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Cave-Astrola 8" f/7 Model B Deluxe restoration / upgrade

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#101 apfever

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Posted 22 August 2021 - 07:07 PM

Hi BRye,

 

Do you have Tom Cave's actual name inscribed on the mirror? This is rarely the case. I had a 1979 mirror that he personally etched his name on. That scope is now sold. There is a Cave mirror registry. To avoid highjacking Dave's string here, could you possibly get pictures of the writing on your mirror for entry into the registry?  Here is a link to the registry.

 

Cave mirror registry 

 

I'll pm you with more details to keep this string clear.


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#102 Dave Cook

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Posted 03 August 2022 - 05:35 AM

Rumors of my demise are exaggerated...mostly been working on rockets for several months, and I recently did a set of fixes to the #$%! mini lathe.  A while ago I lost out on a chance to get a pair of Byers 6" drives, which would have been a huge win.  Aarrgh.  Anyway I've been using the instrument a bit with mostly the original mount together with the new SS dec shaft, machined adapter and Losmandy dovetail instead of the laughably bad hand-ground-to-a-rough-approximation cast saddle.  It's actually pretty good as a push-around mount now; the main noticeable fault at the moment is slop/backlash in the dec drive worm system which I've talked about before.  I'm thinking about a temporary modification to change the dec stack to take out the Cave worm wheel and just have a friction clutch.  That seems like it should be pretty easy and with the CNC mill and lathe both back in operation I've got the wherewithal to make any needed parts.



#103 orion61

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Posted 03 August 2022 - 08:43 AM

Hi!

 

I've embarked on a project to put my one-owner 1975 Cave-Astrola 8" f/7 back into operation.  This is pretty much my "one true telescope", bought when I was in high school by saving lawn mowing money for a couple of years, and it's still my only telescope of any size.

 

Its configuration:

  • Has the declination worm drive, no tangent arm
  • Dual power cords into the housing
  • Rotating rings
  • Steel pier tube, which I gather may be unusual for the date of manufacture
  • Gray and black original color scheme

At the starting point here, it's not quite stock...

  • Has a Meade add-on 60mm guide scope (I think purchased from Cave) from ~1977-1978
  • Extra counterweight rail to make up for the 60mm and cameras
  • Williams Crayford type 2" focuser replaces the awful original spiral one that you couldn't adjust without the OTA moving
  • Primary cell moved forward a bit less than 2" to handle the focuser height (secondary size is just barely enough now)
  • 50mm finder relocated a bit to accommodate the larger focuser base, and also because it toppled long ago and broke the finder mounting screws out of the tube. (ouch)

Overall it's in good shape, having been stored in benign indoor conditions for nearly its whole existence.  There's a little rust on the steel pier and chrome dec shaft, and some moderately corroded hardware, but that's about it.  The counterweight comes off the shaft fine despite a bit of rust there.  Oh, and the AC wiring scares me, we'll get to that...

 

Caveat:  this is not going to be a "p scopesut it back to factory original" project.  </me puts on asbestos underwear!!> Some things are gonna get modified to improve function and rigidity, sloppy parts are going to get machined, some things replaced.  I've a good mind to convert it to DC steppers to gain a useful slew capability.  It might get a new larger RA drive and "go naked", you have been warned.  Tube color is up for grabs but it will not be Pink. wink.gif

 

The "before" photos will come in the next post after I figure out the media album UI on this board.

 

-Dave

Hi Dave: another Cave-A-Holic here, I don't know about others, but  I think the 8" f7 are the perfect scope. Some guys have their 20+ inch scopes, yes they give great deep sky views! Myself I love the changes of the Planets, the transits of Jovian Moons, and  Saturn's ring system.
A great Cave mirror makes my heart go thump....bump.....thump! the colors match my 1974 8-F7 perfectly. I have chosen to allow My scope to stay stock, allowing age to allow small cracks, scratches (UM we dont call those things scratches! we call them MEMORIES) Everything looks great. My 1974 is as it is, marks, fine cracks...er Memories. my 8"F7 happens to be of fantastic figure, so far only slightly bettered by a Tac of close to the same size and f- Ratio. The 1970's offered different optical qualities, some ok/some great/and then the thud... lucky enough the Quality was still decent. I had the chance to take out my newly recoated 8"F7 against decent quality 8" F10 and F 6.3 scopes, the Meade EMC scopes did fairly close, the F 10 Celestar came the closest, but nothing short and stubby touched thie Caves Quality! I just wish I had brought my cameras. most of the SCT's did better than I thought  they would, but the Cave shined through....
Great job, keep up the good work. Some of us like to keep things original, others are mmmm unique. as long as those wonderful mirrors are cared for, who cares, personally A Marvel Spiderman scope might be pretty cool!!! With thanks, and love for keeping her close to stock (she is your's) the more Caves the Happier I am. God Bless and enjoy your special baby!
With love from Orion61 AKA Larry "DUANE" Beach.... 


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#104 Dave Cook

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Posted 11 August 2022 - 11:14 PM

A small update now that things are moving again - I measured the RA shaft diameter.  Similar to the dec shaft, it's noticeably undersized at about 1.4980 to 1.4982.  Combined with the plating deteriorating and some visible rust, the odds that I will go get a Mitsumi stainless steel one have jumped to about 100%.

 

More excitingly, I've cornered a pair of vintage Byers drives for the project.  Photos coming when they show up.



#105 marvyyk

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Posted Yesterday, 06:41 AM

@Dave Cook : Colossal work, wow! waytogo.gif


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