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
DavidinFL
member
Reged: 08/28/09
Posts: 52
Loc: Navarre, FL
|
|
Back when the Surplus Shed 80mm f/5 scopes posts were all over this forum I decided to make one. (Back before I lost my old user name, DavidB82.) Well, a couple years later and after not using it much I decided to upgrade.
To show the evolution I'll start with my first version of the scope. The scope had no collimation adjustment and the focuser was rather crude.
--------------------
Orion XT8 - Orion StarMax 102 EQ
|
DavidinFL
member
Reged: 08/28/09
Posts: 52
Loc: Navarre, FL
|
|
Next, I decided to upgrade the focuser with a home made crayford design that I found on the internet somewhere. If anyone is curious I can try to dig up the link from the archives. The focuser worked ok but would slip if the scope was elevated much. To cure this you had to crank down on the adjustment screw which made it harder to move the focuser.
--------------------
Orion XT8 - Orion StarMax 102 EQ
|
DavidinFL
member
Reged: 08/28/09
Posts: 52
Loc: Navarre, FL
|
|
For the next upgrade I bought a used GSO focuser. This focuser wouldn't fit the PVC tube so I had to fab up a tube out of aluminum flashing. I don't have a picture of that version of the scope though.
Now to the present. I decided to fix a couple problems I had with the scope. The main problem was that the scope was unable to be collimated. Before I had shimmed the lens cell into the tube using some thin PVC pipe. This worked ok but there was no way to fine adjustment it other than trying to sand the end of the tube. For the current scope I drilled three equally spaced holes near the end of the tube. I filed the holes into slots which allow me to collimate the lens cell. This also meant drilling three holes through the lens cell. I threaded these holes, but as I expected they stripped out the plastic. So, I had to put nuts on the machine screws. Luckily, they're not in the light path but I painted them black to kill any reflections.
The inside of the tube was primed and then I shook sawdust around the inside. Once this dried, I painted the inside ultra flat black. The combination of the saw dust and paint makes for a very dark surface. The outside of the tube was primed and painted with several coats of cobalt blue metallic.
I also installed a single baffle made from a CD as described in a post by Happy-Idiot. (Awesome scope by the way!) It's 2" behind the back of the lens. I used silicone to hold the baffle in place. It holds well but the silicone looks pretty bad. Luckily it's hard to see.
Next, I improved my "scope rings". Before I had simple band clamps and a pine block base with a T-Nut in it. This time around I made some rings out of some spare maple and oak I had. I retained the T-Nut since it worked well.
Finally, I made a dew shield out of some craft foam. It's removable via Velcro and can be flattened for storage.
--------------------
Orion XT8 - Orion StarMax 102 EQ
|
DavidinFL
member
Reged: 08/28/09
Posts: 52
Loc: Navarre, FL
|
|
Another picture with the dew shield removed.
--------------------
Orion XT8 - Orion StarMax 102 EQ
|
stevenf
member
Reged: 10/11/09
Posts: 31
Loc: Vancouver, BC
|
|
Awesome, thanks very much for posting this. I'm in the process of assembling an 80mm F/5 from a Surplus Shed lens...missed out on all the posts over the last couple of years...guess I'm late to the game  I really am enjoying seeing what other people have put together and getting ideas for my own projects. Thanks again.
--------------------
Meade ETX-60BB
Meade ETX-90EC UHTC
Skywatcher ST80
Orion ST120
Skywatcher 90mm Mak
Meade 9x63 binoculars
Celestron Explorascope
|
magic612
professor emeritus
Reged: 09/30/08
Posts: 561
Loc: Somewhere south of Chicago, IL
|
|
Looks nice David - nice job!
--------------------
- Celestron C8+, Orion 90mm f/10, Orion ST-80, 5" f/8 Dob, 127mm f/9.4 refractor, 114mm f/8 on DS GoTo, 60mm Sears 6333-A, 127mm f4.4 refractor lens (current project), 12" f/5 mirror (future project)
- Orion Vista 10x50s (5 deg), Sears #6207 7x35 (7 deg), Jason #138 Statesman 7x35 (11.5 deg)
Yes, I'm addicted to telescopes and binoculars. I am getting help. Every time I look at the heavens, it helps.
http://www.eyesonthesky.com
|
jimarshall
sage
Reged: 03/20/07
Posts: 206
Loc: Virginia
|
|
Great upgrade David, I gave up on mine when the star test looked really bad. I am very interested in your fine collimation adjustments. I shimmed up my lens while looking at the blue reflections through a cheshire eyepiece. Even though the blue spots looked well centered the star images were badly flared. How did your star images look before and after fine collimation?
--------------------
Jim
|
DavidinFL
member
Reged: 08/28/09
Posts: 52
Loc: Navarre, FL
|
|
Thanks for the comments!
Jim,
So far I haven't been able to perform a star test as it sits currently because of clouds. I've only collimated it with a cheshire tube. Before, when I had the lens shimmed, the lens star tested pretty well. The defocused star was slightly elliptical. Once the clouds clear, later this week, I'll try to get this one star tested.
--------------------
Orion XT8 - Orion StarMax 102 EQ
|
|
10 registered and 7 anonymous users are browsing this forum.
Moderator: Don W, Mike I. Jones
Print Thread
|
Forum Permissions
You cannot start new topics
You cannot reply to topics
HTML is disabled
UBBCode is enabled
|
Thread views: 164
|
|
|
|
|
|
|
Previous
Index
Next
Threaded
Edit
Reply
Quote
