Bausch & Lomb 4000


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Bausch & Lomb 4000
I bought one of these scopes used. It looked like it was beautifully crafted, and offered a 4 inch aperature with exceptional portability it a great used price. Unfortunately, it was very poor optically. I learned from others familiar with the 4000, that there is no uniformity with regard to them -- in other words THERE ARE GOOD ONES OUT THERE! For me, it worked out ok, because the dealer I bought the scope from allowed me to return it. I would recommend a 4000 if you can test the optics and return it if they're faulty. If they're good then you'll have a pretty good scope for what'll probably be a great price. -- i.e. pretty good aperture for it's exceptionally portable size and a nicely crafted Optical tube assembly -- (ditto for the fork mount).

Overall Rating: 8
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.46.179)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39503


Bausch & Lomb 4000
I,ve had my 4000 for 15 years, and it has served me well. For a
mass produced telescope, the optics are fairly decent. My scope
shows some mild astigmatism, but nevertheless is able to show
the companion of Rigel and cleanly split Eta Orionis (1.5" 3.7 - 5.1).
I would rate it's Planetary performance slightly inferior to a 3 inch
refractor. Cassini's division can just barely be seen when the rings are
"open". Overall, while it certainly isn't a Questar, it serves it's perpous
as a very portable travel scope or as a scope to play with when you don't fell like dragging out the heavy artillery.

Overall Rating: 9
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.162.188)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39504


Bausch & Lomb 4000
I have owned two of these and I have to agree with another reviewer as to the optic quality. The first one I owned was tack sharp and never needed collimation. The one I currently own never has come close to the quality of the first, even after repeated fine tuning.

Mechanically, the AC clock drive works well and all adjustments are smooth. However the knobs tend to loosen and fall off if not regularly tightened. The non-standard thread for the visual back makes adding accessories a challenge.

Overall it's a good alternative to an ETX for travel if you can get one for under $250. If not, go for an ETX. The optics are better and the DC motor is better for travel.

Overall Rating: 7
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.23.80)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39505


Bausch & Lomb 4000
Shows fairly uniform first and weak second diffraction rings. Resolves doubles as expected for aperture. Poor contrast.

Overall Rating: 7
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.195.23)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39506


Bausch & Lomb 4000
A friend who had never used this scope loaned it to me for a few weeks. Have had a great time splitting doubles and viewing clusters. Good star performance with nice background. Nice small package to grab and do quick viewing. Had it on a stable tripod so viewing was good except near zenith. Neat to see the father of the ETX (more metal than plastic). Only problem was too much play in the focuser.

Overall Rating: 8
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.193.157)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39507


Bausch & Lomb 4000
I've had my Criterion 4000 since 1983 and have used it strictly as a camera lens. At the time, I wasn't interested in the stars. Since owning my "lens", it has traveled to Alaska, Panama, New York, and various points in-between. The only problems that have come about is the adapter to my camera is starting to slip, and I can't put it on really fast when at air-shows. Other than that, I've only had problems getting Baush and Lomb to acknowledge building it so I can aquire accessories or schematics to have them built.

Overall Rating: 8
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.134.101)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39508


Bausch & Lomb 4000
As with most SC's made during this period, there appears to be a great disparity with the optical quality of these scopes. Back in 1988 three of us each bought one, and the optical quality varied from very good to poor between our three samples. Mine was "tweaked" to an almost very good performance by re-aligning the front corrector plate (NOT something to be done by anyone who is worried about a warranty issue). Now, it performs rather well, being able to handle powers up to 100X per inch of aperture on nights of good steady seeing, when splitting double stars. Contrast is quite good on planets, probably owing to it's F-12 focal ratio. - A good buy on the used market - provided you know hwo to do a star test before buying!

Overall Rating: 8
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.71.135)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39510


Bausch & Lomb 4000
I had one of these for a few months a few years back. It was very mediocre optically, nowhere near the comparable products from Celestron and Meade. Avoid is my advice.

Overall Rating: 5
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.247.74)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39511


Bausch & Lomb 4000
Optics were poor, with the best collimation obtainable yielding triangular
star images. Finder was too small for easy use. Not a very good telescope
(a 2.4 inch refractor we had beat it easily)

Overall Rating: 3
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.37.132)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39512


Bausch & Lomb 4000
I owned one for a couple of years when I was looking for a portable scope. It's optics were quite poor, never really achieving sharp focus. I ended up selling it and buying a Questar which was orders of magnitude better. I hear that there are good ones out there, but mine was sure a dog.

Overall Rating: 3
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.248.27)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39513


Bausch & Lomb 4000
Worst scope I ever owned. Nothing good about it really. Sold it.

Overall Rating: 1
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.103.172)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39514

I have one I bought on ebay. I really like it. with a 4incher you're not going to get great images at large magnification and yes, the finder scope is awful, but, then, I have never seen a finder scope that came with a scope that was anything but crap, and that includes the 8 inch Meades.

Yours,
Marty Rice


>Worst scope I ever owned. Nothing good about it really.  Sold it.

Bausch & Lomb 4000
I bought an older version that didn't have the silver band on the tube. The mount motions were jerky and the optical performance was awful. An etx tested with it side by side was far better using the exact same eyepiece. Test before buying.

Overall Rating: 3
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.10.226)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39515


Bausch & Lomb 4000
I have owned 2 of these, one I bought because I wanted something
portable to take on the plane with me. The optics on this scope
were poor. I got the second one when I traded it for a duplicate
eyepiece,(the guy really wanted to get rid of it) though the
optics on the second scope were "slightly" better.

Although both scopes give you fairly good images at powers
below 90x, it is when you try and look at Jupiter and Saturn
over 100X that you see the inferior quality of these scopes.

You cannot use these scopes anything over 150x, and 150x is really
pushing it. Not recommended.

Overall Rating: 4
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.202.5)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39516


Bausch & Lomb 4000
Let's be fair. The Criterion 4000 is a Schmidt cat with a 4" aperture. One common definition for small telescope is four inches or less. This makes the Criterion a small Schmidt cat. It is the only small Schmidt cat ever produced in quantity and this puts it in in a class by itself.

The design is quite good as evidenced by the excellent images taken by Denis Bergeron of Val-des-bois, Quebec, Canada. An example can be seen at .

There were three models in the Criterion line; The 4000 4", 6000 6" and the 8000 8". All three were available from telescope shops but only the 4000 was regularly available through any Bushnell dealer. (Mine came from a drug store). At the time the Criterion 4000 was the only serious astronomical telescope available from the mass marketers and the interest in Halleys comet meant that the scope was produced in huge volumes. These volumes would have challenged any company's ability to maintain good quality control. Some of them were probably lemons. This was made worse but the fact thar most the dealers did not know how to handle the instruments and more were damaged in handling. This means that a very small proportion of the scopes sold were imperfect. This small proportion would be a large number as far as telescopes go due to the huge numbers produced. Nevertheless, most of the scopes were good.

The large production creates the illusion that this was a bad scope. The few percent of model 4000 that were bad exceeds the total production of most other manufacturers. This illusion is strengthened by the fact that the bad scopes are sold and resold. The bad ones are pretty well the only ones that are in circulation because those of us who have good ones are not going to sell them. A four inch Schmidt cat is irreplaceable. The five inch tubes that are available today weigh more than twice as much. Since all other components must be heavier to accomodate the tube it makes for a much bulkier and heavier assembly. It is no wonder that the good 4000s are not for sale.

The scope is given 8 of 10 because the focusing assembly could be better and B&L did not support the product properly after they discontinued it. Overall it is a wonderful little scope.

Hope this helps settle the Criterion 4000 issue.

Sincerely,
Murray B.
E-mail 102132.1651@compuserve.com

Overall Rating: 8
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.58.110)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39517


Bausch & Lomb 4000
I bought mine used with a cracked corrector plate (!!!) on EBay for $50. Fork mount and drive base work fine and are in pristine condition. I replaced the corrector plate (myself!!!) with a used Tokina 105mm multi-coated UV filter (!!!) as I was desperately trying to restore it to somewhat usable order. I figured that I would have nothing to lose if the "modification" did not work. The view turned out OK (!!!) when I pointed the scope at Mars last week - obvious undercorrection but nevertheless the Martian disk is bright and quite contrasty. After tweaking with the collimation I was able to use over 100X with acceptable results. A surprise considering the total cost ($65.00) I spent and the total lack of technical considerations that had gone into the "optical transplantation". As it turns out my little Criterion 4000 now performs pretty "healthy" in comparison to several other quality 80mm achromats my friend owns.

Overall Rating: 8
Weight: 3 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.105.176)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39518


Bausch & Lomb 4000
That's right. The good ones are not put up for sale. I've had mine for 16 years and no one will be able to buy it from me. It has a good star test and handles magnification quite well. It does anything a good 80mm. refractor will do and it's even more portable.

Overall Rating: No Vote
Weight: <none>
Date:
By: Anonymous (xxx.xxx.218.12)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39519


Bausch & Lomb 4000
I've had mine since 1988, and it star-tested very good, but around 1991 it developed a large image-shift when focusing, so I took it back to where I bought it. When it came back, I found that some idiot had replaced the primary mirror (mine was round, but this one had "facets" cut all around the outer edge), and the images would not come to focus. I took it right back, and they claimed that the original mirror had been misplaced, so they put in another one. The images were a bit better, but not great. I took it onto myself to radially align the corrector plate, and after many many tries, I got it almost as good as it was with the original mirror in place, but deep down I know that it isn't quite the same. I wonder who got my original mirror . . . . . (BTW - the "idiot" is not longer working there)

Overall Rating: No Vote
Weight: <none>
Date:
By: Anonymous (xxx.xxx.239.226)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39520


Bausch & Lomb 4000
This scope is a typical SCT from what i have seen. Mine performs on par with what you would expect a C8 to do with aperture in consideration. The mount is steady, it is easier to use than the etx 90. The optics seem good for a C8 but i would like to replace the diagonal, but can't because the threads aren't standard with meade and celestron. It is good for a travel scope but not as a primary. I would want more aperture for a primary scope. If you can get one for 250 or less not a bad deal.

Overall Rating: 8
Weight: 3 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.203.149)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39521


Bausch & Lomb 4000
Adequate optics, small and portable, with an utterly useless finderscope and substandard tripod

Overall Rating: 4
Optics:4 Mount:4 Ease of Use:7 Value:5
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.22.154)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=342198


Bausch & Lomb 4000
I own 2 of these. Optics on one are OK up to about 150x - the optics on the other are much better - I often use magnification of 200x .

Nice light portable scope - certainly one of the easiest scopes to take on vacation with you or use as a guide scope -

Too bad they don't make these any more.

Overall Rating: 8
Optics:7 Ease of Use:7
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.141.175)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=348730

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