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6" Tinsley Saturn Cassegrain Restore

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#351 Bomber Bob

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Posted 02 September 2019 - 01:10 PM

Thanks!  The Tinsley Project feels like it's on either Repeat or Shuffle since I first got the OTA.  Getting the EQ mount from Dave Trott was the watershed moment for me.  It's driving this 2nd restoration.  I want the scope & mount to at least coordinate color-wise -- the styles already do.

 

Once the DEC axis gearing is done, I start what I plan as the last OTA restore -- at least by Ol' BB.  The secondary cell was missing.  I made a quick & dirty one for mirror testing; then, the better quality version in it now.  But what I want is an all-brass final version, and for that I'll have to go to my local machinists -- and if they take it on, it'll be on their schedule.  "A brass can with an 8 inch brass rod" is how I'll describe it to them.  They built the complicated shock-resistant lens cell for my Jaegers 4" F5 refractor, having never done any work like that before, and I know they can build to precision.

 

I went crazy polishing the brass on my 3" Mogey, and learned some lessons for the Tinsley:  Now I only remove black tarnish, with the idea of having it look Old & Used -- but not abused.

 

JD, my powder-coat guy, has done 4 vintage scope tubes for me -- brass, aluminum, & steel -- and he does great work.  I've already talked to him about 2 different medium-gray high gloss colors for the Tinsley that'll make all the brass hardware really stand out.  All I gotta do is get the optics & cells safely removed -- no spare parts with this scope! -- and pick one.

 

It's a shame that the mount & pedestal are just too massive to keep indoors.  Talk about a grand old scope!  She really should be on display.  Can't tell y'all the number of times I've had to explain to family & friends that the Tinsley is most certainly a telescope.  It doesn't look like any of refractors, which are Real Telescopes to them.


Edited by Bomber Bob, 02 September 2019 - 01:14 PM.


#352 Bomber Bob

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Posted 08 September 2019 - 12:27 PM

The restored gear box is back on the mount -- for now.

 

I want to use the slow-motion controls, so I have to put that planetary gear back in.  It drives the 2 other gears that in turn drive the worm, and consequently the big gear on the axis.  All I have to do is thread the hole that the motor shaft went through, put in a short brass screw that'll fit the gear & let it turn, and install the gear.

 

This box is really more of a frame.  With it bolted on the bracket, I can remove 6 screws, and pull the long front panel off.  All 3 motor drive screws have posts that end in it -- including the planetary gear -- and in the long back panel.  I like the simplicity, and having all the parts back together.



#353 Bomber Bob

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Posted 01 April 2020 - 02:27 PM

Forgot I had these pix.  Here are the changing faces of my Tinsley EQ...

 

When Bob Midiri had it.  Alpha Instruments modified it to carry a Brandon 4" F15 refractor -- probably for solar work -- in 1956:

 

6612744-wholescope.jpg

 

Note the paint color -- and all the corrosion & rust.

 

When Dave Trott was the owner:

 

01 - TPM (Dave Trott).jpg

 

I like the gray better than that blue-green, and the clear acrylic gear box cover vice the metal one.

 

Today, I removed the 2 machined aluminum rectangles, and changed the color from black to silver.  The smaller one bolts to the DEC axis cap with 4 large hex bolts plus that large nut that threads onto the extended axis shaft.  The larger one is attached to the smaller with 4 hex bolts.  Both have center holes to fit the axis nut.  Together, they make an adapter plate for other scopes.


Edited by Bomber Bob, 01 April 2020 - 02:32 PM.

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#354 Bomber Bob

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Posted 06 April 2020 - 01:54 PM

Last night was my first session with the Tinsley 6" F20 Cassegrain riding on the improved mount.  Loved the views!

 

This EQ is pure pleasure to use:  very smooth & stable.  All it needs is rust removal & re-painting to prevent future corrosion.  Dual axis motors would be great, but for my observing, they're not required.  Can't recall if I've posted this before, but both axes have ball bearings in the axis disks.  Those in the DEC axis appear smaller than the polar axis -- maybe half the diameter.  Anyway, it's one of those mounts that gets better as the scope weight increases.

 

The Tinsley's big advantage over my RV-6 is focal length:  I get 100x with a flat-field 30mm Kellner, 240x with a fine UO HD 12.5mm Orthoscopic.  But the F8 Newt has higher contrast -- most apparent observing the waxing gibbous Moon.


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#355 macdonjh

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Posted 06 April 2020 - 02:53 PM

 

The Tinsley's big advantage over my RV-6 is focal length:  I get 100x with a flat-field 30mm Kellner, 240x with a fine UO HD 12.5mm Orthoscopic.  But the F8 Newt has higher contrast -- most apparent observing the waxing gibbous Moon.

That's surprising.  I wonder if the Tinsley's baffling is optimally designed?  I would have thought the Cassegrain and Newtonian would have had about equal contrast.  Contrast in my Driveway Scope (an 8" classical Cassegrain) isn't the best, but then I didn't build proper baffles the first time around.  That was on purpose, of course, I knew seven years ago I'd need a project to keep busy during the next global epidemic.  Sometimes it sucks being right.


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#356 Bomber Bob

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Posted 06 April 2020 - 03:13 PM

I made a lot of improvements to the RV-6 to suppress glare / boost contrast.  The Tinsley's primary baffle is original, and is a good diameter / length for an F20 system.  The secondary mirror holder was missing when I got the scope.  It's currently using the 2nd version of my own design & construction.  I have all the parts (mostly OLD brass) gathered to build a 3rd / final version that I think will help.  I blackened the tube interior by gluing powder sand to the metal, then painting over it with flat black.  

 

Contrast isn't bad, it's just not as good as my improved RV-6.


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#357 oldmanastro

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Posted 06 April 2020 - 04:06 PM

I found this old Tinsley ad in a 1967 Fawcett book (645). It's the 12 inch Cassegrain. Both the 6 and 12 inch look like twins except for the size. The mount looks similar too. I thought this could be of interest. 

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#358 Bomber Bob

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Posted 06 April 2020 - 05:23 PM

From a 1935 Tinsley Catalog:

 

1935 Tinsley Cassegrain Catalog Page.jpg

 

My scope & mount are most like the 1935 version.  BUT, Tinsley did make changes over the years to both...

 

From a 1948 Tinsley Ad in S&T:

 

1948 Tinsley Saturn Ad.jpg

 

The 2 huge black motors that I removed may have been original, or may have been added by an owner, or even by the last known vendor, Alpha Instruments.  The motors are from the 1940s.

 

Mine has those 3 foot long slow-motion cables that bolt into the knobs -- forgot to attach them last night, and it can be a LONG reach depending on where the scope is pointed...

 

This is a rare Tinsley.  It may be a one-of-a-kind.

 

Neither Ol' BB nor the ATS have evidence of any other 6" Cassegrain.  Depending on the catalog date, the smallest models offered are 10" -- shipping weight of 400 pounds...

 

BIF:  The current mirror set is not Tinsley.  I bought the bare OTA from Bob Midiri, and I gotta thank Bob for it; and, for going back to the last owner's widow, trying to find the original optics.  Odds are, they were removed & packed for storage, and lost...  The F20 set are from an unknown maker.  They were coated in the 1960s by Delta-Lambda Thin Film Optics (Laguna Niguel,  CA), and that company is long gone.  I had the mirrors re-coated by Majestic in 2016.


Edited by Bomber Bob, 06 April 2020 - 05:48 PM.

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#359 oldmanastro

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Posted 06 April 2020 - 06:17 PM

Nice history on that 6" Tinsley Bob. It may be one of a kind. It must look terrific in its mount like those in the ads. I learned about Tinsley here at CN. I guess they never sold one over here and if they did it is probably long gone.

 

Guido



#360 macdonjh

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Posted 06 April 2020 - 08:21 PM

Too bad none of those Tinsley ads have prices for the Cassegrains.  It would be interesting to compare their pricing to current pricing.  The 3" and 4" refractors are pretty expensive ($325 x 3% inflation for 72 years is $2730).


Edited by macdonjh, 06 April 2020 - 08:22 PM.


#361 Bomber Bob

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Posted 06 April 2020 - 08:44 PM

The 10" Cassegrain was $636 in 1935...  $12,000 in today's dollars.



#362 macdonjh

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Posted 07 April 2020 - 09:18 AM

I suppose that's not too shocking, especially if the mount was included in that price.  A luxury item to be sure, but not Jeff Bezos territory.

 

Oh, do you have a recent photo of your scope and mount assembled?  I paged back a few pages (not too many) and don't see a photo of your whole project all at once.


Edited by macdonjh, 07 April 2020 - 09:18 AM.


#363 Bomber Bob

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Posted 07 April 2020 - 11:44 AM

$636 was for the complete kit -- scope + mount.  Keep in mind:  The Depression wasn't over, and money was tight for most folks.

 

Here's how she looks right now:

 

Tinsley - Progress Check S01 (Assembled).jpg Tinsley - Progress Check S02 (Assembled).jpg

 

As you can see, I've been nibbling around the edges on the mount.  The head weighs about 100 pounds, and even in chunks it's tough to lift up to my workbench.  

 

Before CV-19, my plan was to take the bare scope tube to JD, and have him powder-coat it dark gray gloss.  Given the circumstances, I may strip off the goofy blue, and re-paint it myself.


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#364 macdonjh

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Posted 07 April 2020 - 01:27 PM

Thanks again.  I also saw your other post about two 6" Cassegrains.  The Tinsley mount, with its bulk and brass is quite Steam Punk.  Too bad it's such a pain for you to move around.


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#365 Bomber Bob

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Posted 07 April 2020 - 01:45 PM

Now that y'all see the pix:  What color would you choose for the mount -- satin black, medium gray, silver, or... something Victorian, like red, green, or blue?

 

- OR -

 

Glossy red or blue scope...  Black or dark gray mount...

 

No matter what, the 3 feet will be black.  My personal standard for pedestals:  black feet + gray / silver column.  Black feet don't show the scuffs from my shoes & such, and the gray column stands out at night.


Edited by Bomber Bob, 07 April 2020 - 02:11 PM.

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#366 macdonjh

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Posted 07 April 2020 - 09:25 PM

I don't know, that weird green-y/ blue looks kind of good with the brass.  Kind of nautical, like something Captain Nemo would have.  You could do the scope and mount in that color, and then use your standard gray/ black for the pier.

 

Of course, a deep red, perhaps half way between fire engine red and maroon would look really good with polished brass.  Perhaps paint the scope and pier gloss red, and the mount head and legs black.



#367 Kasmos

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Posted 07 April 2020 - 09:37 PM

I'd keep it all in the colorless region of blacks and or, greys. Isn't that the how some of them came?

 

My personal problem with colors (especially bright ones), is I'm moody and grow tired of them.

 

Anyway, it looks pretty good now. So if the OTA's tube and the pedestail were both the same gray as the mount, it would keep the same vibe but look even better.

 

That all said, having worked as an artist/illustrator what do I know? grin.gif


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#368 davidmcgo

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Posted 08 April 2020 - 08:15 AM

I like how it looks now!

 

Dave


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#369 Terra Nova

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Posted 08 April 2020 - 09:37 AM

The 10" Cassegrain was $636 in 1935...  $12,000 in today's dollars.

Yes, that was at the height (or more aptly the depths) of the Great Depression!



#370 Bomber Bob

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Posted 08 April 2020 - 03:42 PM

I'd keep it all in the colorless region of blacks and or, greys. Isn't that the how some of them came?

 

My personal problem with colors (especially bright ones), is I'm moody and grow tired of them.

 

Anyway, it looks pretty good now. So if the OTA's tube and the pedestail were both the same gray as the mount, it would keep the same vibe but look even better.

 

That all said, having worked as an artist/illustrator what do I know? grin.gif

I hear ya, Chris.  The blue didn't turn out right -- sure didn't match the cap!  In any kind of light, it looks baby blue.  Some Tinsley Casses had green tubes, and I love how my Dakin 4 turned out -- the yellow brass hardware contrasts with the racing green tube very very well.  And, green is my favorite color, too.  Technically, the Tinsley is post-Victorian, but I do like the reds of some Clark and Brashear fracs that I've seen photos of.

 

The mount, with all those rust spots, needs more attention than the scope.  Black would be a good default choice, I guess.  I'd like to tackle the mount while we're in this work-from-home status.  I'll have to strip ALL of the paint layers off it, polish out the rust, then immediately primer the parts -- we're already in the Summer heat & humidity!  Disassembly ain't no stroll in the park -- it would be easy for me to lose ball bearings getting the axes apart.

 

Thanks y'all for your suggestions.  I'm gotta check out the available Rustoleum colors.  I think a black EQ mount, and glossy red tube would be an eye-grabber, but we'll see...



#371 Bomber Bob

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Posted 28 June 2020 - 01:09 PM

Okay... my Second & Final OTA Restore...

 

As a refresher on the hardware, here's how the OTA breaks down:

 

Saturn Restore 2020 T02 - Optics.jpg Saturn Restore 2020 T03 - Bare OTA.jpg Saturn Restore 2020 T04 - Focuser End.jpg Saturn Restore 2020 T05 - End Ring.jpg

 

Most of the parts are original (except for the secondary's mirror cell), and OLD Brass that can be both brittle & soft at the same time -- oh, joy!  At some point, a head broke off one of the screws holding the back of the mirror cell on.  I had to carefully work it loose after I got the other 2 removed -- without cracking the mirror, that is.

 

The Spider is a nightmare to work with & around.  8 thin brass rods hold the secondary disks in the center assembly.  I tried for almost an hour to un-thread just 1 from that center cylinder, and it would not budge.  So, I will once again paint around the threaded stubs poking out...

 

Majestic did a fantastic job on the re-coat -- KUDOS to this company!!  Y'all won't see the mirrors again until the OTA is 100% ready for them.  They're boxed-up & on a shelf in my Man Cave closet.

 

As a reminder:  That all brass mirror cell & focuser weighs 12 pounds.  Crazy over-build for a 6" Cassegrain.

 

The Tube:  Lots of extra holes that'll get the aluminum filler treatment.  New holes for my 2 re-vamped & matching finders.  I think they're gonna look swooooft.  Tube Color will be Rustoleum Cranberry Satin.  No more Baby Blue!  The tube will be stripped-down to bare aluminum, and a few deep scratches that I tried to paint over last time will be buffed-out (as with my Mogey).

 

I wish y'all could see the tube interior.  For some zany reason, Tinsley put pairs of small brass tabs / buttons at random locations from front to back.  I see no purpose in them, but maybe an antique scope guru will chime in.  The tops are about 3mm across, and they're almost flush with the tube wall.

 

A couple of cosmetic details:  One, I don't like the original focuser clamp.  It's LONG, and gets in the way.  Two, with the new paint, do I re-polish all the brass, or leave the patina it's acquired since the last time? The end ring is a pretty reddish brass, while the focuser end has a warm gold to it.  Three, the screws & such.  It was missing the 6 screws for the focuser, so I bought anodized steel Allen-head screws from M-C.  I thought these would be rust-proof.  Nope.  And y'all, this scope is inside a dry & clean house 99% of the time.  The same M-C hardware on mounts & such out in the shed have lots of rust.  I'm disappointed with M-C.  Their parts cost more than Lowes / Home Depot, and I expect better.

 

The Springs are Sprung!  Note in the first photo those 3 long springs that help adjust the primary mirror cell.  1 is wider than the other 2, and it is loosey-goosey!  I found some smaller diameter black anodized steel springs at Lowes, but I'd have to stack 2 for each bolt to match the original length.  In use, that 1 spring could shift the mirror, and I'd have to adjust.  Took just seconds, but I want a firmer solution.


Edited by Bomber Bob, 28 June 2020 - 01:42 PM.

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#372 Bomber Bob

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Posted 01 July 2020 - 10:39 AM

It's another work-at-home day, but I took a break this morning to start stripping the Baby Blue off the tube.  I'm using a 4" disk-brush with brass bristles in my drill.  Takes more time, but using just the weight of the tool, won't dig scratches in the aluminum.  Kinda cool to watch those paint layers melt away.  This afternoon, I'm gonna start on a pair of brass-column brackets for my small finder.  

 

I'll post pix when I do the aluminum filler on all those excess holes in the tube.  For a small taste of Eye Candy...

 

Small Finder

 

TL24 Finder Scope S01 - Restore (Top).jpg TL24 Finder Scope S02 - Restore (Bottom).jpg TL24 Finder Scope S04 - Restore (Optics).jpg

 

This brass beauty came from an antique Adelaide (mounting holes on the tube bottom).  Its objective is a thin, uncoated, cemented doublet with a 24mm clear aperture, and about ~220mm focal length or F9.  The "donut" at the eyepiece end held a tiny glass reticle, and 4 equally tiny brass thumbscrews positioned that reticle.  The eyepiece housing is threaded for focusing on the reticle.  Very nice rack & pinion mechanism with a single knob on the right side.  Views are pretty bright given its age & original purpose.  I may decide to add a cross-hair reticle at the original spot...

 

It was in a 1960s Edmund-style bracket, and those steel screws made stains on the brass that'll I'll have to polish out.  I'm cannibalizing the brackets from an ESC 24mm "jewel" finder for the brass & gray ones that'll coordinate with the Large Finder.


Edited by Bomber Bob, 01 July 2020 - 12:51 PM.

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#373 oldmanastro

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Posted Today, 06:58 PM

It's another work-at-home day, but I took a break this morning to start stripping the Baby Blue off the tube.  I'm using a 4" disk-brush with brass bristles in my drill.  Takes more time, but using just the weight of the tool, won't dig scratches in the aluminum.  Kinda cool to watch those paint layers melt away.  This afternoon, I'm gonna start on a pair of brass-column brackets for my small finder.  

 

I'll post pix when I do the aluminum filler on all those excess holes in the tube.  For a small taste of Eye Candy...

 

Small Finder

 

attachicon.gifTL24 Finder Scope S01 - Restore (Top).jpgattachicon.gifTL24 Finder Scope S02 - Restore (Bottom).jpgattachicon.gifTL24 Finder Scope S04 - Restore (Optics).jpg

 

This brass beauty came from an antique Adelaide (mounting holes on the tube bottom).  Its objective is a thin, uncoated, cemented doublet with a 24mm clear aperture, and about ~220mm focal length or F9.  The "donut" at the eyepiece end held a tiny glass reticle, and 4 equally tiny brass thumbscrews positioned that reticle.  The eyepiece housing is threaded for focusing on the reticle.  Very nice rack & pinion mechanism with a single knob on the right side.  Views are pretty bright given its age & original purpose.  I may decide to add a cross-hair reticle at the original spot...

 

It was in a 1960s Edmund-style bracket, and those steel screws made stains on the brass that'll I'll have to polish out.  I'm cannibalizing the brackets from an ESC 24mm "jewel" finder for the brass & gray ones that'll coordinate with the Large Finder.

This is such a nice and interesting project on a superb telescope that I will continue following it right through the finish line. BTW, I sort of like that blue tube color. It goes well with the brass. In any case that classic Tinsley will always  look great.

 

Guido



#374 macdonjh

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Posted Today, 08:54 PM

I also do not hate the gray-blue color.  I thought I'd read earlier in this thread it is a close match to the original Tinsley color?

 

That said, I can't say I oppose using red, either.  I'll bet the right shade of red will look really good with that polished brass trim Bomber Bob is working so diligently on.  I had an urge for a red scope, so I did this:

 

19 first light.jpg

 

Not as ambitious, or as complete a job, as Bomber Bob's project, but it gave me something to do while I wasn't spreading germs.  Having the rotating ring and a flocked OTA has made a significant improvement in usability and a small gain in contrast. The original GSO flat black paint wasn't bad, but Proto-Star flock is better.




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