Why are images in finder scope upside down - TwinStar Blue AstroMark 50mm 75x Power Refractor Telescope

Astro telescopes normally do show an inverted image, since for most purposes this does not matter. For terrestrial viewing, such as thru someone's window, you can buy an "erect image" or "correct image" prism which gives an upright image.

http://www.optcorp.com/telescope-accessories/optical-tube-accessories/diagonal-prism-eyepiece-holder.html?a_diagonal_design_f=1090

I don't know of such a thing for the finder scope, you would have to buy a new finder.

http://www.optcorp.com/celestron-9x50-illum-ra-correct-image-finderscope-93781.html

The image of all astronomical telescopes are upside down (SCTs are upside down and reversed). RACI (right angled, correct image) finders do produce a right-side up image. For daytime use a erect image prism eyepiece.
Follow below instructions (except 7 in your case)

1. Get Stellarium or another fine astronomy program
2. During the day, point the telescope at a part of the landscape about 100 yards away.
3. Use the lowest power eyepiece (highest number) in the focal tube.
4. Center the landscape object in the telescope.
5. Align the finder scope so that it points exactly where the main telescope is.
6. At night, leave the scope out to reach thermal equilibrium (about an hour for small reflectors and refractors)
7. If the scope is on a EQ mount, polar align.
8. Point the finder at the moon. The moon should be in the main scope also.
9. Practice finding the moon before you start on the planets
10. Once you are comfortable with the moon and planets, you can go for the deep sky objects

Astronomical telescopes are made this way. (There are RACI-right angle correct image) finders on the market. It just takes some getting used to.

It's NOT really a problem. ALL reflector style telescopes show upside down images. This will not affect your star gazing since there is no UP OR DOWN in outer space. Read my tips on my profile page.

You can buy an "erecting diagonal" for terrestrial viewing- BUT this is not what an astronomical telescope is actually used for.

So align the small finder scope on a distant object like the top of a telescope pole during the day time. Point the main tube at the pole and get the tip top in the main tube's eyepiece. Without moving the telescope adjust the crosshairs on the finder scope on the exact same spot. The moon should be your first target at night and you can check and refine the finder scope on the moon.

Astronomical telescopes usually show an upside down image. There is a good reason for this- erecting the image needs more bits of glass in the light path, which reduces the amount of light and increases aberrations. Even if this is only slight, astronomers prefer to avoid it, and they don't really care which way up the Moon or Jupiter appear. It is possible to fit an erecting prism or eyepiece to most astronomical telescopes, and some of them come with one, but one wouldn't bother to do this with the small finder scope.

Telescope manuals recommend that you align the finder scope in daylight, by pointing the main scope at an object on the horizon and adjusting the finder to match (never point a telescope toward the Sun!). Once you have a tree or mountain peak in the center of the main scope's image, you can then adjust the screws around the finder scope to get the crosshairs (or red dot) centered on the same object. It is very difficult to do this job in the dark, especially as objects in the sky are constantly on the move.

Yes, most finder scopes show upside down images, it's completely normal.

This is an astronomical telescope. Even the main tube shows upside down images unless you use what is called an "erecting prism" for terrestrial viewing.

The end with the FOCUSER is the UP end. The mirror is the BOTTOM.

Like the picture in your question. The small finder scope is also mounted near the focuser as in the picture above.

You probably have the scope tube mounted upside down !

Yes, all astronomical telescopes and some finder scopes show images upside down.

Some finders show things upside down. There is no up or down in outer space.

During the daytime focus on an object like the top of a telephone pole a good distance away.

Without moving the telescope adjust the finder scope so that the "crosshairs" in the finder are centered on the same object as the main tube. Most astronomical telescopes show upside down and reversed images.

You are not missing any lens. All astronomical telescopes present the image upside down and reversed. This is normal--- no up or down in space!