Telescope question?

Question

I just bought a telescope from Costco and when I look at houses about a half mile away, the image is upside down. What gives?

Answer 1

The image formed by the primary (lens or mirror) of a telescope is always upside down. In binoculars or in "land telescopes", there are extra optical devices (lenses, prisms) to make the image right-side up (erect).

Since "upside-down" does not have much meaning in space, astronomers prefer to have less glass in the way; therefore, they go with the upside-down image which is clearer than one that had to go through extra glass.


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If you have a magnifying glass try this:
find a room that has a window and a relatively blank wall opposite the window (or set up a piece of white paper or cardboard against the wall opposite the window).
Turn off all other lights in the room. Check to make sure the Sun is not shining through the window, towards the target wall (you do not want sunlight to go through the magnifying glass).

By moving the magnifying glass towards or away from the wall, you will find the correct distance (focal distance) at which you get an image of the window on the wall. Inspect that image and you will see that the image is upside down.

If you could fix the magnifying glass in position, you could then get a smaller but more powerful magnifying lens and inspect the image (the details will appear bigger).

This is basically how a telescope works. The primary forms a 'virtal', upside-down image (virtual, because you don't want a wall inside the telescope) and you inspect this virtual image with the eyepiece.

You could form an erect image on the wall by inserting another lens between the wall and the magnifying glass, but the details in the image would be degraded.

Astronomers prefer quality to right-side-up.

Answer 2

Astronomical telescopes do not need to give right side up and un-reversed images. There's no up or down in space, and image erecting lenses or prisms absorb light as well as induce other optical headaches for telescope makers. When you're straining to see objects just within reach of a telescope, you don't want anything to steal precious incoming light. There's nothing wrong with your telescope, and if it's a refractor there are image erectors for use during the day time available. Newtonian and other reflecting telescopes are not suitable for daytime use at all. Their images tend to be oriented at odd angles for terrestrial viewing, and they're vulnerable to the effects of heat waves blurring the view. If that's the sort of telescope you've bought, you'll prefer to use it for astronomical observing only.

Answer 3

This is normal with all astronomical telescopes. To make the image right side up would require extra lenses or prisms, and that would cut down some of the light, which astronomers never want to do. Besides, there's no "right way up" in space!

Most of the scopes from Costco are poor quality, so I'd recommend returning it and buying a better telescope for the same money from a store specializing in telescopes, such as these:
http://www.telescope.com/shopping/product/detailmain.jsp?itemID=4644&itemType=PRODUCT&iMainCat=4&iSubCat=8&iProductID=4644
http://www.telescope.com/jump.jsp?itemType=CATEGORY&itemID=9

Answer 4

It sounds to me that you bought one of those telescopes I've been trying to warn people about staying away from... IE:
A cheap, department- store- type of refracting telescope.
It probably advertised a HUGE amount of magnification, and came with a spindly aluminum tripod and mount.
Regardless, if it truly is a refracting telescope, then the optics are performing as they should; you'll get an inverted image when using the scope for terrestrial observations.
This can be corrected by obtaining a 'correct image' prism; a diagonal who's mirror is placed at a 45 degree angle to the axis of the telescope and eyepiece.
You'll see things right- side- up now.
Clear Skies!

Answer 5

Look at the accessories that came with your telelscope. You should have a star diagonal and possibly an accessory called an image erector (for straight through viewing only). Put either one of these between the telescope and your eyepiece. This will solve your problem.

Answer 6

That is totally normal. It is because you need to use another lense like a barlow to correct this. What happens is when light enters the concave lense at the front of the telescope it focuses the light waves at the eye piece near your eye and all the light waves intersect at this point and not at your eye. This causes the image to appear upside down when the light waves enter your eye.

Answer 7

That's the way telescopes work - simple clean optics invert the image. You either need to get an inverting eyepiece or use binoculars which contain inverting prisms to see an upright image. Or practice head standing.

Answer 8

You bought it at Costco, instead of a telescope specialist like you should have.

Answer 9

You are looking at it the wrong way then. if it is upside down then you need to look at it backwards so that the telescope is pointing toward your back rather then pointing away from your face.

Answer 10

thats how a Telescope works
it turns the image upside down

if you REALLy want to fix it
you have to buy some-thing