It doesn't seem to be, because it comes already mounted on a round platform that rotates on another platform of the same size, as you see in the photo. However, someone handy with their hands might be able to detach it from the platform and modify it to fit a tripod. Also, the base sits on 3 rubber feet; highly recommend the vibration pads from Celestron (available on Amazon) to absorb vibration.
Just to add to the previous answer by Smile'in Jack, when practicing during the day. As the manual says, the object you practice focusing on is going to be upside down when you view it through the scope. Also, you must be able to focus on an object that is several hundred yards away, with no obstructions. This is when you should align the red laser finder. Without the finder aligned, you'll never be able to find an object in the sky. Double check that the eyepiece is inserted properly & the screws tightened. Good luck! This scope has worked great for me. I love it's portability.
The diameter is 1.25". The focal lengths are 20mm and 10mm, but those are used to determine the magnification, while the diameter is the width of the eyepiece barrel. The 1.25" is considered standard size, although you can buy 2" eyepieces for much more money. Most telescopes accept 1.25, but the pricier ones accept both 1.25 and 2 inch diameter eyepieces.
To increase the size you will need a stronger magnification lens. I suggest a 2x barlow lens. That will double size and magnification on what you are looking at. Just remember the eye piece is 1.25 inches so it limits the types that you can get.