Click here if you are having trouble logging into the forums Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User You are not logged in. [Login] Entrance · Main Index · Search · New user · Who's Online FAQ · Calendar Equipment Discussions >> ATM, Optics and DIY Forum Previous   Index   Next   Threaded   Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | >> (show all) PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas 20 inch RC Robitic Build...a TEAM Effort....       #2360748 - 04/29/08 10:29 PM Edit   Reply   Quote Quick Reply   Hi Guys and Gals... This will evolve slowly... We have the optics set... We have the design... We are building... And we have taken pictures... The group will likely benifit from this thread... OTA to be completed within a few months... Pictures coming soon...like tomorrow..of the start... Best Regards, Preston -------------------- A few I enjoy, and a few more in the works ;<) Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2360800 - 04/29/08 10:46 PM Edit   Reply   Quote Quick Reply   Ok... Everyone has ask me to start this thread... and now I have... Tomorrow I'll post pictures of the machining of the bits and pieces...like the tube ends...the tube end capture blocks and the spherical ends in Invar.... You will love the details....I hope... Best Regards, Preston -------------------- A few I enjoy, and a few more in the works ;<) Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2360834 - 04/29/08 11:02 PM Edit   Reply   Quote Quick Reply   Hi guys... This started as one of my projects....and then lingered... Far TOO long.. I offered the optic set on Astromart...and it was quickely picked up...We are a team of 5 currently...they will take the OTA and finish the Robotic build somewhere to be determined...and they have looked at Australia... From there I offered to both design and build the OTA... That was 2 years ago... And to day we are seeing the back plate, collimation plate and mid rings being machined....Finally.... I know this sounds like a fairy tail... But it is the total truth... Please follow our path... Regards, Preston -------------------- A few I enjoy, and a few more in the works ;<) Edited by PrestonE (05/02/08 07:42 PM) Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2364685 - 05/01/08 04:05 PM Attachment (178 downloads) Edit   Reply   Quote Quick Reply   Ok, some pictures of the start of the tube ends and capture blocks in 6061 T6 aluminum. All done manually 32 tube ends and 16 capture blocks and capture plates... Enjoy, Preston -------------------- A few I enjoy, and a few more in the works ;<) Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2364755 - 05/01/08 04:32 PM Attachment (144 downloads) Edit   Reply   Quote Quick Reply   Drawing of the capture block. You will notice the use of lots of holes for lightening. We are trying to keep the entire OTA with optics, focuser, filter wheel, and camera under 100 pounds. The optic set weighs in at 53 pounds for the primary and secndary. The tube ends premachining weighed 170 grams or 6 ounces and after machining weighted 28 grams of 1 ounce for each tube end. Quite a savings and well worth the time. Each step was completed on all 32 ends and then the next step was machined...in toll 18 hours to machine the 32 ends. By the end, I was really wishing for a CNC lathe...as one starts to get very bored doing the same thing 32 times with 15 differant machining steps... Regards, Preston -------------------- A few I enjoy, and a few more in the works ;<) Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2364764 - 05/01/08 04:37 PM Attachment (120 downloads) Edit   Reply   Quote Quick Reply   One of the 16 Catch Blocks getting the bevel that will hole the ball end that fits into the Tube End. Thats, enough for now. Thanks and enjoy, Preston -------------------- A few I enjoy, and a few more in the works ;<) Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2364777 - 05/01/08 04:46 PM Attachment (101 downloads) Edit   Reply   Quote Quick Reply   Ok, well do the ball turning with the 0.500 inch diameter Invar and call it a day. First pic of machined pieces in two differing stages. Left after first turning and right ready to turn the ball. -------------------- A few I enjoy, and a few more in the works ;<) Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2364803 - 05/01/08 04:59 PM Edit   Reply   Quote Quick Reply   And turning the radius of the ball to 0.375" diameter. This was the first real test of my Hardinge toolroom lathe since getting it home. Edited by Don W (06/14/08 10:37 AM) Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2364809 - 05/01/08 05:02 PM Attachment (106 downloads) Edit   Reply   Quote Quick Reply   A close up of the finished ball ends. -------------------- A few I enjoy, and a few more in the works ;<) Post Extras:       The bear professor emeritus Reged: 02/11/08 Posts: 691 Loc: rushville, indiana Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2364816 - 05/01/08 05:09 PM Edit   Reply   Quote Quick Reply   this is very nice i love the machine work wish i had one would make some awesome stuff also. i will watch this thread religiously thanks PrestonE for your doing this build. i would hope you will do it from start to finish from this work to the electronics involved with this for the benefit of all especially me... doc -------------------- Longitude -85.42786 Latitude 39.59153 when all else fails use duct tape "works for me" Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: The bear]       #2364866 - 05/01/08 05:39 PM Edit   Reply   Quote Quick Reply   Thanks Bear, I'll do my best. We fell way behind when a shipping company that I hired to move my new to me CNC mill last April and dumped it over in the truck while changing trailers here in Houston...total loss and I'm still working on trying to rebuild the control system. But thanks to Kerry aka "The Captain" here on CN, we have contracted someone to do the really large mid rings, upper ring, back plate and collimetion plate... That should all be here next week and then I can recheck the lenght of pvc tubing being used to simulate the lengths of carbon fiber tubing...before cutting the CF tubing. The mirror spacing is fairly critical between the primary and secondary in a RC so we will be trying to hit it within .020 inches or plus or minus .010" at least that's the plan. Regards, Preston -------------------- A few I enjoy, and a few more in the works ;<) Post Extras:       The bear professor emeritus Reged: 02/11/08 Posts: 691 Loc: rushville, indiana Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2364899 - 05/01/08 05:55 PM Edit   Reply   Quote Quick Reply   i would say that is cutting it close for sure but if you are going to do it right that is the way to go. i am learning about RC through several threads here very interesting design for sure. thanks for your work doc -------------------- Longitude -85.42786 Latitude 39.59153 when all else fails use duct tape "works for me" Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: The bear]       #2365128 - 05/01/08 08:00 PM Attachment (111 downloads) Edit   Reply   Quote Quick Reply   Thanks Doc, We are trying to get this OTA completed ASAP...within reason... Here is a shot of the Capture Plate being chamfored for the ball end... -------------------- A few I enjoy, and a few more in the works ;<) Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2365134 - 05/01/08 08:03 PM Attachment (84 downloads) Edit   Reply   Quote Quick Reply   And then the capture block and plate being radiused... fixture and then assembly -------------------- A few I enjoy, and a few more in the works ;<) Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2365139 - 05/01/08 08:06 PM Attachment (80 downloads) Edit   Reply   Quote Quick Reply   Assembled Capture block ready to machine the radius... -------------------- A few I enjoy, and a few more in the works ;<) Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2365398 - 05/01/08 10:02 PM Attachment (78 downloads) Edit   Reply   Quote Quick Reply   Ok this was roughed on the mill in a rotary table and then finished on tha lathe in the same fixture... -------------------- A few I enjoy, and a few more in the works ;<) Edited by PrestonE (05/02/08 11:02 AM) Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2365415 - 05/01/08 10:06 PM Attachment (103 downloads) Edit   Reply   Quote Quick Reply   Finished piece after turning on the lathe... -------------------- A few I enjoy, and a few more in the works ;<) Post Extras:       Sky Captain Scope Builder Reged: 11/07/04 Posts: 5548 Loc: Seattle Washington Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2365586 - 05/01/08 11:12 PM Edit   Reply   Quote Quick Reply   Thats looking great Preston! I'm really happy the machine shop I use will be able to handle your larger project too. Do you know when they will get the aluminum plates? -------------------- Equipment Overload! http://scopebuilder.webs.com/ Kerry. Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: Sky Captain]       #2366339 - 05/02/08 10:57 AM Edit   Reply   Quote Quick Reply   Thanks Kerry, The plates are being shipped from 2 locations as we had already purchased the 18.5" diameter x 1.25" thick cast aluminum tooling plate Being machined for the collimation plate. It shipped Wednesday and I'll have to get the tracking number from Speedy Metal. I can say that Speedy Metal was $750 for everything and Jim $1100...so we went with Speedy. I'll find out and let you know. Thanks again for the introduction to Jim the owner of the machine shop doing the work. Best Regards Preston -------------------- A few I enjoy, and a few more in the works ;<) Post Extras:       PrestonE professor emeritus Reged: 04/29/05 Posts: 628 Loc: Houston,Texas Re: 20 inch RC Robitic Build...a TEAM Effort.... [Re: PrestonE]       #2366757 - 05/02/08 02:16 PM Attachment (115 downloads) Edit   Reply   Quote Quick Reply   Ok, next let's take a look at the collimation plate...CAD rendering. I'm working on attaching the Rendering, not like attaching a picture It has 3 two point pivots to suspend the mirror, with 1" diameter pads at the ends that sit on ball ends so that there will not be any binding... Included is the mirror support tube in the center, this goes out the back and is centered in the mirror back plate with a metal o-ring to keep it centered in the back plate when collimating... Notice the second slots from the ends of the three arms...these have an oilite bronze incert that can rotate slightly during collimation. These will be the tightening cap screws that oppose the push secrews that will push against the back side of the outer 3 holes on the arms... The diameter at the edge of the arms is 18.5" and the thickness of the cast aluminum tooling plate is 1.25" This collimation plate will likely be the first to get machined early next week. Regards, Preston -------------------- A few I enjoy, and a few more in the works ;<) Edited by PrestonE (05/02/08 02:27 PM) Post Extras:       Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | >> (show all) Previous   Index   Next   Threaded   Extra information 9 registered and 11 anonymous users are browsing this forum. Moderator:  Don W, Joe Cipriano  Print Thread Forum Permissions       You cannot start new topics       You cannot reply to topics       HTML is disabled       UBBCode is enabled Thread views: 8890 Jump to *Announcements and News* -----   Cloudy Nights Announcements   Discussion of CN Articles, Reviews, and Reports   Beginners Forum   Celestial Events   Light Pollution*Equipment Discussions* -----   ATM, Optics and DIY Forum   Binoculars   Binoviewers   Cats & Casses   Classic Telescopes   Equipment   Eyepieces   Mounts   Observatories   Reflectors   Refractors    Celestron SkyScout and Meade mySky   Video and Electronically Assisted Astronomy*Astrophotography and Sketching* -----   Beginning Imaging   Film Astrophotography   DSLR & Digital Camera Astro Imaging & Processing   CCD Imaging & Processing   Solar System Imaging & Processing   Sketching   Astro Imaging/Sketching Contest *Telescope Specific Forums* -----   Celestron NexStar    NexStar GPS / CPC Telescopes   Questar Forum   Meade ACF/RCX / LX / GPS    Meade ETX*Observing* -----   General Observing   Planetary and Solar System Observing   Lunar Observing   Deep Sky Observing   Double Star Observing   Solar   Variable Star Observing and Radio Astronomy*Other* -----   Science of Astronomy & Space exploration   AstroWebsites   Space Rocks*Speciality Forums* -----   AstroArt   Astronomy Software & Computers   Stellar Media   Astro Outreach, Clubs and Star Parties*CN Feedback and Vendor Announcements* -----   Vendor and Group Announcements Home

Cloudy Nights Sponsor: Astronomics