I have tried to find a 90 degree adapter for a reflector telescope. They seem to be unavailable.

yes, and a 45 degree one also-- they are called an "erecting prism diagonal". Like this one:

http://www.telescope.com/catalog/product.jsp?productId=7216&utm_source=channeladvisor&utm_medium=cse&utm_campaign=Channel%2Badvisor&CA_6C15C=245938822

All astronomical telescopes show upside down images. For terrestrial viewing you can buy an erecting diagonal--
http://www.highpointscientific.com/product/ORI-08787/Orion-125-90-Degree-Erect-Image-Star-Diagonal-08787.html

Read my TIPS and frequently asked questions on my profile page.

This link points to a document which has most of the instructions in both German and English. It may help you understand better how to use your telescope. Additionally you'll probably get 90% of the way there reading up on the use of Equatorial Mount Newtonian Reflector telescopes.

Once you have the telescope properly oriented to the compass you'll be able to use the telescope easily.

http://www.nimax-gmbh.de/downloads/bresser-teleskope.pdf

Happy Stargazing.

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 if you want a telescope primarily for terrestrial use, you are much better off buying what is called a "spotting scope".

If the telescope has a standard 1.25 inch diameter eyepiece, then an erecting eyepiece may be found on Amazon or eBay. An erecting prism or diagonal of the type that bends the light through 90 degrees is not right for a reflecting scope. These are used on refractors.

there are 3 types of telescopes:
1)refractor, uses lenses
2)reflector, uses mirrors
3)catadioptric, uses both

try this and practice doing this during the day time, it's easier.

get your eyepiece, the one with the highest number on it (# mm); this is your lowest power eyepiece, always use this first (wider view and easier to see where you're pointing it), and place it in your telescope.

next, use the focusing knob to focus on a target (a faraway tree, lamp post, etc.). once you have it focused, and if you want to get a closer look, get the next highest number eyepiece and refocus on the target. this is how you change magnification.
if you have a barlow lens (2x or 3x) this will also change the magnification by 2x or 3x without having to buy other eyepieces, although you can still buy more.
put it together in this order:
eyepiece-->barlow lens-->telescope

use the star diagnal for land viewing.

if you have a reflector telescope,
the open part of the telescope tube next to the focuser points to your target. focus it the same as above.

oh, and sometimes, with refractors, you might have to use the
45 degree or 90 degree diagnal to focus the telescope.

and google how to use a telescope. there's nice observing tips :D

hope this helps :D

oh, and check out the moon at night. it's a very nice target.
best time to observe the moon is when it's not full.
you gotta check out the 'terminator' (area on the moon where the light and darkness is separated.

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

Astronomical telescopes produce an upside-down and reversed image (image is rotated 180 degrees from an upright position) since this doesn't matter when you are looking at things in the night sky. Accessories are available for rotating the image to an upright position, but most of those accessories do not work well with Newtonian style reflector telescopes such as the 114EQ reflector.

This is not only perfectly normal, but for this type of telescope, imperative! Land (and everything else) seems upside down due to how the light is bounced between the mirrors. It can be kinde tricky to get used to, but it's the way all Newtonian reflectors (it's the type of scope you have, big mirror at the botom, smaller one that's at a 45 degree angle neer the top, and an eypece on the side of the tube) are.

Dear Tarno,
I don't understand your question.You have 90 mm reflector telescope but talk about thermometer.I have not seen thermometer in those telescope.
Thanks.
Dhananjay

you have to make sure your primary mirrow is level, there are a set of screws that will help you do it, then the secondary mirrow at 45 degree, start in a daylight to align the telescope. good luck