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Criterion Dynamax

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#1 ANM

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Posted 11 July 2020 - 10:07 AM

There's a rather complete looking Criterion Dynamax 8, includes tripod and table top legs, on eBay...


Edited by ANM, 11 July 2020 - 10:10 AM.


#2 Terra Nova

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Posted 11 July 2020 - 10:08 AM

I think I would look right on past it! :lol:


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#3 ANM

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Posted 11 July 2020 - 10:34 AM

I think I would look right on past it! lol.gif

No good? 

 

It's got the AltAz/Equitorial tripod and table top legs, tripod bag...



#4 Terra Nova

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Posted 11 July 2020 - 10:35 AM

Nope, no good. They're a legend in the annals of bad telescopes. They look good but they're not! Walk on by!


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#5 ANM

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Posted 11 July 2020 - 10:39 AM

Nope, no good. They're a legend in the annals of bad telescopes. They look good but they're not! Walk on by!

Make it into and aquarium?


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#6 Bomber Bob

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Posted 11 July 2020 - 10:48 AM

Your money would be better spent on an 8" Newtonian -- just about any 8" Newtonian from just about any company.


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#7 Terra Nova

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Posted 11 July 2020 - 12:07 PM

Make it into and aquarium?

A space age solar hot-dog cooker.


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#8 ANM

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Posted 11 July 2020 - 12:57 PM

A space age solar hot-dog cooker.

Yes! You drop a hotdog in through the visual back into the secondary baffle, point it at the sun, and in a few minutes, if the collimation is ok, you have a cooked hotdog!


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#9 clamchip

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Posted 11 July 2020 - 01:07 PM

I still say if one shows up in my neighborhood for a cheap and cheerful price 

I'm buying it.

Then I'll put that rough corrector on a arbor in my lathe with the lower half of the corrector

in a pan of water/rouge slurry to keep it cool.

I will be at 12 O' clock with my tool and I'll run the lathe at it's slowest speed.

Give it a polish that has never been seen before.

 

 

Robert


Edited by clamchip, 11 July 2020 - 01:10 PM.

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#10 davidmcgo

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Posted 11 July 2020 - 01:10 PM

Or at least put enough clamshells in it it will feel at home ,-)

 

Dave


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#11 Karl Fabian

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Posted 11 July 2020 - 01:32 PM

Maybe use it with a 65mm off axis mask rotated to the best part of the corrector. Might be useful for solar observation.



#12 ANM

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Posted 11 July 2020 - 01:33 PM

I still say if one shows up in my neighborhood for a cheap and cheerful price 

I'm buying it.

Then I'll put that rough corrector on a arbor in my lathe with the lower half of the corrector

in a pan of water/rouge slurry to keep it cool.

I will be at 12 O' clock with my tool and I'll run the lathe at it's slowest speed.

Give it a polish that has never been seen before.

 

 

Robert

I probably would too, but from what people think of it the one on eBay is too expensive, a grand including shipping.



#13 Terra Nova

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Posted 11 July 2020 - 01:42 PM

Yes! You drop a hotdog in through the visual back into the secondary baffle, point it at the sun, and in a few minutes, if the collimation is ok, you have a cooked hotdog!

Or better, remove the corrector plate secondary and run a skewer up through the hole in the primary. Point it to the sun and turn on the tracking! :lol:


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#14 Supernova74

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Posted 11 July 2020 - 01:42 PM

I do vaguely remember them and a very prestigious telescope dealer in London sold them. on there actual performance I cannot comment on I think it was around the same time bauch alomb was on the scene who happens to make spectacles my advice would be is do a little research if you can on the brand.thats the only way you will find out the pros and cons.also just as one forum member said it was no good where is the evidence to back that claim up.as for exsample it’s like saying to a friend have you seen that film yet!? Your friend replies yes it’s rubbish.and all becauce of one statement you may not go to watch that film.and maybe missed out!?


Edited by Supernova74, 11 July 2020 - 01:43 PM.

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#15 Terra Nova

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Posted 11 July 2020 - 01:45 PM

I do vaguely remember them and a very prestigious telescope dealer in London sold them. on there actual performance I cannot comment on I think it was around the same time bauch alomb was on the scene who happens to make spectacles my advice would be is do a little research if you can on the brand.thats the only way you will find out the pros and cons.also just as one forum member said it was no good where is the evidence to back that claim up.as for exsample it’s like saying to a friend have you seen that film yet!? Your friend replies yes it’s rubbish.and all becauce of one statement you may not go to watch that film.and maybe missed out!?

Right here in this forum, you can find lots and lots of research including DPAC results from numerous samples, all coming to the same conclusion: if you want an optically functioning telescope that does 20X per inch or better, avoid them.


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#16 Supernova74

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Posted 11 July 2020 - 01:49 PM

um yes I get what you mean now lol 


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#17 ANM

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Posted 11 July 2020 - 02:30 PM

Or better, remove the corrector plate secondary and run a skewer up through the hole in the primary. Point it to the sun and turn on the tracking! lol.gif

You could do a roast!


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#18 Jeff B

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Posted 11 July 2020 - 04:11 PM

There is a reason why we stopped taking Dynacraps in on trade for C8's back in the 80's.


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#19 clamchip

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Posted 11 July 2020 - 05:03 PM

Lately I've switched to baking hot dogs in the oven on a foil lined baking sheet.

They come out marvelous, 400degF for 15 minutes.

A Dynamax  hot dog cooker or Celestron (if you break the plate it's history) is a 

interesting idea but something tells me the dog will explode, or you will have a

crispy splitter to die for !

 

Robert


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#20 oldmanastro

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Posted 11 July 2020 - 07:33 PM

The Criterion B & L 8000 (basically a black Dynamax 8) was my first SCT. Big mistake. That thing could not focus a star into an Airy disc. Not even an astigmatic Airy disc. I entered the secondary, rotated the corrector, prayed. Nothing worked and to top it off the thing started leaking grease from the focuser into the corrector plate. It was only usable for very low power views. Only the mount worked well. Oh, I forgot the image shift too. After I got rid of it no more SCTs arrived here for years until a Celestron 8 appeared. The difference was astronomical. My only regret was not getting rid of the Criterion telescope but also my Tuthill Isostatic tripod that went with it.

 

Guido


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#21 Senex Bibax

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Posted 12 July 2020 - 06:07 AM

Or better, remove the corrector plate secondary and run a skewer up through the hole in the primary. Point it to the sun and turn on the tracking! lol.gif

Point it at the sun, start the clock drive and make rotisserie chicken


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#22 bobhen

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Posted 12 July 2020 - 06:52 AM

Everyone likes jumping on the DX8.

 

I owned one (purchased new in 1978) and used it for years. Here is the scoop on “my” example.

 

The deep sky views were equal to a good 6 to 7-inch Newtonian.

 

The lunar views were fine and sharp at 200 to 250x

 

Mars and Saturn were decent. One night I had Saturn to 333x. The planet was definitely not refractor sharp but it wasn’t mush either – not by a long shot. 

 

Jupiter suffered the most. The moons were, of course, visible but the subtle features on the disk were never resolved. You could see banding and the GRS but not much else.

 

I was also using a pretty standard diagonal in those days and definitely NOT the Astro-Physics 2” diagonal that I use today.

 

The tripod was a nice piece of kit.

 

Back in the 90s, at one of my club’s star parties, I had the chance to observe with another DX8 and the deep sky views were really nice. For example, M27 through this DX8 was as good as any Celestron or Meade 8” SCT on that night.

 

Would I buy one today – absolutely not. There are better choices. Then again, I wouldn’t buy any Meade or Celestron SCT from the 80s either.

 

Meade and Celestron put out some very mediocre scopes during that decade, as is evident by the December 1989 S&T 8” SCT review. One of the Meades in that review was unusable (yes unusable!) as delivered to S&T. And the rest were all optically average at best. At least I could use my DX8 when it arrived.

 

Lunar drawings using my 1978 DX8.

 

Bob

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Edited by bobhen, 12 July 2020 - 06:53 AM.

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#23 Terra Nova

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Posted 12 July 2020 - 06:54 AM

The Criterion B & L 8000 (basically a black Dynamax 8) was my first SCT. Big mistake. That thing could not focus a star into an Airy disc. Not even an astigmatic Airy disc. I entered the secondary, rotated the corrector, prayed. Nothing worked and to top it off the thing started leaking grease from the focuser into the corrector plate. It was only usable for very low power views. Only the mount worked well. Oh, I forgot the image shift too. After I got rid of it no more SCTs arrived here for years until a Celestron 8 appeared. The difference was astronomical. My only regret was not getting rid of the Criterion telescope but also my Tuthill Isostatic tripod that went with it.

 

Guido

Guido, I take it you still have it? If so, perhaps a B&L solar cooker is in your future! :lol:


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#24 photiost

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Posted 12 July 2020 - 09:31 AM

Stellafane 1993 swap table ... I almost bought a complete Dynamax but friends strongly advised me against it.

 

I am sure there are a few good ones out there but they certainly don't have a good reputation.

 

Ended up buying a new Celestron SPC 8 instead.

.


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#25 oldmanastro

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Posted 12 July 2020 - 09:39 AM

Guido, I take it you still have it? If so, perhaps a B&L solar cooker is in your future! lol.gif

Terra, I bought it in 93 and it went out the door in 96. I even remember the year when I got rid of it. It was that bad. The devilish thing took with it the isostatic tripod. It was either that or keep it. It's future as a solar cooker would have been assured if it had stayed with me. I told the new owner not to go over 100x with it. Galaxies! I even remember that!! It was a baaaaad scope! lol.gif

 

Guido


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