Focusing the Barlow lens

No the barlow increases the magnification by 3 TIMES for any eyepiece --
this will be too much for that small 76mm telescope.

Magnification is the least important quality of a telescope. Aperture and quality ioptics are much more important. I usually never use a barlow -- just the straight eyepieces in various mm sizes.

Read my tips on my profile page.

Sorry-- there are several different ways it could go depending on the barlow. NEVER disassemble an eyepiece or a barlow. Only the outside surfaces need to be cleaned from time to time.

It multiplies the normal magnification of the eyepiece. They come in 2x, 3x, 4x, and 5x powers.

Normally in a very small telescope like your scope, they are completely useless! They generate too much magnification for that small aperture.

You would normally put the barlow into the telescope, and then put the eyepiece into the barlow lens.

There is no such thing as a 3x barlow telescope. A barlow is a small accessory that multiplies the magnification of any eyepiece.

This is a barlow-
http://www.agenaastro.com/GSO-1-25-2x-Barlow-Lens-p/obar-gs-gs2bl.htm

I believe this is a refractor style telescope. Put the eyepiece with the largest number written on it into the telescope. DO NOT use the 2x or 3x barlow if you have one.

Practice focusing on a distant object during the day time. The moon should be your first target at night.

Read the web site listed below and my TIPS on my profile page.
http://www.texasastro.org/telescope.php

Thanks for the additional info.

Your telescope is a basic introductory model and so has very limited performance, but used correctly it's still a great introduction to astronomy. If you don't have it, download the user manual from here (courtesy of Retrevo).

If complete, it should have come with a 5mm and a 20mm eyepiece, also an erecting tube (so called as it ensures images are upright and also laterally corrected: used for terrestrial viewing only), a diagonal mirror and a 3x Barlow lens.

Only use the erecting tube for daytime viewing of distant objects on land or at sea. The diagonal mirror is what you use for astronomy and it allows a more comfortable viewing position: without it you'd be trying to crouch beneath the telescope and craning your neck upwards to look into the eyepiece. Check that the mirror inside is bright and clean; if it's dirty or corroded then images will be low contrast, dim or even impossible to see. The eyepieces allow different image magnifications; the 20mm one has the lowest magnification, but also the brightest images and vice-versa for the 5mm. To calculate the magnification, divide the objective lens focal length (in this case 700mm) by the eyepiece focal length. For the 20mm eyepiece you end up with 700/20 = 35 and for the 5mm it's 700/5 = 140. If you then add the 3x Barlow lens you end up with 105x and 420x.

You're probably thinking, "OK, but how does this fix my problem?" As long as the diagonal is clean then your problem is almost certainly badly chosen eyepieces by the manufacturer: the greater the magnification, the dimmer the image, and realistically the maximum useful magnification for a 60mm objective in perfect conditions is 120x and more usefully is 30x to 60x and these limits apply to a good quality telescope. Meade, Tasco and a few others are built to price first, impressive sounding features second and quality a very distant third, so those limits can be comfortably reduced. All of this means that whilst the 20mm eyepiece may be capable of providing a useful image, the 5mm really isn't and the 3x Barlow will be low quality and far too powerful. Using the 5mm even without the Barlow is going to result in too high a magnification. As the night sky is mostly dark, unless the telescope is directly pointing at a bright star you'll see nothing. Although a magnified image will show planets as discs, stars are so incredibly distant that even at the unusable 420x magnification they will still appear as near invisibly dark pinpoints, and at 140x will be very dim pinpoints. I use the word pinpoint hesitantly, as in all but the best conditions the Earth's atmosphere will cause the star to twinkle, so the pinpoint will be a blurry blob. The only reason to include the 5mm and the 3x Barlow is marketing: to a novice, a 420x telescope sounds far more impressive than one which may be more expensive but which only offer 120x maximum magnification.

In short, don't use the 5mm eyepiece or the 3x Barlow at all. Stick to the 20mm and if you only have the 5mm then go and buy a budget 20mm and a 12.5mm. If you join a local astronomy club you may even be offered them free of charge as someone is bound to have upgraded to better quality examples. If you stick to these eyepieces then your telescope will be great for observing the Moon and will be able to see Jupiter's four largest moons (don't expect to see details on Jupiter though). It will also be able to show Saturn as a spot with ears sticking out either side (the rings) but you won't see any detail. Mars will be a noticeably red disc but lacking in much detail. Although you won't be able to make stars appear to be any larger, you are able to see how many of them are actually binary stars. You need to upgrade the telescope quite a bit to improve on those images, and also to ensure that you're viewing away from city lights if possible. It also helps immensely if you leave the telescope outside for a few hours before using it, as warm air currents inside the telescope tube itself can be enough to ruin images. As long as you understand the limits of your telescope then even as a budget model it will teach you a lot and show you things you haven't seen before.

One final tip: it can be awkward to get the focus adjusted correctly using the rack and pinion mechanism. Use it to get as good as possible, and then adjust the fine focus using the eyepiece itself: if you examine yours then you'll probably find that the actual lens assembly is simply secured to the eyepiece tube by a screw thread. By tightening the small screw on the diagonal to grip the eyepiece tube you'll find that you can fine focus by turning the eyepiece lens assembly itself back and forth.

Sorry for so much detail, but I hope that you now understand that your bargain find probably isn't faulty at all but just needs the correct eyepiece under the right viewing conditions. Please take a moment to rate my answer or to ask for clarification if anything I've written is unclear.

It multiplies the normal magnification of each eyepiece THREE times! In your small telescope you will probably never be able to use it. Magnification is the least important quality of a telescope.

Use the eyepiece with the largest number written on it, which is your LOWEST magnification. Practice focusing on a distant object during the day time. At night the moon should be your first target.

You mean your 2x or 3x barlow. These can be purchased from many on-line retailers:

Here are two:

http://www.telescope.com/control/category/~category_id=barlows

http://www.agenaastro.com/Barlow-Lens-1-25-inch-s/66.htm

ALL astronomical telescopes show upside down images it is normal. Put the eyepiece with the LARGEST number written on it into the diagonal. Do NOT use the 2x barlow it is too much magnification for that small aperture telescope.



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The moon is big so use the 25mm. The Barlow will have a multiplication marking on it 2x 3x etc. A 2x Barlow lens will effectively double the power of the eyepiece you are using. Do not use the erecting eyepiece for anything other than land viewing. Erecting eyepieces generally reduce the amount of light reaching your eye and thus reduce brightness of the faint objects in the sky.
So basically just place the 25 mm lens in the focuser and point the scope at the moon and you will be amazed at what you can see and how bright it is.