What is an illuminated finderscope ?

Question

found the description here

http://www.escience.ca/telescopes/RENDER/5/2022/3054/13660.html

Answer 1

Hey, that looks just like my 9x50 finder scope.  Mine is not illuminated.

In addition to having a finder scope that has illuminated cross hairs, you can also get an eyepiece for your main scope that has illuminated cross hairs.  They can be handy for measuring angular distances - like the separation between double stars.

Answer 2

Many finder-scopes come with cross-hairs.  If the finder is well aligned, you place the object right on the cross hairs and it will be in the field of view of the main telescope.

However, if you are looking for relatively faint object (not a planet, for example), and it is dark, you will not see your cross-hairs...

unless they are illuminated.

There is a tiny light (and battery) inside the finder-scope, and it makes the cross hairs visible at night.  Many come with a dimmer so you can turn it up just enough to see the cross hairs yet not drown the faint object.