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Hello, my neighbor just gave me a " Jason discoverer 454" and I am missing the erecting prism and lenses ... which compatible prism and lenses would you recommend? Thank you Eric

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Look on Ebay, or contact the manufacturer

Posted on Dec 03, 2016


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How to get my image right side up

For astronomical viewing this is unnecessary-- there is no up or down in space. :) For terrestrial viewing you can but an erecting diagonal which will make the image right side up.
Here is one

Feb 14, 2015 | Tasco Optics

1 Answer

No image through lenses

1. During the daylight point the telescope towards an object (water tower, building ) something about 1/2 mile away.
2. Locate the object in your finder.
3. Use the 12.5mm lens (50x) and look through the telescope. Do not use the erect prism
4. Align the finder to what you see in the scope.
5. You can use the 4mm to fine adjust the finder.
6. On a good, clear night.Leave the scope out to reach thermal equilibrium ( about a hour) Point the finder towards the moon
7. Use the 12.5mm and then focus on the moon.

Note: This is NOT a quality scope. Avoid any scope with .965 eyepieces and silly magnifications! Max power on this scope on a PERFECT night is 200x and Huygens (H12.5) eyepieces give very narrow and poor viewing. Do not use the 3x barlow or the erecting prism. the erecting prism is for terrestrial viewing only and the barlow, although it increases the eyepiece by 3x, will also narrow the view.
Good Luck!

Dec 05, 2011 | Rokinon 62550 Telescope

1 Answer

I have a jason saturn telescope and everything is upside down

That's completely normal and correct for all astronomical telescopes.

If you want upright images for viewing terrestrial objects then you need to buy an adaptor called an "erecting prism" which sits between the eyepiece and the focuser. Astronomy telescopes don't use them as any unnecessary optical elements reduce image quality and contrast.

To get the correct sized erecting prism, measure the diameter of your eyepiece where it fits into the telescope. If it's 1.25" (31.75mm) then you'll find loads of them from online sites. If it's 0.965" (24.5mm) then it will be harder to find one as those sizes are only used on cheap chuck away toy telescopes, and any you do find are likely to be of very poor optical quality. IIRC, "Jason Saturn" was a brand name applied to a number of different models sourced from various manufacturers in N.America; the quality of individual models varies but I think they all used 1.25" viewfinders.

Aug 27, 2011 | Optics

1 Answer

I want to use my telescope for searching the horizon but the image is upside down am i missing a lense?

All astronomical telescopes show upside down images. You can buy an "erecting prism diagonal" for terrestrial viewing like the ones shown on this web site:

Dec 20, 2010 | Tasco Starguide Computerized 80mm...

1 Answer

My friend was given a Jason Model 313 Discoverer Astronomical Telescope F=910 D=60mm Discoverer 454 and does not know how to assemble it. Is there any way he can get some kind of paperwork showing how...

No one makes manuals for these small telescopes. However MEADE BRAND scopes have a web site with all of their manuals. Look under the REFRACTOR heading for one that is similar to your scope.

Nov 06, 2010 | Optics

1 Answer

We have a refractor AZ2 holder (the only name we have.) No manual, several lenes, but how to put them together??? The lenses are SR4mm, H12.5mm, 1.5X erecting eyepiece & 3X Barlow Lens. Hope you can...

The 3 x barlow will be useless for this small telescope.

Put the 1.5 x erecting PRISM into the telescope and then put the eyepiece with the largest number written on it into the erecting prism. This is your lowest magnification.

Take the scope outside during the daytime and practice focusing on a distant object. Turn the focuser knobs slowly until the object comes into sharp focus.

Aug 07, 2010 | Optics

1 Answer

Bushnell Discoverer 78-8945

All astronomical telescopes show upside down images. Read my Frequently Asked Questions Tip on my profile page. These scopes are made to view objects in the night sky which are very small, and faint. To erect the image would require more glass or mirrors in the optics and would further dim these objects.

You can buy an "erecting prism" to use for terrestrial viewing. Like this:

Your scope is working just fine.

Jul 07, 2010 | Bushnell Discoverer 78-8945 (325 x 114mm)...

1 Answer

Why is the image upside down?

All astronomical telescopes show up side down images. There is no up or down in space. However you can buy what is called an "erecting prism" diagonal for terrestrial viewing.

Most of the objects in the sky are very dim. Adding another series of glass lenses just to erect the image would only reduce the light transmitted through the telescope.

Dec 21, 2009 | Optics

1 Answer

Bushnell Deep Space Series 525x 78-9500 We didn't assemble when we received as a gift a couple of years ago and now realize that the assembly instructions were left out of box. We assembled telescope but...

The erecting prism can be used for both terrestrial and star gazing-- put it innto the scope first.

The 3x barlow probably will NOT be very useful... it triples the power of any eyepiece. Your small scope cannot go much over 100 power-- before the image degrades.

Put the eyepiece with the BIGGEST number written on it into the erecting prism which you previously stuck into the scope... now go outside during the daytime and practice focusing on a distant object.

The bigger the number on the eyepiece the LOWER the magnification.

Apr 13, 2009 | Bushnell 525x Deep Space Reflector...

1 Answer

Want to see images right side up

You do not need an erecting prism to view objects at night. These are used if you wish to view terrestrial objects since it turns them right side up.

If you have a reflecting telescope (it uses mirrors) it's normal to not use an erecting prism or as they are also known as star diagonals. Objects will appear inverted and that's normal. A refracting telescope (no mirrors, just lenses) will also invert the image but it is quite often used with a star diagonal to make it easier to view. There are many other types of telescopes that use a combination of mirrors and lenses.

I hope this helps.


Mar 29, 2009 | Optics

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