So this astronomy disease is progressing faster than I expected. With my recent find of a relatively nearby dark site (30 minutes) and fun with my quite recently acquired 114 Newt I am contemplating building something a little bigger.
My germ of an idea is to build a 8" f6 Truss Dob collapsible so it can easy pack in the wagon but I had the notion that if I build the cell big enough I could upgrade the mirror to a 10" f5 later when finances allow or if I just decided to go that way when it all comes togther. (intention is to buy the mirror but price nearly doubles for the 10").
There is only 50 mm difference in the focal length calculated and that would be adjustable in the truss rods or maybe even with an extender.
OTA length would be about 1100mm and collapsed down to 800 or 700. That length would make it an easy fit across the back rather than some awkward diagonal placement it otherwise requires.
Are there any major obstacles or differences in the mirror sizes that might cause problems ?
The only two I can think of is mirror support points and eyepiece depth to the secondary mirror but I can engineer that out with either buying the 10" sized secondary to begin with or an adjustable side plate for the eyepiece.
I have already started some basic designs Cell depth 4-500 mm with 300 mm side width. Mirror plane at about 150 mm from the base with a fan cavity below the mirror.
An 8" only option would be only 50 mm smaller in side width so for the sake of 2" of wood .....
Can anyone give me some average weights for a 8" and 10" mirror so I can do some geometry exercises with the pivot placements.
Why the 10" option ? I was just stunned by the difference in light grasp between the 8" (817) and the 10" (1326).
Any comments/ideas/information etc appreciated.
