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Questar Standard Restoration - advice?

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#76 Optics Patent

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Posted 08 July 2019 - 09:07 PM

I updated my previous post to reflect $145 for a 1.5” replacement element.

I saw $20 for a used one, presumably left over after an upgrade, likely pinhole riddled.

I grabbed that because I have an original housing with broken element that came in a collection of stuff. If not too pinholed can fill an empty spot in a case. 



#77 dougspeterson

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Posted 21 July 2019 - 06:36 PM

The Panoptic 19mm (68x, 140x) is a favorite single ocular solution.

 

The Explore Scientific 68degrees are similar in reputation to the Panoptic, fatter, quite a bit cheaper. I tried the 20mm in the Questar (65x, 130x). Although I was expecting the onset of vignetting it is not at all clear there is any! Natch the barlow steps the apparent field down quite a bit—that will be true of any wide field, and not a problem for me—to approximately Brandon level.

 

I was afraid the fatter body would not allow the case door to close, but it does. The ES 24mm 68deg flat out does not fit. Neither does the tubby Baader 8-24mm. You cannot close the door.

 

Note I have not confirmed the finder focus w the 20mm.

 

The 82deg 150x 8.8mm ES Nagler-esq on sale might be an attractive 2 ocular solution. I do not know if it fits the case, nor parfocal w the 68 series, nor finder focus.


Edited by dougspeterson, 21 July 2019 - 06:52 PM.


#78 dougspeterson

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Posted 21 July 2019 - 06:38 PM

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#79 dougspeterson

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Posted 21 July 2019 - 08:47 PM

Elsewhere on CN in April a user posted interesting relative focal positions of the 68 and 82 degree series

 

eyepiece        position (mm)
4.7 ES 82       63.5
6.7 ES 82       65
8.8 ES 82       64
11  ES 82       66
14  ES 82       63.5

16 ES 68        64.5
20 ES 68        64.5
24 ES 68        63.5

 

 

Note the 8.8 and 20 are close to parfocal. They have about the same bulk, 8.8 slightly narrower and slightly taller, neither likely to fit in the ocular pocket in the door, but probably will fit the PG controller pocket.


Edited by dougspeterson, 21 July 2019 - 08:56 PM.



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