Questar 3.5" 50th Anniversary

[TerryC]

I have been lucky enough to purchase a Questar 3.5" telescope from USA. The previous owner, now deceased, apparently bought the Questar as an investment and never used it despite being purchased in 2007 !

To make it suitable for use downunder I have cut the centre leg by approximately 40mm. This makes it suitable for use as far north as the Sunshine Coast (26.5 deg South!). In addition I have added a 1kg counterweight which fits snuggly on the centre leg.

[strongmanmike]

Awesome, never looked through one but heard all the stories. Grew up staring at S&T ads for them and dreaming, especially about the 7"...:)

I assume you meant 26.5 deg S..?

Mike

[TerryC]

Photo with counterweight. I'd prefer stainless steel to match the Questar looks !

[TerryC]

Oops, yes !

[FlashDrive]

They are nice alright ... Quartz Mirror ...??

Col.

[strongmanmike]

Yeah, but still looks good :thumbsup:

Mike

[strongmanmike]

Is the meniscus 88.9mm or 90mm?

[TerryC]

Yes, it has a quartz mirror.

The Questar 50th Anniversary telescope differs from the regular production models in the following ways:

- The moon map, the star chart, and the RA setting circle are etched and silk screened as was done on the original Questar of 1954. This is intended to give a 3D feel and appearance.

- The primary mirror is made of Quartz (fused silica) for thermal stability, with enhanced protected silver reflective coatings.

- The corrector lens is made of the usual borosilicate crown, but with a durable magnesium fluoride anti-reflection coating on both front and rear surfaces.

- The optics are hand figured to 1/10th wave or better. Each set is professionally certified across the full aperture by an accompanying Zygo GPI interferogram.

- On the lens cover, fork arms and left side at rear of the barrel are special 50th anniversary model logos.

- The Questar Powerguide II Drive and Corrector is installed.

- A full aperture solar filter is provided

- The telescope is delivered with the deluxe leather carrying case, with combination lock.

- Questar 50th Anniversary Telescope bears a serial number with the prefix "50TH" and suffix "SQTZ".

[TerryC]

It's 89mm.
The only opportunity I've had to use the scope so far was to observe the Jupiter - Saturn conjunction. I was stunned at the detail I could see from such a small aperture !

[JA]

Hi Terry,

I agree. That could be "easily" polished/buffed to a similar shiny finish. First strip the paint, preferably non-abrasively if possible so as not to leave any scratches and then polish/buff to a mirror finish.

Best
JA

[TerryC]

Good idea, I might try that !

[strongmanmike]

I bet! :thumbsup:

Mike

[astroron]

I observed M46 through a Questar owned by an American attaché to Expo 88.
It was at an AAQ "Star Party" at Marburg near Ipswich Queensland.
It was in a grave yard of a deconsecrated church.
The view was superb from what I remember.
That is the only one I have seen in real life since.
Cheers:thumbsup:

[TerryC]

I have just completed a tripod mount for the Questar. It includes the following:

- Innorel RT90C carbon fibre tripod
- Williams Optics High Latitude Vixen style base mount
- Custom-built aluminium disc

Note that you need the high latitude mount for use in Australia for mounting the Questar as shown.

I have found that the tripod is rock steady and the WO mount with disc is completely stable with the Questar mounted. I don't feel completely comfortable having one 1/4" bolt to hold the Questar on the mount so I intend to fabricate three soft clips around the base.

I have an as-built drawing of the aluminium disc. It was fabricated from 8mm grade 5085 aluminium and polished after the waterjet cutting.

[TerryC]

There are two bolts which secure the disc to the WO mount. One of those bolts prevents the dovetail slipping through the clamp !

[lfulham]

TerryC,
Your use of wedge and mounting plate is a similar solution to what I did using an AstroTrack base and plate. I machined the plate differently so the base is self centering and one is not feeling for the bolt hole to hold the scope.

I made this from a piece of 12mm alum plate which I had on hand; if buying for the job I would choose a thicker plate so the lip was higher. Even so it works well, a lot better than the flat plate supplied with the Questar Tristand.

I appreciate your thought re holding the scope with a single 1/4 inch bolt but the loads are quite low really.

Len.

[TerryC]

Nice design there Len.

As an engineer I don't like to have a single point of failure, especially given the cost of these babies ;)

[Peter Ward]

I have a mint 1990's vintage Questar 3.5 (broad-band coated) which I picked up in the USA in about 2002.

The 50th Edition you've acquired sounds like a cracker. It's amazing how well they work... even on a table top....Nice pick up. Superb design never dates :thumbsup:

[TerryC]

I think you need to own one to appreciate how good they are :)

[strongmanmike]

I can imagine :prey2:...not quuuuiiite in the same god like league (..almost) but a bit like just about anything Astrophyiscs too ;) :thumbsup:

Mike