not sure(which is to say, I don't recall) what motors Cave used on those mounts, but maybe you might find a suitable replacement here.

http://www.hansen-motor.com/ac-synchronous-motors.php?mm_campaign=e860a03aaeb...




After taking the mount apart and removing the motor, I found that it does indeed work!

Welcome to Cloudy Nights Classics, Jeff!


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Jeff Phinney
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Reged: 02/20/13

Loc: CA
Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5691701 - 02/20/13 08:27 PM

Well that certainly makes things much easier.

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Jeff Phinney]
      #5697455 - 02/23/13 10:16 PM Attachment (9 downloads)

After thinking about what color scheme this scope should be, I decided to just go for what it currently has and take it from there. Whoever and wherever it was originally painted and/or possibly painted later by the owner, I'll probably never find out, so, it's going to be Gray and Wrinkle Black. I'll follow the the usual scheme with the legs, pier column, RA and Dec shaft housings, clock drive backplate and outer rotating rings all painted gray. The pier cap, cradle, inner rotating rings, clock drive housing, shaft collars and knobs will all painted wrinkle black.

I found a nice gray with Ace's Rust Stop Medium Gray Gloss. I applied 2 coats of light gray primer and then 3 coats of the gray. It comes out as more of a greenish gray rather than a blueish gray, which was what I was after. Not too glossy either - somewhere between a satin and gloss shine.

Sky it blue


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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5697473 - 02/23/13 10:24 PM Attachment (5 downloads)

I've become much better with the Eastwood Wrinkle Black. It requires 2 thick coats applied about 3 minutes apart. The quality of the wrinkle effect depends on the temperature and humidity as well as the thickness of the 2 coats. If the coats are too thin, the wrinkles wont come out during the cure, and if the time between the coats is too long, then there will be flat areas along with long wrinkles. Here in Tucson, the humidity is usually pretty low, so I've shortened the time between coats to about 2 1/2 minutes. Here's the Pier Cap about 2 hours after the application. It can take a good 12 hours for the wrinkles to fully come forth and another day before I even handle the part after it's painted.

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gfeulner
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5697496 - 02/23/13 10:40 PM

0.113 pv is about 1/8th wave. Gerry

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: gfeulner]
      #5697522 - 02/23/13 10:58 PM

Quote:

0.113 pv is about 1/8th wave. Gerry




Yup, kind of disappointing, but not surprised. I had a long trail of PM's with DavidG about the test results and here's a summary (paraquoted):

The 0.113 PV is at 635nm which is in the red and the eye is most sensitive to around 540nm in the green. Since green light is shorter in wavelength than red the wavefront error is worse at shorter wavelengths.

The wavefront at the eyepiece is 2x 0.113 PV, or 0.226 PV, and 1/4 wavefront is 0.250...

On the Ronchi test, the images show some problems. They are not very good. The lines should be evenly and smoothly bowing. They should look like this (( )) and the closer you get to focus like this () On this mirror they start at the edges bowing inward then change direction and bow outward. This shows the figure is not smooth and this is also confirmed in the computer image showing the blue ring at around the 70% zone. From what I can see the mirror is just under 1/4 wave. Bob Romeo, the CEO at Composite Mirror Associates also mentioned this - the mirror has a turned edge.

It's interesting to note that in the series of Cave Catalogs out there, only in the early Red Catalog did Cave ever claim 1/10 wave accuracy in his mirrors. Subsequent Pink and the series of Blue Catalogs changed the wording to "highest quality". All Catalogs state the secondaries are 1/10 wave. Thanks goes to Jon "Pisigma" who probably has all the catalogs for following the claims of mirror quality as stated in the catalogs.

I intend to do a little more research on the 1/10 wave and "Highest Quality" claims. I have the '75 8" f/7 mirror at the shop now getting recoated and tested along with an RV-6 mirror and the Horsetrail Cave mirror, which might not be a Cave Mirror, but that might actually be a good thing! We'll find out next week.

Now I know a lot of people are going to say that Cave only made exceptional mirrors. Heck, they even made mirrors for Questar and the Government! Hmmm, what was that saying about "close enough for government work"?

I would like to hear from anyone who has had their Cave mirror on the bench and their test results.


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tim53
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5697547 - 02/23/13 11:15 PM

Well, I haven't had my Cave mirrors tested. Probably should. But I did a shootout between my Cave 8" f/7 lightweight deluxe, the OC 8" f/6 Connoisseur, and the OC 8" f/6 Discoverer on Saturn. The discoverer was not very good, but the mirror might be pinched in the cell. Both the Connoisseur and the Cave were very good, though, with the Cave being ever so slightly better than the OC. I really wanted the OC to "win" because it's such a better telescope over all, with the 1.5" shaft mount and stuff.

My 12.5" f/7 Cave is also very good. Finest detail on Jupiter I've ever imaged. Real potential there.

My 10" f/16 Cave DK has Tinsley optics, so maybe it "doesn't count". I should probably test it, because all I've done is a visual assessment, and it might not have been performing up to snuff those couple nights.

My 6" f/8 Model A Deluxe needs a recoat worse than any Newt I've ever had! So the low contrast in it might be due to the awful coatings.

I would definitely not be afraid to refigure a mirror, even a Cave, if it wasn't a killer already. I'd bring it to a mirror class, like the one in Delaware next month that Dave works on, if it were me. Those classes are a blast!

-Tim.


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actionhac
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: tim53]
      #5697643 - 02/24/13 12:25 AM

My 6"f8 Student Deluxe has a very good mirror and it was made March 1972, 238 mirrors before yours Dan.
I wonder how far Cave Optical was from the beach in Long Beach. Just thinking as the weather got nicer and with the glass store front and a sidewalk right there maybe Tom had more than one figure on his mind.

Robert


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tim53
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: actionhac]
      #5697659 - 02/24/13 12:49 AM

Well, the Cave shop was pretty far from the beach!

-Tim.


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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: tim53]
      #5711746 - 03/03/13 11:38 PM

That would be cool if you could bring the best mirror over to David G's workshop and put it on the bench, Tim. I also wouldn't be concerned about re-grinding the glass of a Cave Mirror to get a better figure. But since this one has been recoated, I don't think that's going to happen any time soon!

Cave's shop was far from the beach, but there is that mystery Corvette parked in front of the shop from those old photos, so maybe he took a cruise on Fridays?


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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5711754 - 03/03/13 11:42 PM Attachment (5 downloads)

Meanwhile, restoration continues... Mostly stripping off the old paint, applying primer and putting on the new coat of either "Instrument Gray" or Black Wrinkle Finish. It's a lot of work to do this - Aircraft grade paint stripper, sometimes two times, sanding off rust and blotches of paint, refinishing the Dec and RA shafts, and just the time it takes to apply a good coat of paint that will last a while is definitely a trial of patience. On the table are most of the major mount parts that have been reconditioned over the past 3 weeks. Once they have cured completely (a minimum of 1 week) then I'll start to put it back together. Can't wait!

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5711774 - 03/03/13 11:58 PM Attachment (6 downloads)

Another shot of the staging area for the mount and rotating rings before assembly. The Wrinkled Black application has been the most challenging - unless done right, the wrinkles come out uneven and I start over again - stripping, priming and spraying it on once more. It takes a good 12 hours for the wrinkle paint to fully cure. I do each piece individually...

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5711777 - 03/04/13 12:01 AM Attachment (3 downloads)

There are quite of few fasteners - nuts, washers, bolts and so on that put the scope together. I found it much easier to measure and inventory every one of them and put that info into an excel spreadsheet. I then place the order for those fasteners and when they get delivered, inventory them again, checking off each one on the spreadsheet and labeling each ziplock bag for which the fasteners are intended for.

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5711792 - 03/04/13 12:19 AM Attachment (2 downloads)

Although the tube was already in very good shape to begin with, it still needed refinishing to match up with the fresh paint job of the rest of the scope. The fiberglass tube is waterproof, so with that in mind, after cleaning it up with some 409, I commenced to lightly wet sand by hand it with 600 and 1500 grit sandpaper, to smooth out any blemishes. This also helps subdue the spider cracks that tend to happen on the finder ring and mirror cell mount holes when they get bumped or tightened up too hard. Later, rubbing compound and a coat of wax will finish it off to a lustrous finish.

Wet sanding with such fine grades only takes off microns from the surface and does not intrude upon the coating enough to make a difference.

Any deeper gouges left are part of the assembly and covered up by the original parts that were there. In this photo, that would be the focuser edges, spider washers and finder base.


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Datapanic
Carpal Tunnel
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5711802 - 03/04/13 12:28 AM Attachment (4 downloads)

The inside of the tube was weathered with dust and grime and even after washing it, there was still a dull flat black that would not be acceptable for contrast performance. So, I coated it with Krylon Ultra Flat Black. But before applying the paint, I used blue painter's tape to cover up all the holes so that the black paint would not seep onto the white finish from the inside. It turned out to be overkill after I finished, but better to be cautious than loose time in the restore.

This tube is so short - only 38" long, that I was able to reach inside it with the rattle can of paint and get a good coating all the way up and down. The ends of the tube were not hit with paint very well, but that doesn't matter since they will be covered up by the aluminum end rings.


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Datapanic
Carpal Tunnel
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5719738 - 03/08/13 12:49 AM Attachment (2 downloads)

The mount and tube are shown in this photo. First, the front end of the mount is complete. The RA and Dec Shafts have been refinished and shined up, along with the Dec Circle and its pointer. The Tube has been finished with a rubbing compound and wax. The Inner Rotating Rings have been reinstalled on the tube.

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5719745 - 03/08/13 12:57 AM Attachment (3 downloads)

The Inner Rotating Rings can be a bear to reinstall if the orientation is not noted before taking the scope apart beforehand. On this scope, I made pencil marks, small punch marks on the inside of the rings and even paper and pencil notes for the correct position of the rings as well as which ring was the upper and which was the lower on the tube when I took the scope apart. This is absolutely essential to do because the drill holes on the Inner Rings to the Tube are not perfectly 90-degrees apart; the rings only go back on one way.

So, after letting the wrinkle paint cure for a week, I slide the rings back on, used tooth picks to hold and verify that all the holes line up before fastening them back on.

It is important to be gentle with the fasteners and not force anything - because the tube is 40 years old and it can easily be spider-cracked if anything is forced against it!


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Datapanic
Carpal Tunnel
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5719747 - 03/08/13 01:01 AM Attachment (4 downloads)

The old tube still has some damage that we just have to live with - here is the worse of it where one of the finder rings mounts to the tube...

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5719754 - 03/08/13 01:07 AM Attachment (4 downloads)

When reassembling the scope, after painting, it's very important to clean out all the old threaded holes before putting things back together. Not only new paint, but any kind of crud can interfere with installation of new fasteners and a smooth calibrated elbow torque amount during reassembly. Here is a tap (3/8 - 24) being run through one of the Outer Rotating Ring Adjustment Holes before it is attached to the already installed Inner Rotating Rings...

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5741901 - 03/18/13 10:02 PM Attachment (6 downloads)

When putting the Outer Rotating Rings back on, I try to evenly space the adjustment so the gap between the outer and inner rings are about the same all the way around and so that there is a smooth, but not too loose amount of tension when rotating the outer rings. Later, when performing celestial alignment the first time on the mount, there is a method to follow that will use these set screws to put the optical axis perpendicular to the Dec Shaft.

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5741908 - 03/18/13 10:05 PM Attachment (5 downloads)

Once both Outer Rings are installed, the 3 spacer rods are then installed to complete the Rotating Rings.

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5741927 - 03/18/13 10:15 PM Attachment (7 downloads)

Here's how I get the Tube Ring to Cradle Studs nice and tight without marring them up. This method also works great during disassembly too.

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5741947 - 03/18/13 10:27 PM Attachment (8 downloads)

Next, I cut strips of cork and punch a hole in the middle for the studs to fit through. The strips are longer than needed and trimmed to fit after the OTA is installed. I used contact cement to adhere them to the cradle. The Cave 8" f/7 Lightweight Deluxe was like that new from the factory, so I have been doing this method for all my restores.

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5741958 - 03/18/13 10:31 PM Attachment (7 downloads)

Cave Clock Drives have been covered quite a bit here on CN, so here's the assembled drive for this scope. The original power cord and plug was in good shape, so I reused it.

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Datapanic
Carpal Tunnel
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5741962 - 03/18/13 10:35 PM Attachment (6 downloads)

I used all new brass fasteners for the Dec Shaft Lock Knob. 1/4-20 Brass Threaded Rod was cut to size and beveled on the end. This was a problem when I was removing this piece because somebody had put so much force on it that the tip had mushroomed and was difficult to remove. The Dec Shaft Lock Knob must be removed before the Dec Shaft Housing Bolt to the RA Shaft can be accessed...

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5741978 - 03/18/13 10:40 PM Attachment (5 downloads)

Finally, the OTA is placed on the mount. The excess cork on the cradle is trimmed to fit. The Clock Drive Housing, polished setting circles, counterweights and collar rings are all installed. All that's left is to install the Mirror and Mirror Cell, Secondary, Focuser, Finder and End Rings!

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5741984 - 03/18/13 10:44 PM Attachment (7 downloads)

Another view. I kinda like this hybrid transitional period color scheme The contrast between Wrinkle Black, Gray and White with a little Brass, Stainless and Black Oil Finish Alloy Steel fasteners makes the whole thing look nice

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5741997 - 03/18/13 10:54 PM Attachment (4 downloads)

The Mirror Cell was refinished with flat black and new cork along with new stainless fasteners. I kept the original thread teflon adjusters since they were in good shape and I didn't have any extra material laying around to make new ones!

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Datapanic
Carpal Tunnel
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5742001 - 03/18/13 10:57 PM Attachment (6 downloads)

Next, the Mirror is carefully mounted in its cell...

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5742007 - 03/18/13 11:02 PM Attachment (6 downloads)

And Then, I went Camping! This time, I didn't bring any scopes for observing, But did see the comet with binoculars one night while at Picacho Peak State Park.

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dgreyson
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5742087 - 03/19/13 12:06 AM

It's coming along great. I definitely needed a tap and die set, a lot of my threads were in bad shape when I got it.

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: dgreyson]
      #5742640 - 03/19/13 10:53 AM

RonE500 mentioned in his 8" Edmunds Restoration thread that he used cleaning taps and dies. I never knew they made specialized taps and dies for that purpose. I do have a good set of popular sizes from #4 to 1/2" in coarse and fine thread though. They do get expensive for the larger sizes.

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dgreyson
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5742694 - 03/19/13 11:19 AM

Most of the Cleaning Taps I've seen were designed to clean and or re-thread damaged or jammed pipe threads. Taps also come as bottoming Taps for threading holes that do not go thru , and Plug which are best for thru holes and Taper, the most common style, to start the thread square with the surface .

I just use the common taper ones to do everything and usually can just drill the blind hole slightly deeper to get enough thread to hold.


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gelkin
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5743209 - 03/19/13 03:19 PM Attachment (3 downloads)

Dan that looks superb. Excellent work as always. I'm kind of liking that color selection too. Love your circles especially.

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: gelkin]
      #5750382 - 03/22/13 06:51 PM

Thanks Gerald

On your 8" Lightweight Deluxe - is that a factory tangent arm? How do you keep the Dec Circle from hitting the Pier?


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dgreyson
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5750469 - 03/22/13 07:48 PM

my dec dircle was hitting the pier too. I just put another collar above it to space it down and it clears fine now.

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: dgreyson]
      #5750486 - 03/22/13 07:58 PM Attachment (2 downloads)

Here's the finished Dec Circle and Pointer area...

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5750489 - 03/22/13 08:00 PM Attachment (2 downloads)

The Clock Drive area. All the brass parts were polished up as well.

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5750495 - 03/22/13 08:03 PM Attachment (1 downloads)

I refinished the Carle Photo/Visual Focuser as well. Here it is at focus in visual mode - way out there!

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5750503 - 03/22/13 08:06 PM Attachment (2 downloads)

And the Finder Rings. (Just ignore that off-brand finder scope - still working on the original!)

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gelkin
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5750717 - 03/22/13 09:36 PM Attachment (5 downloads)

Quote:

Thanks Gerald

On your 8" Lightweight Deluxe - is that a factory tangent arm? How do you keep the Dec Circle from hitting the Pier?



Dan
I'm glad you forgot the times i pestered you for tanget arm measurements. I made that one. Because of it i made myself a dec circle problem too. To fix it i also made a longer dec pointer to allow the circle to be lower on the shaft. details here. I just can't leave well enough along.


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bremms
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: gelkin]
      #5750738 - 03/22/13 09:46 PM

That is nice resto work. Need to find myself a Cave, Always wanted a 10" F6.

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: gelkin]
      #5750741 - 03/22/13 09:48 PM

Doh! And that was only 2 years ago. I'm getting old.

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gelkin
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: bremms]
      #5750747 - 03/22/13 09:50 PM

I'm longing lately for a 10 or 12 in Cave myself. After seeing Tims huge mount and 12 in i'm not sure if anything else will satisfy.

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gelkin
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5750750 - 03/22/13 09:53 PM

Quote:

Doh! And that was only 2 years ago. I'm getting old.




Oh how i feel your pain.


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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: gelkin]
      #5750798 - 03/22/13 10:18 PM Attachment (7 downloads)

Here's the Finder. I'm not sure who made it as there are no markings on it at all. It is 50mm and has a helical focus ring and about 3/4" of travel. The diagonal also has no markings and is required to get focus. It did not come with an eyepiece, but I have a few lying around that could be used for that purpose - 1.25". It seems to be high quality but has a little bit of play in the focus.

Edited by Datapanic (03/22/13 10:20 PM)


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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5936649 - 06/23/13 03:51 PM

So last week, I did a field test and that finder is now in my "Don't Like It" category. First, the thing is nearly twice as heavy as a standard circle-T 50mm finder - it weights in at a hefty 654g which is a lot for a finder! Second, I don't have an eyepiece around 18mm or so with crosshairs and due to it's limited focus travel of 1", it cannot use longer FL eyepieces without some sort of extender. But mainly, it's just too heavy and would require somewhere between 0.5lbs to 1.0lbs of additional tube weight to balance it out.

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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5936653 - 06/23/13 03:57 PM Attachment (3 downloads)

In the back of the garage, there's an ATM 6" OTA with everything but the mirror that I bought with a Cave 1.5" mount for a song a couple months ago. It came with a nice circle-T convertible right-angle/straight through finder that was in pretty good condition, so after cleaning it up, paint and replacing the broken cross-hairs, this one will be used for the finder instead.

It weighs in at 424g in right-angle mode and 376g in straight through mode - more than 0.5lbs lighter than the other finder!


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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5936681 - 06/23/13 04:14 PM

Quote:

In the back of the garage, there's an ATM 6" OTA with everything but the mirror that I bought with a Cave 1.5" mount for a song a couple months ago. It came with a nice circle-T convertible right-angle/straight through finder that was in pretty good condition, so after cleaning it up, paint and replacing the broken cross-hairs, this one will be used for the finder instead.

It weighs in at 424g in right-angle mode and 376g in straight through mode - more than 0.5lbs lighter than the other finder!




That looks like the finder Meade used to sell in the later 70's. Had a few of them over the years and liked them.

Chas


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turk123
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: CHASLX200]
      #5936703 - 06/23/13 04:31 PM

Quote:

Quote:

In the back of the garage, there's an ATM 6" OTA with everything but the mirror that I bought with a Cave 1.5" mount for a song a couple months ago. It came with a nice circle-T convertible right-angle/straight through finder that was in pretty good condition, so after cleaning it up, paint and replacing the broken cross-hairs, this one will be used for the finder instead.

It weighs in at 424g in right-angle mode and 376g in straight through mode - more than 0.5lbs lighter than the other finder!




That looks like the finder Meade used to sell in the later 70's. Had a few of them over the years and liked them.

Chas




Yep, I just bought a 70's meade (God rests their sole) for my Cave Cass. It looks a lot like that also. Mine has a white shield on the front that will get painted. The optics are a little too short for terrestrial, but I'm thinking put a few thousand light years at it and it will do fine.


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tim53
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: Datapanic]
      #5936954 - 06/23/13 06:56 PM

Quote:

In the back of the garage, there's an ATM 6" OTA with everything but the mirror that I bought with a Cave 1.5" mount for a song a couple months ago. It came with a nice circle-T convertible right-angle/straight through finder that was in pretty good condition, so after cleaning it up, paint and replacing the broken cross-hairs, this one will be used for the finder instead.

It weighs in at 424g in right-angle mode and 376g in straight through mode - more than 0.5lbs lighter than the other finder!




That looks like the 8x50s we sold with the Meade newtonians in the late 70s, early 80s.

-Tim.


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tim53
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: tim53]
      #5936955 - 06/23/13 06:57 PM

Sorry, hadn't read the subsequent posts!

-Tim.


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Datapanic
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Re: A 1972 Cave 8" f/4.5 RFT Lightweight Deluxe new [Re: tim53]
      #5936958 - 06/23/13 07:00 PM

It's the same as the 7 and 8x50mm straight through circle-T's I've seen on the Caves except those have longer tubes and a diagonal is not an option. Wonder if Cave got them from Meade or if he bought them bulk from somewhere else...

They are nice finders - double cemented objective with a Kellner eyepiece.


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