Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Cats & Casses

Pages: 1 | 2 | (show all)
BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Bausch & Lomb 4000 repair?
      #5483428 - 10/22/12 11:06 AM

Here is what I did for at least temporary repair of my 4000.

On my Criterion 4000 the corrector plate holder simply screw on the end of the main tube .Grasp firmly and unscrew.Simple. BUT the corrector glass is held in the holder by a threaede ring with two holes.Being the impatient type I used a heavy paper clip firmly grasped as close to the ring as possible with pliers and was able to unscrew it.Scratching the glass was of no concern since it was already shattered in shipping. Not knowing any source for replacement corrector plates I had a glass shop cut disk from clear window glass.

Still have to collimate the scope(s) Actually "fixed" two this way;I 've had very bad luck with this model scope being shipped to me.

Can anyone say if the original was optically flat of shaped ? And where one might get correct replacements REASONABLY ?


Post Extras: Print Post   Remind Me!   Notify Moderator  
jrcrillyAdministrator
Refractor wienie no more
*****

Reged: 04/30/03

Loc: NE Ohio
Re: Bausch & Lomb 4000 repair? new [Re: BigC]
      #5483460 - 10/22/12 11:28 AM

Quote:

Can anyone say if the original was optically flat of shaped ? And where one might get correct replacements REASONABLY ?




The manufacturer advertised it as an SCT and I think we must take them at their word (any correctorless alternative would have required mirrors that were very expensive to produce in those days). It's a Schmidt corrector and not to be found on the shelf anywhere.


Post Extras: Print Post   Remind Me!   Notify Moderator  
orion61

*****

Reged: 10/20/07

Loc: Birthplace James T Kirk
Re: Bausch & Lomb 4000 repair? new [Re: jrcrilly]
      #5483527 - 10/22/12 12:08 PM

if the corrector was shatteed, the optical tube is a total loss, if you have the fork mount you could strip everything,
sell the finder scope and holder, the casr is nicely made and works well for an ETX. can you post a picture?,
did you take insurance?


Post Extras: Print Post   Remind Me!   Notify Moderator  
rmollise
Postmaster
*****

Reged: 07/06/07

Re: Bausch & Lomb 4000 repair? new [Re: orion61]
      #5483546 - 10/22/12 12:18 PM

I was going to say that I wouldn't have gone to the trouble, since without that corrector you have an uncorrected spherical mirror. But, OTOH, some of the Criterion correctors I've seen haven't been much better than flat glass, anyway...

Seriously, these correctors were lenses. The only source would be another Criterion scope.

Edited by rmollise (10/22/12 12:19 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Geo.
Carpal Tunnel
*****

Reged: 10/01/08

Loc: Upstate NY
Re: Bausch & Lomb 4000 repair? new [Re: rmollise]
      #5483701 - 10/22/12 01:46 PM

There may be a source for replacement correctors in China. May be worthwhile pursuing this for a 10" or so, I can't imagine that it would be for a $100 optical tube.

I have an email address you can follow up on if you want to pursue it. PM me as the posting rules won't permit me to make it public.


Post Extras: Print Post   Remind Me!   Notify Moderator  
BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Re: Bausch & Lomb 4000 repair? new [Re: orion61]
      #5483752 - 10/22/12 02:20 PM

USPS did pay off on the insurance and sent a letter they might want to inspect or pick up the item;that was maybe a month ago and have heard nothing more.Took pictures that are too big to post here. I may? need to install a program on this computer to trim the pic size.

As for the glass ,someone stated that some 4000 used a special mirrored seconady lense that allowed simple flat glass window.

The lady at the glass shop cut the disk out of scrap.A small donation to her favorite charity was the cost.

I figured there was little to lose by trying this and I might learn something.


Post Extras: Print Post   Remind Me!   Notify Moderator  
jrcrillyAdministrator
Refractor wienie no more
*****

Reged: 04/30/03

Loc: NE Ohio
Re: Bausch & Lomb 4000 repair? new [Re: BigC]
      #5483805 - 10/22/12 02:52 PM

Quote:

As for the glass ,someone stated that some 4000 used a special mirrored seconady lense that allowed simple flat glass window.




It's the primary that would have to change. Even if the secondary is changed to a paraboloid or, as in the Meade ACF, all the way to a hyperboloid, the spherical primary still requires a corrector.


Post Extras: Print Post   Remind Me!   Notify Moderator  
tim53
Postmaster
*****

Reged: 12/17/04

Loc: Highland Park, CA
Re: Bausch & Lomb 4000 repair? new [Re: jrcrilly]
      #5484066 - 10/22/12 05:40 PM

Does it actually say "Schmidt Cassegrain" or might it say "Mirror Lens".

The Meade spotter version of the 4" was often a Mirror Lens - like a Klevtsov - which used a corrector lens doublet as a secondary. If you have it apart, take a gander at the secondary. Is it first-surface aluminized? Or is the aluminization on the back? Because if it's really a mirror lens, then you could use an optical window. If it's an SCT, scavenge the parts you think you might want to keep, crush the rest, and get the cryin' over with.

-Tim.

Edited by tim53 (10/22/12 05:41 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Re: Bausch & Lomb 4000 repair? new [Re: tim53]
      #5484681 - 10/23/12 01:24 AM

It seems that after buying FOUR of these,I will actually have ONE in working order by combining parts. I can use the star diagonal from the last shipping victim to complete the first 4000.I also acquired seperately the porro prism ,and solar filter.

I wonder if there is even a small central? portion of the FOV in which focus will be correct? I was able to see and read a sign some 400 feet away that appeared normal.Maybe the 4000 with flat glass can serve as a bird scope.

The secondary appears to be first surface.

Being the packrat ,not going to crush the unused pieces;someone may need a primary mirror to replace theirs.


Post Extras: Print Post   Remind Me!   Notify Moderator  
orion61

*****

Reged: 10/20/07

Loc: Birthplace James T Kirk
Re: Bausch & Lomb 4000 repair? new [Re: BigC]
      #5485810 - 10/23/12 06:20 PM

You can try Fred Pauli here.. http://www.astroptx.com/bauschlombcriterion.html
He bought out all the old Criterion/B&L parts when they closed down, I know he has a couple of old New Stock 6" scopes for sale and misc parts/accys.
he takes a few days to answer.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starhawk
Space Ranger
*****

Reged: 09/16/08

Loc: Tucson, Arizona
Re: Bausch & Lomb 4000 repair? new [Re: orion61]
      #5486354 - 10/24/12 01:12 AM

Given how inexpensive used SCTs are in general, why not just replace the scope?

-Rich


Post Extras: Print Post   Remind Me!   Notify Moderator  
BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Re: Bausch & Lomb 4000 repair? new [Re: Starhawk]
      #5486367 - 10/24/12 01:29 AM

Quote:

Given how inexpensive used SCTs are in general, why not just replace the scope?

-Rich


Because fixing things gives a sense of accomplishment.Like those in the ATM forum.

I have other scopes,both smaller and larger.

Inexpensive is relative.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starhawk
Space Ranger
*****

Reged: 09/16/08

Loc: Tucson, Arizona
Re: Bausch & Lomb 4000 repair? new [Re: BigC]
      #5487533 - 10/24/12 07:36 PM

In this case, there is no real fixing unless you're prepared to make a custom SCT corrector. You could retrofit the optics from a celestron into the OTA, though I don't know what purpose this would serve. Sort of like building a Gremlin on a Pinto chassis.

-Rich


Post Extras: Print Post   Remind Me!   Notify Moderator  
orion61

*****

Reged: 10/20/07

Loc: Birthplace James T Kirk
Re: Bausch & Lomb 4000 repair? new [Re: Starhawk]
      #5487693 - 10/24/12 09:36 PM

Quote:

In this case, there is no real fixing unless you're prepared to make a custom SCT corrector. You could retrofit the optics from a celestron into the OTA, though I don't know what purpose this would serve. Sort of like building a Gremlin on a Pinto chassis.

-Rich




Post Extras: Print Post   Remind Me!   Notify Moderator  
rmollise
Postmaster
*****

Reged: 07/06/07

Re: Bausch & Lomb 4000 repair? new [Re: Starhawk]
      #5488141 - 10/25/12 07:38 AM

Quote:

In this case, there is no real fixing unless you're prepared to make a custom SCT corrector. You could retrofit the optics from a celestron into the OTA, though I don't know what purpose this would serve. Sort of like building a Gremlin on a Pinto chassis.

-Rich




Well, maybe a Meade. Celestron hasn't made a 4-inch SCT...


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starhawk
Space Ranger
*****

Reged: 09/16/08

Loc: Tucson, Arizona
Re: Bausch & Lomb 4000 repair? new [Re: rmollise]
      #5488859 - 10/25/12 03:45 PM

Indeed. Just the one option for a 4". But then again, it's back to wrecking a perfectly good scope to make another.

-Rich


Post Extras: Print Post   Remind Me!   Notify Moderator  
BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Re: Bausch & Lomb 4000 repair? new [Re: Starhawk]
      #5489433 - 10/25/12 10:58 PM

The Gremlin and Pinto filled a need for affordable small cars.I get tired of the negativity.

Back to the 4000. As the corrector plate on unit 1 is unbroken,the star diagonal from unit 4 will be moved there.Unit 2 had only a porro prism and unit 3 never arrived!Units 2 and 4 now sport window glass ,which at least protects the primary mirrors.

Attempted to view the Moon as test of just how bad a plain plate would be only to have clouds cover the whole sky,so will try another day,...err , night.


After looking at the damage to unit 4,and its case, and considering the foam lining plus the packing,I conjecture the scope was broken by the seller's shipping clerk. Point against the clerk is that he claimed to have wrapped the 4000 case in bubble wrap as well as packing the box with foam peanuts. There was no bubble wrap.

THe corrector obviously received a strong impact because the glass was not just cracked but the secondary broken out of the center and bits of glass speckled the main mirror.

Most likely the worker had a bit of difficulty putting the tube cover on, and SLAPPED it as I have seen many people do when putting a lid on a can or tube.Might not have heard it break.

Stuff happens.

Since my money was refunded,essentially I received a perfectly usuable diagonal , two eyepieces ,and some 1984- era telescope literature, and a spare motor ,all "free".

Certainly am not going to sacrifice a good scope to repair unit 2 or 4 to original specs.


Post Extras: Print Post   Remind Me!   Notify Moderator  
tim53
Postmaster
*****

Reged: 12/17/04

Loc: Highland Park, CA
Re: Bausch & Lomb 4000 repair? new [Re: BigC]
      #5490437 - 10/26/12 03:34 PM

I agree. I had a 1971 Gremlin X. It had poor weight distribution, but it was a sharp looking car!

Tim


Post Extras: Print Post   Remind Me!   Notify Moderator  
Dennis_S253
Pooh-Bah


Reged: 11/22/11

Loc: West Central Florida
Re: Bausch & Lomb 4000 repair? new [Re: tim53]
      #5490604 - 10/26/12 05:34 PM

I've always wondered about the corrector plate also. I was wondering how to check mine. I always wondered if it was put on backward. I love my 4" B&L. But, they did use a lot of wierd parts. The diaginal also appears to have a built in field stop. I do not believe any parts for a SCT will work on the B&L.

Post Extras: Print Post   Remind Me!   Notify Moderator  
BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Re: Bausch & Lomb 4000 repair? new [Re: Dennis_S253]
      #5490879 - 10/26/12 09:12 PM

The B&L has a different thread than the standard SCT.At least it does accept standard 1.25" EPs!

Went back out in early a.m. and Orion was there so grabbed scope and patio table and looked up and Orion hidden by clouds again....pointed 4000 WITH WINDOW GLASS at Moon and waited for hole in clouds.Had a very strange view: focusing was very critical , and I saw ONE sharp image of the Moon with a couple blurred ghost images flickering in and out of sight.Note no collimation has been done yet.

The 4000 with a actual corrector plate wasn't tried as it began to rain.

The curve of the corrector must be very subtle but is there;I suppose one could measure the unbroken plate.I do not have the optical tools to do so.

Wonder how many of these scope might be stored away across the country needing a new corrector? B7L must have sold a large numnber as they advertised for a year or two on the cover pages of S&T and probably elsewhere.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | (show all)


Extra information
21 registered and 28 anonymous users are browsing this forum.

Moderator:  Cotts, Starman27, kkokkolis 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 2343

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics