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Criterion Dynamax 8 Schmidt Cassegrain Telescope

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#1 mloffland

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Posted 15 December 2009 - 12:54 PM

Criterion Dynamax 8 Schmidt Cassegrain Telescope

#2 Joe Lalumia

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Posted 15 December 2009 - 01:12 PM

HEY! that's my Dynamax SCT you are talking about! :) Look behind me in my SIG picture.

SON! it came with a Golden Pyramid tripod and built-in wedge! What else do you want!

Thanks for bringing back old memories! I sold the scope and tripod to a guy who said he would never part it out but keep it as one unit.

Thanks for the nice article.

Clear Skies!

#3 Clive Gibbons

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Posted 15 December 2009 - 02:01 PM

A non-masochist buddy in our local astronomy club owned (mebbe still does...) one of those Dynamax 8's.
Original light beige and blue color combo.

It wasn't the greatest SCT in the vicinity, but the scope delivered a decent diffraction image. No really gross aberrations. I've heard of others who weren't so lucky. :doah:

Anyways, there's at least one usable Dynamax 8 out there.
If the price is low enough and the potential buyer gets a chance to try 'er out before spending their money, it could be worth a shot.

:shrug:

#4 Feidb

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Posted 15 December 2009 - 02:34 PM

I think they were just in time for the Halley's Comet rush.

#5 Clive Gibbons

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Posted 15 December 2009 - 02:50 PM

The Criterion Dynamax 8 hit the market in the very early '70s.
So, it predated the Comet Halley craze by quite a number of years.

Many of the scope's optical problems could be traced to the way the corrector plates were made. VERY high speed polishing.
The glass would come off the machine steaming hot.
Not a great way to produce a smooth polish or figure.

#6 Zamboni

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Posted 15 December 2009 - 03:07 PM

The Halley's comet craze supply/demand issue is what led to the sharp decline in the quality at Meade and Celestron during the eighties. The Dynamax was already around, and already stinkin' up the joint!

#7 David Knisely

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Posted 15 December 2009 - 03:19 PM

Although the Dynamax 8 was a somewhat poor example of the SCT, it was not the death nail of Criterion. That came when Bausch and Lomb bought them and basically ran the company into the ground. The quality control went south and the company soon folded. I used a Dynamax 8 when I was in college helping the public nights at Behlen Observatory (University of Nebraska). It was OK, but the RV-6 we also had was a better performer. Clear skies to you.

#8 highfnum

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Posted 15 December 2009 - 06:56 PM

the early ones were real bad
later ones were better but never as good as c8

#9 David Knisely

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Posted 15 December 2009 - 07:04 PM

the early ones were real bad
later ones were better but never as good as c8


They weren't the only ones that were bad. Some of the Celestrons came out with some bad optics as well, although in general, the quality control seemed to be somewhat better than that of Criterion's Dynamax series. Over the past ten years or so, optical quality in the catadioptrics has tended to be fairly good, but back in the 1970's and 80's, it was sometimes hit or miss. Clear skies to you.

#10 highfnum

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Posted 15 December 2009 - 07:13 PM

I almost forgot I did a face off between aC 9.25 and Dynaax 8 -- Idid in IR to reduce effect of seeing
here is results
c925
http://www.cloudynig...php?photo=20004


dynamax 8

http://www.cloudynig...php?photo=20003


c925 put it to bed --BUT dynamax image is not that BAD

#11 oldtimer

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Posted 15 December 2009 - 10:09 PM

Was the 6" version as bad as the 8". I hope not as I picked one up last fall. Its out of collimation and I need to get an artifical star to work it back in. Maybe after Christmas.

#12 Barry Kawa

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Posted 15 December 2009 - 10:20 PM

Bausch and Lomb never ran Criterion into the ground. I interviewed John Krewalk Jr. at his home in the late 1990s for a book on the history of commercial telescopes that never came to pass, he was put in charge of the B&L telescope division after Criterion was sold to B&L.
This is all from memory, I never transcribed my 6 hours of tapes with him on the history of Criterion and B&L, but he told me that to a large corporation like B&L, the telescope division was a tiny drop in the bucket, so it had no qualms about discontinuing the line without a second thought when top officials realized that the market for telescopes was so small.
John told me that the B&L 4000 had sold very, very well, and the 8001 and other SCs being made at the end were all fine scopes.
Indeed, I couldn't resist when John offered to sell me all the scopes he had in his attic, several B&L 4000s that were the last off the line, a mint Criterion 4000 and a B&L 6000. All were fine scopes with excellent optical quality. Not as good as my Questar, but not bad scopes.

#13 Joe Lalumia

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Posted 15 December 2009 - 10:42 PM

Barry, I would like to find and buy one of those last B&L 4000 with the table top legs. Everyone says they were very nice scopes. (Especially of the RA motor still works!)

Sure was a PRETTY telescope-- B&L 4000

Joe

#14 David Knisely

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Posted 15 December 2009 - 10:53 PM

Barry, I would like to find and buy one of those last B&L 4000 with the table top legs. Everyone says they were very nice scopes. (Especially of the RA motor still works!)

Sure was a PRETTY telescope-- B&L 4000

Joe


No, I'm afraid that many of the B&L 4000s were not very nice scopes. Their quality control was worse than the Dynamax was (quality varied from fair to nearly unusable). They tended to give oval or triangular star images as the secondaries were sometimes pinched and were hard to collimate. I would suggest avoiding them. Clear skies to you.

#15 Barry Kawa

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Posted 15 December 2009 - 11:09 PM

Well, these B&L 4000s were the ones that Krewalk had chosen for himself, and I tested them on Mars and all gave decent planetary performance, good enough that I didn't mind passing them along. I didn't have a need for that many scopes, and I bought them all for one good price, so I sold them all through a friend's stereo shop near Cleveland where I was living at the time.
I would say if you could test the scope out, you might find a good one, and really like the scope's portability, the black molded carrying case, sleek styling and two decent eyepieces that came with the package. Certainly no Questar, but at about $150-$200 for a used one right now, it's worth it.
I've also found out through the years that there are no absolutes in telescopes, and quality varies on every SC, so I enjoy trying and testing each scope, before passing on them, especially if I can get a good price on it.

#16 Feidb

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Posted 16 December 2009 - 05:03 PM

Thanks for jarring my memory. Got the decades off a bit! I guess I equated Criterion with the Halley craze because the scopes being made during the rush were so crummy. I loved their RV-6 but heard the RV-8 had it's problems.

#17 highfnum

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Posted 16 December 2009 - 09:06 PM

well I found an old deep sky shot taken with
Dynamax 8 -- it will not win apod of the day but
its not that bad

http://www.cloudynig...php?photo=20007

#18 mcoren

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Posted 16 December 2009 - 09:21 PM

I bought a used Dynamax 8 when I was in high school in 1981 through a classified in the back of Sky & Telescope (back in the day when those classified ads used to run for many pages!) It was never great, but it was my first real telescope. I kept it for way too long, finally replacing it with a C9.25 ASGT in 2004.

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#19 TASQUASAR

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Posted 17 December 2009 - 11:51 AM

Hello All

Firstly - this post motivated me to join Cloudy Nights and respond to this post. Thanks to Joe Lalumia for his reply!

Secondly - what I'm about to write will almost certainly label me as a dweeb or schmuck, but away we go anyway. If you want to skip the story of how I got the B&L 8000 just scroll to 'The Low Down' for the pertinent info.

Thus far in my life I've had two scopes. A Tasco Refractor in my youth, regrettably I do not have that scope anymore; and a Bausch & Lomb Criterion 8000 that I still have to this day. So how did I end up with one of the worst, darn near most reviled scopes in history you ask - well read on!

Back in 1988 after doing a stint in the military, I returned home to go to school. My little brothers friend had an eccentric oil millionaire granpa that wanted a scope to look at Halleys Comet. So he telephoned a Camera store which recommended the B&L 8000. Afterall it was a Bausch & Lomb for God's sake. They make good eyewear, surely they must make quality optics!

I was invited over for a social party, and when I saw that thing for the first time on the golden tripod I thought "What the heck is this guy doing with a missile launcher?". As I got closer I just fell in love with the scope. He didn't use it since no one knew how to operate the thing. I volunteered but this guy was more about look and don't touch than the Grinch that stole Christmas. As is often said, I wanted it so much I could taste it!

Fast forward and after his death the scope goes to his son, who also can't use the thing. The son's gig is model trains. So much in fact that he has a very thorough store that no one visits - really. But despite my asking, he wouldn't part with it. Many years latter the family had a medical emergency but no medical insurance, kinda sounds familiar in todays world doesn't it. Reluctantly he sold it to me with a whole slew of extra's, stuff I didn't even know existed. So from 1st sight to eventual purchase was 10 years give or take a couple of months. Talk about delayed gratification.

The Low Down!

OK - I now have this B&L 8000 with a golden tripod with roll around contraption, many B&L eyepieces of multiple designs with barlow, a RFT adapter, Prime focus eyepiece tube for planetary imaging with 'T' adapters for a whole host of camera models, variable frequency DC to AC clock drive, off axis guider with illuminated eyepiece, nebula filter, spectroscopic eyepiece - and other stuff frankly packed away that I haven't even used. Honestly I think this thing is a cross between a B&L 8000 and has some, but not all of the 8001's features, kind of a hybrid of sorts.

Yes, the scope isn't the best, and really performed much, much better when profesionally collimated. The very knowledgeable individual was concerned enough about the optics that he telephoned me to discuss them.

I'm not going to say that their reputation isn't justified - probably so. Folks - I know people who have Dynamax'es, and frankly we swear that they are better than the bad wrap they universally get.

So why do I write about this decrepit SCT wannabe? Because in my opinion it is the best Star Party scope there is!

Star Parties are for the kids, but face it they are gonna almost smash your stuff. What better than an expendable scope? Kids are easily impressed - so this scope looks BIG to them and not much different than the other SCT's on the lot. Put your hands all over the cheap eyepiece, no problem. Move the scope because what you were looking at moved out of view, no problem. At the dark sky site, I left it out overnight and it even endured the dew. Was dripping wet before sunrise, no problem - pointed it into the rising sun and in no time the moisture boiled off - packed up in the supplied cases and off we go! Still works GREAT!

So this scope gets a bad wrap - so what? Maybe if I'd stop drinking Shiner Bock when I observe my visual acuity would go up enough where I'd give a hoot about it not looking like a Hubble Picture.

I learned many lessons using this scope, for instance how to polar align for the first time - a good experience to have - and it tracked so very well. No GoTo - oh gasp - well you better know how to read charts and Star hop. I've had invaluable experiences with this scope!

So it's the junk yard dog of the SCT's you say when at the drag races and doesn't posses the snob appeal of the other entrants at the show - so what! The kids love the thing, afterall it's like a cheap mans Porsche.

So before you rag on a scope - keep in mind that there is no arguing with taste. This scope might be a low down dirty shame, but with a little spice it sure is palatable to this guy.

Sorry for the long rambling post - and more importantly thanks for suffering my feeble writing.

#20 Joe Lalumia

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Posted 17 December 2009 - 12:00 PM

Hugh, great post! and I agree, AND they had a BIG focus knob, that was great for small little hands.

:)

#21 highfnum

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Posted 17 December 2009 - 06:51 PM

Its hard to make a general statement on a telescope brand based on one copy - too small a sample, SCT's made in 1970's varied alot -- some very good , some OK, some bad-- based on the one copy I used its "average"

#22 Darenwh

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Posted 18 December 2009 - 11:57 AM

One really good thing for that scope. Golden tripod is, IMHO, still the nicest looking OEM tripod out there ever offered with an SCT.

#23 Mark Swanson

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Posted 13 November 2012 - 11:37 PM

This review should be taken down. It is not credible. You cannot tell if a SCT is collimated just by looking into the back of the scope. You have to have a star image that is defocused at moderate to high magnification to accurately check collimation. This is just a hit piece.

Mark Swanson

#24 David Knisely

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Posted 14 November 2012 - 12:53 AM

This review should be taken down. It is not credible. You cannot tell if a SCT is collimated just by looking into the back of the scope. You have to have a star image that is defocused at moderate to high magnification to accurately check collimation. This is just a hit piece.

Mark Swanson


Agreed. This was more of a rant than a "review", and does the Dynamax 8 something of an injustice. It provides little to back up its statements, and is too short and slanted to be of much use. As I said, the Dynamax quality control varied somewhat, but the 8 inch units I used were at least passable, although again, not the best (but the same could be said of some C8's at the time). Clear skies to you.

#25 orion61

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Posted 01 December 2012 - 09:59 AM

I almost forgot I did a face off between aC 9.25 and Dynaax 8 -- Idid in IR to reduce effect of seeing
here is results
c925
http://www.cloudynig...php?photo=20004


dynamax 8

http://www.cloudynig...php?photo=20003


c925 put it to bed --BUT dynamax image is not that BAD

That Dynamax image isn't bad at all. Your compairing a smaller scope made before computer controll, not to mention the 9.25 has a slightly different optical configuration (slower Primary)
Compair the performance of a 1976 Vega to a new car.
I have a Dynamax 6" SCT the DX6 that has superb optics!
even compaired to my NexStar C6 SCT. the C6 is brighter
but not sharper.






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