The only real difference between the 3 different sizes is the actual aperture of the telescope. The bigger the aperture the more light you can collect and the more contrast you will see in the image, plus the more magnification you can get out of the scope. All the accessories are the same with each of the aperture sizes.
The Travel Scope is ideal for terrestrial as well as casual astronomical observation.
The Celestron TravelScope is really easy to set up and there are no tools required. The Celestron Travelscope comes with its own pre-assembled aluminium full size photographic tripod to support the scope whilst in use and ensure a stable platform for a better viewing experience.
In addition, both the telescope and tripod fit inside the handy customised backpack for convenient and easy travelling and storage so that you can take it with you wherever you go.
You also get two eyepieces, a 10mm and 20mm eyepiece together with an a finder scope and erect image diagonal. There is also some free planetarium software called The Sky X – First Light Edition. The software is a computerized sky map that features a 10,000 object database, 75 color images, horizontal projection, custom sky chart printing, and zoom capability.
All versions of the Celestron TravelScope are useful travel scopes which comes with lots of useful extras and a customised backpack. There are 3 aperture sizes of this scope, at three different prices. The smaller the apeture the smaller the price, but for the price difference I would recommend the larger 70mm apeture. You may find the 70mm may be a little heavier, but it will show you so much more detail and give you more contrast through the eyepiece. This is especially important if using it for astronomical use.