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Criterion Dynamax 8 question

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#1 NVDW

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Posted 05 February 2020 - 01:29 PM

While browsing the local Craiglist, I stumbled on this one.

I have read some threads about this already and it seems it's not the best brand out there.

Would this be worth it?

Seller claims it's from the 90's???

 

Prices in Europe seem to be higher than in the US. Just saying :p

 

https://www.2dehands...sPage=mympBuyer


 

#2 Chuck Hards

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Posted 05 February 2020 - 01:33 PM

I've owned four of them, both old and newer style.  My advice:  If you want one for decoration, buy it.  If you want one to use on the stars, the DX8 is not the scope for you.  Never found one with good optics.


 

#3 Stellar1

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Posted 05 February 2020 - 01:51 PM

Be aware, those scopes have reputations of being real dogs, as a novelty scope, just to say you have one is a good reason to get it.


 

#4 Augustus

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Posted 05 February 2020 - 02:36 PM

That's a rare one with black forks from right before the B&L buyout. Weird that we just saw someone else with one of these post on here. They are not common......


 

#5 NVDW

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Posted 06 February 2020 - 03:41 PM

Thanks all for the info.
I indeed read that these can be stinkers, well most of the time, they are.
Seller claims optics and mechanics are good. But what is good.... I admit that I don't have the skills to judge the quality.

I'd love to have it for 'fun' but is the price OK?
Not that I have money to burn too...

There is a black C8 from I believe the 90's for sale too. All so tempting :)

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#6 Augustus

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Posted 06 February 2020 - 03:43 PM

Thanks all for the info.
I indeed read that these can be stinkers, well most of the time, they are.
Seller claims optics and mechanics are good. But what is good.... I admit that I don't have the skills to judge the quality.

I'd love to have it for 'fun' but is the price OK?
Not that I have money to burn too...

There is a black C8 from I believe the 90's for sale too. All so tempting smile.gif

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I would not pay over 200-300 Euros for one.


 

#7 Chuck Hards

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Posted 06 February 2020 - 03:45 PM

Not most of the time, all are bad.  There is not one instance of a DX8 with documented "good" optics.  Since the problem is due to their method of corrector figuring, none of them can possibly be good unless they were re-figured by an owner.

 

I would wager that either the seller can't tell good optics from bad, or just wants to sell the scope.  Having gone down this path four times myself, I would not pay anything.  I wouldn't even take it if it was given to me.  


 

#8 NVDW

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Posted 06 February 2020 - 03:46 PM

I would not pay over 200-300 Euros for one.

I'd buy it for that price but I don't believe the seller has that price in mind...

Thanks for the advice Chuck, I'll follow it with utter confidence!

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Edited by NVDW, 06 February 2020 - 03:48 PM.

 

#9 Ben H

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Posted 06 February 2020 - 04:29 PM

I haven't seen one DPAC test that showed good optics.
I have heard from people who were well satisfied with the optics.

That is probably more an indication of the low bar people set for telescopes, but I think its worth mentioning. 

DAVIDG spent a fair bit of time polishing up his DX8 corrector, but not sure I ever saw the final result. Its something I plan to do some day with mine.

Optically they may be dogs, but mechanically they're excellent. A shame. 

 


 

#10 Ben H

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Posted 06 February 2020 - 04:32 PM

That's a rare one with black forks from right before the B&L buyout. Weird that we just saw someone else with one of these post on here. They are not common......

That is only the 2nd one I've seen. Its also the only one I've seen with the cursive "Dynamax 8" script on the OTA, and Dynamax on the tripod legs. 

In theory there should be no way it was made in the '90s, since Bausch and Lomb had already bought Criterion and converted everything to their brand. 


 

#11 G-Tower

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Posted 06 February 2020 - 04:41 PM

Had one in the 70's, returned it. They sent me another one that was just as bad. Sent it back...good riddance!


 

#12 NVDW

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Posted 06 February 2020 - 04:48 PM

Well I'm not going to spend my money on a rare **** it seems. Probably he won't let it go for 200'ish. Sone people think they have gold.

Thanks for the info all, really appreciate it!

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#13 Steve Allison

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Posted 06 February 2020 - 05:25 PM

The blue 6 inch model I had looked really cool but the optical quality was abysmal.


 

#14 CHASLX200

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Posted 06 February 2020 - 07:00 PM

Never gave one a thought let alone buy one.


 

#15 tim53

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Posted 06 February 2020 - 11:44 PM

Not most of the time, all are bad.  There is not one instance of a DX8 with documented "good" optics.  Since the problem is due to their method of corrector figuring, none of them can possibly be good unless they were re-figured by an owner.

 

I would wager that either the seller can't tell good optics from bad, or just wants to sell the scope.  Having gone down this path four times myself, I would not pay anything.  I wouldn't even take it if it was given to me.  

Hey, you made me pay for the two I got from you!lol.gif

 

No worries.  I bought them for the optical challenge of refiguring the corrector.


 

#16 NVDW

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Posted 07 February 2020 - 02:10 AM

Hey, you made me pay for the two I got from you!lol.gif

No worries. I bought them for the optical challenge of refiguring the corrector.

Lol!

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#17 highfnum

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Posted 07 February 2020 - 02:19 AM

I have one

I keep it because of its bad boy rep

here is problem 

the corrector plate is very rough 

this adds noise to the image 

think of it like a radio playing nice music with load cracking noise added

here is ronchi

underlying optics - mirror are not bad but corrector is bumpy 

notice bumpyness of lines

one shot no processed film shot of moon

dy8ronchrelaxed.jpg

dy8filmmoonsml.jpg

 

 

 


 

#18 highfnum

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Posted 07 February 2020 - 02:24 AM

well made scope otherwise

one of best asyc tracking at the time IMHO

dy8sec.jpg

 

 

 


 

#19 highfnum

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Posted 07 February 2020 - 02:29 AM

for compare 

a celestron ronchi 

notice lines are smooth 

c925ronc1.jpg


 

#20 NVDW

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Posted 07 February 2020 - 02:35 AM

Those images are indeed bad. Not worth the price he asks then. Too bad, I always like outsiders...

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#21 bobhen

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Posted 07 February 2020 - 07:35 AM

The scope in question could not be a 90s scope. The black looks like it was painted on and a decal applied.

 

If people think that Meade and Celestron were only producing gems back in the day then they haven’t read the December 1989 S & T review of 6 Meade and Celestron 8-inch OTAs. The Ronchi bands in the Meade’s look horrible. One Meade was completely unusable as tested. The Celestrons showed rougher optics than the Meades. None of these scopes could be called excellent or even very good optically by today’s standards.

 

I owned a DX8 and in my example yes the planets, (particularly Jupiter) being mostly low contrast objects, got soft too quickly. But the deep sky views were fine and about equivalent to a 6 or 7-inch good quality Newtonian. The moon being a mostly high contrast object held up better than the planets and could take reasonable magnification.

 

There are better choices on the used market. If purchasing one make sure it comes with the Golden Field tripod and make sure the price is low enough that reselling the tripod alone will cover all of your initial costs.

 

Below is a lunar drawing I did many years ago using the DX8.

 

Bob

 

Attached Thumbnails

  • IMG_0050 (1).jpg

 

#22 NVDW

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Posted 07 February 2020 - 08:07 AM

According to the label, this is the golden pyramid no? But in black now....
It's highly possible that they put some labels on the legs since Dynamax is written with an I instead of an Y.

A good price hmmmmm. Europe seems to have higher prices here on the second hand market. I browse local sites here and so far never saw one.
But paying 600€ is a bit too much for me, but as stated before, he will want the maximum out of it.

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#23 G-Tower

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Posted 07 February 2020 - 08:13 AM

You would be better off with an 80mm refractor, short tube ED or long focus achromat...


 

#24 NVDW

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Posted 07 February 2020 - 08:20 AM

I know there are better things to buy but this would be a nice Classic display thingy that sometimes gets used.
There are better things to throw money at... :)

My LX90 is my main scope and recently I bought an ES AR127. So enough for now even though a 80mm grab and go refractor would be nice...

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Edited by NVDW, 07 February 2020 - 08:23 AM.

 

#25 Chuck Hards

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Posted 07 February 2020 - 08:29 AM

Hey, you made me pay for the two I got from you!lol.gif

 

No worries.  I bought them for the optical challenge of refiguring the corrector.

 

Yeah, and you got the best of the lot (along with the worst, lol).  That grey one you got was one of two older ones that performed OK up to medium powers.  

 

Like you, I am still thinking of refiguring a corrector in retirement, but I am also entertaining the idea of transplanting Celestron optics into one.  As has been pointed out, the mechanicals are very nice and intuitive.


 


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