Vivitar telescope I am using parts from your vivitar telescope for an optical monitor. This includes lens adjustment, eyepiece and mount. I have an ad for it, I found in Sunday post and would like to include the Vivitar name and model. If I remove the ad pricing would you have a problem with being part of the subject of a project which 'pretty much' destroys your orignal product for it's pieces? The article will be submitted to appear in 'Gadget Freaks' in 'DesignNew'.
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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.
You don't say whether this is an astronomical telescope or a terrestrial one (spotting scope). However, I have a Vivitar scope which was sold as an astronomical scope, but is actually a spotting scope, although it uses astronomical style eyepieces, so...
I am not sure that it is the eyepiece you want, either. It is hard to break an eyepiece, but much easier to break the eyepiece mount or diagonal mirror fitting.
Most astronomical telescopes use a standard fitting eyepiece with a 1.25 inch outside diameter barrel. You can measure the mount where the eyepiece goes to make sure that yours is this size, then search on eBay or Amazon for "1.25 eyepiece" and you will find many available. It doesn't have to be made by Vivitar, any make will fit.
The other variable will be the focal length of the eyepiece, which is what determines it's power. The power of the scope will be the focal length of the main objective divided by the focal length of the eyepiece, so a 9mm eyepiece will give a higher magnification (and be dimmer and harder to focus and find objects) than a 20mm eyepiece. It is usual to have two or three different focal length eyepieces for viewing different objects.
The only thing I know of that can cause this effect is if you are looking into the eyepiece mount of a reflector telescope without there actually being an eyepiece in it. Seeing your own eye in this situation is a check that the collimation (lining up of the optical elements) is good.
You need to put an eyepiece into the mount. This scope is meant to come with two eyepieces, but if you bought it second-hand and didn't get them, you can buy eyepieces from several sources, including Amazon and eBay. Measure the eyepiece tube's inside diameter. The most common barrel size for eyepieces is 1.25 inches, but there are also some small telescopes that use eyepieces just under an inch (.965") in diameter, which are harder to find. If you have to buy eyepieces, they are likely to cost more than this scope is really worth.
There is a good website for telescope beginners at THIS LINK
The only thing I can think to ask is whether you have fitted an eyepiece (NOT the barlow lens, if it came with one). Eyepieces are small lenses marked with a focal length (in mm, like 20mm or 9mm). They fit into the part that does the focussing, and are held by a small screw that you tighten with your fingers. If you have fitted an eyepiece and it still won't focus then I don't understand what is going on.
I would suggest that this is one of those problems best sorted by an experienced person physically present.
You don't need to get Vivitar brand eyepieces to get additional ones for your telescope. I'm not sure of the specifications for this particular telescope but in general they come in two barrel sizes for the eyepieces. The diameter of your eyepiece is probably 0.965" but could come in the more standard 1.25". You can measure the diameter and determine this quickly.
Once you know the diameter to shop for you can look for the focal length of the eyepiece you wish to purchase. They are rated such as 4mm, 10mm, 25mm, etc. The smaller numbers give you higher magnification. You can calculate the magnification by dividing the telescopes focal length by the eyepiece focal length. For example, let's say your telescope is has a focal length of 360mm and you have an eyepiece rated 10mm. Divide 360 by 10 and that gives you a magnification power of 36.
You can find eyepieces at many telescope dealers on the internet. Your selection will be far less if you use 0.965" eyepieces. You can purchase 0.965" to 1.25" adapters so that you can use the larger eyepieces with your telescope. However, on some telescopes the adapters will cause the new eyepiece to not come into focus.
You'll also find that eyepiece prices go all over the place. A good general purpose eyepiece is a type called the Plossl. The better eyepieces have more coatings too that allow more light to get through to your eye. You'll find these listed with terms like "fully multi-coated".
Eypieces in telescopes usually come in two sizes .9" and 1.25" diameter. There are hundreds of scientific companies or telescope companies that can supply you with an inexpensive replacement. The eyepiece focal lengths, usually in millimeters, determines the magnification of the telescope. The focal length of the main lens divided by the focal length of the eyepiece is the magnification of the telescope. Usually two eyepieces are enough for your scope. Good luck
If it is a focused image but hazy or foggy, you have to clean the optics in your telescope. If you have a focus problem but a clean image, then you are having travel limitations of your focus equipment usually rack and pinion. Wearing eyeglasses can also effect that mechanical problem and so does other added components like "Barlow Lenses" that are used to double or triple eyepiece magnifications. You might also have the lenses in the optical system not in the right order or direction when it was taken apart.
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