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Criterion Dynamax 8

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#126 Mark MacKenzie

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Posted 03 September 2014 - 09:02 AM

Attached File  DSCF1382.JPG   217.08KB   0 downloads    My DynaMax 6....

 

My corrector is mounted on cork pieces on both sides of the glass. I.E. between scope and corrector and between corrector and plastic black ring with 8 hex socket screws. No engraving on the plastic ring.  The screws are not too tight but I wonder if maybe the cork is causing my blobs of light around my startest pattern.

 

Oh and the serial number is 4762. 

 

Many thanks to Gil for the help on this scope!

 

Mark

 

 


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#127 DAVIDG

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Posted 03 September 2014 - 11:00 AM

 The blobs of light are most likely caused by zones in the corrector plate  when it was made. If you get a speck of dust bewteen the plate and  the Master it causes a high spot and when it is ground and polished, that high spot turns into a hole. Here is a picture of a plate and circled area are showing these types of defects. They can also be caused by the back "flat" surface of the corrector. The back surface is suppose to be optically smooth and free of zones. The glass used to make the correctors was never ground and polished optically smooth on the back surface so it most likely will have zones as well.

 

             - Dave

Attached File  schmditplate.jpg   22.42KB   0 downloads


Edited by DAVIDG, 03 September 2014 - 11:02 AM.


#128 Gil V

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Posted 03 September 2014 - 07:28 PM

Comment about serial numbers -

We used to keep an index card on each base serial number - it described the optical performance of the scope as built by the alignment technician.

When we got a call from a customer about the optical performance of the scope, if the index card from the tech indicated that the scope was borderline, we knew to take the issue seriously. If the index card indicated the scope was of a higher quality, we would make efforts to really understand the customer's issue, since we had a record indicating the optical performance on the bench was good.

It was, unfortunately, a way to give credence to a customer's concern about the performance of their particular scope.

That's the sad reality of it. The corrector cells were picked at random, any attempt to categorize the product by the corrector cell, while noble, will not achieve fruitful results.

#129 Chuck Hards

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Posted 05 September 2014 - 09:05 AM

I'm taking the Dynamax over to the optical shop tomorrow in case we have enough time to test it.  If we do, I'll report on the results later in the weekend.  Have to work it in between the paying jobs so there's no guarantee.


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#130 terraclarke

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Posted 05 September 2014 - 10:32 AM

:stooges: It's way too bad that they didn't expend the same effort making them good as they did making them pretty! :foreheadslap:



#131 terraclarke

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Posted 05 September 2014 - 10:33 AM

I can't believe I just said that! :blush:


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#132 Chuck Hards

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Posted 05 September 2014 - 01:15 PM

I can't believe I just said that! :blush:

 

Sad but true, they are gorgeous scopes, but the quality was so hit-and-miss, that it's about the most charitable conclusion you can come to.  Hoping I can bring mine into the "hit" category with a little massage.


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#133 Gil V

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Posted 05 September 2014 - 05:44 PM

Yes, they are very attractive scopes. So much so, that I feel that if you can get one in good mechanical condition, they are worth picking up, because you can do a lot with them to improve performance.

I am so grateful that a fellow member here made it possible for me to reacquire one. At least once a month, I beat myself up for selling the one I built when I worked there. I would put that scope up against any 8" telescope of any design, and it would hold it's own. It was that good.
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#134 Chuck Hards

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Posted 07 September 2014 - 12:19 AM

I hauled the Dynamax over to the optical shop today, but we ran out of time and didn't get it tested.  Spent 8 hours working on a 20" Cass optics set; I ground the primary while the boss worked on the convex secondary.  We'll try again in a couple of days.  He has a nice 10" flat that we were going to use but we both had to be other places after 8 hours of mirror grinding.  He did look it over though, and feels that no matter what the problem is, it shouldn't be too difficult to correct.  He marveled at the excellent condtion it's in.

 

I was leafing through the blue-covered owners manual, it's copyrighted 1977 and in excellent condition.  I also found something in the case I hadn't noticed before.  The original owner used the scope for wildlife photography, as I found several full-page sleeves of B&W 35mm negatives of what appear to be deer.  I'll scan them soon and see how sharp they are, I have a 5mp slide and negative scanner.



#135 orion61

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Posted 07 September 2014 - 01:50 PM

Here is my DX-6

Attached Files


Edited by orion61, 07 September 2014 - 01:53 PM.

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#136 terraclarke

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Posted 07 September 2014 - 01:55 PM

That sure is a pretty one Duane! I love the colors.


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#137 Bomber Bob

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Posted 07 September 2014 - 02:03 PM

Indeed!  I prefer the blue & white to Celestron and Meade versions.



#138 orion61

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Posted 07 September 2014 - 08:24 PM

Thanks! It is usually a pretty sure bet if you can find a Dyna 6" they nearly always have good optics!

I think the classic form with it's simplicity, the Dec lugs Formed right into the cell, focuser on the upper Right rear

make them beautiful along with the paint. The Phenol Resin tubes are super stable for currents!

They track like a Dream! they are also silky smooth manually slewing! Much smoother than a Celestron.

One issue with ALL of them is image shift. I take some Super Lube Grease and mix it with a little Mobile one motor oil.

Get the mixture to where a glob will sag then SLOWLY drip down your finger, Place it around the baffle with the Primary out and a quick swirl

of it on the bottom inside of the mirror cell! Too much and it can drip down the back of the primary!

This usually takes about 80% of the mirror shift out.

To tell you how much I love mine, I sold my Celestron 6" SCT before I'd part with mine!

I love the 6" so much more than the 8" they are so easy to transport and lite to set up, plus they are Cute!

I have left mine set up on the table top legs, in my Living room, just so I could stare at it!

Nobody else around here, has ever done that with their favorite scope, have they?????

 

 

 

 

 

 

 

 

 

 

1



#139 fjs

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Posted 07 September 2014 - 09:16 PM

Nobody else around here, has ever done that with their favorite scope, have they?????

 

Er...Nope not me! :fingerscrossed:



#140 orion61

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Posted 07 September 2014 - 10:03 PM

 

Nobody else around here, has ever done that with their favorite scope, have they?????

 

Er...Nope not me! :fingerscrossed:

 

LOL... I knew there were others! I need help here! We must stand United, so I can show the Wife I am not the only one....



#141 orion61

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Posted 08 September 2014 - 03:12 PM

Here is a Pic of a Dynamax that you don't see. Everybody takes shots of the beautiful polished setting circle and red Badge.

I haven't seen a single photo of the focuser!

Gil are you kicking yourself yet you turned down our trade? These things are like Hens teeth! Once people get a Dyna 6 they hardly ever let them go!!!

I might work out something with you on the long visual back.... call me. I sent you my Phone number once if you lost it PM Me and I'll send it again.

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#142 Gil V

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Posted 08 September 2014 - 06:18 PM

I'm just glad that I can help out fans of the products that I worked so hard to build. I'll take that long visual back, but I can't part with a working latitude adjuster, I would no longer have a working set.

The 10' near-focus of the Dynamax 6 makes it in effect a long-distance microscope. Not many competitor's products could make that claim - and none could at the time.

Had I not been able to get my 8" to perform better optically, we would have made that trade. But for me to have both a 6" and 8" Dynamax, that would be pushing my wife's tolerance level.

It really is a beautiful instrument, and if you can get your hands on one with decent glass, they are definitely keepers. I loved them before I worked there, while I worked there, and after they were no longer being made.

Bausch and Lomb ended the RV-6, cheapened the Dynamax instead of improving it, and did the amateur astronomy community a huge disservice. All for what, a line on a balance sheet? Sad.

I'm just eternally grateful for the opportunity to have been a part of it before it went away.

Edited by Gil V, 08 September 2014 - 06:21 PM.

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#143 Chuck Hards

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Posted 08 September 2014 - 07:13 PM

Here is a Pic of a Dynamax that you don't see. Everybody takes shots of the beautiful polished setting circle and red Badge.

I haven't seen a single photo of the focuser!

 

How soon you forget!

 

Page 2 of this very thread.

 

http://www.cloudynig...ax-8/?p=6157006



#144 orion61

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Posted 09 September 2014 - 07:11 PM

Yeah but look closely, mine is a 6" they are a bit different, lol.. but Chuck your Max is freeking beautiful!!

Did you get the Dyna Tracker? I have one that is mint, Dave fixed it for me and he didn't even charge me, what a great guy..

Unfortunately it only worked 2 or 3 times and quit working again... bummer...

but I'll take your DX-8 off your hands anytime..... :p


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#145 Gil V

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Posted 11 September 2014 - 06:27 PM

Those drive correctors blew up almost as soon as you plugged them in.

Piece of junk. I think that we may have gotten more back than we actually shipped. :)

#146 Chuck Hards

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Posted 11 September 2014 - 07:49 PM

Mine came with a Meade AC/DC drive corrector. 



#147 DAVIDG

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Posted 12 September 2014 - 08:03 AM

 

Those drive correctors blew up almost as soon as you plugged them in.

Piece of junk. I think that we may have gotten more back than we actually shipped. :)

 I've fixed a couple of the Criterion drive correctors. The one I did for Larry was a real challenge since it required redesigning most the circuit and must have been the first version of the design. It could never have worked right from the start and as Gil stated it blew the fuse as soon as you plugged it in. I've done a couple since then and the design is different. In those the issue is usually a bad diode in the rectifer section so it is 5 cent fix.

- Dave

#148 orion61

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Posted 12 September 2014 - 09:06 PM

I may have a Bausch & Lomb 6000 coming to me. I serviced this scope about 8-10 years ago, and was STUNNED at it's optical quality.

It comes with 3 B&L eyepieces. Not the best, but OEM, It comes with a really nice form fit Hard Carrying case,

I have to admit it was the reason I bought my Dynamax DX-6. The Dynamax 6 are pretty rare, but the Bausch 6" are super rare!

They are basically the same scope except they are Black.

If anybody ever gets the chance to get a B&L 8001 grab it, They were every bit as good as a C8, but the drives were silky smooth.

I have had the chance to look through 2 of them in my life. Both out performed the C8's around them at the Star Party!

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