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Let the antique speak for itself...

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#76 John Higbee

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Posted 18 January 2019 - 02:55 AM

So - the way ahead looks (roughly) like this:

Part 1 - (while it's too cold to paint outside)
- Clean the objective/finder lenses and do DPAC testing on them
- Work with a local machinist to fabricate the replacement drawtube (could be in brass or aluminum - I prefer brass)
- Determine the optimum method to remove dents from the OTA, then do it.
- Make two additional OTA baffles, and install them, in parallel with properly reinstalling the loose baffle. This will give the scope a four-baffle arrangement.
Once this is done, reassemble the scope for "first light" testing. Once complete:
- Strip the OTA, finder tube/rings, tube rings, focuser, and the mount/pier pieces to get them ready for repainting. Given Robert's experience in rebuilding his 4", this looks like a hand-sanding job, vice chemical stripping
- Determine what replacement hardware is needed and get it (again, could be either brass or aluminum)

Part 2 - (Late March/April - once it's consistently warm enough to paint outside)
- Prime all the above pieces (the scope originally had no primer)
- Paint (OTA - dark green; all other of the above pieces in black (finish TBD)). The finder rings are brass...will probably polish and clearcoat them.
- Refinish the tripod legs in the original color (dark reddish-brown); remove the casters (not original to the scope)

Reassemble, first light, and use!

John

Edited by John Higbee, 18 January 2019 - 03:03 AM.

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#77 deepwoods1

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Posted 18 January 2019 - 08:50 AM

I didn’t see deplay at NEAF listed!


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#78 John Higbee

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Posted 18 January 2019 - 09:32 AM

probably in 2020!
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#79 John Higbee

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Posted 19 January 2019 - 08:30 AM

Hi John,
I am not surprised the mount is rock solid. Maybe you can get in touch with Clint and he can tell yo how to get in touch with the employee at the Tinsley Corp. Hopefully they have records of where and when the 3 6" refractors were manufactured and who purchased them. Doe your Astronomy club know how and from whom they acquired the telescope?
 
Good luck with your search,
Dan

Dan - Clint is on Facebook - I have talked with him occasionally.
Will ask him for the contact information and see what I can find out. With only three 6" Saturns manufactured, hopefully at least the dates of manufacture are available.
Who they were sold to would be an even bigger bonus, but that may not be available due to privacy issues. In any case, worth a try!
As for history of the scope...the club got it more than a few years ago "as you see it"...and the folks who might remember the transaction are not there anymore.
John

Edited by John Higbee, 19 January 2019 - 08:30 AM.


#80 John Higbee

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Posted 19 January 2019 - 08:40 AM

I was leafing through Starry Nights (Leslie Peltier's autobiography) recently.
When he received the donation of the 12" Clark (and its observatory) from Miami University, he did an early star test on the objective and was horrified to see purple haloes around each of the stars in the field.
He thought that one of the elements might have been flipped in the past, reversed it, and tried again...the haloes disappeared, and the images were sharper.
Might be the case here...in any case, the DPAC we're planning to do with Johann will conclusively tell us what the proper orientation is!
John
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#81 John Higbee

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Posted 19 January 2019 - 09:24 AM

Just happened to find one of (aveman's old threads on Tinsley from 2010.
One of the contributors posted this 2001 picture of what he thought was either a 5" or a 6" Tinsley...definitely NOT the one I have!

different 6 inch Tinsley.jpg

John
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#82 starman876

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Posted 19 January 2019 - 06:29 PM

I was leafing through Starry Nights (Leslie Peltier's autobiography) recently.
When he received the donation of the 12" Clark (and its observatory) from Miami University, he did an early star test on the objective and was horrified to see purple haloes around each of the stars in the field.
He thought that one of the elements might have been flipped in the past, reversed it, and tried again...the haloes disappeared, and the images were sharper.
Might be the case here...in any case, the DPAC we're planning to do with Johann will conclusively tell us what the proper orientation is!
John

let DPAC set you freesmirk.gif



#83 John Higbee

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Posted 25 January 2019 - 07:39 PM

Objective for this weekend...cleaning the objective! (with the help of Dave and Johann).


20181226_155354.jpg


Pictures will be provided...stay tuned.


John
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#84 Kasmos

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Posted 25 January 2019 - 08:51 PM

 fingerscrossed.gif


Edited by Kasmos, 25 January 2019 - 08:52 PM.

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#85 starman876

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Posted 26 January 2019 - 08:47 AM

Objective for this weekend...cleaning the objective! (with the help of Dave and Johann).


attachicon.gif 20181226_155354.jpg


Pictures will be provided...stay tuned.


John

I will bring my buffer in case we need to polish the lens.


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#86 TOM KIEHL

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Posted 26 January 2019 - 01:53 PM

I will bring my buffer in case we need to polish the lens.

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#87 John Higbee

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Posted 26 January 2019 - 11:01 PM

Tom - This objective is too valuable to hazard...and we won't let that happen!

We're going to stick to Dr. Clay Sherrod's ASO lens cleaning process for Sunday's evolution...nothing more or less.

If we run into issues while using that process, we will stop and determine the cause before proceeding farther. There is no urgency required or desired here.

John

Edited by John Higbee, 26 January 2019 - 11:03 PM.

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#88 starman876

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Posted 27 January 2019 - 10:22 AM

You have never seen me polish a lens with my bufferlol.gif


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#89 DAVIDG

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Posted 27 January 2019 - 11:45 AM

  Test the lens before you do anything do it so you have a baseline of the performance. That way upon reassembling and it doesn't test the same you know something is not right.

 

                       - Dave 



#90 DAVIDG

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Posted 27 January 2019 - 09:41 PM

 How did it go ?

 

                 - Dave 



#91 John Higbee

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Posted 27 January 2019 - 09:45 PM

Today's evolution went well. The objective is in excellent condition!

Dave and I dismounted the objective cell from the tube. Completed step one of the ASO cleaning procedure...gently stroking (without pressure)
the front and rear surfaces of the objective with a soft camel hair brush to remove loose dust and particulate.

The irregular "blob' on the center of the objective was on the rear surface...turned out to be the remnants of an insect with
peculiarly bad luck (must have flown into the tube during eyepiece changeout in the distant past). Fell off the objective when
touched by the brush. Much dust was also removed.

Only found two pinpoints of fungus on the objective (located on the rear surface)...put the objective in full sunlight for
20 minutes as a first step. These will be removed when the objective is cleaned using the ASO formula later this week.

Objective is definitely uncoated...so dates before the late 1940s.

For info, the first light baffle is 26" from the front of the OTA...and could be slightly "cocked' in the tube.

Johann did some good initial DPAC work on the objective...this was hampered by the lack of the original drawtube for the focuser,
so the results were inconclusive.

My thanks to Dave and Johann! More tomorrow...John

Edited by John Higbee, 27 January 2019 - 09:58 PM.

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#92 Earthbound1

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Posted 27 January 2019 - 09:55 PM

Newbie question. Once you have it cleaned up, is it possible to send the crown and flint to be coated? Not that you would if keeping it stock, so to speak, is more desirable, but maybe an anti reflective coating would be worth it if it wouldn't endanger or devalue the objective. Just curious. Looks great so far!!!- Chip

#93 starman876

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Posted 27 January 2019 - 10:21 PM

Newbie question. Once you have it cleaned up, is it possible to send the crown and flint to be coated? Not that you would if keeping it stock, so to speak, is more desirable, but maybe an anti reflective coating would be worth it if it wouldn't endanger or devalue the objective. Just curious. Looks great so far!!!- Chip

That would be rather expensive.  Also, to apply the coatings the lenses need to be heated to a high temperature.  I do not believe John would gamble with the lens to do that.  Considering it is one of three ever made I doubt John is willing to take any chance with the lens.  


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#94 Earthbound1

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Posted 27 January 2019 - 10:35 PM

No doubt! Wasn't sure about the process involved in coating. Was operating on the assumption that eyeglasses (polycarbonate) sometimes get anti-reflective coatings, and thought perhaps that would be a safe alternative to high heat process coatings.

#95 DAVIDG

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Posted 28 January 2019 - 10:59 AM

  Glad to hear that the initial part of the cleaning process went well. Just a bit of advice, don't go over board with "special" cleaning processes or solutions. Been doing high res spectroscopy for many years that require ultra clean optics along with optical fabrication and I have cleaned many antique optics. A simple bath in warm water with a few drop of liquid dish soap, then a risen in clean water and pat dry with a cotton cloth works the best. All this other stuff with alcohol and other "magic" solution cause more damage then good.

   Here is a picture of me cleaning a 4" Clark objective and also a 10" Brashear objective. Again a simple bath in warm water with a little soap and risen is all you need. So I would recommend that you test the lens via double pass and see what the results show. Remove the lens from the cell and take any alignment marks with a good amount of skepticism. Clean the the elements, clean the cell. Reassemble and test. If the test show bad results, turn the whole lens around on the test stand. If it test well it was backwards in the cell.  If that makes it worse then test it in the  original position but flip the front element and see if that makes it test better. If so then the crown was flipped, if not then the lens is just poorly figured.

   By the way the 10" Brashear had the elements cemented together and backwards in the cell. Totally wrong and was that way for many years ! Testing showed it was wrong and testing showed when correctly mounted it was excellent.

 

                         - Dave 

 

cleaning.jpg

03_RemovingRing_Dave.jpg


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#96 starman876

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Posted 28 January 2019 - 11:13 AM

  Glad to hear that the initial part of the cleaning process went well. Just a bit of advice, don't go over board with "special" cleaning processes or solutions. Been doing high res spectroscopy for many years that require ultra clean optics along with optical fabrication and I have cleaned many antique optics. A simple bath in warm water with a few drop of liquid dish soap, then a risen in clean water and pat dry with a cotton cloth works the best. All this other stuff with alcohol and other "magic" solution cause more damage then good.

   Here is a picture of me cleaning a 4" Clark objective and also a 10" Brashear objective. Again a simple bath in warm water with a little soap and risen is all you need. So I would recommend that you test the lens via double pass and see what the results show. Remove the lens from the cell and take any alignment marks with a good amount of skepticism. Clean the the elements, clean the cell. Reassemble and test. If the test show bad results, turn the whole lens around on the test stand. If it test well it was backwards in the cell.  If that makes it worse then test it in the  original position but flip the front element and see if that makes it test better. If so then the crown was flipped, if not then the lens is just poorly figured.

   By the way the 10" Brashear had the elements cemented together and backwards in the cell. Totally wrong and was that way for many years ! Testing showed it was wrong and testing showed when correctly mounted it was excellent.

 

                         - Dave 

 

attachicon.gif cleaning.jpg

attachicon.gif 03_RemovingRing_Dave.jpg

As always good advice David.waytogo.gif



#97 John Higbee

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Posted 20 February 2019 - 08:25 AM

Was skimming Ebay several weeks ago and bought this:

 

Capped 1.jpg

 

It came with the objective and focuser caps (objective cap is a friction fit; focuser cap screws on).

 

It's the same diameter (40mm) and tube dimensions as the finder that came with the Tinsley 6"...but with certain important differences

 

On the original finder, the drawtube slides out to focus the scope.  On this one, the drawtube slides out  about two inches, then hits a "clickstop".  The last inch of travel has ten clickstops, and the drawtube can be rotated between clickstops for fine focusing.

 

drawtube in.jpg

 

Drawtube out.jpg

 

Optics need a little cleaning, but the views are sharp and clear.

 

Next - report on Johann (Starman 876), Dave (Combat Dad) and my get together over the weekend to clean and test the Tinsley 6" objective.

 

John 


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#98 Bomber Bob

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Posted 20 February 2019 - 11:40 AM

I bought one of those Saturn 40mm spotters.  The lens was totaled, so I cannibalized the hardware, adapted an antique 50mm F5 & cell to the tube, and created a right angle finder for my 6" Tinsley Cassegrain: 

 

TL40 Finder Scope S71 (Complete).jpg

 

The brass "columns" for the brackets came from an antique adelaide (another Goodwill find).

 

I like having the Saturn label on both the scope and this finder.


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#99 John Higbee

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Posted 20 February 2019 - 01:04 PM

So - Sunday, we (Dave Johann and I) went to Johann's home to do a cleaning and optical testing of the objective.

 

First - we checked out the Newton rings on the objective...they were equally spaced (no pinching of the objective indicated) but they were skewed off the center by about half the diameter of the objective (we worked on this following the cleaning).

We then removed the objective retaining ring, after loosening the three ring set (grub) screws.  Using Johann's spanner wrench, the ring came out very smoothly.  We then used the "cylinder and cloth" method to gently remove the objective from its cell.

 

20190217_135040.jpg

 

20190217_130638 (3) - Copy.jpg

  

Objective inspection revealed several interesting details:

  • the index marks on both objective elements were not aligned, but about 130 degrees apart

20190217_130629 (2) - Copy.jpg

  • the lens had marking on the sides in light pencil:  the name "Patterson", and the numbers 5, 6, and 48 (maybe "May 6th, (19)48)?

20190217_130756 (3).jpg

 

Separated the objective into its two component (the shims stayed on the lower component)

 

Cleaned the objective carefully on each of its four surfaces; did the air blast on each surface, then, did a careful wash to remove any remaining dirt, followed by mopping up remaining moisture using clean cotton swabs with no pressure applied.

 

The objective looks spectacular (only marks on it are two very small pinpoint "etchings" where the two pinpoint fungus were (on the edge of the tube side surface of the lower element).

Clean Objective.jpg

 

Stand by for Part 2!  John

 


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#100 John Higbee

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Posted 20 February 2019 - 01:19 PM

Last comment on Part 1:  Here is the name on the objective:

 

20190217_130810 (2).jpg

 

Part 2:

 

Once the objective was reassembled, we worked to get the Newton rings centered on the objective by incrementally rotating the upper element and retesting at each step; found the "best position" - the Newton rings were still slightly offset from objective center.  Put the objective back in its cell (delicately reseatiing it), and experimented with various tightening levels of the retaining ring to see the effects of tightening on the Newton rings.  As the ring was tightened, the center of the rings migrated towards the center of the objective...when got to hand tight, the rings were still slightly offset but much improved in location.  Made sure the objective was not "pinched".

 

We then did dual-pass autocollimation on the objective (using Johann's testing set up):  We ran out of time, but got a first look at the objective assembled with the elements in the "as-found" order:

 

WIN_20190217_14_17_13_Pro (2).jpg

 

We still need to reverse the objective in the test rig...and if need be, flip the objective elements to see where the best testing result occurs.

 

So, a good afternoon, where we made good progress on the objective!   Johann believes he may have an original Tinsley draw tube and diagonal...while he looks for it, I'm working to get a replacement draw tube fabricated.  Once the draw tub is in hand and the DPAC testing completed, we'll reassemble the scope and star test the telescope...and optically compare it to the 6" Spacek.   By that time, "Spring should be springing", and the restoration and repainting/refinishing of the rest of the scope will begin!

 

Many thanks to Johann and Dave for their sage advice and good conversation!

 

John


Edited by John Higbee, 20 February 2019 - 04:42 PM.

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