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Criterion Dynamax Quality or Junk?

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#1 Robert Frenette

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Posted 02 October 2015 - 10:05 AM

I work for a school, and came across a Criterion Dynamax 8'' telescope in mint condition. The only parts missing are the eye piece mount, and the eye piece.

I have found another telescope , the same thing on ebay for 400 to 600 bucks. Is it worth spending the money on , or should I just go to best buy and spend 400 on a new computerized scope.

Please advise. 

Bob Frenette



#2 Ken Sturrock

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Posted 02 October 2015 - 10:19 AM

You might enjoy reading through our own Uncle Rod's Used CAT Buying Guide.


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#3 Jon Isaacs

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Posted 02 October 2015 - 10:19 AM

I recommend reading Uncle Rod's Used SCT Buyer's Guide.. Uncle Rod is Rod Mollise who has written at least two books on SCTs plus other book and articles... 

 

The Criterion Dynamax 8 is listed the Dog Pound Section:

 

"Was the Dynamax 8 just a telescope that was ahead of its time?

 

Sadly, no. There’s a lot bad about the Dynamax, starting
with the optics. I don’t doubt some good scopes were
produced, but after 40 years I have yet to run into a
Dynamax whose optics were any better than fair. Many
of them were poor, very poor—some I’ve tried being
nearly unusable."

 

Jon


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#4 orion61

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Posted 03 October 2015 - 01:59 PM

If someone with experience can look through it, that is the only way I would buy it if I were you. I have 2 Outstanding Criterion Dynamax Telescopes. I also had one that wasn't very good.

A lot of the bad reputation is from the last year of production, they had drained their funds so badly on the lawsuit with Celestron that nobody but the Lawyers Won.  EVERYTHING had to go out the door, recently people have been finding that many suffered from poor final assembly, off centered secondary and Correctors. Primary Mirrors mounted on the cells tilted, Zones in the poor float glass in  correctors that should have been rejected. Another thing is bad scopes getting sold and resold MANY times on the used Market because they were bad. Also I cant tell you how many people bash them that have NEVER owned or looked through one. That is the one that peeves me. My DX6 is every bit as sharp as my Celestron C6 SCT as a matter of fact I sold the Celestron.

I am familiar with the scope on Ebay (the early Grey one) It has great optics and is as good or better than most Celestron C8's built at the same time. Unfortunately you just never know when a klunker is going to show up.

For students I believe a safer bet would be finding a used Celestron C8. Even most of the Meade 8" SCT's made in the 80's have only fair optics, but you hardly hear anybody bashing them.

If you are only looking for Deep Space only viewing any 8" SCT will work, it is when they have to earn their keep by providing

high power detailed images is where they, fall on their face along with the Meade 2080 (from 1980-1987), and many of the Halley era telescopes.

The scopes being sold for $500.00 that are computerized are probably not going to be the highest quality, A used Celestron NexStar 5, or 6 SE are close to that price. I would stay away from the ETX line, there is just too much plastic for me.

Good Luck.


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#5 Gil V

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Posted 03 October 2015 - 03:45 PM

I don't understand. Are you considering buying the school's scope, or some random EBay scope?

Pics of school's scope, please.

#6 Jeff B

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Posted 03 October 2015 - 04:29 PM

Crap.  Optically and mechanically.  

 

We got them into the shop fairly often in trade for a C8.  Then we wised upped and said no.



#7 Robert Frenette

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Posted 06 October 2015 - 09:22 AM

Thank you so much for all your help. All of your suggestions, and input, have been very helpful. 


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#8 Gil V

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Posted 06 October 2015 - 06:09 PM

I'd be willing to buy the school's telescope if I can get some details.
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#9 rmollise

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Posted 07 October 2015 - 03:28 PM

I was offered a Dynamax for free a while back. Turned it down. No point. ;)


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#10 bobhen

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Posted 07 October 2015 - 04:46 PM

If I was offered a D8 for free, I would also turn it down but that is because I don’t need one. It has nothing to do with the telescope.

 

I owned a D8 back in the seventies and it was an okay telescope. Was it crap optically – no. Was it perfect optically – no. It tracked well and the tripod was first rate.

 

On one night with steady seeing my D8 delivered a decently sharp view of Saturn at 333x, always did a respectable job on the moon, and delivered deep sky detail and views about the same as a 6.5 or 7 inch Newtonian. It’s not like the views were always a blurry mess or never came to focus.

 

SCTs are notorious for slow thermal equilibrium and the D8 was even slower with its resin tube. I think that is “one” of the reasons that the scope gets bad press.

 

I’ve only looked through one other D8 and the view of M27 through that D8 would rival the view through any other 8” SCT.

 

I cannot tell how many D8s were better or worse than mine but I have a strong suspicion that mine was about average for that model and time.

 

If most D8s were crap or unusable, why would they not have been returned? Would anyone today accept a telescope that produced nothing but blurry views? Then why would amateurs back then?

 

I’m sure there are many people in the world who cannot afford a telescope that would love to have my old D8 and would be wowed by the views it delivered.

 

Bob


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#11 Gil V

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Posted 07 October 2015 - 06:36 PM

When we built them, if anyone had an issue with the optical quality of the Dynamax, we spoke to them on the telephone, and we brought back anything that the customer deemed unacceptable.

You tell me no other company shipped a set of sub-par optics in the 1970's.

I'm keeping my Dynamax, and I use it regularly.

To each, their own.
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#12 rmollise

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Posted 08 October 2015 - 09:59 AM

I have no doubt there are good Dynamaxes out there. It's just that in the 40+ years between then and now I've never encountered one. A couple that were average optically. Mostly poor ones. And the occasional crazy-poor one. So undercorrected that it was nuts. The fours and sixes tend to be especially nasty.

The closest I have come to the Good Dynamax is the B&L 8001 Pro, produced after Criterion was sold. Good scope. As good mechanically as a C8? Probably not, but good anyhow.

Edited by rmollise, 08 October 2015 - 10:00 AM.


#13 bobhen

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Posted 08 October 2015 - 12:06 PM

I don’t know what the percentages are compared to other scopes or even among D8s but there were also some pretty nasty 70s and 80s Meades and Celestrons produced. Sky and Telescope did a optical QC test back in December 1989 that showed what was what.

 

In that test, S&T tested 3 Celestrons and 3 Meade 8” SCTs. The Meade LX5 was basically unusable. A Celestron Classic had and I quote “the roughest optics with several narrow but pronounced zones”.  So in the S&T test, “one third” of the scopes tested were very poor/poor, one third were decent, and one third were good. None were what anyone would consider really great optically.

 

According to most things are better today but we are not talking about today’s SCTs we are talking about SCTs that were produced back in the 70s and 80s.

 

Bob



#14 rmollise

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Posted 08 October 2015 - 02:45 PM

I don’t know what the percentages are compared to other scopes or even among D8s but there were also some pretty nasty 70s and 80s Meades and Celestrons produced. Sky and Telescope did a optical QC test back in December 1989 that showed what was what.

 

In that test, S&T tested 3 Celestrons and 3 Meade 8” SCTs. The Meade LX5 was basically unusable. A Celestron Classic had and I quote “the roughest optics with several narrow but pronounced zones”.  So in the S&T test, “one third” of the scopes tested were very poor/poor, one third were decent, and one third were good. None were what anyone would consider really great optically.

 

According to most things are better today but we are not talking about today’s SCTs we are talking about SCTs that were produced back in the 70s and 80s.

 

Bob

 

Meade didn't produce any SCTs in the 1970s. The Newtonians and refractors they sold in the 70s were generally outstanding optically.

 

Nobody's saying Celestron and Meade didn't produce some dogs during Halley, but their average was, I'm sorry, still much better than Criterion's, which was just pitiful.

 

;)


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#15 DuncanM

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Posted 08 October 2015 - 03:13 PM

My B&L 2001 8001 arrived (circa 1990) with a loose primary mirror. However I was able to examine the diffraction pattern (by pointing it at Polaris) and it showed the cleanest airy rings of any SCT I've ever owned and I was very excited about it's potential. However, as I related in an earlier thread, after B&L "fixed" the loose primary, it then exhibited a triangular diffraction pattern typical of pinched optics.

 

I expect that had I repaired the primary myself or locally, that it would have been an excellent scope.


Edited by DuncanM, 10 October 2015 - 01:02 AM.


#16 Gil V

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Posted 08 October 2015 - 06:19 PM

I grant you that the Dynamax 8 is a bit of a crap shoot. Try before buy. There are good models out there.

However, I would suggest you are way off base with your opinion about the Dynamax 6 optics. Those scopes were outstanding. You may have never seen a good one, but I've never seen a bad one.

And I've looked through one hell of a lot of Dynamax telescopes.
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#17 rmollise

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Posted 08 October 2015 - 06:52 PM

I've looked through many, many as well with uniformly poor results. But glad to hear you've used some good ones. ;)



#18 orion61

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Posted 09 October 2015 - 11:58 AM

I feel like I am in the middle of a puppet show..



#19 orion61

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Posted 09 October 2015 - 12:17 PM

All I know is I have a B&L 6000 that I would put up to and win head to head with any Standard Celestron 6" in every way, except coatings, I have looked through. I sold my Celestron 6 when I got the 6000 because it out performed the Celestron on Doubles and Planetary, (which I am into). I have owned 2 C6 SCT's.

My Dynamax 6 is very good as well. My experience has been exactly opposite, the 6" Dynamax and B&L were quite a bit better than the majority of the 8" sold the last 18 months of Criterion Production.

Even if Most were only fair, I cannot believe a Company could keep selling them for 8-10 years.

I could even believe the last gasp year at Criterion put out more bad DX8 than good, I also don't trust opinions on used scopes from that era that have been resold to countless others, where one tube could see 15 different owners claiming every SCT was trash, (Like the Article here where after looking through one Dynamax the author proudly proclaims EVERY Dynamax to be Junk at the end of it.

There was a point I could have honestly said every Meade made up to 1985 and every Celestron 8 made during Hally's latest return I had looked through were nothing more than fair.

I have to be satisfied the Dynamax opinion will always be the ugly Step Child of the SCT world, especially to the people that bash every one, while never owning or looking through one..



#20 rmollise

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Posted 09 October 2015 - 12:23 PM

If you're referring to me, I'm not "bashing." I'm just relating my experience. I'm glad you're happy with these old scopes. That's fine. But my experience is that I've never seen a better one than barely average. Bottom line? I don't want a novice or an uninformed person buying the proverbial pig in a poke. :lol:



#21 Binojunky

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Posted 09 October 2015 - 12:28 PM

People ask for sound advise and when they get it do not want to believe what they read, how sad, :( I had one many years ago and it was a total dog. An absolute waste of hard earned money, no wonder they went out of business.TD.


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#22 TG

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Posted 09 October 2015 - 12:41 PM

There's a B&L 8001 on Astromart right now. They were said to be the best of the bunch with very good optics. If it weren't pickup only, I would be tempted.

 

 

Tanveer.


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#23 rmollise

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Posted 09 October 2015 - 01:50 PM

The 8001 is a completely different proposition than the Dynamaxes or the other B&Ls. It's a good scope. Generally as good optically as a C8, if maybe not quite as good mechanically. I certainly admired them during the 80s. Shame that when B&L finally got it right they decided to get out of the telescope biz.



#24 Robert Frenette

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Posted 09 October 2015 - 02:25 PM

I just bought a Celestron 127EQ powerseeke.

I haven't had a clear night to try it out yet, but I cant wait. The anticipation is killin me. I have never had a telescope before, so this will be my first time. I don't even know what to expect. I am new at all of this, and was surprised to see how much was involved. I am very interested n getting into this, And to think it all started by trying to find an eye piece for this Criterion Dynamax 8. who would have thought. 

Thanks 

Bob F 



#25 rolo

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Posted 09 October 2015 - 09:32 PM

I work for a school, and came across a Criterion Dynamax 8'' telescope in mint condition. The only parts missing are the eye piece mount, and the eye piece.

I have found another telescope , the same thing on ebay for 400 to 600 bucks. Is it worth spending the money on , or should I just go to best buy and spend 400 on a new computerized scope.

Please advise. 

Bob Frenette

I highly recommend someone with experience to test it out before you buy. If its one of the old Criterion models don't walk away from it, run from it! :step:

I've had four in search of a goof one and I finally gave up searching. Horrible performance despite adjusting and collimating every thing to perfection. The best one was a B&L 8000,Jupiter was a white ball with barely any contrast. Imaging with webcam just for kicks did show detail but you had to process the heck out of it. Lots of sharpening, saturation and contrast enhancement. You may get lucky as I have read a couple of guys here have found good ones...Test before you buy! The one on ebay has been relisted four to five times in the past month and no one wants it.


Edited by rolo, 09 October 2015 - 09:33 PM.



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