My 8 inch f/2.9 rich field telescope refurb project

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StarBru United States of America
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My 8 inch f/2.9 rich field telescope refurb project

#1

Post by StarBru »


Some of you may have heard this story before. I was seduced from a small ad in Sky & Telescope some time around 1979, and I ordered and bought an 8 inch f/2.9 reflector with a front optical window as my first "big" telescope after receiving a brochure in the mail that I requested from the Sky Research company. Here's part of the brochure (now a little defaced):
20170420_235735.jpg



Five long months after I ordered it, I received the scope, and I was amazed I could see thousands of stars through it that I couldn't see with the naked eye. It was great until I realized it needed a little tweaking in the alignment. I was shocked to find out there were no adjustment screws for the main mirror and the secondary was mounted in the center of the optical window, also with no adjustment screws. Sky Research was not answering my calls, so I took the scope to a local telescope shop in Tucson called The Image Point. A guy named Pierre that created the Big Foot Mount, and later his own telescopes, tried to pry the glued-in optical window apart from the tube, accidentally cracked the optical window. He offered to build me a spider and diagonal holder and that seemed to improve the performance of the scope somewhat. Here are pics of what the scope looked like before and after the optical window broke. The last pic is what the scope looked like without the optical window. The first pic is not my scope, I would never let the window get that dirty!
Gebelein scope window.jpg
Gebelein scope focuser.jpg
Gebelein scope badge.jpg
20170420_185722.jpg



In 1993, I decided to re-design the scope; my first ATM project. I made the mistake of making the tube too long and it was quite top-heavy (the Telrad didn't help!), but a great light deflector. I also swapped out the focuser with a simple helical focuser, another mistake IMO because it did not have a fine enough focus to it.
20170420_190114.jpg



A few years ago, I decided to refurbish: shorten the tube, strengthen the focuser area (by using a technique recommended from a fellow ATM person on another forum) using an extra inside layer of cardboard tube located inside the main tube, then repaint it inside and outside, upgrade to a 2 inch JMI Crayford focuser, refigure (if needed), and recoat the mirror, and get rid of the Dobson mount. Well, I obtained a JMI 2 inch crayford focuser (not shown), strengthened the focuser area (shown in the 2nd and last pics with focuser hole not cut out yet), and completely repainted the tube and end rings, but that's about it. I have lots of work to do, but I'm hoping I can join a local ATM club that can help me finish it! Here are the pics:
Attachments
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1492464823840.jpg (54.03 KiB) Viewed 917 times
20170430_154011.jpg
20170430_120423.jpg
Bruce

Refractors: Meade AR-5 127mm f/9.3, Meade ST-80 f/5 and Meade 60mm f/12, Jason 60mm f/15 #313, Jason 60mm f/12 #306 S7, Bushnell Sky Chief III 60mm f/15.
Reflectors/Catadioptrics: Meade 10" F/4 Schmidt-Newtonian, Galileo 120mm f/8.3 Newtonian, Meade 2045D 4" f/10 SCT, Meade ETX-90EC f/13.8 & Sarblue 60mm f/12.5 Maksutov-Cassegrains.
Mounts: Skywatcher EQ6-R Pro & Meade LXD55 Equatorial mounts, ES Twilight II and Meade 2102 ALT/AZ mounts, a modified 10" SkyQuest Dobsonian mount, various 60mm EQ mounts.
Misc: Celestron 20x80mm binoculars, Revolution II Imager/accessories, & lots of optical accessories/eyepieces.
Projects: 8" f/2.9 and 65mm f/10 reflectors, Dobson-style binocular mirror mount.
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Re: My 8 inch f/2.9 rich field telescope refurb project

#2

Post by StarBru »


Here's some more pics of the secondary and main mirror and mirror mount.
Attachments
1492463665262.jpg
1492462691474.jpg
1492462691474.jpg (49.33 KiB) Viewed 914 times
1492462658772.jpg
1492462658772.jpg (43.85 KiB) Viewed 914 times
Bruce

Refractors: Meade AR-5 127mm f/9.3, Meade ST-80 f/5 and Meade 60mm f/12, Jason 60mm f/15 #313, Jason 60mm f/12 #306 S7, Bushnell Sky Chief III 60mm f/15.
Reflectors/Catadioptrics: Meade 10" F/4 Schmidt-Newtonian, Galileo 120mm f/8.3 Newtonian, Meade 2045D 4" f/10 SCT, Meade ETX-90EC f/13.8 & Sarblue 60mm f/12.5 Maksutov-Cassegrains.
Mounts: Skywatcher EQ6-R Pro & Meade LXD55 Equatorial mounts, ES Twilight II and Meade 2102 ALT/AZ mounts, a modified 10" SkyQuest Dobsonian mount, various 60mm EQ mounts.
Misc: Celestron 20x80mm binoculars, Revolution II Imager/accessories, & lots of optical accessories/eyepieces.
Projects: 8" f/2.9 and 65mm f/10 reflectors, Dobson-style binocular mirror mount.
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Re: My 8 inch f/2.9 rich field telescope refurb project

#3

Post by Lady Fraktor »


Wow, f/2.9!!
Now that is a fast telescope. Good luck with the refurbishing.
Gabrielle
See Far Sticks: Elita 103/1575, AOM FLT 105/1000, Bresser 127/1200 BV, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS 100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, SXP2, AXJ, AXD
Az/Alt: AYO Digi II, Stellarvue M2C, Argo Navis encoders on both
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Tak prism, TAL, Vixen
Eyepieces: Antares to Zeiss (1011110)
The only culture I have is from yogurt
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Re: My 8 inch f/2.9 rich field telescope refurb project

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Post by StarBru »


Lady Fraktor wrote: Mon Aug 14, 2023 3:37 am Wow, f/2.9!!
Now that is a fast telescope. Good luck with the refurbishing.
Thanks! As you an see, the main mirror coating is coming off , but I want to have it tested to see how good the mirror is, which I never had tested before. It definitely will be the most expensive part of the refurbishing. I only wish I could make it look like the Sharpstar reflectors without too much expense! That would be the best!
Attachments
8aa39c92-a8d4-4a9f-9e83-fb77f213d1ff.png
Bruce

Refractors: Meade AR-5 127mm f/9.3, Meade ST-80 f/5 and Meade 60mm f/12, Jason 60mm f/15 #313, Jason 60mm f/12 #306 S7, Bushnell Sky Chief III 60mm f/15.
Reflectors/Catadioptrics: Meade 10" F/4 Schmidt-Newtonian, Galileo 120mm f/8.3 Newtonian, Meade 2045D 4" f/10 SCT, Meade ETX-90EC f/13.8 & Sarblue 60mm f/12.5 Maksutov-Cassegrains.
Mounts: Skywatcher EQ6-R Pro & Meade LXD55 Equatorial mounts, ES Twilight II and Meade 2102 ALT/AZ mounts, a modified 10" SkyQuest Dobsonian mount, various 60mm EQ mounts.
Misc: Celestron 20x80mm binoculars, Revolution II Imager/accessories, & lots of optical accessories/eyepieces.
Projects: 8" f/2.9 and 65mm f/10 reflectors, Dobson-style binocular mirror mount.
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Re: My 8 inch f/2.9 rich field telescope refurb project

#5

Post by Lady Fraktor »


Well since I like to be helpful and more importantly, help spend other people money I know how you can do this.
Teleskop-Service sells carbon fibre tubes and red anodized tube ends.
https://www.teleskop-express.de/shop/in ... Teile.html
You are welcome :lol:
Gabrielle
See Far Sticks: Elita 103/1575, AOM FLT 105/1000, Bresser 127/1200 BV, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS 100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, SXP2, AXJ, AXD
Az/Alt: AYO Digi II, Stellarvue M2C, Argo Navis encoders on both
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Tak prism, TAL, Vixen
Eyepieces: Antares to Zeiss (1011110)
The only culture I have is from yogurt
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Re: My 8 inch f/2.9 rich field telescope refurb project

#6

Post by StarBru »


Lady Fraktor wrote: Mon Aug 14, 2023 6:40 pm Well since I like to be helpful and more importantly, help spend other people money I know how you can do this.
Teleskop-Service sells carbon fibre tubes and red anodized tube ends.
https://www.teleskop-express.de/shop/in ... Teile.html
You are welcome :lol:
:o Ouch, too pricey for me! Hmmm.....I think I'm going to re-think the tube. I may wrap the tube with carbon fibre vinyl wrap, clean up the end rings, paint them red and get a red tube ring assembly. It'll be like a pseudo-Sharpstar Newtonian! :lol:
Bruce

Refractors: Meade AR-5 127mm f/9.3, Meade ST-80 f/5 and Meade 60mm f/12, Jason 60mm f/15 #313, Jason 60mm f/12 #306 S7, Bushnell Sky Chief III 60mm f/15.
Reflectors/Catadioptrics: Meade 10" F/4 Schmidt-Newtonian, Galileo 120mm f/8.3 Newtonian, Meade 2045D 4" f/10 SCT, Meade ETX-90EC f/13.8 & Sarblue 60mm f/12.5 Maksutov-Cassegrains.
Mounts: Skywatcher EQ6-R Pro & Meade LXD55 Equatorial mounts, ES Twilight II and Meade 2102 ALT/AZ mounts, a modified 10" SkyQuest Dobsonian mount, various 60mm EQ mounts.
Misc: Celestron 20x80mm binoculars, Revolution II Imager/accessories, & lots of optical accessories/eyepieces.
Projects: 8" f/2.9 and 65mm f/10 reflectors, Dobson-style binocular mirror mount.
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Re: My 8 inch f/2.9 rich field telescope refurb project

#7

Post by Lady Fraktor »


You could also look at purchasing a small anodizing kit, it is quite easy to do with metal or aluminium.
If you could find a plastic bin large enough you could even do the tube.
Gabrielle
See Far Sticks: Elita 103/1575, AOM FLT 105/1000, Bresser 127/1200 BV, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS 100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, SXP2, AXJ, AXD
Az/Alt: AYO Digi II, Stellarvue M2C, Argo Navis encoders on both
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Tak prism, TAL, Vixen
Eyepieces: Antares to Zeiss (1011110)
The only culture I have is from yogurt
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Re: My 8 inch f/2.9 rich field telescope refurb project

#8

Post by StarBru »


Lady Fraktor wrote: Tue Aug 15, 2023 4:08 am You could also look at purchasing a small anodizing kit, it is quite easy to do with metal or aluminium.
If you could find a plastic bin large enough you could even do the tube.
Sounds like a great option! Thanks!
Bruce

Refractors: Meade AR-5 127mm f/9.3, Meade ST-80 f/5 and Meade 60mm f/12, Jason 60mm f/15 #313, Jason 60mm f/12 #306 S7, Bushnell Sky Chief III 60mm f/15.
Reflectors/Catadioptrics: Meade 10" F/4 Schmidt-Newtonian, Galileo 120mm f/8.3 Newtonian, Meade 2045D 4" f/10 SCT, Meade ETX-90EC f/13.8 & Sarblue 60mm f/12.5 Maksutov-Cassegrains.
Mounts: Skywatcher EQ6-R Pro & Meade LXD55 Equatorial mounts, ES Twilight II and Meade 2102 ALT/AZ mounts, a modified 10" SkyQuest Dobsonian mount, various 60mm EQ mounts.
Misc: Celestron 20x80mm binoculars, Revolution II Imager/accessories, & lots of optical accessories/eyepieces.
Projects: 8" f/2.9 and 65mm f/10 reflectors, Dobson-style binocular mirror mount.
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