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Questar Design Change History

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#26 Optics Patent

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Posted 20 July 2018 - 08:56 AM

I was responding to the question "How did Questar avoid bankruptcy?"  by clarifying that they didn't avoid it.



#27 Chris Lord

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Posted 20 July 2018 - 09:26 AM

So was it a coincidence bankruptcy occurred in July 1996 a few months before Peggy Braymer died?

#28 Chris Lord

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Posted 20 July 2018 - 09:54 AM

Also is there a Patent for the Denny triple pass meniscus lens design?
Chris Lord
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#29 Billydee

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Posted 20 July 2018 - 12:16 PM

Chris,

 

This may help, a little:

 

http://www.questarco...com/dknight.htm

 

Bill



#30 Optics Patent

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Posted 27 November 2018 - 01:23 PM

To supplement the discussion of purple colors, I decided to compare the blue colors from 1957, 1993, and current (50th Anniversary) - shown in order left to right:

 

IMG 0485
 
The shiny 1957 is darkest and most vivid.  The middle 1993 is also shiny, but a slightly greener tone and less indigo.  The modern 50th Anniversary model appears almost identical to the 1957, but it a matte or frosty surface.  This is shown better below in a onse to nose comparison, but I think the direct sun-lighting is concealing more differences that it reveals.
 
IMG 0487


Here they are in the same order in diffuse lighting.  The addition of dew shields to the two available reveals somethings greater differences in color in one scope and era than between scopes.  This will remain somewhat of a mystery.
 
IMG 0488

 

Several photographs at Company Seven of a 1956 reveal a much lighter blue moon map than the 1957 above.


Edited by Optics Patent, 27 November 2018 - 01:38 PM.


#31 Pragmatist

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Posted 27 November 2018 - 05:38 PM

I never fail to be impressed with seeing these stunning instruments in a line up.


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#32 R Botero

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Posted 28 November 2018 - 02:50 AM

Interesting!  grin.gif

 

In my case, my (now sold) 1992 Duplex was somewhat darker than my (current) 1960 Standard. Both great though!

 

Roberto

 

 

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#33 Pragmatist

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Posted 28 November 2018 - 04:46 AM

Interesting!  grin.gif

 

In my case, my (now sold) 1992 Duplex was somewhat darker than my (current) 1960 Standard. Both great though!

 

Roberto

Nice scopes. Interestingly I was in Orpington the other day. 



#34 Optics Patent

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Posted 30 January 2019 - 03:45 PM

I've done some research (going back through nearly 20 years of AM ads for the second time after they changed the old indexing system) to answer some design change questions.

 

First, I found that the R.A. ring changed design from the 0, 10, 20, 30...350, to the modern 0, 20, 40, 0, 20, 40... around 1999.  8-10852 was the last with the old (the last I found of 1988 production code), and 10921 is the oldest of the new.  If anyone has any intervening serial numbers they can report it would fine tune the transition.

 

Second, I have been curious about the design of the R.A. and Declination knobs.  Some have a machined circumferential groove at the midline of the knurling, and some are knurled without a groove.  Note that the Dec knob has a large flange and these are not interchangable.  What I found was this:

 

1954-1967: R.A. ungrooved, declination grooved.  My Cutaway #7-2980 happens to be the last I have in the records. 

1967-1973: Both grooved.  7-QTZ-3038 is the first I have of these.  5389 is the last.

1974-1985: R.A. grooved, Declination ungrooved (opposite of the 54-67 configuration).  5404 is first, 8856 last.

1985-present: Both ungrooved.  Starting with 8935.  This coincides with the switch to flat leg hole plugs from the screw plugs.  But, from 86-91 they reverted to grooved Declination knobs, presumably using up some back stock - except that grooved dec hadn't been used since 1973 so perhaps there was a supplier change or confusion - this was about 1000 knobs - maybe a order batch size?).  After 1-10156 grooves are no longer found.

 

There are a small number of exceptions to these patterns in the earlier era that are presumably explained by replacement of missing or damaged knobs.  For instance, 1342 has both ungrooved, but also mismatched arm logo caps.  2132 has both grooved and an odd vinyl case for 1964, suggesting a factory visit.

 

I hope this may be helpful to anyone seeing to restore or correct a scope to the details of the appropriate era.


Edited by Optics Patent, 30 January 2019 - 04:28 PM.


#35 Optics Patent

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Posted 30 January 2019 - 04:59 PM

Lens caps.

 

Preliminary research:

 

Questar originally did not include a lens cap, and the scope fit snugly in the case with the instruction booklet covering the corrector at top.  I've never encountered one without a lens cap, either because I haven't encountered one that old (my earliest is 1961) or because most owners of early models have acquired caps.

 

Here's what I have found:

  1. All metal caps made from a solid piece of aluminum, black anodized except the from rim which is machined bright.  Weight 83-100 grams.  Seen on scopes from 1962 (83g), '66, '79, '83 (91-100g).
  2. Ultralights.  Thin metal rings with synthetic panel glued in (these often come loose and need re-gluing).  26-27 grams.  My 1974 and 1961 have these.  1961 was a re-glue I did and presumably not original.  This era ended 1978 (#7040 is the last noted)
  3. Modern massive.  ~7/32" thick plate. 114-118 grams (more than a quarter POUND).  These boat anchors are found on my 1993, 2008, and 1963 that was serviced in 2016.  These may lack the bright rim and be all black with a visual weight to match their mass.  Current orders are all black, and an upgrade to trimmed can be requested at additional cost.

For a seven-pound scope that touts portability, I think that going from a 1-ounce cap to a 4-ounce cap is giving away needless portability.  Perhaps there's room in the aftermarket for an old style cap with a carbon fiber insert panel routed to receive a Questar badge?

 

Question: were the ultralights the original, or were there the lighter metal caps that preceded?  (Transition date?)


Edited by Optics Patent, 31 January 2019 - 04:05 PM.


#36 Gregory Gross

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Posted 11 July 2019 - 05:21 PM

1961  Change in focal length and F-number from 1070mm, f12 to 1280mm, f14, with some production of 1156mm.  (Source: Company 7)


I'm digging into the minutia surrounding when Questar changed the focal length of their 3.5" scopes and what those focal lengths were. Company 7 notes that early production models "had a nominal effective focal length of 1,070 mm at f/12." Company 7 further notes on another page that "by late 1961 Questar made several changes to the design of the main optics." This change resulted in Questar implementing "an intermediate production focal length of 1,156mm before finally settling in on 1,280mm that has been the standard for Questar 3-½ telescopes since."

My 1962 Questar has printed on the underside of the OTA a visual focal length of 50.5", f/14.4.

The spec sheet that Company 7 has posted for the currently-produced 3.5" Questar indicates that the basic visual focal length is "50.5 inches, f/14.4, 1300mm." (A side note: 50.5 inches = 1282.7mm. Further, 89mm [the clear aperture of the 3.5" Questar] x 14.4 = 1281.6mm. But who's counting a few stray millimeters here or there?)

I'd love to know if anyone with a 1961 Questar can tell me if their OTA indicates what Company 7 describes as an intermediate production focal length of 1156mm. I wonder how rare those are.

I'm also curious to know if anyone who has a newer Questar (one built in, say, the past ten or twenty years or so) can tell me what is printed on the bottom side of the OTA for visual focal length. Is it still indicated as 50.5", f/14.4?

Edited by Gregory Gross, 11 July 2019 - 05:38 PM.

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#37 spereira

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Posted 11 July 2019 - 06:22 PM

I purchased my Q 3.5 Standard new last year at about this time.

 

My optical tube states:  Variable focal length.  Visual: 50.5”, f/14.4.  For close coupled cameras: 56”, f/16.  With reflex housings, or ext. tubes: 64”, f/18.

 

Hope this helps!

 

smp



#38 Matt Looby

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Posted 11 July 2019 - 06:51 PM

Basic of 1300 mm is probably ballpark since the Q has a moving primary.



#39 Chris Lord

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Posted 11 July 2019 - 07:27 PM

My Questar is #1-1118 April 23rd 1961. It's 1280mm focal length.

 

Chris Lord


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#40 Optics Patent

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Posted 11 July 2019 - 08:39 PM

There was also the later change that lengthened the barrel to reveal maybe 1cm length of the corrector cell forward of the moon map and dew shield (and bane of custom case fitters).

What optical specs might that have changed?

#41 Kevin Barker

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Posted 12 July 2019 - 12:31 AM

The 1300 mm reflects the 3.5 x 14.4 equals 51 " focal length in mm to two significant figures.
I bet this reflects the slight variations that occur due to distances between mirrors and slight variations of their radius of curvature.

#42 Gregory Gross

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Posted 14 July 2019 - 01:41 PM

Does anyone have any definitive information about when Questar started to offer quartz as a primary mirror substrate?

As Company 7 notes, "by 1963 Questar customer would be offered the choice of the standard Pyrex® Primary Mirror or at extra cost the more thermally stable Quartz Primary Mirror substrate." Later, as Company 7 also notes on the same webpage, Questar started to offer Cervit mirrors as a replacement of quartz in 1967.

But Questar Corporation itself notes that, in 1950 (they probably meant 1954, the first year that they started sales), "the Standard (Deluxe) model was produced in two mirror types, Pyrex and Quartz."

There would seem to be a conflict in Company 7's account vs that of Questar Corporation.

A quick internet search revealed this Astromart listing for a 1961 Questar (#1-1101), which, as the seller claims, has a quartz mirror. This suggests that Questar began offering quartz mirrors as an option much earlier than 1963.
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#43 Matt Looby

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Posted 14 July 2019 - 03:33 PM

My quartz is 52 years young and it is still a super fine lunar and planetary weapon. 


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#44 Optics Patent

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Posted 14 July 2019 - 04:48 PM

The Questar ad in the December 1957 Sky and Telescope magazine first offered the Quartz version for $1100.
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#45 Toddeo

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Posted 14 July 2019 - 05:57 PM

My '69 Quartz turned "50" this yearband2.sml.gif


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#46 Chris Lord

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Posted 25 July 2019 - 07:44 AM

Just learned my Questar Standard #1-1118 was made on 10/24/61, for William MacQuitty the director of, "A Night to Remember".

Chris Lord 🙂
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#47 Gregory Gross

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Posted 19 August 2019 - 12:29 PM

1972  Change from Konig/Erfle to Brandon.

In the opening post for this thread, Ben noted that Questar switched away from the "Made in Japan" Konig/Erfle eyepieces and changed to Brandon eyepieces. But on Questar's website there is an article entitled "Eyepieces Used by Questar" that identifies an interim period of early Brandons between 1968 and 1972. Does anyone have a Questar of this era with Brandons that are different from the modern, post-1972 Brandons?

#48 JHollJr

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Posted 19 August 2019 - 01:39 PM

In the opening post for this thread, Ben noted that Questar switched away from the "Made in Japan" Konig/Erfle eyepieces and changed to Brandon eyepieces. But on Questar's website there is an article entitled "Eyepieces Used by Questar" that identifies an interim period of early Brandons between 1968 and 1972. Does anyone have a Questar of this era with Brandons that are different from the modern, post-1972 Brandons?

There have been threads earlier in this forum that explain that the eyepieces for Questar’s in the time frame you suggest are not brandons, but Questar eyepieces. I have a 1970 Questar and the 16mm and 24mm of this type.


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#49 Gregory Gross

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Posted 19 August 2019 - 02:01 PM

There have been threads earlier in this forum that explain that the eyepieces for Questar’s in the time frame you suggest are not brandons, but Questar eyepieces. I have a 1970 Questar and the 16mm and 24mm of this type.

Are these different from the eyepieces that Questar produced between 1979 and 1983 (again, see "Eyepieces Used by Questar")?

Without having tried to search for the threads you reference, would you include a link or two to those threads?

#50 JHollJr

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Posted 19 August 2019 - 02:13 PM

Are these different from the eyepieces that Questar produced between 1979 and 1983 (again, see "Eyepieces Used by Questar")?

Without having tried to search for the threads you reference, would you include a link or two to those threads?

I don’t have a link offhand to that thread, but have a memory of it, because it applied to my eyepieces. Your link is where I got my information, but was referred to that article by the thread here.


Edited by JHollJr, 19 August 2019 - 02:15 PM.



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