The Galileoscope has been with us now for five years. Some in the amateur astronomy community have embraced the small 50mm telescope, while others still view it as an educational tool only, and only a mediocre telescope at best. Personally speaking, I sort of belong to both groups, having found that the telescope has plenty of use, but far from mediocre.
I have used my telescope for a number of projects, and have even extended its use. In that time, I have learned the following.
1. Other eyepieces - Since the Galileoscope uses the standard 1 1/4" diameter, other eyepieces can be used. Caveat: weight. Since the eyepieces are simply a friction fit, it is crucial to limit weight.
2. Diagonals - Not exactly. You can use a diagonal if you use a Barlow ahead of the diagonal. Again, the problem is weight. While I converted a commercial eyepiece by adding a 29mm plano concave lens, this isn't always practical. The Galileoscope could of course be modified by shortening it up, but this is probably more trouble than it is worth. Best avoided.
3. Barlows - Yes. The Galileoscope already comes with a simple Barlow, and other commercial units can be used. In the image, a small inexpensive (and lightweight) Meade 2x Barlow is being used. Again, the biggest problem is weight.
4. Solar work - Certainly. While I caution users about problems with the projection method, others have reported success. My preferred method is with a solar filter. Baader film is inexpensive, and it is easy to build a solar filter.
5. Tripod and other mounting systems - The Galileoscope works best as a straight through, traditional telescope. Depending upon what you plan on viewing, you could find yourself being contorted into some extremely odd angles. When it comes to tripods, the taller, the better with the Galileoscope. Using a chair to effectively sit under the telescope is recommended. A tripod will probably be the single most expensive purchase you could make in conjunction with this telescope. Certainly, there are probably other ways you could mount this telescope, depending upon how imaginative the user is.
There are still plenty of projects planned for my Galileoscope. As the top image shows, recently, it was used in alongside my main sunspot telescope, a Monolux 60mm f/7.5 I call "Bianca", and it performed flawlessly. Who knows, I may one day use it for a Messier hunt. As an experimenter's telescope, I believe that it is without peer for its small size.