A question on Newtonian collimation

No tools collimation will *only* achieve accurate collimation by dumb luck.

The no-tools approach ends with fine collimation using a star test. Any method
which ends with this will be correct, any which does not would rely on dumb
luck.
Understand something before you knock it.
Clear, Dark, Steady Skies!
(And considerate neighbors!!!)

No tools collimation will *only* achieve accurate collimation by dumb luck.

The no-tools approach ends with fine collimation using a star test. Any method
which ends with this will be correct, any which does not would rely on dumb
luck.
Understand something before you knock it.
Clear, Dark, Steady Skies!
(And considerate neighbors!!!)

No tools collimation will *only* achieve accurate collimation by dumb luck.

The no-tools approach ends with fine collimation using a star test. Any method
which ends with this will be correct, any which does not would rely on dumb
luck.
Understand something before you knock it.
Clear, Dark, Steady Skies!
(And considerate neighbors!!!)

No tools collimation will *only* achieve accurate collimation by dumb luck.

The no-tools approach ends with fine collimation using a star test. Any
method which ends with this will be correct, any which does not would rely on
dumb
luck. Understand something before you knock it.

First, my comments didn't knock the no-tools approach, they pointed out its
limitations. The best the no-tools approach will regularly achieve is a rough
collimation that has not adequately addressed the two most overlooked aspects
of Newtonian collimation: focuser alignment and secondary alignment.

For the beginner, a no-tools approach may be a good place to start. It doens't
get too technical and will get a scope in the ball park. But if a person wants
accurate collimation, the no-tools approach is not the way to go. Stephen
Paul's not some wet-behind-the-ears novice. He deserved better than your
off-the-cuff recommendation that he abandon tools for a simplistic approach
that offers no guarantee of improved collimation.

The barlowed-laser technique of aligning the primary is as easy as easy gets
and it's more accurate than the no-tools approach. If you don't believe me, try
it yourself. I have and, in more than 10-years collimating Newtonian
reflectors, the lasered-Barlow techique produces better collimation with less
work than any "no-tools" approach will.

Regards,

Bill Ferris
"Cosmic Voyage: The Online Resource for Amateur Astronomers"
URL: http://www.cosmic-voyage.net
=============
Email: Remove "ic" from .comic above to respond

No tools collimation will *only* achieve accurate collimation by dumb luck.

The no-tools approach ends with fine collimation using a star test. Any
method which ends with this will be correct, any which does not would rely on
dumb
luck. Understand something before you knock it.

First, my comments didn't knock the no-tools approach, they pointed out its
limitations. The best the no-tools approach will regularly achieve is a rough
collimation that has not adequately addressed the two most overlooked aspects
of Newtonian collimation: focuser alignment and secondary alignment.

For the beginner, a no-tools approach may be a good place to start. It doens't
get too technical and will get a scope in the ball park. But if a person wants
accurate collimation, the no-tools approach is not the way to go. Stephen
Paul's not some wet-behind-the-ears novice. He deserved better than your
off-the-cuff recommendation that he abandon tools for a simplistic approach
that offers no guarantee of improved collimation.

The barlowed-laser technique of aligning the primary is as easy as easy gets
and it's more accurate than the no-tools approach. If you don't believe me, try
it yourself. I have and, in more than 10-years collimating Newtonian
reflectors, the lasered-Barlow techique produces better collimation with less
work than any "no-tools" approach will.

Regards,

Bill Ferris
"Cosmic Voyage: The Online Resource for Amateur Astronomers"
URL: http://www.cosmic-voyage.net
=============
Email: Remove "ic" from .comic above to respond

No tools collimation will *only* achieve accurate collimation by dumb luck.

The no-tools approach ends with fine collimation using a star test. Any
method which ends with this will be correct, any which does not would rely on
dumb
luck. Understand something before you knock it.

First, my comments didn't knock the no-tools approach, they pointed out its
limitations. The best the no-tools approach will regularly achieve is a rough
collimation that has not adequately addressed the two most overlooked aspects
of Newtonian collimation: focuser alignment and secondary alignment.

For the beginner, a no-tools approach may be a good place to start. It doens't
get too technical and will get a scope in the ball park. But if a person wants
accurate collimation, the no-tools approach is not the way to go. Stephen
Paul's not some wet-behind-the-ears novice. He deserved better than your
off-the-cuff recommendation that he abandon tools for a simplistic approach
that offers no guarantee of improved collimation.

The barlowed-laser technique of aligning the primary is as easy as easy gets
and it's more accurate than the no-tools approach. If you don't believe me, try
it yourself. I have and, in more than 10-years collimating Newtonian
reflectors, the lasered-Barlow techique produces better collimation with less
work than any "no-tools" approach will.

Regards,

Bill Ferris
"Cosmic Voyage: The Online Resource for Amateur Astronomers"
URL: http://www.cosmic-voyage.net
=============
Email: Remove "ic" from .comic above to respond

Bill Foley wrote:
The no-tools approach ends with fine collimation using a star test.
Any method which ends with this will be correct, any which does not
would rely on dumb luck.

For an interesting rebuttal to this, see the last myth in Nils Olof
Carlin's article on collimation misconceptions, he

http://w1.411.telia.com/~u41105032/myths/myths.htm

Understand something before you knock it.

Heh.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

Bill Foley wrote:
The no-tools approach ends with fine collimation using a star test.
Any method which ends with this will be correct, any which does not
would rely on dumb luck.

For an interesting rebuttal to this, see the last myth in Nils Olof
Carlin's article on collimation misconceptions, he

http://w1.411.telia.com/~u41105032/myths/myths.htm

Understand something before you knock it.

Heh.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

Bill Foley wrote:
The no-tools approach ends with fine collimation using a star test.
Any method which ends with this will be correct, any which does not
would rely on dumb luck.

For an interesting rebuttal to this, see the last myth in Nils Olof
Carlin's article on collimation misconceptions, he

http://w1.411.telia.com/~u41105032/myths/myths.htm

Understand something before you knock it.

Heh.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

Hello, Gary,
.. If, like me, a person is not too great at spatial visualization, I can
offer a suggestion.
Ask someone to show you how, on your own telescope. On more than one
occasion. Have them coach you as you go through the proceedures yourself.. This
can be done at a star party if you arrive early and if there are knowledgeable
people with Newtonian Dobs there, as there usually are. Scott Naylor in my
observing group has been a big help to me. (Or if you are a Starmaster owner,
as I am, Rick Singmaster will run through the procedure with you as you stand
with your cell telephone by your scope outdoors some afternoon.) This has
helped me a lot and now I can collimate a Newtonian, though I still don't
understand the diagrams. While the Sky & Tel article is not as turgid and
incoherent as most of the collimation web pages, the diagrams on page 3 of the
Sky & Telescope article are laughable as explanatory devices for the
non-engineer.
When I lived in Boston I knew Paul Valleli, and his opinion I would
trust. It seems to me he wrote a very good article about collimation for Sky &
Telescope years ago and I wish I could find it now.. ..
The best idea for those who find spatial visualization --- seeing two
dimensional diagrams in three dimensions and holding them in memory at least
briefly -- is to have someone coach you as you do it. on several occasions
(Spaced learning is more effective than massed learning.).
Clear skies,
Bill Meyers.

wrote:

"Stephen Paul" wrote:


Does anyone have a web page with images like Bryan's, that is more
comprehensive on the _process_, without going into overkill optical theory

Try the instructions on Sky&Telescope's Web page
(www.skyandtlescope.com). Look for the article in the "How-To"
section, under "Telescopes and Binoculars."
(http://skyandtelescope.com/howto/sco...icle_787_1.asp)

They're the best instructions out there in my opinion. The main thing
is to relax, and proceed methodically. You can do it.

Regards,
Gary
Gary Seronik

(Remove the "z" for my actual e-mail address.)