Scubaguy
member
Reged: 03/05/08
Posts: 46
Loc: Mississauga, Ontario
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Well, I've finally started putting together the 127 mm wide field refractor with the lens from Surplus Shed. After reading some posts in the refractor forum about collimating a refractor lens, I decided to try to make a collimatable lens system, as well as a collimatable focusser.
I put the whole thing together, and with a couple of hose clamps, mounted the scope on my SVP EQ mount.
Found Saturn with a 30 mm 2 inch eyepiece, and although small, it was very sharp. Stars had a bit of coma,( when slightly out of focus) but with a little more tweaking of the collimation, I'm confident it'll improve.
Anyway, here are some photos of what I've done so far.
Here's the collimatable lens.
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Celestron 114 GT
10 inch ATM Truss
Skywatcher 102 refractor,70 refractor
Skywatcher EQ6 with SS2K
Orion 102 mak
127mm ATM refractor
Orion 8 in f/5 newt
EQ 2,EQ 1
SkyMaster 15X70 binoculars
and a bunch of other assorted equipment
Edited by Scubaguy (05/20/08 12:24 AM)
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Scubaguy
member
Reged: 03/05/08
Posts: 46
Loc: Mississauga, Ontario
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The collimatable focusser.
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Celestron 114 GT
10 inch ATM Truss
Skywatcher 102 refractor,70 refractor
Skywatcher EQ6 with SS2K
Orion 102 mak
127mm ATM refractor
Orion 8 in f/5 newt
EQ 2,EQ 1
SkyMaster 15X70 binoculars
and a bunch of other assorted equipment
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Scubaguy
member
Reged: 03/05/08
Posts: 46
Loc: Mississauga, Ontario
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The interior of the tube.
The baffles also serve to hold the cardboard tube, which I'm going to cover with wood veneer.
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Celestron 114 GT
10 inch ATM Truss
Skywatcher 102 refractor,70 refractor
Skywatcher EQ6 with SS2K
Orion 102 mak
127mm ATM refractor
Orion 8 in f/5 newt
EQ 2,EQ 1
SkyMaster 15X70 binoculars
and a bunch of other assorted equipment
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The bear
scholastic sledgehammer
Reged: 02/11/08
Posts: 824
Loc: rushville, indiana
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this is interesting as i hope to try and build a refractor one day i will mark this as favorite and cool
doc
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Longitude -85.42786 Latitude 39.59153
"current build 6 inch F6.5 "Little Toe"
"if all else fails use duct tape "works for me"
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Scubaguy
member
Reged: 03/05/08
Posts: 46
Loc: Mississauga, Ontario
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I didn't take any pictures of the scope on the mount, but will tomorrow.
After checking out Saturn, I turned to the moon, low in the sky at about 10:30. Super sharp. Moved the 'scope a few degrees away from Luna, (which happened to be next to a very bright street light) and saw about a dozen stars, despite the glaring light just out of the field of view.
I can't wait to try this out in a dark area.
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Celestron 114 GT
10 inch ATM Truss
Skywatcher 102 refractor,70 refractor
Skywatcher EQ6 with SS2K
Orion 102 mak
127mm ATM refractor
Orion 8 in f/5 newt
EQ 2,EQ 1
SkyMaster 15X70 binoculars
and a bunch of other assorted equipment
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Biff
Carpal Tunnel
Reged: 09/04/05
Posts: 2372
Loc: Courtice, Ontario
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Which FL one is it? Hows the CA?
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Ryan
Antares 200mm f/6 Dob & 130mm f/5 Travel Dob.
Projects on the go...
- a couple 80mm SS refractors on the back burner.
- a few small mirrors awaiting polishing
- 260mm f/7.15 mirror... still polishing
Member of DRAA
 My house.
 DRAACO
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Mirzam
super member
Reged: 04/01/08
Posts: 118
Loc: Lovettsville, VA
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I've noticed that those Synta focusers can have quite a bit of sag. Did you need to do anything to address this? (I have one I need to fix if anyone has advice. Was thinking to rework the teflon bearings somehow).
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Scubaguy
member
Reged: 03/05/08
Posts: 46
Loc: Mississauga, Ontario
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Ryan, it's the 700 mm one. I've already got a 1200 mm f/l refractor, so I thought I'd try an inexpensive short f/l one. After the SS discount, and using parts I had lying around, it only cost me about $150.
I couldn't see any CA when I took it out last night, but I was really only checking for collimation and range of focus.
As for the flex in the focusser, it does seem to sag a tiny bit, when the tube is drawn all the way out. My 1200 mm scope has the same focusser, and it does sag quite a bit. I see the image move side to side when I use the electronic focus motor on it.
As for fixing it, I was thinking of perhaps adding a teflon strip to the bar located under the tensioning screw next to the finder bracket. Hopefully, this will eliminate the gap I see between it and the drawtube.
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Celestron 114 GT
10 inch ATM Truss
Skywatcher 102 refractor,70 refractor
Skywatcher EQ6 with SS2K
Orion 102 mak
127mm ATM refractor
Orion 8 in f/5 newt
EQ 2,EQ 1
SkyMaster 15X70 binoculars
and a bunch of other assorted equipment
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Mirzam
super member
Reged: 04/01/08
Posts: 118
Loc: Lovettsville, VA
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If you place a laser into the focuser you can see the focuser sag effect by the displacement of the laser spot on the objective lens. It looks like you made a nice collimatable focuser mounting adapter, but it won't help much if the sag is not addressed first.
I'm curious if anyone else has found a simple way to fix this (without buying a new focuser).
Jim
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Chris T
super member
Reged: 01/05/05
Posts: 151
Loc: Florida
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How about tapping little holes in the tube that holds the drawtube for small nylon screws. Adjust them just tight enough to keep things aligned without introducing too much friction.
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Chris Tackett
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Steven Aggas
sage
Reged: 04/15/08
Posts: 463
Loc: Arizona
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Quote:
How about tapping little holes in the tube that holds the drawtube for small nylon screws. Adjust them just tight enough to keep things aligned without introducing too much friction.
I've done this...., to my R&P focuser on a 4.5"f9 guide scope used to carry an ST-4 piggy-backed on the 20" which used a 1k square Photometrics camera. The motion of the focuser was greatly improved and I did not get a shift of the star on the ST-4 when getting it focused. It was the original cheap focuser and I would not have minded seeing four tapped holes in it if it did not work, but it was better.
Steven
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Mr. Wizard
Walking on a Dob: http://darkskyobserving.com/MtGraham.html
Elements in Harmony I, an 8"f6 German Equatorial - Stellafane Winner,
II a 20"f4.2 Newt-Dob - Astrofest Winner,
III a 6"f3.5 Finder/Newt-Dob, and
IV a 36"f4.5 Newt-Dob - "If it's up there, it's in here."
Apache-Sitgreaves Center for Astrophysics
www.DarkSkyObserving.com
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Steven Aggas
sage
Reged: 04/15/08
Posts: 463
Loc: Arizona
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Are these 127mm air-spaced achromat's anti-reflective coated? The Surplus Shed photo's don't appear so, but could be.
Also, do you guys think these 127's would make for a good 5"f5.5 binocular? Do you think there is good focal length control to do it?
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Mr. Wizard
Walking on a Dob: http://darkskyobserving.com/MtGraham.html
Elements in Harmony I, an 8"f6 German Equatorial - Stellafane Winner,
II a 20"f4.2 Newt-Dob - Astrofest Winner,
III a 6"f3.5 Finder/Newt-Dob, and
IV a 36"f4.5 Newt-Dob - "If it's up there, it's in here."
Apache-Sitgreaves Center for Astrophysics
www.DarkSkyObserving.com
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Trondur
member
Reged: 03/09/07
Posts: 94
Loc: Cumberland County, Maine USA
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Scubaguy, looks great! Can you talk about how you made the collimatable cell? I see 3 rings of plywood and a push/pull arrangement of screws.
What do the screws bear against/run through? How is the cell secured to the plywood? Which rings move, which are static?
Inquiring minds want to know. I've got an SS 80mm f11 that I haven't secured the objective in permanantly, hoping that someone would build a low-tech (read: something I could make in my limited shop) collimatable cell.
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Terry
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Lots of Budget Glass:
60mm f11 Sears 2419 Refractor on Homemade Alt-Az Mount
80mm f11 Surplus Shed Refractor on Homemade Alt-Az Mount (Almost Done!)
100mm f6 Orion Refractor on modified Majestic mount and tripod
114mm f9 Tasco Reflector on EQ-1 mount (Apparently, a rare Tasco, because it seems OK)
7x50 Swift Swiftfocus Binoculars
Barska Blackhawk 60mm Spotting Scope on an Ambico video tripod
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Scubaguy
member
Reged: 03/05/08
Posts: 46
Loc: Mississauga, Ontario
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Hi, Terry. Unfortunately I didn't take photos of the cell as I was building it, but all I did was glue together some rings of plywood which fit around the thermoplastic cell the lens. Three 10-24 machine screws go through the plywood into the plastic to secure the lens.
Around the tube are two more rings of plywood the same OD as those of the cell. On the two mating surfaces of the two sets of rings are two rings of one eighth inch aluminum plate which are screwed onto the plywood. The aluminum was drilled and tapped to allow for the push pull collimation system.
Same thing was done for the focusser, but on a smaller scale.
The whole thing was easy to make using a router with a circle cutter, a jigsaw and some sandpaper.
I like the idea of tapping the focusser for some nylon screws to help eliminate the sag. Should be easy to do.
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Celestron 114 GT
10 inch ATM Truss
Skywatcher 102 refractor,70 refractor
Skywatcher EQ6 with SS2K
Orion 102 mak
127mm ATM refractor
Orion 8 in f/5 newt
EQ 2,EQ 1
SkyMaster 15X70 binoculars
and a bunch of other assorted equipment
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Mirzam
super member
Reged: 04/01/08
Posts: 118
Loc: Lovettsville, VA
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I also have just noticed on my Synta focuser that there are some tiny set screws on the top surface. Tightening these greatly reduced the sag. I suspect this will need to be done periodically. Don't tighten too much or the focuser will be stiff to operate.
Jim
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Wes James
Post Laureate
Reged: 04/12/06
Posts: 3454
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Quote:
Same thing was done for the focusser, but on a smaller scale.
Good idea that you made the focuser collimatable as well!
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Wes
Atlantic Beach, FL
Some bino’s from Miyauchi 5x32 Binon's up through Garrett 20x110 Signature's,
Some telescopes from a Stellarvue 80mm NHNG up through a couple of 8” reflectors…
And a wonderful 4.25" Delmarva Shiefspiegler!
Some good friends, made here on C/N.
Oh- several cats and a wonderful wife!
Anyone want a cat???? :-O
"When your work speaks for itself- Don't Interrupt" -Gamble Rogers
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Trondur
member
Reged: 03/09/07
Posts: 94
Loc: Cumberland County, Maine USA
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Thanks for the response. Did you remove the lens when you drilled the holes for the 10-24 screws? It seems like you would have, but I'm curious if you used another approach.
I'm believe that I could use your plywood construct for the cell side. I could drill and tap the 4" to 3" PVC sewer pipe reducer that I'm using at the front of the tube for the "push-pull". Not as nice as aluminum of course, but not a 127mm either.
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Terry
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Lots of Budget Glass:
60mm f11 Sears 2419 Refractor on Homemade Alt-Az Mount
80mm f11 Surplus Shed Refractor on Homemade Alt-Az Mount (Almost Done!)
100mm f6 Orion Refractor on modified Majestic mount and tripod
114mm f9 Tasco Reflector on EQ-1 mount (Apparently, a rare Tasco, because it seems OK)
7x50 Swift Swiftfocus Binoculars
Barska Blackhawk 60mm Spotting Scope on an Ambico video tripod
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Scubaguy
member
Reged: 03/05/08
Posts: 46
Loc: Mississauga, Ontario
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No, I didn't have to remove the lens at all.
There were already three holes in the plastic, and it was a simple enough matter to tap them. The only hard part was drilling through the plywood in exactly the right place.
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Celestron 114 GT
10 inch ATM Truss
Skywatcher 102 refractor,70 refractor
Skywatcher EQ6 with SS2K
Orion 102 mak
127mm ATM refractor
Orion 8 in f/5 newt
EQ 2,EQ 1
SkyMaster 15X70 binoculars
and a bunch of other assorted equipment
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Happy-Idiot
Carpal Tunnel
Reged: 04/06/06
Posts: 2818
Loc: 3rd Rock
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Great job! What material did you use for the baffles and how did you cut them? I also have a 127mm SS lens and cell, i am using an aluminum tube, neither focuser or cell will be collimatable, not as nice as yours. Keep up the good work!
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Brian
A small scope that gets used often is a better investment than a big scope that stays in the closet.
Unitrons, you spend more time looking at them than you do through them.
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Preston Smith
Military Observer
Reged: 04/24/05
Posts: 3440
Loc: Eureka, Pa
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Scubaguy - Great setup! Go for it!
Scubaguy and Brian: I am on backorder for one of these objectives but I'm running out of time (my other projects are soaking up my astro bucks). I'm debating on canceling the order. Have either of you done a full star test yet? Any astigmatism?
Thanks!
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Preston
Lift your eyes and look to the heavens: Who created all these? He who brings out the starry host one by one, and calls them each by name. Because of His great power and mighty strength, not one of them is missing. Isaiah 40:26
SV115T,NHII,SV70,SV50 and Tele Vue Ranger
Vintage Refractors: Asahi-Pentax, Edmund Scientific, Tasco, Unitron
60mm Telescope Club
Edited by Preston Smith (05/26/08 02:20 PM)
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