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Criterion Dynamax Quality or Junk?

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#26 rolo

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Posted 09 October 2015 - 09:39 PM

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.

Ditto!



#27 rolo

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Posted 09 October 2015 - 10:11 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..

 

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.. I'm not sure this statement is fair because most of the bad I've read has been from folks who have looked through them, not bashers of everyone.


Edited by rolo, 09 October 2015 - 10:13 PM.


#28 rmollise

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Posted 10 October 2015 - 09:18 AM

There's no reason in the world to waste time hunting down and testing one of the Critieron/B&L scopes (except the 8001 Pro). Orange tube C8s are plentiful and can be had for 400 dollars or less and are invariably much better optically and mechanically. ;)

Edited by rmollise, 10 October 2015 - 09:19 AM.

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#29 jgraham

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Posted 10 October 2015 - 09:33 AM

It just goes to show how statistics work. Most are gonna be in the middle, but some are gonna be out on the ends. It just depends on where the middle is. If you are lucky to own something out on the end on the good side, that's fantastic! Me, most of my stuff seems to be in the middle, though I do believe that I've gotten lucky twice; the optics in my 8" LX50 and 10" LX200 seem to be above average. My little 4" 2045 also has good optics (good, not great) which I believe is also on the good side of the curve for this model.

 

Sometimes you get lucky.



#30 Jeff B

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Posted 10 October 2015 - 04:56 PM

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.

 

Agreed actually.  The Max 6's, as we used to call them, that came our way (maybe six or seven used) were very good as a lot as were the RV-6's (and at a great price too).  The Max 8's (similar number as the 6's)...terrible.  I have no idea why the differences.  Good point about the golden field tripod.  They were excellent.

 

Another good point that both Celestron and Meade were pushing crap out the door as well for a while around Halley Mania.

 

Jeff



#31 CHASLX200

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Posted 10 October 2015 - 05:00 PM

There's no reason in the world to waste time hunting down and testing one of the Critieron/B&L scopes (except the 8001 Pro). Orange tube C8s are plentiful and can be had for 400 dollars or less and are invariably much better optically and mechanically. ;)

I agree.  Never saw a good one. Did have a D-6 that was ok years back.



#32 orion61

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Posted 10 October 2015 - 06:11 PM

I have only had one out of my Six Dynamax 6" or 8" scopes that was not at least VG. That one was bought by a member here, that took it apart and when assembled properly ended up having diffraction limited optics.

I still have to have to believe a member that worked for them, that was there to see complaint or lack of them. I also believe any company that could put out scopes and last for 10-15 years doing it, HAD to have had a decent product.

Those that went into the field and were good stayed where they were, and still are, while the bad ones produced the final year of production have been bouncing from user to user gaining the reputation of All are bad. I tracked mine to at least FIVE previous owners.

I would bet each one of the scopes the person posted who tried 4 of them owned had a minimum of 5 or 6 previous owners. Reading stories from people that had reworked underperforming Dynamax telescopes the majority had severe assembly issues. In fact most of the Astigmatism issues were from the Primary mounted improperly. Also the Primary baffles were mis aligned, correctors and secondary mirrors were off centered, this prohibited collimation. It is easy to make comments like just fair, posting optical issues such as rough optics or zones is more helpful there were some with SA, those were mostly produced at the end and should have been rejected.

I have always preferred the mechanics and tripod of the Dynamax, also the resin tubes were more stable from thermal issues when they were at outside temp. 

In other Astronomy sites I haven't seen nearly the percentage of negativity  I have here. We all know this site is heavily sided toward one brand that is fine, but I sold my Celestron when my Criterion Schmidt out performed it, substantially.

BUT I wouldn't buy ANY Schmidt from 1970-1989, unless I could look through it, know the seller, or the seller describes the optics in a way that shows they know what they are talking about, and they are guaranteed good.

For everybody else keep an open mind and look through as many as you can.

I agree with the 4000, it seems about 1/4 of them were just plain awful! I happen to have one that is superb, BUT it took a few Dogs to find it!

I know the Dynamax on EBAY right now and it is superb! and if anybody wants to send ME a Dynamax, unlike some I'll gladly take it! It might be a fun project!



#33 Darren Drake

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Posted 10 October 2015 - 08:40 PM

I'm picking one up tomorrow for free from a craigslist add.  Its a 3 hr drive each way we will soon learn if it was worth tank of gas or not.  Will report back.


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#34 Gil V

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Posted 11 October 2015 - 08:05 AM

Looking forward to an update.

#35 Bomber Bob

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Posted 03 May 2016 - 04:54 PM

About to start my own Dynamax 8 adventure.  This early run (Serial #1941) DX8 was delivered yesterday.  It's as close to pristine as 40+ year old scope can be, and included the original blue case.

 

DX8 - Arrival S01.jpg

DX8 - Arrival S03.jpg

DX8 - Arrival S04.jpg

 

A quick check, and I see already the collimation is off.  Will get that taken care of before star testing this weekend.  Mirror coatings look brand new, and the corrector has a smudge near the secondary holder.


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#36 Mitrovarr

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Posted 03 May 2016 - 07:23 PM

I would avoid them, unless you just want them for the antique or nostalgia value. I've had one for about 14 years now and I've been trying the entire time to make it work, optically. Nothing I've ever done has fixed it (although collimation and flocking helped a little). It's ok for deep sky, as it collects a solid 8" of light (although a scope with more modern coatings would almost certainly beat it) but it's always been bad for planetary and double star use. I had a Sears 76mm F/15 at the same time and it consistently outperformed the Dynamax on planets, the entire time.

 

Any decent 8" dob would be a better purchase on essentially every level.



#37 Bomber Bob

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Posted 03 May 2016 - 08:15 PM

I got this old DX8 for just $250.  If the views are at least average for an 8" SCT, I'll be a happy camper.  If not, it'll do for driving in tent posts.


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#38 Starsareus

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Posted 03 May 2016 - 08:37 PM

While all of my Criterions are Newtonians, I did buy a 8001 from one of their employees. I have only looked through this one SCT and there is NO WAY I would sell this baby. I still have to remind myself that is is NOT a refractor! No issues with scope and contrast is great.  I would buy one again IF I lost this one. But that will not happen . While the tripod sits in my observatory, the OTA is in a bedroom!  I think this is the one to get.


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#39 orion61

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Posted 04 May 2016 - 11:36 AM

That 8001 is one of the finest telescopes ever made. It is a complete redesign of the 8000. they went through one of the toughest QA measures of any mass production scope. Their Coatings were on par with Celestron's Starbright and better than Meade's MCOG and closer to their later EMC.

The secondary obstruction was smaller than Celestron and Meade 8".

It is a shame that B&L jumped out of the SCT market when they did. The 8001 looked different than the 8000 and Dynamax,

the lines were sleek, they went to an Aluminum tube, and the Black and Gold color scheme is still tied with the Meade gloss Blue for my favorite all time. But the biggest thing is, they performed well on every single tube. I have never seen or even heard of a sub-par 8001. That is the reason they get snatched up about as soon as they hit the market.


Edited by orion61, 04 May 2016 - 11:37 AM.

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#40 orion61

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Posted 04 May 2016 - 11:40 AM

I would avoid them, unless you just want them for the antique or nostalgia value. I've had one for about 14 years now and I've been trying the entire time to make it work, optically. Nothing I've ever done has fixed it (although collimation and flocking helped a little). It's ok for deep sky, as it collects a solid 8" of light (although a scope with more modern coatings would almost certainly beat it) but it's always been bad for planetary and double star use. I had a Sears 76mm F/15 at the same time and it consistently outperformed the Dynamax on planets, the entire time.

 

Any decent 8" dob would be a better purchase on essentially every level.

What is the problem it has? it has recently been discovered the optics on many of the poor performers were ok, but there were errors in the final alignment during the assembly. Tilted Primary Mirrors or the whole baffle system, Correctors and secondarys

off center.



#41 Mitrovarr

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Posted 04 May 2016 - 12:14 PM

I've tried to recenter the secondary. It didn't help much, but honestly I'm not really sure how to do it properly.

The star test is a mess. It isn't symmetrical one either side of focus - one way looks good but the other is a disaster. The circles are not clean during a star test either - there are rays and such (even inside with an artificial star) and I think it's all slightly out of circular too. There is at least a little astigmatism. Not much image shift, though, so I guess it at least it has that going for it.

I used it for years and I wouldn't say it's useless. But once I got a 10" dob all I used it for was to try and fix it for fun.

#42 Bomber Bob

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Posted 04 May 2016 - 09:55 PM

Got in a brief first light with my 1974 DX8 tonight.  Collimation is finickier than my Tinsley Cass, but once that's set, this SCT does well on double stars and Jupiter.  Pearly white disk, 6 belts, and brown mottling in the EQ belts at 176x.  Sharper limb than I expected, too.  Didn't have time to let it fully temp adjust, but it did well anyway.  Definitely a keeper, and worth $250.


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#43 Mitrovarr

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Posted 04 May 2016 - 10:22 PM

Got in a brief first light with my 1974 DX8 tonight.  Collimation is finickier than my Tinsley Cass, but once that's set, this SCT does well on double stars and Jupiter.  Pearly white disk, 6 belts, and brown mottling in the EQ belts at 176x.  Sharper limb than I expected, too.  Didn't have time to let it fully temp adjust, but it did well anyway.  Definitely a keeper, and worth $250.

 

That's better than mine does on Jupiter (caps + 2 bands, no mottling). Yours must be a good one. That's great!

 

I recommend, if you have access to a spare visual back tightening ring (say, from an unused photographic accessory that came with the scope), you can replace the ring on a 2" SCT diagonal to make one that fits the scope. Fitting my Dynamax with a 2" diagonal was the best thing I ever did for it. Gives you a much wider field of view than you can get without it and the low magnification helps with the poor sharpness (even if yours is good it helps when the sky is poor or the scope isn't fully cooled down yet).


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#44 Phil Barker

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Posted 06 May 2016 - 02:17 AM

The only one I looked through was described as fair by its owner I guickly realised it wasn't perfect collimation wise.

gave it a wee tweek and it wasn't bad at all excellent detail on Jupiter at 180-200 times I recall.

looked ok alround really very old version too.

#45 Bomber Bob

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Posted 06 May 2016 - 07:54 AM

I haven't taken the secondary assembly apart, but it doesn't hold collimation as well as my Tinsley.  I'll have to tweak it again before I use it for planetary -- it slipped just taking it down from the tripod and moving it back indoors.



#46 Mitrovarr

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Posted 06 May 2016 - 12:02 PM

The only one I looked through was described as fair by its owner I guickly realised it wasn't perfect collimation wise.

gave it a wee tweek and it wasn't bad at all excellent detail on Jupiter at 180-200 times I recall.

looked ok alround really very old version too.

 

I hear the oldest ones and the youngest ones (the ones produced by B&L) are the best, and the ones in the middle are the worst.



#47 Bomber Bob

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Posted 06 May 2016 - 05:45 PM

My main DX8 thread is over on the Classics forum --> http://www.cloudynig...rion-dynamax-8/

 

Mine is an early model, and performs competently, which seems to confirm some of the reports.



#48 orion61

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Posted 06 May 2016 - 11:51 PM

Got in a brief first light with my 1974 DX8 tonight.  Collimation is finickier than my Tinsley Cass, but once that's set, this SCT does well on double stars and Jupiter.  Pearly white disk, 6 belts, and brown mottling in the EQ belts at 176x.  Sharper limb than I expected, too.  Didn't have time to let it fully temp adjust, but it did well anyway.  Definitely a keeper, and worth $250.

Hi Bob, if your comment on the collimation is from what I believe it to be, you can tweak the system further yet!

With the highest power eyepiece you have, look at the Airy Disk as it is coming into fine focus. If it is perfect coming to focus on one side of focus but it isn't quite centered on the other side of focus, either and/or both the secondary holder is off centered a little 1/16" or so. OR the whole corrector is off center. I had one that went from fair-OK, to VG plus.

If that is what it is, faint and fine detail will jump right out at you!!!

Good luck my Classic friend

Duane


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#49 Bomber Bob

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Posted 07 May 2016 - 09:09 PM

I measured & made sure the secondary holder was centered both before & after cleaning.  But, I didn't verify that the mirror itself is centered in the cell.  That could be an issue.  I know with my Tinsley that the first holder I made let the mirror slip too much horizontally, and I fixed that in the new & improved version.  The Criterion unit is lighter and probably flimsier than mine, but I didn't have to worry about weight.


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#50 DuncanM

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Posted 09 May 2016 - 03:34 AM

One thing that I liked about the Dynamax is the overall appearance. They just look really cool!

 

C-8s looked crude in comparison.




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