Graf Von Wolfsburg

Hi - the main mirror is 250mm in diameter and about 35mm thick. The elliptical secondary mirror is 62.5mm across it's minor diameter and is probably about 12mm thick. (I can't measure the secondary thickness exactly without pulling out the spider assembly...which sounds like a lot of work before breakfast.) Both mirrors were manufactured by GSO and can be purchased from Agena Astro Products.

Oh - sorry, I misinterpreted your question. The object you are referring to is a limit switch. I used fairly large TemCo industrial limit switches because they are inexpensive and fairly reliable, even though they are rather large. The cable coming off of it is 2-conductor shielded security wire. The one you've pointed to is the home/zero limit on the Y-axis.

Hi Bob - sounds like you have a nice shop! I am not currently a member of any clubs, but I have been considering attending this month's meeting of the Oakland club just to see what it's all about. Maybe I'll see you there. Cheers!

Oh - sorry, I misinterpreted your question. The object you are referring to is a limit switch. I used fairly large TemCo industrial limit switches because they are inexpensive and fairly reliable, even though they are rather large. The cable coming off of it is 2-conductor shielded security wire. The one you've pointed to is the home/zero limit on the Y-axis.

Sorry - I misinterpreted your question. The item you're referring to is a limit switch on the Y-axis. I used Temco switches, even though they're a little on the large side, and I have found that they work well. Cheers!

The spindle is the motor section from a Dewalt 611 trim router. It accepts 1/4" shank tooling (or 1/8" with an alternative collet) and has adjustable speed. I have used it successfully on plastic, MDF, plywood, ren foam, and aluminum, but it spins too fast for use on steel. Many people use this router on CNCs and it's readily available and fairly inexpensive. (It is also much more powerful than a Dremel.)

Thank you for your kind words, I am glad that this was useful to you.Regarding the cutting of the aluminum - I cut the aluminum to coarse dimension using a reciprocating saw ("Sawzall"), leaving approximately 1/16" extra stock from the scribed line of the finished cut. I then did a final trim using a clamped straight-edge and a router to put a square, accurate edge on the piece. If I had access to a larger lathe or mill, it would have been easier to do a rough cut followed by a final clean-up pass with a fly cutter, but in the absence of such equipment the saw and router method was effective.With respect to the design, yes, I did design the machine from scratch. I did an overall design of the major pieces in Fusion 360, but the details were implemented during the build a…

Thank you for your kind words, I am glad that this was useful to you.Regarding the cutting of the aluminum - I cut the aluminum to coarse dimension using a reciprocating saw ("Sawzall"), leaving approximately 1/16" extra stock from the scribed line of the finished cut. I then did a final trim using a clamped straight-edge and a router to put a square, accurate edge on the piece. If I had access to a larger lathe or mill, it would have been easier to do a rough cut followed by a final clean-up pass with a fly cutter, but in the absence of such equipment the saw and router method was effective.With respect to the design, yes, I did design the machine from scratch. I did an overall design of the major pieces in Fusion 360, but the details were implemented during the build and weren't completed captured in CAD.Finally, with respect to build-versus-buy, I ended up building this machine for just under $1000, which included the router, linear motion components, and the electronics. From what I can tell looking at similar commercially-available machines, a comparable machine would probably be $4000-$5000, and a machine of comparable price would have significantly less rigidity and capacity. If you have the skills and time to do a DIY, I believe it is a more cost-effective way to go.Cheers!

Interesting idea - that might work! I only have a "woodworking tolerances" stop on my drill press (the kind that looks like a ruler and is maybe accurate to 1/32" if you're lucky) but adding a digital depth gauge would certainly make this approach more feasible. That being said, if you get pretty close on the initial cut and you don't need to take too much off, the trial-and-error method I used isn't too cumbersome. My suggestion: give it a try and post your results!

I would share pictures if I had some...but I don't have a ready means of getting images. You can do astrophotography of "bright stuff" - planets and moon - with a Dob, but the really cool stuff requires tracking and long exposures. They make little web-cam like things that will fit in the focuser to let you take pictures, but I don't own one, so (short of holding my cell phone up to the eyepiece) I don't have an easy way to provide images, let alone good ones that accurately represent the quality of what you see looking through the scope. Sorry!