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John Higbee
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Another Cave 12.5" reporting aboard, with pictures
      #5426488 - 09/17/12 11:31 PM Attachment (135 downloads)

Well, I took the plunge and can now cross something off my "bucket list" - owning an Astrola 12.5"!

Carol and I drove up to pick up the scope on 8 and 9 Sep (7.5 hour trip from the DC area). Rented a mini-van, which turned out to be an excellent idea...taking the Cave back in our Subaru Outback would have been an interesting (and difficult) proposition!

Carol's reaction on seeing the Cave was priceless...after 34 years together, my ability to surprise her has shrunk, but this did it (wide eyes, slack jaw, mouthing "OMG").

Aside from driving through some pretty rough weather in PA on the way back to DC (we cut obliquely through a 400 mile long squall line), the trip back was uneventful, and my son helped me unload and reassemble the model D in our garage.

First impressions (this scope was manufactured in 1979 - the last year of manufacture):

- Overall: great cosmetic condition (Sonotube is sound, with several small areas of missing paint
- Mount and pier; paint is good, with only small paint scrapes on several areas; both axes are bright with very minor rust
- Focuser: 2" rack and pinion with 1.25" adapter...no helical focusing feature. Marked "Japan".
- Mirrors: both the primary and secondary have bright coatings, with minor dust.
-- Primary: No label on the back. Primary is engraved with Cave Optical Company, focal length, and a 1979 date on the side (will be providing the specific info to the Cave Mirror registry shortly).
-- Secondary: One of the vanes for the secondary spider is not at a right angle to the adjacent vanes (off by 5 - 10 degrees...looks like it came this way from the factory.) Will drill the tube to reattach/straighten it out.
- 60mm guide scope: No name on the tube (looks a lot like my old Tasco 60mm). Has a .965 20mm Kellner eyepiece.
- Finder: 8X50 - works great - comes into sharp focus!
- Mount:
-- Declination Axis - Declination set screw is a MONSTER Allen set screw!
-- RA Axis - need to tighten the clutch - scope is "freewheeling" in RA.
-- Cradle - no "knurled disc nuts" on the two bolts coming off the rings - just wing nuts (went to two local hardware stores - a Home Depot and a "mom and pop" neighborhood shop...neither had them...so I'll be looking for replacements). Collar for the Decl quadrant slow motion on the axis (under the cradle) is held on by three machine bolts with "wing nut" heads, rather than allen head bolts.
- Drives:
-- Declination "slow motion": Motor works well in one direction; labors in the other. Hand paddle appears to work (need to check connections inside).
-- RA Drive: Looks like the drive baseplate (attached to the RA Axis support) is made of wood. No separate "power on" light - instead, the top of the toggle switch has a red "grain of wheat bulb" built in, which works. Drive motor is operational (watched it turn the large gear attached to the worm gear) Need to adjust the worm gear/RA axis gear alignment - it's slightly off.

So, I'm really excited to have it! Working on the above items is a lot easier with the good info the Forum provides on recent Cave maintenance. Once I finish up on those and collimate the optics, it'll be on to "first light"...wish me luck!

John

Edited by John Higbee (09/18/12 07:48 PM)


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bob midiri
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Reged: 06/17/04

Loc: pa 19320
Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5426494 - 09/17/12 11:38 PM

Welcome to CN and an AWESOME find. Anxious to hear your first light reports. Congrats!! Bob

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tim53
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Re: Another Cave 12.5" reporting aboard! new [Re: bob midiri]
      #5426504 - 09/17/12 11:54 PM

Very cool! Looking forward to seeing some pix.

Generally, if you keep them below 100K or so, you shouldn't have any problem attaching them.

-Tim.


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Da Bear
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Re: Another Cave 12.5" reporting aboard! new [Re: tim53]
      #5426558 - 09/18/12 12:26 AM

Photo's please......

Da Bear


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: Da Bear]
      #5426579 - 09/18/12 12:37 AM

just broke the code - picture posted!

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JohnRW
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Reged: 09/02/12

Loc: Oakland, California
Re: Another Cave 12.5" reporting aboard! new [Re: Da Bear]
      #5426583 - 09/18/12 12:38 AM

That is HUGE! Way to go! I suspect you'll need a ladder, right? I keep scrolling back up to grasp the sheer size in the photo you attached. Wow!

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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: JohnRW]
      #5426604 - 09/18/12 12:51 AM Attachment (71 downloads)

Thanks, John - here's one from the other side!

John


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5426835 - 09/18/12 07:40 AM Attachment (69 downloads)

And a picture of the drive with the case off...note that the RA axis gear and the drive worm are hardly engaged, and that the adjustment bolts with springs that I've seen in every other Cave drive aren't present here...the three bolts have what look like two split collar washers, and a nut on the other side...with everything "tightened up". Any thoughts on that?

Edited by John Higbee (09/18/12 08:27 PM)


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chuck52
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5426864 - 09/18/12 08:09 AM

Beautiful Cave John, would love to see some more pictures!

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JohnRW
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Loc: Oakland, California
Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5428046 - 09/18/12 06:45 PM

I'd like to see more pictures too! Down the OTA? I'm going to have to inspect the clock drive on my own Cave a bit more closely to see how the gears are meshing.

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tim53
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Re: Another Cave 12.5" reporting aboard! new [Re: JohnRW]
      #5428092 - 09/18/12 07:23 PM

Looks like the whole clutch/hub/gear assembly is mounted too far up the polar shaft to line up properly with the worm.

-Tim.


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: JohnRW]
      #5428139 - 09/18/12 07:51 PM Attachment (51 downloads)

John - here's the "down the OTA" shot!

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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: tim53]
      #5428145 - 09/18/12 07:58 PM

Tim - agree...looks like the assembly needs to move around 1/2 inch down the shaft.
The three "bolts without springs" through the shaft drive gear assembly concern me more...all the drive pictures I've seen on the Forum so far show spring tensioners (my term for it) on each bolt. So, is this a late configuration, or a mistake?


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: chuck52]
      #5428157 - 09/18/12 08:09 PM Attachment (46 downloads)

Chuck - more pictures as requested! We'll start with the focuser/finder...(the left hand side of the tube looks distorted, but isn't - that's a combination of late afternoon light and a piece of white trim/gutter in the line of sight)

Edited by John Higbee (09/18/12 08:25 PM)


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5428160 - 09/18/12 08:11 PM Attachment (45 downloads)

...and a closeup of the mount...

Edited by John Higbee (09/18/12 08:19 PM)


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Grava T
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Re: Another Cave 12.5" reporting aboard! new [Re: tim53]
      #5428264 - 09/18/12 09:02 PM

Quote:

Looks like the whole clutch/hub/gear assembly is mounted too far up the polar shaft to line up properly with the worm.

-Tim.




I agree with Tim.

You need to loosen the screws holding the worm assembly to the plate and move the RA gear further down the shaft. The screw holes for the worm gear should be a little oversized to allow some play for the gears to mesh.

Nice Cave scope BTW.


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PiSigma
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5428283 - 09/18/12 09:19 PM Attachment (39 downloads)

John, that one looks to be in excellent condition. Great find!

Tim's right, that clutch certainly looks like it needs to be slid down so that it is centered on the worm. Getting it right can be a bit tricky.

First, be sure you have the mount and OTA under control and balanced on both the dec and polar axes. Once you loosen the RA clutch the scope is going to be free to rotate around the RA axis.

I start by loosening the screw in the center of the drive motor and turning it so the small drive gear on the motor shaft disengages from the spur gear on the end of the worm gear shaft. Then loosen the screws through the top plate for the worm gear mount a little bit so that you can move the mount around. Then loosen the set screws that hold the RA shaft clutch to the shaft and center it on the worm.

Now slide the worm gear and mounting block around so that the mesh with the clutch gear isn't too tight, the worm gear shaft is parallel with the motor shaft, and that, when you go to turn the drive motor back, the spur gear and motor drive gear line up. It takes a few tries to get this right. When the mesh is just right I can spin the spur gear in both directions with my index finger and the mount and scope will move smoothly around the RA axis with very little backlash. Rotate the motor back up so those gears mesh and you should be good.

This assumes the clutch tension is not too loose. None of my Cave clutches have springs under those three clutch screws (I've only seen springs on my Criterion RV-6). They are socket head cap screws and, like yours, have split washers under them (although only one on each of mine). Mine do not have nuts on top, the upper hub is tapped for the screws. But mine are all 8" and 10" Caves so maybe the 12.5" are different there. The tension is controlled by a teflon(?) band inside the clutch. Most of my clutch screws are snug but not tight. There is a point where just a small additional turn on the screws makes a big difference in the clutch tension and this is when it is really starting to 'squash' the teflon band.

I've not seen a Cave with a drive cover seal like yours. It looks like felt around the edge of the top plate.

Your tube end rings are also different than later Caves I've seen. Rather than being the cast aluminum pull off rings they appear to be L shaped bands with a split and little screws.

I would love pictures of the mirror engraving for the Registry. Maybe yours is later than the latest one known?

Here is a shot of one of my RA clutches. The clutch at the upper left with the big center hole is my dec. drive clutch.


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: Grava T]
      #5428320 - 09/18/12 09:42 PM

Thanks, Mike!

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Datapanic
Carpal Tunnel
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Re: Another Cave 12.5" reporting aboard! new [Re: PiSigma]
      #5428340 - 09/18/12 09:52 PM Attachment (34 downloads)

The older Cave's with the steel front and rear plates may have had springs - at least that's what I found when I started rebuilding the Horsetrail Cave. I think springs give a little bit finer adjustment than split washers.

While you're adjusting all the clock drive, there's also a lateral adjustment on the worm gear itself with two bolts with their heads overlapping those brass bushings. The main adjustment there is to not have any motion along the shaft the worm gear is on.

Overall - looks really nice and well taken care of - congratulations!


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: PiSigma]
      #5428344 - 09/18/12 09:53 PM

Jon - Thanks for the detailed instructions on realigning the drive, and the exploded views of the drive gear/clutch assembly. It's exactly what I needed to do that job correctly.
You'll have the detailed data on my mirror this weekend. I plan to dismount the primary and secondary mirrors so I can give the inside of the OTA a good dusting/cleaning...so I'll take pictures of the primary and send them to you then.
The drive plate cover is not metal...looks to me to be wood, painted to match the rest of the mount (the surface of the plate has a wood texture through the paint). It does have a felt "gasket" around the edge of the plate. Could be another "late production anomaly"!


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: Datapanic]
      #5428397 - 09/18/12 10:23 PM

Dan - thanks! I feel lucky and very fortunate to have gotten this scope...and owe a big "thank you" to Stan Lopata and his wife Terry for making it possible for me to own it (we had a nice visit with them when we drove up to pick up the scope).
Different topic - I can rotate the OTA within the rings, but it takes some effort to do so...is there anything I should check that might make the rotation easier?

John


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tim53
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5428407 - 09/18/12 10:30 PM

As Meade was actively putting cave out of business, I heard all kinds of stories of ways cave got scopes completed after his suppliers stopped supplying things like fiberglass tubes and such. All the late caves seem to have Meade focusers and finders on them, though Meade only labeled Japanese imports themselves. I hope that drive wasn't assembled that way at cave, but it might have been!

Tim


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CHASLX200
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5428761 - 09/19/12 06:09 AM

Quote:

Dan - thanks! I feel lucky and very fortunate to have gotten this scope...and owe a big "thank you" to Stan Lopata and his wife Terry for making it possible for me to own it (we had a nice visit with them when we drove up to pick up the scope).
Different topic - I can rotate the OTA within the rings, but it takes some effort to do so...is there anything I should check that might make the rotation easier?

John




I would check all the hex heads on the outer rings and make sure they are not too tight.

Chas


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Calypte
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Reged: 03/20/07

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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5429774 - 09/19/12 07:34 PM

Quote:

And a picture of the drive with the case off...note that the RA axis gear and the drive worm are hardly engaged, and that the adjustment bolts with springs that I've seen in every other Cave drive aren't present here...the three bolts have what look like two split collar washers, and a nut on the other side...with everything "tightened up". Any thoughts on that?



I don't have an answer to your question, but I do notice something about your RA drive. In 1993 I bought a consignment Cave 12.5-inch f/5 with the lighter mount, like yours. Almost in the center of your picture is a brass thrust bearing for the worm, and it's held in place by the lip of a small round-head Allyn screw. As you move the scope around in RA, the entire mass of the scope pushes on the tiny contact of that screw and thrust bearing. On my scope, the force of moving the scope would rip the screw head right through the flange of the thrust bearing. I found a local hardware store that stocked those thrust bearings, and I went through a boatload of them. Eventually I replaced the drive with a Byers 9-inch drive. The mount is still too small for the scope, but the Byers drive turned a nightmare into something usable.


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Calypte
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5429779 - 09/19/12 07:37 PM

Quote:

John - here's the "down the OTA" shot!



On mine (my scope was made in 1978), the spider was way too light. The diagonal would sag as the scope was moved, making accurate collimation impossible. I replaced the spider with a Novak spider, which is orders of magnitude more rigid than the original.


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: Calypte]
      #5429844 - 09/19/12 08:20 PM

Calypte - thanks for the information and advice on the drive and the spider...if repositioning the "crooked leg" of the spider to a right angle position dosn't give me the necessary stiffness, I'll be looking for a replacement quickly. As for the drive, I'll be on the lookout for the behavior you experienced once I get it realigned and operating. John

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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: CHASLX200]
      #5429937 - 09/19/12 09:15 PM

Chas - took your advice - backed all eight hex heads in the outer rings out 1/2 turn, and the tube spins smoothly! Thanks, John

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CHASLX200
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5430395 - 09/20/12 06:15 AM

Glad that helped.

Chas


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: PiSigma]
      #5434332 - 09/22/12 12:12 PM

It's Saturday, and I've begun taking the primary and secondary mirrors out of the OTA (so, Jon, should have the data for the registry soon).

Once that's done, I'll begin realigning the drive.

If I need to clean the mirrors while they're out (and I won't do it unless they're a lot dirtier than they look), what would you recommend as the best way to clean the primary?

John


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amicus sidera
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5434788 - 09/22/12 05:20 PM

Quote:


If I need to clean the mirrors while they're out (and I won't do it unless they're a lot dirtier than they look), what would you recommend as the best way to clean the primary?






FWIW, this page from P. Clay Sherrod's Arkansas Sky Observatory website might prove of interest to you: The Cleaning of Optical surfaces: Mirrors...YMMV.



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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: amicus sidera]
      #5435045 - 09/22/12 08:27 PM

thanks, Fred! John

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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: tim53]
      #5435917 - 09/23/12 11:22 AM

Well - I've begun my effort to realign the drive, and now things are getting interesting.
Tim - Per your comment, I think the condition of the drive IS as it was assembled at Cave; the gears all look pristine (no wear on any of the gear surfaces).
I dismounted the worm gear assembly to get more room for working on the clutch/axis drive gear assembly. The clutch/drive assembly was held on by 1 allen head set screw in the upper plate hub...is that the normal configuration?
After taking the set screw out, I was able to work the assembly off the polar axis. I took out the three machine bolts (each with two lock washers and a nut). Jon - turns out that the machine bolts were undersized..the upper plate was indeed tapped for a larger machine bolt. I've replaced the original hardware with three stainless steel cap head machine bolts of the right size, with a stainless steel lock washer and regular washer installed on each. So far, so good...
I took out the new hardware, so I could separate the three parts of the assembly...and so far, haven't been able to get them apart to check the teflon ring (remember that the original bolt/nut hardware was found "tightened up").
So - two questions:
- how can I get the three disks apart without damaging the axis drive gear?
- If I find the teflon ring trashed (or not there), what thickness/type of teflon should I use to repair it?

thanks, John


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Datapanic
Carpal Tunnel
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5435982 - 09/23/12 12:01 PM

Soak the whole thing in warm soapy water for a while - the grease has probably dried up and it just needs to be worked loose.

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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: Datapanic]
      #5436339 - 09/23/12 03:11 PM

Dan - your suggestion worked like a champ...all three components are apart...congealed brown grease (very sticky - more like an adhesive than a lubricant) on all the edges. First step now is to get that stuff off...once it's off, what sort of gear lube do you use to replace it?
The teflon strip is intact, but seems very thin...would you reuse it, or replace it? If replace it, who sells teflon sheets?

thanks for the help, John


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Datapanic
Carpal Tunnel
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5436445 - 09/23/12 04:04 PM

I would first clean up the teflon strip with some dish soap and reuse it - it should be okay.

For lube, I've gone with "Super Lube" brand Synthetic Grease "With Syncolon" over petroleum based lubes and it seems to work just fine. It has a wide temperature range and doesn't start dripping off the gears and making a mess during hot weather.

Once the teflon strip is cleaned up, coat it as well as the ring gear and the area where it rotates on the front and back of the assembly.


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: PiSigma]
      #5437116 - 09/23/12 10:35 PM

Jon - just got the mirror data (with the help of my son...that mirror cell is heavy)...
Cave Optical Co
M793839
F/6 75 1/8 F.L.
Mar 27 1979

Picture will follow tomorrow once my son sends it off his phone.

John


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: Datapanic]
      #5438593 - 09/24/12 06:26 PM

Dan - thanks - lube both sides of the teflon strip, or just the side in contact with the inner hub of the ring gear? (sorry for the stupid questions...just want to get it right).
John


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Datapanic
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5438603 - 09/24/12 06:35 PM

Both sides - just a thin coat by putting a dab on your fingers and pulling the strip between them.

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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5438914 - 09/24/12 10:50 PM Attachment (15 downloads)

...and here's the mirror engraving...John

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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5516438 - 11/12/12 06:14 PM Attachment (13 downloads)

Well, it's been a while since the last post (what with work and Superstorm Sandy), but I've made steady progress on my Cave 12.5 in the interim. Thought I'd provide some pictures of what's been done, as well as one of my latest challenge. So, here goes:

First, I've realigned and overhauled the drive. If you compare this drive picture with the one I took early on, you'll see that I've aligned the drive gear/clutch assembly with the worm gear, after taking that assembly apart, cleaning it and relubing it with lithium grease (many thanks to Jon (PiSigma) and Dan (Datapanic) for walking me though the process). When I reassembled the drive gear/clutch, I got rid of the "funky" undersized machine bolts and nuts, and substituted the original design cap head machine bolts with lock washers (stainless steel)...they fit perfectly in the existing threads machined into the "upstream" disk.
On the test run, everything ran well...the Synchron motor was smooth and almost silent throughout. The tube now holds position in RA...no more "freewheeling".

I'm pretty sure now that the "as received" condition of the drive was the way the drive left the Cave shop in 1979, as Tim theorized earlier.

Edited by John Higbee (11/12/12 06:16 PM)


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5516455 - 11/12/12 06:22 PM Attachment (20 downloads)

And another shot of the drive...

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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5516475 - 11/12/12 06:31 PM Attachment (19 downloads)

While I was at it, I reworked the secondary mounting assembly to incorporate the modification that Dan had recommended...easy to do, and works like a champ (only challenge was finding the right springs).

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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5516496 - 11/12/12 06:43 PM Attachment (17 downloads)

I was having problems getting the 60mm guidescope to focus (translation: it wouldn't focus), until Bob Midiri asked if it had a 90 degree diagonal - amazing how well the scope focuses now that one is installed

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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5516536 - 11/12/12 07:06 PM Attachment (16 downloads)

Now for the challenge...take a look at the primary's mounting cell in the picture below. You'll note that the three alignment bolts/springs (underneath the adjustment wing nuts) are very close to the three "structural" bolts. In fact, two of the adjustment wingnuts are SO close to the structural bolts that they cannot rotate more than a half turn (the wings strike the structural bolts)...making primary alignment difficult at best.
I think the ultimate fix for this is to take the cell apart, rotate the mirror holder 60 degrees, drill the lower cell and reinstall the alignment bolts and springs. Since I'm a little leery of drilling the cell, I may just diassemble the cell and replace the wing nuts with hex nuts...would just mean that alignment would require a small wrench rather than twisting wingnuts. Anybody have an opinion as to which way is better?


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tim53
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5516550 - 11/12/12 07:14 PM

You could take the locking screws out while you collimate with the wing nuts. This should work fine unless the springs are tired. If they are, you should replace them.

-Tim.


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: tim53]
      #5516562 - 11/12/12 07:26 PM

Thanks, Tim - didn't realize that I could do that.
Much simpler than either of my options!


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Mirzam
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5516633 - 11/12/12 07:59 PM

You could also grind off part of the ears on the wing nuts to give a bit more clearance. Looks like it would not take much.

JimC


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Datapanic
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Re: Another Cave 12.5" reporting aboard! new [Re: Mirzam]
      #5516787 - 11/12/12 09:23 PM

Thumb/Knurled Nuts likes these http://www.grainger.com/Grainger/ecatalog/N-1z0dq8e would probably work; they seem to go up to 3/8-16. Grainger's price seems kinda high, maybe you can find a better price somewhere else.

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gelkin
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Re: Another Cave 12.5" reporting aboard! new [Re: Datapanic]
      #5516832 - 11/12/12 09:45 PM

McMaster Carr has a selection of thumb nuts also.

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albert1
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Re: Another Cave 12.5" reporting aboard! new [Re: Datapanic]
      #5516834 - 11/12/12 09:46 PM

Quote:

Grainger's price seems kinda high, maybe you can find a better price somewhere else.




Gee, should have gotten in on Stainless Steel when the price was low. Those prices are crazy.


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John Higbee
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Re: Another Cave 12.5" reporting aboard! new [Re: albert1]
      #5523360 - 11/16/12 07:37 PM

Well, it had to happen sometime, and it did...

FIRST LIGHT!!! (6:10 pm)

First lighted in my driveway, with several porchlights on from neighbors, and light pollution from DC to the north...that's the down side. On the good side, temperature's in the high 40's, there's no wind, and the sky's clear with steady seeing. Completed a rough collimation this afternoon. Using a Celestron 1.25" 25mm orthoscopic (so, about 75X)

Bob Midiri bet me that I would have a great mirror...well, Bob, you won the bet...my first impression is that the optics are AWESOME!

I love my orange tube C8 from 1976, but the Cave blows it away...the starfields sharply focus to a mass of pinpoints, and the field is much brighter and more populated (larger aperture wins here, naturally). The rotating tube is a great feature, but I'm still using a two-step kitchen stepladder to get to the eyepiece at elevations above 40 degrees (no problem there).

Went for easy stuff to begin with...
Vega: Like looking at a blue white acetylene lamp, with four delicate diffraction spikes from the spider...I can't get over the number of faint stars in perfect focus I can see in the same field!
Albireo: the VIVID orange and blue of this double in the Cave is a new experience for me, and I've observed this double hundreds of times over the last 37 years.
Ring Nebula (M57): First time I've not had to use averted vision to get the full impression of this planetary. Again, all these star fields are so much more populated than I was expecting...it's great!

Mount's working great (no wind obviously helps there). Next stop...Jupiter (have to wait about 2 1/2 hours for it to clear the tree in my yard). Moon was behind the western treeline by the time I was set up...gives me something to look forward to tomorrow!

Thanks again to all of you that helped me get the scope ready to go back in service...what a great group you are! Couldn't have done it without your help!

John


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tim53
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Re: Another Cave 12.5" reporting aboard! new [Re: John Higbee]
      #5523454 - 11/16/12 08:55 PM

Excellent news! I can't wait until you tell us about the views of Jupiter. Hope you don't fall of that step stool with excitement!

I think I need a taller step ladder for my 12.5". One with 4 steps and a rail, not just 3. I don't like being that close to the top of the 3-stepper. And at the zenith, I still can't reach the eyepiece with it.

We're socked in, probably for the whole weekend.

-Tim.


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albert1
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Re: Another Cave 12.5" reporting aboard! new [Re: tim53]
      #5523491 - 11/16/12 09:32 PM

Congratulations John. It is pretty amazing looking through one of these after an 8" SCT.

Tim's right, be careful when you feast your eyes upon Jupiter when you're 2 feet off the ground.


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Datapanic
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Re: Another Cave 12.5" reporting aboard! new [Re: tim53]
      #5523509 - 11/16/12 09:46 PM

I hear the bands on Jupiter are excellent this year!

Back in the 70's, when I lived in Springfield, VA, the light pollution from DC and the Alexandria/Arlington counties was just encroaching the area, but now it's all over. That's unfortunate, but with 12.5" of light gathering power, you should be able to bring in lots of stellar detail that an 8" would not give. A light pollution filter might help as well.

On the Horsetrail Cave at f/7.5, I usually have to use an 8-foot ladder and go up to the 3rd or 4th step to get to the viewfinder and focuser - One of these days I'm going to make an observing stand similar to aircraft maintenance stands I know from way back when I worked on military aircraft that are easy to move around and have rails for safety.

Unfortunately, I still have eyeball problems with central serous retinopathy and haven't done much observing for the past 6 months. I can barely see 3rd magnitude stars at this point and everything is distorted, so for now, it's more like tinkering with scopes than looking through them. But, it's supposed to go away and my vision is supposed to get better after a while!

With years of looking through scopes, it's nice to roll out the Cave's and just enjoy them, no matter what you see


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chuck52
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Re: Another Cave 12.5" reporting aboard! new [Re: Datapanic]
      #5523538 - 11/16/12 10:11 PM

Hi John,
Congratulations on first light!!I have the same issues as you,Tim and Dan with the 12.5 inch.Access. We should put our heads together on an observing platform design.Sounds like Dan has some good ideas!!


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tim53
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Re: Another Cave 12.5" reporting aboard! new [Re: chuck52]
      #5523575 - 11/16/12 10:44 PM

A handful of years ago, when I was building Hatch Observatory, I looked into these rolling platforms: http://xdeck.com/products/x-deck/. At the time, they were really expensive. I got a quote of almost $1K for the one I was looking at. They look a lot more reasonable now, and I might consider one again for the 12.5"

For Hatch Observatory, where I have my Nexstar 925GPS mounted in the roof of my house, I needed a platform at comfortable height below the scope that could be rolled away or dismantled and stored without taking up a lot of space. I ended up with two moderate sized rolling scaffolds from Step-Up Scaffolds. I can take the metal deck planks off and fold the frame up and stow both of them in my "secret hideaway" behind the walls, turning the attic space into an entertainment room for the fam.

-Tim.


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John Higbee
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Re: My Cave 12.5 "first light"...continued new [Re: chuck52]
      #5523627 - 11/16/12 11:22 PM

Tim, Albert, Dan, Chuck - thanks for the congratulations...having been there yourselves, you know how good it feels to have all the work come together in a vintage scope that exceeds your hopes. That's the way I feel tonight!
First light (phase 2) was Jupiter. I took your advice about not falling off the stepstool by substituting my "Little Giant" stepladder for it.
Observing Jupiter...I boosted up to my 15mm ortho EP for this...approximately 130X. Jupiter looked like a globe, vice the disk I'm used to seeing with the C8. There was definitely an impression of depth to the scene...both for Jupiter's disk, and the relative positions of Jupiter and the Galilean moons(all four of which were preceding Jupiter through the field of view). As for Jupiter itself, I saw detail similar to Dan's (Datapanic's) shots of Jupiter using the Horsetrail Cave...three reddish detailed belts with eddies and texture...two tinted polar regions, one of which had a distinctive greenish-gray tint to it...the best viewing of Jupiter I've ever been fortunate enough to experience.
And, to top it off, I did NOT fall off the stepladder! (Success across the board!)
More to follow...but this "first light" was all I hoped it would be!
thanks again...John


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bob midiri
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Re: My Cave 12.5 "first light"...continued new [Re: John Higbee]
      #5523653 - 11/16/12 11:39 PM

Great reports John!!! Those Cave scopes are fantastic. Sounds like you have a WINNER
bob


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John Higbee
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Re: My Cave 12.5 "first light"...continued new [Re: bob midiri]
      #5523972 - 11/17/12 09:02 AM Attachment (18 downloads)

First light - just before I shut down for the night!

Edited by John Higbee (11/17/12 09:09 AM)


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PiSigma
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Re: My Cave 12.5 "first light"...continued new [Re: John Higbee]
      #5524912 - 11/17/12 07:06 PM

Hi John,

That is a great first light report. I'm glad to be of help and even happier that everything is working great. It sounds like you have a superb mirror!

Congratulations. I'm always glad to see a classic scope preserved and things put back on it the way it was originally, especially a Cave!


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John Higbee
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Re: My Cave 12.5 "first light"...continued new [Re: PiSigma]
      #5533308 - 11/22/12 02:26 AM

First - hope all of you and yours have a happy and peaceful Thanksgiving, and safe travels.

Up a little bit late tonight after observing with the 12.5" for over three hours, and am waiting for the ibuprofen to kick in (running up and down the ladder, and wrestling the tube from NE (Jupiter) to SW (Moon) have my back acting up a bit -- but I was so excited during the session that I didn't notice anything until I restowed the scope in my garage).

Conditions were OK...clear sky, with the same porchlights and skyglow I had during first light. Temps in the low 40s...no wind, but the atmosphere was "boiling" a lot, with periodic short lulls of good viewing. Main viewing was the Moon, in the Mare Imbrium area, with periodic side trips to Jupiter and the Pleiades.

Cutting to the chase...I have never seen the Moon through a telescope the way I saw it tonight. Used my Celestron 1.25" Plossls (from 6MM (310X) to 40MM (46X)). Looking at the triad of big craters in Imbrium (Autolycus, Aristillus and Archimedes) and their surroundings was truly a new experience. I had never seen the subtle swelling and rolling of Imbrium's surface before...or the dozens of small to tiny craters surrounding the "big three". The twin peaks west of Archimedes stood out like tiny needles, with exquisitely thin twin shadows stretching further westward towards the terminator. Unbelievable, even with the "boiling"...beyond unbelievable when the boiling ceased.

Following the southern mountain boundary of Imbrium west towards the terminator, I happened upon Copernicus...and went no farther for a long time. Copernicus was on the terminator, so I knew the vertical relief would appear exaggerated...but what I saw stunned me. The closest I can come to a description is that it looked like a vast version of the ruined Roman Colosseum with the closely concentric walls towering into sunlight; the interior obscured. Further to the south, I viewed a major crater with half of its floor in bright sunlight, bisected by a ridge...the other half (beyond the ridge) in black shadow. I could go on with what I saw further to the south, but you've seen it yourselves...I'd just be "piling on" superlatives.

Sounds horrifying to say this, but Jupiter (although great) was merely an afterthought tonight.

I ended up holding an impromptu star party/viewing session tonight for 5 or 6 of my neighbors who noted a BIG white tube pointing skyward in my driveway...showed them the Moon and Jupiter...for most, it was their first look through a telescope, and they were uniformly "blown away". (I should add that several of the porchlights went out after my neighbors left. ) May end up being the first meeting of the "cul-de-sac" astronomy club!

Tried the refurbished drive for the first time tonight, with a rough alignment on Polaris...worked well enough to keep the Moon virtually stationary in the field at 310X. The declination quadrant slow motion worked well in one direction, poorly in the other, so I'll have to dig into it (checking alignment and electrical connections).

One question...need to complete the collimation...the one I did leaves much room for improvement. What laser collimator would you recommend?

Enough for now...the ibuprofen has kicked in! More to come later...

John


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clintwhitman
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Re: My Cave 12.5 "first light"...continued new [Re: John Higbee]
      #5533354 - 11/22/12 04:19 AM Attachment (14 downloads)

John,
Thanks for the great and entertaining star/moon report from the eyepiece of your Classic Cave Astrola. As telescopes go these are the pinnacle of classic USA workmanship and will always have a place in my heart. I have done quite a bit of observing of the Moon with the 65 10" F8 and it always leaves me in a great frame of mind. The Moon, so close and so far.
Here is a shot of Petavius that was shot with my 1965 Cave. When I was done processing the Video I was, needless to amazed what a ToCam was able to pull from the old Cave.. Keep up the great reports!!

(aveman.


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joerbiker
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Re: My Cave 12.5 "first light"...continued new [Re: John Higbee]
      #5533755 - 11/22/12 11:10 AM

John, great report, thanks! It inspires me to get off the computer and get out there to my little restoration project.

Best,


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