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sftonkin
sage
Reged: 02/25/04
Posts: 395
Loc: Kent, UK
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Quote:
I have a question about something said in Steve's book. he commented that with binoculars, the longer the focal length, you higher quality eye piece you need.
"obtuse light cones are more demanding of eyepiece quality than those that are more acute" (p4)
Obtuse light cones derive from smaller focal ratios and hence, for equivalent apertures, shorter focal lengths.
It may well be that I have inadvertently contradicted myself elsewhere or that an error has crept in during the copy-editing stage that I have missed, but I have just searched all instances of "focal length" and "eyepiece" in the original manuscript, and I can't find it.
Can you cite a page reference and I will let you know if I need to produce an errata sheet PDQ! Thanks in advance,
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Stephen
Hindsight: The only truly diffraction-limited system
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sftonkin
sage
Reged: 02/25/04
Posts: 395
Loc: Kent, UK
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(Bump)
Quote:
I have a question about something said in Steve's book. he commented that with binoculars, the longer the focal length, you higher quality eye piece you need.
Hi Cameron,
Re the request in the post above:
I PM'd this to you a week or so ago; I guess it must have got lost in cyberspace:
Quote:
Please could you give me the precise reference to your " the longer the focal length, you higher quality eye piece you need " query. If I have fouled up, I am anxious to correct it as soon as possible.
Thanks in advance,
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Stephen
Hindsight: The only truly diffraction-limited system
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camvan
Carpal Tunnel
Reged: 05/02/05
Posts: 2086
Loc: British Columbia
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hi Stephen...I swear I answered your PM! the section that had me befuddled was on page 4 under the short focal length heading. after re-reading it several times, I finally got the context. I was mis-reading it...my fault with my lack of optical understanding.
sorry for the confusion! but I swear I answered you...I know I typed the message out anyhow 
edit - well, I just checked my CN inbox and it seems that the message I typed up for you was never sent. there's no 'R' showing I replied, so I double apologize! 
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Cameron
"Aperture can only be replaced by even more aperture. Dark transparent skies cannot be replaced by anything else." - Stathis Kafalis
Edited by camvan (01/21/07 06:41 AM)
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sftonkin
sage
Reged: 02/25/04
Posts: 395
Loc: Kent, UK
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Cameron,
Thanks for the reply.
Quote:
my fault with my lack of optical understanding.
Actually, it is my job as the writer to not befuddle the reader. I'll look to re-writing that bit if there is ever a 2nd edition...
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Stephen
Hindsight: The only truly diffraction-limited system
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camvan
Carpal Tunnel
Reged: 05/02/05
Posts: 2086
Loc: British Columbia
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Quote:
Cameron,
Thanks for the reply.
Quote:
my fault with my lack of optical understanding.
Actually, it is my job as the writer to not befuddle the reader. I'll look to re-writing that bit if there is ever a 2nd edition...
with that in mind then Stephen, when I get my book back from my dad (he's been antsy and dancing asking me if I was 'done' reading it yet) I'll re-read it and PM with you with some thoughts and observations if you like... 
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Cameron
"Aperture can only be replaced by even more aperture. Dark transparent skies cannot be replaced by anything else." - Stathis Kafalis
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sftonkin
sage
Reged: 02/25/04
Posts: 395
Loc: Kent, UK
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Quote:
I'll re-read it and PM with you with some thoughts and observations if you like...
I like. Thanks.
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Stephen
Hindsight: The only truly diffraction-limited system
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esdras
member
Reged: 11/24/05
Posts: 24
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Fantastic Stephen!
I've ordered my copy of the book Binocular Astronomy and reed it already.
All of which I find very useful.
I have to say it’s a really nice book.
Very, VERY impressive!
Thanks Stephen.
Esdras
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Bruce MacDonald
Pooh-Bah
Reged: 01/12/06
Posts: 1019
Loc: Devizes, Wiltshire, UK
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It's tempting to order this book. I have not bought a book on binocular astronomy since I got Jim Muirden's "Astronomy with Binoculars" in 1980. And I know how much things have moved on since that one was published.
EdZ's suggestion to get it with Sue French's book is an excellent one.
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Bruce MacDonald
Devizes, Wiltshire, UK
Per Mare Per Terras
Viz Top Tip: Don't waste money buying expensive binoculars. Simply stand closer to the object you wish to view.
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Bruce MacDonald
Pooh-Bah
Reged: 01/12/06
Posts: 1019
Loc: Devizes, Wiltshire, UK
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I've given in. Just ordered a copy from Amazon, but with a copy of Desmond King-Hele's "A Tapestry-of-Orbits" (he is the author of the excellent but now out-of-print "Observing Earth Satellites").
The Sue French book will have to wait...Sue, or Alan if you are reading this, I will get a copy eventually.
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Bruce MacDonald
Devizes, Wiltshire, UK
Per Mare Per Terras
Viz Top Tip: Don't waste money buying expensive binoculars. Simply stand closer to the object you wish to view.
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Bruce MacDonald
Pooh-Bah
Reged: 01/12/06
Posts: 1019
Loc: Devizes, Wiltshire, UK
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It arrived this morning and despite the best efforts of my Jack Russell, Poppy, to chew it up, I have been enjoying reading it.
I haven't even got to the actual astronomy yet but it is easily the best book on the subject I have seen. Well done!
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Bruce MacDonald
Devizes, Wiltshire, UK
Per Mare Per Terras
Viz Top Tip: Don't waste money buying expensive binoculars. Simply stand closer to the object you wish to view.
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sftonkin
sage
Reged: 02/25/04
Posts: 395
Loc: Kent, UK
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Thanks for the kind words, Bruce. I hope you feel the same after you've "got to the actual astronomy"! 
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Stephen
Hindsight: The only truly diffraction-limited system
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