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Criterion Dynamax 8

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#26 John Carruthers

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Posted 06 August 2014 - 12:55 PM

I found my DX mirror to be fine, it was just the corrector that needed a tweak. A floppy petal lap did the job in less than 10 minutes, it was the testing that took the time....



#27 Brian Risley

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Posted 08 August 2014 - 07:48 PM

I'll second the Golden Pyramid Tripod as nice and stable.  I have 2. 

It was my fav up to the CPC tripod with the box leg supports and solid metal spreader.

(Just watch the GPT spreader and the arm supports, they can break easily if the tripod is dropped.  Guess how I know! :( )

I used a turnbuckle setup to replace one of the arms, made it easy to keep lat setting and allow a fine adjust option.  Just put a nut and a fender washer on the hand knob, the nut just fit into the turnbuckle eye and the washer kept it firmly in place.

Brian

 



#28 Gil V

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Posted 08 August 2014 - 10:27 PM

Our tripod was excellent. I'd love to have one again.

The fellow who built them was a super nice guy - and a pretty good poker player to boot!

#29 apfever

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Posted 08 August 2014 - 10:33 PM

I had a Golden Pyramid and regret selling it.



#30 youngamateur42

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Posted 09 August 2014 - 04:10 PM

Looking to see some  :flash: photos!!



#31 Chuck Hards

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Posted 10 August 2014 - 12:37 AM

I'll try and set it up for pics on Sunday.  Just been very busy at work, and after yardwork when I get home, too beat to do much else.  We've also had afternoon rains for the first three days of this past week and there's no room large enough in the house to set it up for good pics indoors.

 

I'm pretty impressed with the tripod, myself. 



#32 Mark MacKenzie

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Posted 10 August 2014 - 11:31 AM

I found my DX mirror to be fine, it was just the corrector that needed a tweak. A floppy petal lap did the job in less than 10 minutes, it was the testing that took the time....

John, can you describe how you corrected the corrector?  My Dynamax 6 shows a pattern of rough surface, I think. It performs ok but an out of focus star shows blobs of light around the ring. Did yours do that?

Thanks, Mark



#33 Chuck Hards

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Posted 10 August 2014 - 09:00 PM

Pics, as promised.  I was going to look at the sun today, but just as I started to set-up, a high cloud deck rolled in, so I set up the Dynamax for a photo shoot instead.

 

Criterion Dynamax 8 SCT.
DmX002_zpsa62b52c1.jpg

 

Drive base.
DmX022_zps6ad8500e.jpg

 

Top of tripod, wedge & latitude adjusters, fork & OTA.
DmX001_zpsba93b2a5.jpg


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#34 Chuck Hards

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Posted 10 August 2014 - 09:01 PM

View from SW side.
DmX003_zps3d93a21d.jpg

 

Fork hub.
DmX007_zps2e90d264.jpg

 

The piggyback camera adapter is held-on by the visual back.  It slips over the threads and the back snugs-down over it.  (Thanks Gil V.!)  Home-made eyepiece used in pics.
DmX004_zpsd396d701.jpg


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#35 Chuck Hards

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Posted 10 August 2014 - 09:03 PM

Table-top legs.  They look like they've never been used.  Pristine.
DmX015_zps4ce1cd79.jpg

South side of wedge.  2-knob attachment of drive base to Wedge.  Pretty easy to mount.
DmX013_zps28ce8f91.jpg

DEC hub.
DmX020_zps974638ae.jpg

 



#36 Chuck Hards

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Posted 10 August 2014 - 09:04 PM

Maybe Gil V. can date it based on the serial number?  How many of these were made?
DmX021_zpsc6c57409.jpg

DEC tangent-arm detail.
DmX014_zpsdcad25db.jpg

East side, looking west.  Dust cover sitting on tripod brace.
DmX019_zps962a8910.jpg

 



#37 Chuck Hards

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Posted 10 August 2014 - 09:05 PM

I'm about 5'-11", and with the tripod legs fully extended, it's just about the perfect height for use while standing.
DmX018_zps6c99e164.jpg

Afocal shot with the phone camera just held-up to the eyepiece.  This phone pole is about a block away.  It's pretty sharp near the center of the field, actually.  I'm wondering if it's mostly just in need of collimation.
DmX017_zps7ed91e66.jpg

Looking up, note tube counterweight bar.  Detaches for storage.
DmX012_zps5a2fd6b9.jpg

Cosmetically it's in great condition, just a few spots to touch-up, and it could use a good cleaning.  Still waiting to do a critical collimation and optical tests.


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#38 Brian Risley

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Posted 10 August 2014 - 09:16 PM

Purdy! 

The wedge has the hole patten for the C-8's with the bottom power plug.  The wedge can fit a lot of different model scopes, which was a great idea.

Brian

 



#39 terraclarke

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Posted 10 August 2014 - 09:49 PM

Wow Chuck! It looks brand new!! I hope it performs as good as it looks. If so, it's bound to be one heck of a telescope!



#40 Chuck Hards

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Posted 10 August 2014 - 10:34 PM

Thanks Brian and Terra, not bad for three bills. And only 42 miles from home!

I will always remember this summer as my "Criterion Summer". Three Criterion scopes in two months, all close to home.
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#41 TOM KIEHL

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Posted 10 August 2014 - 10:55 PM

That thing looks flawless, what a fine specimen , hope the optics prove to be just as flawless, :band: " Thats the way , aha , aha , I like it " ..... :waytogo:


Edited by TOM KIEHL, 10 August 2014 - 10:56 PM.


#42 Rich (RLTYS)

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Posted 11 August 2014 - 05:27 AM

Love the scope. Is that the origional color of the mount?

 

Rich (RLTYS)



#43 Chuck Hards

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Posted 11 August 2014 - 07:04 AM

Rich, that's the original color.   I remember it surprising me the first time I saw one, since the Criterion ads in S&T back in the old days were black & white, so in my mind, the thing was grey, white, and black.  :lol:

 

I'm wondering if the choice of blue was somehow a statement on Celestron burnt orange?  The most opposite, contrasting color they could think of.

 

I am the third owner, the fellow I bought it from knew the original owner and bought it from him.  It was only in the hands of the second owner for a few years.  He said the fellow he bought it from used it quite a bit when he was younger, and even dabbled in AP, which explains the photography & guiding accessories that came with it.



#44 terraclarke

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Posted 11 August 2014 - 07:28 AM

Rich, that's the original color.   I remember it surprising me the first time I saw one, since the Criterion ads in S&T back in the old days were black & white, so in my mind, the thing was grey, white, and black.   :lol:

 

I'm wondering if the choice of blue was somehow a statement on Celestron burnt orange?  The most opposite, contrasting color they could think of.

 

I wondered if the blue color might in some way be related to the earlier Celestron Pacific blue and white color scheme? Either way, it's very pretty. :)


Edited by terraclarke, 11 August 2014 - 07:29 AM.

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#45 Chuck Hards

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Posted 11 August 2014 - 07:30 AM

 

Rich, that's the original color.   I remember it surprising me the first time I saw one, since the Criterion ads in S&T back in the old days were black & white, so in my mind, the thing was grey, white, and black.   :lol:

 

I'm wondering if the choice of blue was somehow a statement on Celestron burnt orange?  The most opposite, contrasting color they could think of.

 

I wondered if the blue color might in some way be related to the earlier Celestron Pacific blue and white color scheme? Either way, it's very pretty. :)

 

 

I hadn't thought of that.  You may be on to something there.



#46 terraclarke

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Posted 11 August 2014 - 07:35 AM

I always thought it odd that Celestron 'went orange'. It is very distinctive, and totally different from anything else, but you have to admit that even though it became commonplace, it is rather a strange color selection for a telescope. I wonder how they decided on it. That, in itself would make for an interesting story, in another thread of course. Now, back to that beautiful blue and white. Go Kentucky Wildcats! (Actually, I'm a Red and Black (Louisville Cards) fan when it comes to the two). ;)



#47 DAVIDG

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Posted 11 August 2014 - 08:35 AM

Chuck,

  The best way to test the complete optical system of your Dynamax is by double pass autocollimation by aiming the scope at an optical flat. Since few ATM's have large flats and the fact that you have completed scope you can use a pan of oil . It is flat to about 1/300 of wave so it near perfect optical surface. You also can test inside so you don't have to wait for clear skies. Since light passes thru the optical system twice it is extremely sensitive. You would place Ronchi screen in the focuser with small light source off to one side of teh Ronchi screen so the light shines through the grating.  Since the test is so sensitive it is also the best way to collimate your optics.

 

                          - Dave

 

                    


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#48 Chuck Hards

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Posted 11 August 2014 - 09:00 AM

Thanks Dave, but I work part-time for a professional optics manufacturer.  He has flats up to one meter, I believe.  The only thing that's keeping me from testing it is both he and I with enough free time, at the same time.  We wanted to do it this past weekend but couldn't swing it.

 

I've got a 9-inch minor-axis elliptical flat, but his are probably of higher quality.



#49 tim53

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Posted 11 August 2014 - 09:19 AM

It occurs to me that an SCT would be very easy to set up for a pan of oil autocollimation test.  You could leave it on the mount, even, and use the slow motion controls for lining everything up.

 

hm...

 

The later Dynamaxes had an even prettier color scheme.  Instead of the bright blue on the mount and tripod, they used a dark blue-gray.  I had a tripod and wedge that color, but the guy I bought them from had already sold the scope.  Turns out I bought the eyepieces from the same seller a few months earlier.  Full set of University Optics mushroom orthos/koenig, plus a barlow or two, and a wonderful 32mm Brandon.

 

-Tim.



#50 Chuck Hards

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Posted 11 August 2014 - 09:26 AM

There's no chance of the primary sliding off, if fully inverted?  I know this is silly, but I hear horror stories...








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