Collimation tools for faster scopes?
- turboscrew
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Re: Collimation tools for faster scopes?
Nowadays I have a laser and a Cheshire.
Using a template mage of baking paper and drilled a hole on the opposite side of of the tube from the center of the focuser. Then covered it with white electric insulation tape. If the laser hits the hole, it glows red outside. Or you can put a bright light outside and check with sight tube.
When I added the secondary offset, I also marked the height of the optical axis with narrow lines on both sides of the secondary mirror. If I turn the secondary mirror sideways, I can adjust the height such that the laser "draws" a line through the side markers.
Using a template mage of baking paper and drilled a hole on the opposite side of of the tube from the center of the focuser. Then covered it with white electric insulation tape. If the laser hits the hole, it glows red outside. Or you can put a bright light outside and check with sight tube.
When I added the secondary offset, I also marked the height of the optical axis with narrow lines on both sides of the secondary mirror. If I turn the secondary mirror sideways, I can adjust the height such that the laser "draws" a line through the side markers.
- Juha
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Senior Embedded SW Designer
Telescope: OrionOptics XV12, Mount: CEM120, Tri-pier 360 and alternative dobson mount.
Grab 'n go: Omegon AC 102/660 on AZ-3 mount
Eyepieces: 26 mm Omegon SWAN 70°, 15 mm TV Plössl, 12.5 mm Baader Morpheus, 10 mm TV Delos, 6 mm Baader Classic Ortho, 5 mm TV DeLite, 4 mm and 3 mm TV Radians
Cameras: ZWO ASI 294MM Pro, Omegon veLOX 178C
OAG: TS-Optics TSOAG09, ZWO EFW 7 x 36 mm, ZWO filter sets: LRGB and Ha/OIII/SII
Explore Scientific HR 2" coma corrector, Meade x3 1.25" Barlow, TV PowerMate 4x 2"
Some filters (#80A, ND-96, ND-09, Astronomik UHC)
Laptop: Acer Enduro Urban N3 semi-rugged, Windows 11
LAT 61° 28' 10.9" N, Bortle 5
I don't suffer from insanity. I'm enjoying every minute of it.
- Ngc1514
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Re: Collimation tools for faster scopes?
After Tom Clark closed down Tectron, not sure the 3 tool set is available any longer. I think it’s worth its weight in gold! The booklet that came with it, “Perspectives on Collimation” by Vic Menard and Tippy D’Auria, is still available from Catseye.John Fitzgerald wrote: ↑Thu May 06, 2021 12:41 am I use the Tectron tool set: For secondary: Sight tube, Cheshire, then Astrosystems 2" laser to hit the primary center spot, followed by the Barlowed Astrosystems 2" laser to collimate the primary. Final check of the entire system with a Tectron autocollimator.
- Don Pensack
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Re: Collimation tools for faster scopes?
And the 3 tool set from Catseye is available, and much better than the Tectron Tools.
The Tectron tools haven't been available since the early '90s.
There are scopes in which the focuser is angle to hit a secondary that is farther up the tube. These are known as "low riders".
They can be successfully collimated, so the straightness of the focuser or its perpendicularity to the tube is really unimportant so long as the secondary mirror is centered under the focuer.
Center marking a secondary is a bad idea for 2 reasons:
1) the optical axis will not hit the center of the secondary in a collimated scope--it hits a few mm above that, toward the upper end of the tube.
2) the center of the secondary is used by off axis light, unlike the primary's center, so adding a dot adds diffraction.
So it is not a good idea to center dot a secondary. It is completely unnecessary in collimation anyway.
The height of the secondary in the tube can easily be ascertained by the use of a sight tube with its pupil at the apex.
Here is an illustrated collimation tutorial I wrote some years ago you might find useful:
https://www.cloudynights.com/articles/c ... e-v4-r2599
The Tectron tools haven't been available since the early '90s.
There are scopes in which the focuser is angle to hit a secondary that is farther up the tube. These are known as "low riders".
They can be successfully collimated, so the straightness of the focuser or its perpendicularity to the tube is really unimportant so long as the secondary mirror is centered under the focuer.
Center marking a secondary is a bad idea for 2 reasons:
1) the optical axis will not hit the center of the secondary in a collimated scope--it hits a few mm above that, toward the upper end of the tube.
2) the center of the secondary is used by off axis light, unlike the primary's center, so adding a dot adds diffraction.
So it is not a good idea to center dot a secondary. It is completely unnecessary in collimation anyway.
The height of the secondary in the tube can easily be ascertained by the use of a sight tube with its pupil at the apex.
Here is an illustrated collimation tutorial I wrote some years ago you might find useful:
https://www.cloudynights.com/articles/c ... e-v4-r2599
Astronomer since 1963
Currently using a 12.5" dob and a 4" apo refractor
Currently using a 12.5" dob and a 4" apo refractor
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