Quote:
Originally Posted by barx1963
Pete
Yes all Newtonian scopes (a Dobsonian is a type of Newtonian) will invert and reverse the image. You get used to it very quickly.
While it is possible to setup a device that will correct this, it is very rarely done as you lose light every time you use a lens or mirror, and in the end does it really matter? There is no up or down in space!
Also with the size of the moon. Magnification is a function of the focal length of the scope and the focal length of the eyepiece. From memory these little scopes are f4 so they have a focal length of 76x4 or 304mm so your 20mm EP gives a power of 304/20 or 15x. So to make the moon image larger, you need an eyepiece with a shorter focal length, or a bigger scope!!
If you are looking at a 6" or 8", I would go the 8", not that much bigger but much more light gathering.
Malcolm
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Thank Malcolm,
Yes I guess it won't matter greatly, just will be hard to learn or say to friends or figure out which lunar crators are what or which is the north south poles on Mars?
Guess I can look at maps in a mirror
Maybe an 8 inch won't even see Mars polar ice?