· Get a Cloudy Nights T-Shirt · Submit a Review / Article    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] Forum Archives · 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 | (show all) neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Uberfractor [Re: neo]       #3341821 - 09/18/09 05:28 PM Attachment (45 downloads) Edit   Reply   Quote Quick Reply   Here's a quick assembly with half of the scope to check the things out, and it seems I have to pay attention on some detailes like flection of some pieces. Man...nothing is easy ! -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Post Extras:       grendel sage Reged: 04/12/09 Posts: 469 Loc: Canterbury, Kent, UK Re: Uberfractor [Re: neo]       #3341850 - 09/18/09 05:55 PM Edit   Reply   Quote Quick Reply   I made a reduction drive using the planetary gearbox from a cheap electric screwdriver. 1:7 reduction from one stage of the gearbox. Grendel Post Extras:       neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Uberfractor [Re: grendel]       #3342542 - 09/19/09 04:11 AM Edit   Reply   Quote Quick Reply   That's a great idea Grendel. I didn't imagine that electric screwdrivers are based on planetary gearboxes. I presume you used a small one. -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Post Extras:       grendel sage Reged: 04/12/09 Posts: 469 Loc: Canterbury, Kent, UK Re: Uberfractor [Re: neo]       #3342603 - 09/19/09 05:59 AM Attachment (30 downloads) Edit   Reply   Quote Quick Reply   yes one of the little cheap hand held ones, I even made a eq drive out of 5 gearbox sections put togrether (I managed to pick up about 4 of the screwdrivers really cheap once in the january sales- about £3 per screwdriver the normal reduction on these is 1:49 (2 planetary sections) and I had a spare section after I had finished, which made the focuser reduction gear Edited by grendel (09/19/09 06:00 AM) Post Extras:       grendel sage Reged: 04/12/09 Posts: 469 Loc: Canterbury, Kent, UK Re: Uberfractor [Re: grendel]       #3342606 - 09/19/09 06:02 AM Attachment (30 downloads) Edit   Reply   Quote Quick Reply   The motor housing and gear were just convenient, it could have been smaller. Grendel Post Extras:       grendel sage Reged: 04/12/09 Posts: 469 Loc: Canterbury, Kent, UK Re: Uberfractor [Re: grendel]       #3342609 - 09/19/09 06:04 AM Attachment (25 downloads) Edit   Reply   Quote Quick Reply   another view of the planetary gearbox. the screwdriver was an even cheaper version of something like this:- http://www.amazon.com/Black-Decker-9074CTN-3-6-volt-Screwdriver/dp/B0000302UJ Edited by grendel (09/19/09 06:10 AM) Post Extras:       neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Uberfractor [Re: grendel]       #3342656 - 09/19/09 07:19 AM Edit   Reply   Quote Quick Reply   Hey, nicely done! Fantastic...I'll look for a cheap (ideally second hand) screwdriver. It would be way easier to mode the focuser like you did than just get everything from scratch. -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Post Extras:       grendel sage Reged: 04/12/09 Posts: 469 Loc: Canterbury, Kent, UK Re: Uberfractor [Re: neo]       #3342680 - 09/19/09 07:50 AM Edit   Reply   Quote Quick Reply   you realise that it can be used almost as is for an electric focuser too dont you. Grendel Post Extras:       neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Uberfractor [Re: grendel]       #3344601 - 09/20/09 10:54 AM Attachment (35 downloads) Edit   Reply   Quote Quick Reply   Today I've installed the objective on my Uber-contraption to check how the focuser works....like a charm..by the way...after a few tweaks. Of course I couldn't resist and I got the first light (un collimated) through my window with my digital camera and a Japanese Meade 26mm SP. I'm very happy with the results. I can't wait to finish all the details and to collimate it properly. Here are a few pics with the scope half assembled and of course the first light. -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Post Extras:       neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Uberfractor [Re: neo]       #3344608 - 09/20/09 10:56 AM Attachment (30 downloads) Edit   Reply   Quote Quick Reply   and another -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Post Extras:       neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Uberfractor [Re: neo]       #3344614 - 09/20/09 11:01 AM Attachment (33 downloads) Edit   Reply   Quote Quick Reply   first light... -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Post Extras:       neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Uberfractor [Re: neo]       #3344617 - 09/20/09 11:02 AM Attachment (30 downloads) Edit   Reply   Quote Quick Reply   yet another...the buildings are about 600 maybe 700 meters away. -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Post Extras:       neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Uberfractor [Re: neo]       #3344620 - 09/20/09 11:03 AM Attachment (32 downloads) Edit   Reply   Quote Quick Reply   .......... -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Post Extras:       jcham21 sage Reged: 12/02/07 Posts: 362 Loc: Tucson, Arizona Re: Uberfractor [Re: neo]       #3344791 - 09/20/09 01:17 PM Edit   Reply   Quote Quick Reply   Cool images. Looks like there's some positive (pincushion) distortion. Could be due to being out of collimation? James -------------------- James Canon XTi Canon EF 200mm f/2.8L II Camera Lens Celestar 8 Main Astrophotography Gallery Comet Lulin Gallery How To Make a 6" F/15 Refractor Post Extras:       neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Uberfractor [Re: jcham21]       #3344895 - 09/20/09 02:17 PM Edit   Reply   Quote Quick Reply   I guess collimation is one reason, but it's not the only thing. The objective has a flat field (being a photo objective, from what I know) but it's more likely that the eyepiece + my cameras objective would cause the distortion. Usually a "normal" astro lens has a negative pincushion because the field is curved and the eyepiece could compensate for it but in my case overcorrected it. Hey...what do you know?...this is the post no. 500 of mine here on CN...I have to celebrate!! -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Edited by neo (09/20/09 02:27 PM) Post Extras:       neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Uberfractor [Re: neo]       #3356514 - 09/25/09 05:23 PM Attachment (24 downloads) Edit   Reply   Quote Quick Reply   After a little break today I've finished the paint job on my scope and flocked the interior with "velur" paper as we call it back here. Tomorrow after the paint is dry enough I'll attempt to finally put everything togather. I hope I'll not have any "surprises". For moment I'll set a bit aside the electric focuser idea, I'll sleap on it for sure. I'll search for a cheap electric screwdriver like Grendel here greatly sugested but first I plan to build the cradle and then a good alt-az mount to use with an aluminum tripod I've got, donated by a fellow from our local astronomy forum. Just a bit of cosmetic job, a bigger base to sustain the fork and it's ready to see the sky Here're a few pics during the flocking and the back end of the scope after painting. -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Post Extras:       neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Uberfractor [Re: neo]       #3356520 - 09/25/09 05:24 PM Attachment (23 downloads) Edit   Reply   Quote Quick Reply   . -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Post Extras:       neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Uberfractor [Re: neo]       #3359808 - 09/27/09 02:07 PM Attachment (24 downloads) Edit   Reply   Quote Quick Reply   Well folks...it seems...I'm out of luck with my project. Yesterday I managed to assemble my scope, even do an autocollimation test which was spot on from the first try, when disaster strikes. Curses....the focsuer's mechanism irremediably broke down. I guess because of the load...it doesn't meter anymore. After the black period of frustration passed away...kind of...I decided to start a new design made by the book with aluminum tubing, some good milling and lathe work. I'll keep only the dewcover from the old project. I don't want to give up on this Rodenstock lens cause in the short time I was able to see what a great little scope could be. The image is very sharp, well corrected and above all it could be superb for reach field astrophotography. So after I've wiped out the tears here's my new design... -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Edited by neo (09/27/09 02:10 PM) Post Extras:       neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Uberfractor [Re: neo]       #3359810 - 09/27/09 02:08 PM Attachment (23 downloads) Edit   Reply   Quote Quick Reply   ...and the focusing axle.. -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Post Extras:       neo professor emeritus Reged: 02/12/08 Posts: 724 Loc: Iasi, Romania Re: Rodenstock Apo refractor [Re: neo]       #3362060 - 09/28/09 04:08 PM Attachment (21 downloads) Edit   Reply   Quote Quick Reply   I got farther with my new design by drawing the ball bearings brackets. The idea is to get two bearings aligned on the bracket to keep them in even contact with the focusing tube. These brackets I still could make them by hand from a 5mm thick aluminum sheet. The bearings are the same 3x6x2,5mm. Here's the drawing...man I really started to enjoy this 3D modeling...it's quiet addicting, it's like an extension of my imagination Well....I hope I didn't bore you all with this..pretty..I guess is the word ...but I have such a great time sharing my bad or good experiences with you. I hope my project will be a happy ending one Your suggetions and thoughts are the most wellcome, as always. Alex -------------------- Russian 15x50 binos Home made 8" f/5 Newton on eq mount Home made 70mm f/6 (Rodenstock Rotelar lens) Apo refractor www.astronomy.ro Edited by neo (09/29/09 10:12 AM) Post Extras:       Pages: 1 | 2 | 3 | (show all) Previous   Index   Next   Threaded   Extra information 10 registered and 14 anonymous users are browsing this forum. 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