precise SCT collimation

A place to post informational content, reviews, and links on observing gear/hardware
TimW
Posts: 614
Joined: Wed Oct 18, 2017 1:15 pm

precise SCT collimation

Unread post by TimW » Wed Aug 01, 2018 9:47 am

Is there a tool that will precisely collimate an SCT?
Im familiar with de focusing a star and centering the secondary mirror in the donut. I was hoping for a more precise way of doing this rather than just eyeballing it.
Tim W.

Laurie J. Wood
March 22, 1967 - August 23, 2019
Forever in my memory. Forever in my heart.

Scope: 8" Celestron SCT on an AVX equatorial mount
Solar Scope: Lunt Solar System 60 mm Double-Stacked H-Alpha
Solar Imaging Camera: ZWO ASI174mm monochrome
Imaging Camera: ZWO ASI1600MC-Cool
Autoguide: PHD2
Image Capturing: SharpCap
DebayerIng: PIPP
Planetary Stacking: Autostakkert
Planetary Post Processing: Registax
Deep Sky Stacking: Deep Sky Stacker
Deep Sky Post Processing: Photoshop
User avatar
Paul D
Secretary
Posts: 2024
Joined: Fri Mar 19, 2004 2:13 pm

Re: precise SCT collimation

Unread post by Paul D » Wed Aug 01, 2018 12:34 pm

Tim,

A lot of people seem to like the Ho-tech laser system for SCT's. I know I personally use the reflector version of it and I think it collimates better than any other laser collimator I have seen. It eliminates a lot of slop in the focuser as well. Here are two videos on Hotech's SCT system, parts one and two. https://www.youtube.com/watch?v=wgDBktsX3fI and https://www.youtube.com/watch?v=4BDwa0RVZw0
Paul...

16" f/5 Night Sky Truss (Midnight Mistress)
10" f/5 Home built Dob with Parks mirror.
Pre-Meade PST
Celestron Skymaster Binos 25-125x80
Meade Travelview Binos 10x50

See that 16" in the sleek black dress? She is all mine. :)
TimW
Posts: 614
Joined: Wed Oct 18, 2017 1:15 pm

Re: precise SCT collimation

Unread post by TimW » Wed Aug 01, 2018 12:44 pm

Wow, those are pricey.
Tim W.

Laurie J. Wood
March 22, 1967 - August 23, 2019
Forever in my memory. Forever in my heart.

Scope: 8" Celestron SCT on an AVX equatorial mount
Solar Scope: Lunt Solar System 60 mm Double-Stacked H-Alpha
Solar Imaging Camera: ZWO ASI174mm monochrome
Imaging Camera: ZWO ASI1600MC-Cool
Autoguide: PHD2
Image Capturing: SharpCap
DebayerIng: PIPP
Planetary Stacking: Autostakkert
Planetary Post Processing: Registax
Deep Sky Stacking: Deep Sky Stacker
Deep Sky Post Processing: Photoshop
User avatar
Paul D
Secretary
Posts: 2024
Joined: Fri Mar 19, 2004 2:13 pm

Re: precise SCT collimation

Unread post by Paul D » Wed Aug 01, 2018 12:56 pm

They are Tim, but if you want as close to perfection as possible you have to pay the price. Like I said I use mine quite often to eliminate the focuser slop in my dobs and you can see the difference. Also not to mention they stand 100% behind their collimation system. Also keep your eyes open, they appear on cloudy nights from time to time for short money.
Paul...

16" f/5 Night Sky Truss (Midnight Mistress)
10" f/5 Home built Dob with Parks mirror.
Pre-Meade PST
Celestron Skymaster Binos 25-125x80
Meade Travelview Binos 10x50

See that 16" in the sleek black dress? She is all mine. :)
User avatar
Pete
Astro Day Coordinator
Posts: 3255
Joined: Fri Jun 13, 2003 9:03 pm

Re: precise SCT collimation

Unread post by Pete » Wed Aug 01, 2018 4:58 pm

Hi Tim, for SCT collimation nothing beats real stars. The gimmicky collimators function in the daylight, sort of. But nothing beats a star of a magnitude appropriate to aperture. A night of really good seeing is necessary to achieve an Airey (sp) disk. Simply start out at a low magnification and adjustment by adjustment work your way up to an insanely high magnification.

Pete
Pete P.
User avatar
Mark G
President
Posts: 3055
Joined: Fri Jun 13, 2003 6:57 pm

Re: precise SCT collimation

Unread post by Mark G » Sun Aug 12, 2018 8:11 pm

Paul good advice. And Pete also. I adhere to both your responses to Tim's query cant go wrong. BUT, I'll take it a step further.

Tim before you buy anything. I humbly suggest you look at the books you just won at Stellafane. I'll bet yours like mine did has a book named "Star Testing Astronomical Telescopes". If your Stellafane bundle doesn't have it I'd be amazed. If your bundle doesn't have it, buy it.

https://www.amazon.com/Star-Testing-Ast ... telescopes

At $79.95 on Amazon it shows you got your raffle tickets worth :!: The book to me is invaluable. Well, that and a Ronchi eye piece. The Ronchi EP will tell you if you have an OTA worth keeping, and if it is worth keeping, the book tells you how to star test and collimate it. Pete's method is correct as is Paul's. It just comes down to what method YOU prefer.

I hope this helps.
Clear skies,

Mark

iOptron CEM25P w/ Tri-pier
CGEM DX
LXD750 w/ CDS #1697
LXD75 w/ #497 autostar Hypertuned
Antares 8" f/5 Newt
Antares 4" f/15 "Vixen Spec" long focus refractor
Orion 4" f/7 ED refractor
Astro-Tech 65mm Quad APO
and so much more
TimW
Posts: 614
Joined: Wed Oct 18, 2017 1:15 pm

Re: precise SCT collimation

Unread post by TimW » Mon Aug 13, 2018 6:59 pm

Mark G wrote:
Sun Aug 12, 2018 8:11 pm
Paul good advice. And Pete also. I adhere to both your responses to Tim's query cant go wrong. BUT, I'll take it a step further.

Tim before you buy anything. I humbly suggest you look at the books you just won at Stellafane. I'll bet yours like mine did has a book named "Star Testing Astronomical Telescopes". If your Stellafane bundle doesn't have it I'd be amazed. If your bundle doesn't have it, buy it.

https://www.amazon.com/Star-Testing-Ast ... telescopes

At $79.95 on Amazon it shows you got your raffle tickets worth :!: The book to me is invaluable. Well, that and a Ronchi eye piece. The Ronchi EP will tell you if you have an OTA worth keeping, and if it is worth keeping, the book tells you how to star test and collimate it. Pete's method is correct as is Paul's. It just comes down to what method YOU prefer.

I hope this helps.
These are the books I got.
20180812_181937.jpg
20180812_181937.jpg (3.96 MiB) Viewed 3049 times
Tim W.

Laurie J. Wood
March 22, 1967 - August 23, 2019
Forever in my memory. Forever in my heart.

Scope: 8" Celestron SCT on an AVX equatorial mount
Solar Scope: Lunt Solar System 60 mm Double-Stacked H-Alpha
Solar Imaging Camera: ZWO ASI174mm monochrome
Imaging Camera: ZWO ASI1600MC-Cool
Autoguide: PHD2
Image Capturing: SharpCap
DebayerIng: PIPP
Planetary Stacking: Autostakkert
Planetary Post Processing: Registax
Deep Sky Stacking: Deep Sky Stacker
Deep Sky Post Processing: Photoshop
User avatar
Apollo XX
MSSF Coordinator
Posts: 2448
Joined: Sun Jul 11, 2010 8:11 pm

Re: precise SCT collimation

Unread post by Apollo XX » Mon Aug 13, 2018 7:13 pm

Wow! GREAT haul! Congratulations 8)
Mike M.
User avatar
AndyG
Network Admin
Posts: 1160
Joined: Wed Nov 30, 2011 10:18 pm

Re: precise SCT collimation

Unread post by AndyG » Mon Aug 13, 2018 7:42 pm

yeah, great books, congrats!
Andy
User avatar
Mark G
President
Posts: 3055
Joined: Fri Jun 13, 2003 6:57 pm

Re: precise SCT collimation

Unread post by Mark G » Tue Aug 14, 2018 7:23 pm

Tim that's an awesome collection :!: I'm sure you will benefit from them. The collection I got was all on telescopes and telescope making.
Clear skies,

Mark

iOptron CEM25P w/ Tri-pier
CGEM DX
LXD750 w/ CDS #1697
LXD75 w/ #497 autostar Hypertuned
Antares 8" f/5 Newt
Antares 4" f/15 "Vixen Spec" long focus refractor
Orion 4" f/7 ED refractor
Astro-Tech 65mm Quad APO
and so much more
Post Reply