Question about Bushnell Voyager 78-9440 (440 x 12.5mm) Telescope

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Eyepieces not fitting into 90-degree penta mirror

My 2 included eyepieces will not fit into the 90-degree penta-mirror. Am I missing a part that fits between the mirror and the eyepieces or should I get a file to make them fit (kidding). Thanks for any ideas. PB

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Re: eyepieces not fitting into 90-degree penta mirror

Here's the link to the user manual if you need it; Check the bottom of page 3, I think it answers your question - eyepieces should insert directly into the penta mirror. check page 9 for a diagram showing the whole assembly. If it turns out you have the wrong eyepieces, you can contact bushnell's spares department on; Hope this helps, please ask again if you need more info :)

Posted on Sep 16, 2007

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Purchased telescience telescope, the diagonal mirror is missing. Where can one be found

Assuming this is the usual size (1.25 inch barrel), you can find these and other eyepieces and accessories on eBay and Amazon. You won't find the telescience brand name, but that doesn't matter.

You don't actually need this to use the telescope. The eyepieces will fit directly in the focussing mount.

Jan 26, 2011 | Telescopes

1 Answer

I need the eyepiece for the vivitar refractor telescope ot accidently was broking when I shipped to the Bahamas

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.

Jan 23, 2011 | Vivitar (1607225) Telescope

1 Answer

Can not focus telescope lens pieces do not fit

What Tasco do you own is it a refractor or reflector? Does it have a lens in front -- then it's a refractor; or mirrors, then it's a reflector.

On a refractor the eyepieces go in the back of the tube, sometimes you also have a diagonal which goes into the scope first and then the eyepiece goes into the diagonal. The diagonal is simply an L shaped device with a mirror inside that makes it easier to look through the scope when it is pointed UP at an angle.

On a reflector the focuser is on the FRONT side of the tube, and the eyepiece goes into the focuser.

Take the scope outside during the day time and practice focusing on a distant object. Put the eyepiece with the largest number written on it into the focuser or into the diagonal. This is your LOWEST magnification.

Practice focusing --- until you get used to how it is done. Turn the focuser knob to the left slowly-- if nothing comes to focus then try turning it to the right. It may take several full turns to come to focus.

At night the moon should be your first target.

Read my TIPS on my profile page.

ABOUT NOT FITTING: eyepieces come in 3 sizes, .975, 1.25, and 2 inch sizes. Measure the hole and then measure the eyepiece-- it may be that you have the wrong size eyepieces for that scope. The correct size can be purchased on line from many retailers. Here is one telescope retailer that sells eyepieces and other accessories:

Jul 29, 2010 | Tasco Telescopes

1 Answer

Missing a piece of my RX-9 +venture

You are missing the 2 inch to 1.25 inch adapter, that fits into the focuser so you can use 1.25 inch eyepieces.


May 19, 2010 | Bushnell 675x5 EQ Reflector Telescope

1 Answer

How do I focus on the moon. Model 1400150. I have been gifted this telescope. Tried to focus on moon. Dont know how. Took big cap off end. Looked throughscope on top of large cylinder. Tried to focus...

first, use the lowest power eyepiece, that's the one with the high number on it with 'mm' after the number.

for a refractor telescope (uses lenses), you might have to add a diagnal lens (either 45 degree or 90 degree, whichever one you have) to focus on an object.
attach it in this order:

low power eyepiece-->diagnal lens-->main telescope

for a reflector telescope (uses mirrors, a telescope with a big tube with a mirror at the bottom and a focusing knob on one side of the tube). the open part of the tube points to your target.

hope this helps :D

Aug 07, 2009 | Celestron Telescopes

2 Answers

Just came into a used tasco 302048 . Everything is upside down!!!

the scope is made for both terrestrial viewing and astronomical. In order to see terrestrially upright, you need an inverting STAR DIAGONAL. The eyepiece will do nothing for inverting the image. you might have 2 diagonals in the kit that came wih the scope. the diagonal is the part that fits into the scope. then you place the eyepiece in the diagonal. if you have 2 diagonals , one is a 90 degree angle,(astronomical) and one is a 45 degree angle, (terrestrial). the eyepieces change the magnification of the image. the bigger the number (9mm, 20mm, 26mm,) the smaller the image. the smaller the number , the bigger the image gets. the number is inverse of the image. Hope this helps.

Jul 01, 2009 | Tasco Luminova 40060660 (660 x 60mm)...

1 Answer


You most likely have eyepieces that have a 1.25" diameter but your telescope only accepts eyepieces with a .965" diameter. You can measure the diameter of the eyepiece barrel to confirm it.

There are two solutions to this problem. One is to purchase .965" eyepieces. They tend to be not as good of quality as 1.25" ones. However, you can find some here:

The less expensive way is to get a 1.25" to .965" adapter. You can find one of those here: If that link is too long go to and look it up.

One thing to note when using an adapter is that sometimes it may not allow the eyepieces to come into focus since it adds a little length to the telescope. This varies by telescope.

Good luck!


Mar 18, 2009 | Bushnell Voyager 78-9440 (440 x 12.5mm)...

2 Answers

The main eye piece is missing the lens.

yes you can..most brands of telescopes will fit others as far as eyepieces if you call bushnell@18004233537 im sure they can help...good luck.......

Oct 31, 2008 | Tasco Astronomical 302675 Telescope

1 Answer

Upside down images

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.

Jan 05, 2008 | Bushnell Voyager 78-9440 (440 x 12.5mm)...

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