RE: [Utah-astronomy] Dave's folded Newt project
Good page. It makes me wish that I could start now. Luckily I wont have to hog mine out as deep since I want to go with an f/10. One question I have is why do you use a flat for the optical secondary instead of a parabolic 8" mirror? I did like the method he used to keep from turning the edge of the 8" mirror. I am sure that I will need to make both of the big mirrors. I will buy the 1.8" diagonal mirror. For the next couple of weeks I am trying to finish the 16" scope from last year. We are building the box and the cradle tonight. I really want to have it done for Dead Horse Point. -----Original Message----- From: Chuck Hards [mailto:chuckhards@yahoo.com] Sent: Monday, March 17, 2003 4:07 PM To: Utah-Astro Subject: [Utah-astronomy] Dave's folded Newt project Dave, have you seen this yet? http://www.kitgear.com/25%20inch%20plans.htm C. __________________________________________________ Do you Yahoo!? Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop! http://platinum.yahoo.com _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy
Could someone refresh my memory about when Dead Horse Point night is? And should I be making reservations to stay in the campground? thanks, Joe Joe Bauman science & military reporter Deseret News bau@desnews.com (801) 237-2169
--- David Dunn <david.dunn@albertsons.com> wrote:
Good page. It makes me wish that I could start now. Luckily I wont have to hog mine out as deep since I want to go with an f/10. One question I have is why do you use a flat for the optical secondary instead of a parabolic 8" mirror?
If the secondary is anything but flat, it will alter the primary f/#. Also, a flat is infinitely easier to figure than just about any convex surface. A concave secondary means a Gregorian configuration, which tends to be much longer than a Cass, and even most Newts. If you really want to go unobstructed, check out the Sasian design- of course it means you must figure a toroidal secondary (royal pain in the butt). All in all, a "folded" Newt is a marvel of optical simplicity. C. __________________________________________________ Do you Yahoo!? Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop! http://platinum.yahoo.com
I'm hoping for the day when physicists find (if it indeed exists) the relationship between gravity and electromagnetic forces, and are able to make an artificial gravitational field; just imagine a scope with an onobstructed large ring at the objective end able to generate a gravitational field powerful enough to bend the light passing through it much like a refractor without the glass; same thing at the eyepiece end, variable power without anything solid between your eye and the deep sky... how cool would that be? -Rich --- Chuck Hards <chuckhards@yahoo.com> wrote:
--- David Dunn <david.dunn@albertsons.com> wrote:
Good page. It makes me wish that I could start now. Luckily I wont have to hog mine out as deep since I want to go with an f/10. One question I have is why do you use a flat for the optical secondary instead of a parabolic 8" mirror?
If the secondary is anything but flat, it will alter the primary f/#. Also, a flat is infinitely easier to figure than just about any convex surface. A concave secondary means a Gregorian configuration, which tends to be much longer than a Cass, and even most Newts.
If you really want to go unobstructed, check out the Sasian design- of course it means you must figure a toroidal secondary (royal pain in the butt). All in all, a "folded" Newt is a marvel of optical simplicity.
C.
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Larry Niven beat you to it. Read "Protector". Of course you realize that the breakthroughs will be made ten minutes after you're dead. :( C. --- Richard Tenney <retenney@yahoo.com> wrote:
I'm hoping for the day when physicists find (if it indeed exists) the relationship between gravity and electromagnetic forces, and are able to make an artificial gravitational field; just imagine a scope with an onobstructed large ring at the objective end able to generate a gravitational field powerful enough to bend the light passing through it much like a refractor without the glass; same thing at the eyepiece end, variable power without anything solid between your eye and the deep sky... how cool would that be?
-Rich
--- Chuck Hards <chuckhards@yahoo.com> wrote:
--- David Dunn <david.dunn@albertsons.com> wrote:
Good page. It makes me wish that I could start now. Luckily I wont have to hog mine out as deep since I want to go with an f/10. One question I have is why do you use a flat for the optical secondary instead of a parabolic 8" mirror?
If the secondary is anything but flat, it will
alter
the primary f/#. Also, a flat is infinitely easier to figure than just about any convex surface. A concave secondary means a Gregorian configuration, which tends to be much longer than a Cass, and even most Newts.
If you really want to go unobstructed, check out the Sasian design- of course it means you must figure a toroidal secondary (royal pain in the butt). All in all, a "folded" Newt is a marvel of optical simplicity.
C.
__________________________________________________ Do you Yahoo!? Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop! http://platinum.yahoo.com
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Chuck, LOL. Yeah, I remember sharing that thought with Mark Dakins a few years ago and him telling me one of the popular SF authors had it in a story; thanks for clarifying who/what it was! I do like a lot of what Niven writes, so I'm not at all surprised. --- Chuck Hards <chuckhards@yahoo.com> wrote:
Larry Niven beat you to it. Read "Protector".
Of course you realize that the breakthroughs will be made ten minutes after you're dead. :(
C.
--- Richard Tenney <retenney@yahoo.com> wrote:
I'm hoping for the day when physicists find (if it indeed exists) the relationship between gravity and electromagnetic forces, and are able to make an artificial gravitational field; just imagine a scope with an onobstructed large ring at the objective end able to generate a gravitational field powerful enough to bend the light passing through it much like a refractor without the glass; same thing at the eyepiece end, variable power without anything solid between your eye and the deep sky... how cool would that be?
-Rich
--- Chuck Hards <chuckhards@yahoo.com> wrote:
--- David Dunn <david.dunn@albertsons.com>
wrote:
Good page. It makes me wish that I could start now. Luckily I wont have to hog mine out as deep since I want to go with an f/10. One question I have is why do you use a flat for the optical secondary instead of a parabolic 8" mirror?
If the secondary is anything but flat, it will alter the primary f/#. Also, a flat is infinitely easier to figure than just about any convex surface. A concave secondary means a Gregorian configuration, which tends to be much longer than a Cass, and even most Newts.
If you really want to go unobstructed, check out the Sasian design- of course it means you must figure a toroidal secondary (royal pain in the butt). All in all, a "folded" Newt is a marvel of optical simplicity.
C.
Do you Yahoo!? Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop! http://platinum.yahoo.com
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http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy
__________________________________________________ Do you Yahoo!? Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop! http://platinum.yahoo.com
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I once had the opportunity to meet him. Great guy, a math professor, IIRC. I wish he had concentrated more on writing and less on teaching...somewhat reminiscent of Tom Lehrer...Lehrer was actually told by his Harvard superiors to either "quit music, or quit teaching". He chose teaching. Sigh. The concept is great. Once science learns to manipulate photons in such a manner, the pro/am dividing line will vanish completely (provided there is still observational research to do by then!) C. --- Richard Tenney <retenney@yahoo.com> wrote:
Chuck,
LOL. Yeah, I remember sharing that thought with Mark Dakins a few years ago and him telling me one of the popular SF authors had it in a story; thanks for clarifying who/what it was! I do like a lot of what Niven writes, so I'm not at all surprised.
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participants (4)
-
Chuck Hards -
David Dunn -
Joe Bauman -
Richard Tenney