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Equipment Discussions >> Classic Telescopes

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John Higbee
sage
*****

Reged: 07/17/12

Loc: Virginia
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
sage
*****

Reged: 07/17/12

Loc: Virginia
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
sage
*****

Reged: 07/17/12

Loc: Virginia
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
sage
*****

Reged: 07/17/12

Loc: Virginia
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
Postmaster
*****

Reged: 12/17/04

Loc: Highland Park, CA
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
sage
*****

Reged: 07/17/12

Loc: Virginia
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
Post Laureate
*****

Reged: 04/01/08

Loc: Lovettsville, VA
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
Post Laureate
*****

Reged: 10/17/09

Loc: Tucson, Arizona
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
Pooh-Bah
*****

Reged: 09/22/10

Loc: Western, MD.
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
Carpal Tunnel
*****

Reged: 01/01/07

Loc: Southern New Jersey
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
sage
*****

Reged: 07/17/12

Loc: Virginia
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
Postmaster
*****

Reged: 12/17/04

Loc: Highland Park, CA
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
Carpal Tunnel
*****

Reged: 01/01/07

Loc: Southern New Jersey
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
Post Laureate
*****

Reged: 10/17/09

Loc: Tucson, Arizona
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
sage
*****

Reged: 12/03/09

Loc: Quartz Hill,California
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
Postmaster
*****

Reged: 12/17/04

Loc: Highland Park, CA
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
sage
*****

Reged: 07/17/12

Loc: Virginia
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
Carpal Tunnel
*****

Reged: 06/17/04

Loc: pa 19320
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
sage
*****

Reged: 07/17/12

Loc: Virginia
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
Carpal Tunnel
*****

Reged: 10/14/09

Loc: North Carolina
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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