This is a blog for amateur astronomers and telescope makers everywhere.
Wednesday, February 10, 2010
Focuser and finderscopes
After a short wait, the focuser, Telrad and the bracket for the 50mm finder scope arrived and I got to work installing them on the upper cage. However, I found the focuser board that I made originally to be all wrong for the focuser, and worse yet I botched the job of mounting it. So I took a piece of Brazilian cherry and made a new one, moving the hole for the focuser 3/4-inch farther back to allow some space for adjusting the position of the secondary mirror and it's holder. The board was made wider to accommodate the focuser better and I made a spacer from left over 1/4-inch aluminum used to make the tail gate so operating the focuser would be easier and there would be a thrust plate for the leveling screws to push against if their use is required to square the focuser with the optical axis. The Telrad fit right into place on it's base, but the bracket for the 50mm finder needs a riser for the finder scope to clear the rings of the upper cage. Ideally, I will be able to leave the finder scopes on the upper cage even when it's in the storage box I will be making to keep it free from dust, dirt and getting damaged. At present the focuser is just held temporarily in place until I can get a nut driver for the nuts and notch the baffle to allow me to finish inserting the screws for it. Once the finders and focuser are mounted permanently in place, the only operation left to complete for the upper cage is to adjust the pole seats, which will not take place until the primary mirror is delivered and I can determine the length and angle of the truss poles. I am in the process of coming up with the money for the primary mirror, when I do, I will contact the optician I've chosen to make the primary mirror.