PDA

View Full Version : Problem with a Bausch & Lomb "4000"



imported_Heather
2003-Aug-20, 03:59 AM
Hello! I was out tonight trying to use my neighbor's telescope to observe Mars, but couldn't see anything whatsoever! I've never used a telescope so I know absolutely nothing and the manual was no help. There's absolutely no light coming through the telescope, is the aperture closed? This model is a Bausch and Lomb 4000, a Schmidt-Cassegrain; does anyone know what I'm doing wrong? If you have an idea, please e-mail or instant message me. Thank you very much!

Fraser
2003-Aug-20, 06:44 AM
This might be too simple an answer, but did you check the lens caps? Usually a telescope has a cap on both the eyepiece and the end of the telescope. Another possiblity is that the eyepiece for the telescope is missing - you won't see much without that part.

Johnny B
2003-Aug-20, 07:58 AM
Prior to using any telescope you must first set the finder scope. That's the little eye piece that sits atop your telescope, usually about 5"-6" in length. Your owners manual will explain how this is done but if your having difficulty understanding the manual here is a tip: the cross hairs in the finder scope should be targeted dead center on a fixed object roughly 1000 meters away, ie.. an atena on a building top several blocks away and the same object should be in the center of the field of view in the eye piece that you will viewing objects through. The trick is to first position the object through the main view piece and try to isolate a portion of the object such as the beacan on the antena in the center of your field of view. Now adjust the finder scope using the little thumb screws to position the cross hairs dead center on that beacan. You are now set to view the heavens but remember not to desturb the settings on the finder less you have to recalibrate it again using the same method. Good luck and let us know how you did. Happy observing!

Johnny B
2003-Aug-20, 08:13 AM
Oh! I forgot to mention that once your finder is set, this is what you use to find objects with prior to viewing them through the eyepiece, hence the term "FINDER". You simply look through the finder after it has been set and position the cross hairs dead on the star or planet, the object should be close to center of the field of view in the telescope's eyepiece. I hope this helps, once again- good luck!

imported_Astrono
2003-Aug-20, 01:12 PM
Hi there Heather!

After checking like the other answer suggests that the lens covers are removed.

A flashlight may help by turning it on and pointing the light into the scope at the big end.

That way you can see any light that comes through to the eyepiece.

By shining the light through it you can tell if the tube is clear and if it is just out of alighnment?

Let the forum know how you resolve this! Thanks!

Good Luck!

B) B)

Don Sevendy
2003-Aug-22, 12:27 AM
First of all, don't try to set up a telescope in the dark. Try it out in daylight on some terrestial target, but be aware that you can't properly adjust the finderscope alignment, due to the inevitable parallax problem with an object at a finite distance. Still, a rough alignment (it's done with those three little screws around the periphery of the finder mount) should allow you to get close when you get out under the night sky; from there you're just going to have to do a random-walk hunt. Once you stumble accross your target, make the final finder adjustment, and you're set for any future use! Unfortunately, the B&L 4000 is not the easiest 'scope to use because of the finder's location, which interferes with the main 'scope's eyepiece; you may need to loosen the right-angle prism adapter, and swing it out of the way to even see through the finder.

There's a reason why B&L/Criterion, out of the three domestic Schmidt-Cass manufacturers, is no longer making telescopes...

Johnny B
2003-Aug-22, 07:31 AM
Hi Heather, any luck? Don Sevendy is right to mention the set up of the finder during daylite hours especially if you're not familiar with the telescope and you've never done it before. I've gotten pretty good at it to the point where I can even fine tune it at night which is why I failed to mention this but I wouldn't attempt it if I were you because you can really throw off the setting bad if you haven't got the experience. Good Luck

Charles Bell
2003-Aug-23, 12:00 AM
At this time of year, telescopes brought from indoors where it is air conditioned to the outside where it is warm and humid, will experience dew formation on the optics. You have to set the scope outside for a while and let it warm up. A hair dryer can clear the dew or fog forming on the optics.

This happens with mine everytime I take it out. It happens to small and large scopes alike.