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Why I Love My Dept Store Scope

classic equipment refractor
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#1 Bomber Bob

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Posted 27 May 2020 - 06:15 PM

Good Grief!  My 1st Love thread was for a... reflector.  What kind of life-long Refractor Fan am I?  Okay, here's my make-up thread...

 

Sears 6336 - 1964 Catalog Page.jpg

 

Yeah, I'm talking about my 1964 Sears Model 6336 Professional-type Motorized Observatory.  It was the first scope that I spent more than $1000 for, and here's what I got:

 

P020 - First Assembly FULL RS CN1.jpg P016 - First Assembly FULL CN01.jpg

 

Dusty & dirty, but otherwise mint and 99% complete -- missing the cardboard box that the mount & pedestal came in.  The OTA & accessories came in a wood case with Styrofoam inserts.

 

While this model is rare, the Astro Optical 76mm F15 refractors are all over the place, and were branded & sold by other importers.  It pays to look for that funky maker's mark on the label!


Edited by Bomber Bob, 27 May 2020 - 06:21 PM.

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#2 Stellar1

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Posted 27 May 2020 - 06:31 PM

That is a beauty! love the look of those old refractors, that is quite a long pier! is it stable enough? I am inclined to think it shakes like a tuning fork when the controls are moved. 


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#3 Bomber Bob

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Posted 27 May 2020 - 06:33 PM

Astro Optical put a lot of thought & craftsmanship into this model.  IMO, pretty gutsy to put a 3" refractor on a pedestal in the first place -- makes it the smaller cousin to the mighty Tasco 20TE.

 

So many things to love about this scope, but as usual it boils down to The Views.  And, those start with the lens:

 

S028 - Objective After Cleaning.jpg

 

It really is a gem.  Near-perfect DPAC pattern.  Textbook star tests.  Incredible resolution for 3" aperture.  Takes magnifications up to 100x per inch without going soft.  This image is a pretty good example of what it can show:

 

Sears 6336 - Jupiter (GRS) 20170514V06A64S99.jpg

 

The ring / rind is an artifact from me trying to get the Galilean Moons brighter with my new ZWO ASI120MC imager.


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#4 Bomber Bob

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Posted 27 May 2020 - 06:40 PM

That is a beauty! love the look of those old refractors, that is quite a long pier! is it stable enough? I am inclined to think it shakes like a tuning fork when the controls are moved. 

Glad you asked!  This was the first pedestal that I did my foam disk + polyfill stuffing technique.  I also replaced the original leveling bolts with rubber casters:

 

P12 - Full Left Side CN1.jpg P19 - Full Right Side CN2.jpg

 

Before these improvements:  Yes, if I tapped the pedestal or the scope, it would vibrate for a couple of seconds.  Now, routine nudges, focusing, swapping eyepieces, etc. it settles within a second or so.  The best technique is to engage the clock drive, and make as few big adjustments as possible.  And, I removed those long springy cables -- knobs with short rods replaced those crazy oscillators!

 

Restoration was mostly on the EQ mount.  I broke it all down, scrubbed away the original "sticky" black grease, and re-lubed with the red automotive grease.  Both axes are now slick as greased lightning.

 

After I got the Tak EM-1S, I stopped using the original mount.  It's mainly a Display now, and I have it positioned by the door to my Man Cave.  When it's open, I can see my antique Mogey 3" refractor in the living room in the background as I admire my Sears 6336.  They're both pointing up at about the same angle -- a pretty sight:

 

Mogey 3 - Complete (R Side Diagonal) S11.jpg


Edited by Bomber Bob, 27 May 2020 - 06:51 PM.

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#5 Senex Bibax

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Posted 28 May 2020 - 08:20 AM

Is the 6336 the predecessor of the 6339, or were they contemporary? Both are RAO 76mm f/15 scopes.



#6 oldmanastro

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Posted 28 May 2020 - 09:41 AM

The 6336 is the model that I always drooled over while looking at it in the old 1960s Sears catalogs when I was 13. I can't complain. In 1966 I was the proud owner of the tripod mounted twin, model 2535. Before that I already had the altazimuth mounted model 2620. This one showed me the first views of the planets, moon and Messier objects under a much darker sky 55 years ago. Without my Dept. Store telescopes I would have never made it into this wonderful hobby. They are both with me and still showing me the night sky. I love them both.

 

 

Attached Thumbnails

  • Scope60Alta.JPG
  • 76mmRefrac.JPG

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#7 LDW47

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Posted 28 May 2020 - 09:55 AM

The 6336 is the model that I always drooled over while looking at it in the old 1960s Sears catalogs when I was 13. I can't complain. In 1966 I was the proud owner of the tripod mounted twin, model 2535. Before that I already had the altazimuth mounted model 2620. This one showed me the first views of the planets, moon and Messier objects under a much darker sky 55 years ago. Without my Dept. Store telescopes I would have never made it into this wonderful hobby. They are both with me and still showing me the night sky. I love them both.

I have always loved that color and oh yea the scope itself is pretty nice, lol !  Clear colorful skiys !



#8 Bomber Bob

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Posted 28 May 2020 - 11:55 AM

Sears Model 6336 - Mounting Options...

 

Vixen Polaris + Eagle Surveyor Tripod:

 

Sears 6336 OTA on Polaris Eagle T02.jpg

 

Yes, that's a Unitron Unihex hanging off the focuser.  Now that's a Portable Observatory.

 

Takahashi EM-1S + Filotecnica Surveyor Tripod:

 

Sears 6336 OTA on Takahashi EM1S S02.jpg

 

This is the most stable portable solution for the 6336, and the eyepiece height at/near the zenith is more comfortable than with the Mizar SP.

 

Goto 106 + Unitron 142 Tripod:

 

Sears 6336 on Goto 106 and Vixen FL80S on Mizar AR-1 S05.jpg


Edited by Bomber Bob, 28 May 2020 - 11:58 AM.

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#9 photiost

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Posted 28 May 2020 - 02:26 PM

Wow !!  

 

Great combinations and they all look fantastic !!


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#10 photiost

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Posted 28 May 2020 - 03:05 PM

Can't say enough about the optical quality of these RAO 76.2mm refractors.

 

I sometimes bring one to Public outreach / star parties and many people often comment on the "very sharp images" 

 

... I have a few of these RAO 76.2mm refractors ... from the serial # the one in the middle is an earlier model ... all are amazing performers.

.

  

 

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  • Tasco IMG_2142 b crop.JPG

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#11 Bomber Bob

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Posted 28 May 2020 - 03:30 PM

Colorful Eyepieces...

 

Sears (AO) 6 EP Set S02.jpg

 

Cool as they look, they don't let these Astro Optical refractors show what they can really do.

 

My first solution:  vintage Swiss-made spectros .965" eyepieces:

 

spectros Eyepiece Set 20160721 S01.jpg

 

Now, we're cooking with gas.  75x / inch was routine in even average seeing, and on 8+ nights, 100x / inch stayed sharp.

 

After a post on this Forum, I started looking at ways to use 1.25" accessories with these dual-drawtube scopes.  Hence, the Vixen 36mm -> 32mm adapter rings + a Vixen 1.25" adapter:

 

Sears 6336 with Vixen 36mm to 32mm Tubes T02.jpg

 

Kinda awkward, and goofy looking, but it works.

 

My current solution was an accident:  I found the top half of an old Televue Barlow in a box of astro-junk, and...  Eureka!  It's thread matched the 30mm manual draw-tube / coarse focus.  So, I keep the flexibility of that long tube, and I have the rack & pinion, and I only swap it on when I use the 6336.  The original is on for Display purposes.


Edited by Bomber Bob, 28 May 2020 - 03:33 PM.

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#12 grif 678

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Posted 28 May 2020 - 04:51 PM

Good Grief!  My 1st Love thread was for a... reflector.  What kind of life-long Refractor Fan am I?  Okay, here's my make-up thread...

 

attachicon.gifSears 6336 - 1964 Catalog Page.jpg

 

Yeah, I'm talking about my 1964 Sears Model 6336 Professional-type Motorized Observatory.  It was the first scope that I spent more than $1000 for, and here's what I got:

 

attachicon.gifP020 - First Assembly FULL RS CN1.jpgattachicon.gifP016 - First Assembly FULL CN01.jpg

 

Dusty & dirty, but otherwise mint and 99% complete -- missing the cardboard box that the mount & pedestal came in.  The OTA & accessories came in a wood case with Styrofoam inserts.

 

While this model is rare, the Astro Optical 76mm F15 refractors are all over the place, and were branded & sold by other importers.  It pays to look for that funky maker's mark on the label!

Did you buy it second hand, because the price on the ad in the first picture says $329, and you paid $1000 for it. I bought a Sears 76mm just like oldastroman's second picture, what great views of the moon and planets, even with the sub par eyepieces. The rivet in the bottom of the mount base, which connects the mount to the base, finally got wobbly, the only complaint I ever had about the scope.



#13 Bomber Bob

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Posted 28 May 2020 - 04:57 PM

Did you buy it second hand, because the price on the ad in the first picture says $329, and you paid $1000 for it. I bought a Sears 76mm just like oldastroman's second picture, what great views of the moon and planets, even with the sub par eyepieces. The rivet in the bottom of the mount base, which connects the mount to the base, finally got wobbly, the only complaint I ever had about the scope.

That first picture is from the 1964 Sears Catalog...  $329 way back then, and $2700 in 2020 dollars...


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#14 Bomber Bob

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Posted 29 May 2020 - 12:16 PM

Can't say enough about the optical quality of these RAO 76.2mm refractors.

 

I sometimes bring one to Public outreach / star parties and many people often comment on the "very sharp images" 

 

... I have a few of these RAO 76.2mm refractors ... from the serial # the one in the middle is an earlier model ... all are amazing performers.

.

Considering how many AO made, I'm really surprised by the consistent quality.  Much higher than TOWA, but the AO models were more expensive -- makes sense.  I've seen a few (usually in Australia) AO 76mm F15 refractors wearing the ROYAL label, and was sorely tempted to nab one, even though I'm sure they're the same OTA as my 6336.  Just thought it was an impressive badge!


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#15 foxshark

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Posted 29 May 2020 - 12:52 PM

Question for this (probably biased) audience - what's the consensus about .965 eyepieces in the modern world?

Now that I've asked a loaded question, allow me to give the context! I'm a computer person for my day job, so for my leisure I have always appreciated the hard to quantify notion of "mechanical delight", that seems to peak around the 1950's to early 1970's before plastics and computers took over. Nikon F2, Leica M4, that sort of thing. I understand the concept of deriving enjoyment from the process of use, not just the end result. There is almost always a cheaper, newer way to get an end result if you are not concerned with how you get it. 

I fully understand that a 1950's 3"ƒ/10+ doublet is a categorically different animal than say a modern 60-80mm APO both in design, material science, and coatings. What I do not feel that I grasp is the .965 eyepieces that you see with this (relatively) small aperture long FL scopes. The exit pupil of most eyepieces I have seen look tiny, and I wear eyeglasses to make matters worse. How wide of an eyepiece can you reasonably go with these kinds of refractors? 20mm? 15mm? Can you realistically see much beyond planets and maybe splitting very bight double stars with that aperture?

One of the best viewing sessions I have ever had was through a 4" Unitron with a nice TeleVue Panoptic; but that's quite a bit beyond 2-3" aperture that we consider "department store" type Sears, Swift, Tasco, etc classic refractors. My primary scope is an orange tube C8 (poor collimation, dirty optics, and obviously no modern coatings) with the standard 20/40mm Kellner eyepieces. To that end, I love the looks and the classic simplicity of the department store GEM refractors, but am curious if the 0.965 eyepieces would be too much of a point of contention.



#16 Bomber Bob

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Posted 29 May 2020 - 01:41 PM

Question for this (probably biased) audience - what's the consensus about .965 eyepieces in the modern world?

 

I don't think there is a consensus.  My 6336 came with a bundled set of eyepieces (plus prisms, Sun & Moon filters, & Barlow) that's about average for the complete package retail price at that time.  Simple designs, very narrow fields, & almost no eye-relief.  Typical, really.  Can't blame the Japanese makers entirely, as the importers and/or retailers had a price point they thought they could sell at.

 

The best bundled set I have came with a 1958 Goto -- but it was a more expensive telescope.  Same traits as the 6336, but better optics & hardware.

 

42 years ago (Ouch!!), I saw potential in my 1978 Tasco (Towa) 80mm F15, and upgraded it to 1.25" accessories, and bought Meade (Tani) Modified Achromatic (low power) & Research Grade Orthoscopics (high power) eyepieces -- and really saw the difference.  Ditto for this better-grade 1964 Astro Optical refractor, except I lucked-out and got the set of spectros .965" Kellners & Plossls.  My reason for adapting the Vixen Barlow piece to the 6336, and thus using 1.25" stuff, is to use more modern eyepieces & diagonals.  My Baader Prism + Televue eyepieces bring out about all this old refractor can show -- but that's still quite a lot.

 

If you're asking:  Should the .965" format be a big negative factor in buying a vintage telescope?   That's an individual decision.  Some make great Displays, whether they're ever used or not.  I have 3 sets of great to outstanding .965" accessories (almost 4 sets, counting the Zeiss), so the small accessory size isn't a factor for me.  If I had no .965" eyepieces, it still wouldn't be a factor, as most of these scopes can be adapted to standard 1.25" format.


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#17 foxshark

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Posted 29 May 2020 - 02:20 PM

 If I had no .965" eyepieces, it still wouldn't be a factor, as most of these scopes can be adapted to standard 1.25" format.

Oh, really? I was under the impression that image circle would not support a 1.25" eyepiece, but that's why wanted to ask! Of course this brings up the secondary issue of modifying a collectible telescope; even a dogged out, poor condition vintage scope might look strange with a modern two-speed GSO crayford. I imagine there are photo and discussion threads here about such a thing.



#18 Bomber Bob

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Posted 29 May 2020 - 03:45 PM

I wouldn't replace a focuser entirely, but others do, EXCEPT for my Reflectors.  I put a vintage Astro Optical rack & pinion on my RV-6.  The original is just too primitive & coarse for the high-power work this scope can do.  And, I just put a new Lumicon helical focuser on my Meade 826.  The original Japan-made 1.25" unit was okay; but again, the scope deserved a more precise focuser for high-power.  AND, I just replaced the 2" focuser on my 6" F5 Newt RFT with a low-profile 2" r&p so I can use my 1.25" eyepieces with it.  But Stubby isn't a Classic -- just a 40+ year old ATM scope with Edmund Scientific mirrors...

 

My Classic Refractors... nope.  Won't swap those focusers out.  My "mods" to these are thread-in rings, adapters, & such that make it easy to use 1.25" accessories.  All the mods are reversible -- like the 3rd photo in my earlier post.

 

Here's the old Televue Barlow mod I've referred to, threaded into the 6336's 30mm manual drawtube / coarse focus tube:

 

Sears 6336 - Televue 125 Adapter S01.jpg

 

What's great about this mod is that it also works with the focus tube on my 1958 Goto 60mm F20.  So, there were some industry standards between makers all those decades ago.  Sweeping the Milky Way with the 6336's original Green 22mm Kellner is nice, but pop the 1.25" Edmund RKE 28mm Space Walk eyepiece in the Baader prism, and it goes to Wow!


Edited by Bomber Bob, 29 May 2020 - 04:07 PM.

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#19 foxshark

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Posted 29 May 2020 - 04:47 PM

Here's the old Televue Barlow mod I've referred to, threaded into the 6336's 30mm manual drawtube / coarse focus tube:

Oh, I see what you mean, and yes that makes sense with a 1.25" barlow tube coupler/half. I did not realize that the draw tubes commonly had multiple threading options back then.

 

Off topic, why do you see such long draw tubes on high ƒ number classic telescopes? For terrestrial use?



#20 Bomber Bob

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Posted 29 May 2020 - 05:08 PM

Oh, I see what you mean, and yes that makes sense with a 1.25" barlow tube coupler/half. I did not realize that the draw tubes commonly had multiple threading options back then.

 

Off topic, why do you see such long draw tubes on high ƒ number classic telescopes? For terrestrial use?

I think AO & Towa did it to keep the wood cabinets shorter -- and cheaper.  Yamamoto & others at that time didn't, hence the much longer tubes -- and cases.  On the plus side, that long pull-tube gives you flexibility on all kinds of accessories & doo-dads, like modern digital imagers & such.



#21 Wildetelescope

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Posted 29 May 2020 - 05:35 PM

Question for this (probably biased) audience - what's the consensus about .965 eyepieces in the modern world?

 

I don't think there is a consensus.  My 6336 came with a bundled set of eyepieces (plus prisms, Sun & Moon filters, & Barlow) that's about average for the complete package retail price at that time.  Simple designs, very narrow fields, & almost no eye-relief.  Typical, really.  Can't blame the Japanese makers entirely, as the importers and/or retailers had a price point they thought they could sell at.

 

The best bundled set I have came with a 1958 Goto -- but it was a more expensive telescope.  Same traits as the 6336, but better optics & hardware.

 

42 years ago (Ouch!!), I saw potential in my 1978 Tasco (Towa) 80mm F15, and upgraded it to 1.25" accessories, and bought Meade (Tani) Modified Achromatic (low power) & Research Grade Orthoscopics (high power) eyepieces -- and really saw the difference.  Ditto for this better-grade 1964 Astro Optical refractor, except I lucked-out and got the set of spectros .965" Kellners & Plossls.  My reason for adapting the Vixen Barlow piece to the 6336, and thus using 1.25" stuff, is to use more modern eyepieces & diagonals.  My Baader Prism + Televue eyepieces bring out about all this old refractor can show -- but that's still quite a lot.

 

If you're asking:  Should the .965" format be a big negative factor in buying a vintage telescope?   That's an individual decision.  Some make great Displays, whether they're ever used or not.  I have 3 sets of great to outstanding .965" accessories (almost 4 sets, counting the Zeiss), so the small accessory size isn't a factor for me.  If I had no .965" eyepieces, it still wouldn't be a factor, as most of these scopes can be adapted to standard 1.25" format.

Got to love those vintage 3 inch F15 achromats.   I like the combination of my Towa and my Brandons.   Really sharp views.  My young son's favorite is the little 60 mm F11 Sears/Towa that I got for 50 bucks on Ebay.  It is HIS scope and loves to take it out with me to outreach events.  Got him a Twighlight I mount for Christmas.  Have to say I am always impressed with how sharp the image is in that little scope!  I have a few UO and Orion orthoscopics that compliment it well.  There is definitely a place for these long focal length refractors and people are always surprised at the outreach events when the see how sharp the images are.   What I would really like to find is prism diagonal with a 0.965 barrel that accepts 1.25 inch EP's.  Anyway, it was your posts about these old refractors that got me looking at them!   Always keeping my eye open at flea markets now:-).  

 

Cheers!

 

JMD


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#22 oldmanastro

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Posted 29 May 2020 - 06:56 PM

I have used .965" to 1.25" eyepiece adapters in my Sears 76mm and they work very well. Bomber Bob's barlow mod seems even better. With 1.25" good quality eyepieces these telescopes deliver all the optical excellence they are capable of. Some of the original eyepieces are not so bad either like the 22mm Kellner and in my case the 6mm HM. Well made Huygens eyepieces usually work very well in long focus telescopes. Three of the original eyepieces belonging to the 76mm Sears refractor are Huygens. The worst performing original eyepiece is the 4mm Ramsden. But.. use a good 6mm or 4mm orthoscopic in this telescope and the images are astounding. For low power Plossls are just right.

 

Guido


Edited by oldmanastro, 29 May 2020 - 06:57 PM.

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