A Scope for the Ages or Just Aging?
Posted 11 February 2010 - 07:08 PM
Posted 11 February 2010 - 07:57 PM
With all due respect and saying this in only the best possible way, why is it so difficult for Questar owners to see the obvious?
With all due respect...it was, in fact, frustration with the self-aligning go-to computer controlled scopes of today that led me to the simplicity of the "point-and-view" Questar. To each his own.
Posted 11 February 2010 - 10:13 PM
I would firmly disagree that the utility of the Questar has been eclipsed. It is precisely its simplicity and timelessness that maintains its relevance. It provides a different kind of observing experience that is, in some ways, more immersive than trolling around the sky with goto. The Questar is not for everyone, but for those that appreciate its simplicity and the back-to-basics style of observing it promotes, the Questar simply shines.
Posted 11 February 2010 - 10:28 PM
1. The Gregory Maksutov (terminology corrected as per Barry, thanks) is the simplest, using all spherical surfaces. The secondary mirror has exactly the same curvature as the corrector. This design is used by Meade and Celestron, because it can be mass produced.
2. The Rumak design has separate secondary mirror, which has the advantage of a separate curvature.
3. The Questar design may have no name, but it is quite unique. The secondary is on the same glass as the corrector, but it is ground to an independent curvature. The secondary has an aspheric curvature, figured by hand. This is a very expensive process, but the secondary can never go out of alignment. The aspheric element provides superior optical performance, but this has apparently escaped the notice of many amateurs.
But the superiority is widely exploited by the U.S. Government. The earth observation telescope on the International Space Station is a Questar 7. The design, which is also produced by Davro, is used uniformly by the U.S. Government for law enforcement, military surveillance, and intelligence gathering.
On the subject of craftsmanship, I have a feeling that many of the general public, perhaps including astronomers, have perhaps not seen enough fine work to really know what it is. The mass market companies have pretty much succeeded in convincing the buyer not to look beneath the surface. But fine machine work is not simply a matter of something being "pretty."
Open up another "very popular brand", and you will see a mirror that rides on a film of grease, plastic gears and plastic fasteners. Open up a Questar, and you will find work as good as a Rolex, which is why you can send a forty year old Questar in for freshening, and it will be as good as new. In fact, there is no plastic at all in a Questar, save the tiny transparent indicator on the right ascension axis.
Precision machine work is difficult to appreciate. I will post some pictures soon.
Posted 12 February 2010 - 04:11 AM
One thing which is not commonly understood is that the Questar optical design is significantly different from Meade and Celestron clones. They are only superficially clones. There are three types of Maksutovs with an axial viewport.
1. The Gregorian is the simplest, using all spherical surfaces. The secondary mirror has exactly the same curvature as the corrector. This design is used by Meade and Celestron, because it can be mass produced.
Posted 12 February 2010 - 05:23 AM
The Questar is not for everyone, but for those that appreciate its simplicity and the back-to-basics style of observing it promotes, the Questar simply shines.
Wow Brian, well said!
This is one of the things I love about my Questar. Last night, I spent roughly 7 (!) hours at the eyepiece of my Questar 7 and was stlll reluctant to go inside and get some sleep. This telescope totally gets out of the way and lets me observe the universe. Mars was absolutely breathtaking and got 95% of the time, with small excursions to the deepsky and rising Saturn.
One of the things I also enjoy about the Questar 7 is it's ability to use both a Binoviewer at the axial port and regular viewing and searching through a Brandon in the regular eyepiece holder. Last night I used my Baader bino with 2 TV 15mm WideFields and the 12 mm Brandon on top. Great combination.
And then there are the optics. The incredible optics. The amazingly sharp and contrasty optics. Polar cap in white, surface color in salmon/yellow orange, beautilul dark surface details all over the globe in many shades of gray including deep dark black.
NO DEW after 7 hours in -10 C, the synchronous motor quietly running. Dec and RA manual control smoothly adjustable, finder- and barlow flip-levers working wonderfully.
Fully cooled optics and mechanics giving a perfectly calm and stable image. The image was so sharp I dared inserting my 4mm Zeiss to observe the polar cap and the dark delineation aound it. A bit dim, but very sharp. Optimum monocular was my 7 Nagler, giving a little bit more magnification then my 12 Brandon barlowed. I guess the perfect ocular for last night would have been the 6mm Brandon that I don't have (yet). Hmmmm......
Anyway, the Q was smootly cruising at around 400x most of the night, providing a wonderful imagescale, brightness and contrast to observe Mars. It actually looked BIG.
Before I get to excited I better stop and wish you all clear and stable skies where our Questars shine and make us glow!
Posted 12 February 2010 - 07:47 AM
The mid 20th Century was a time of Quality. We now live in a time of quantity, in which for most things, leaves a lot to be desired.
The thing about aging is that you can look back and appreciate that quality, where others can not.
Posted 12 February 2010 - 08:45 AM
Yes, it's superb quality. Yup, it's a classic design and still looks ahead of it's time, over 50 years after it was introduced. Sure, it has many lovely convenience features.
It might not utilize goto technology, or employ the latest polycarbonate construction materials, but for observers who have a good knowledge of the sky resident in their noggins (or who can read a star chart), that's not an issue.
S&T wrote an in-depth article about the Questar in one of their 2002 issues. For folks who are looking for further insights into why Questar has continuing appeal, it's worth checking out that article.
I wouldn't say the Questar is "the ultimate" telescope, for active or inactive observers. However, it's extremely good for an amazingly compact "observatory in a briefcase".
Posted 12 February 2010 - 01:29 PM
Posted 12 February 2010 - 01:45 PM
Posted 12 February 2010 - 01:47 PM
Posted 12 February 2010 - 04:26 PM
Posted 13 February 2010 - 12:34 AM
Posted 13 February 2010 - 05:13 PM
I must be one of those rare types that appreciates fine and inovative engineering. I aim to own a Questar one day.
Posted 15 February 2010 - 05:37 PM
Posted 15 February 2010 - 06:16 PM
Anyone who has ever had a cemented rear view mirror knows that, eventually, it falls off. Thermal cycles shear the bond. The owner of the 7" Meade Mak observed that, when this happens, the baffle will fall on the primary mirror. With that kind of impact, scratches, or worse, are inevitable, and these cannot be fixed by a trip to the recoating shop.
Moral of the story: If you buy a telescope that is glued together, it will eventually become catastrophically unglued. Questar owners will never be bothered by this.
Posted 15 February 2010 - 06:25 PM
Posted 15 February 2010 - 08:33 PM
The Questar 50th Anniversary Edition Telescope by Gary Seronik
November 2002 edition of Sky and Telscope
Posted 16 February 2010 - 04:00 AM
Well, I admit the Q was the BroadBand-coated-version, and I do not know how the Standard-version would have compared, but anyway, mine was so clearly superior to the ETX in brightness and even more so in contrast, that nobody better tries to tell me an ETX is sort of equal optically. (I would severely suspect him to be a concealed Meade distributor or even the manufacturer himself:grin:...)
Posted 16 February 2010 - 12:20 PM
And as much as I love GOTO scopes, over time they do tend to cause your object finding abilities to atrophy, much as excessive use of a calculator can affect our math abilities.
Posted 21 March 2010 - 01:09 PM
The biggest complaint about the Meade 7" was that, because it employed the same tube and mount geometry as the Meade 8" Schmidt-Cass telescopes, it required a substantial internal counterweight to balance the heavier corrector of the Mak. Owing to that increased mass, it apparently was extremely reluctant to reach ambient temperature.
Chalk such shortcomings up to the difference between styling and engineering, and the manufacturering expedience of doing things on the cheap.