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Young People Read Old SFF: Nightfall by Isaac Asimov

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  Young People Read Old SFF: Nightfall by Isaac Asimov jdnicoll@panix.com (James Nicoll) - 2016-08-31 19:59 +0000
    Re: Young People Read Old SFF: Nightfall by Isaac Asimov Lynn McGuire <lynnmcguire5@gmail.com> - 2016-08-31 15:54 -0500
      Re: Young People Read Old SFF: Nightfall by Isaac Asimov news{@bestley.co.uk (Mark Bestley) - 2016-08-31 22:43 +0100
        Re: Young People Read Old SFF: Nightfall by Isaac Asimov Lynn McGuire <lynnmcguire5@gmail.com> - 2016-08-31 18:30 -0500
          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-08-31 19:00 -0700
          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Greg Goss <gossg@gossg.org> - 2016-09-01 03:10 -0600
          Re: Young People Read Old SFF: Nightfall by Isaac Asimov jdnicoll@panix.com (James Nicoll) - 2016-09-01 13:41 +0000
        Re: Young People Read Old SFF: Nightfall by Isaac Asimov jdnicoll@panix.com (James Nicoll) - 2016-09-01 03:58 +0000
          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Lynn McGuire <lynnmcguire5@gmail.com> - 2016-09-01 12:37 -0500
            Re: Young People Read Old SFF: Nightfall by Isaac Asimov ted@loft.tnolan.com (Ted Nolan <tednolan>) - 2016-09-01 18:07 +0000
            Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-01 11:34 -0700
              Re: Young People Read Old SFF: Nightfall by Isaac Asimov Lynn McGuire <lynnmcguire5@gmail.com> - 2016-09-01 15:15 -0500
                Re: Young People Read Old SFF: Nightfall by Isaac Asimov tsbrueni@gmail.com - 2016-09-01 13:48 -0700
                  Re: Young People Read Old SFF: Nightfall by Isaac Asimov "Michael F. Stemper" <michael.stemper@gmail.com> - 2016-09-01 16:24 -0500
                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-01 15:45 -0600
                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-01 15:47 -0600
                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-02 00:40 +0000
                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov tsbrueni@gmail.com - 2016-09-01 18:18 -0700
                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-01 20:20 -0600
                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-01 19:46 -0700
                            Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-01 21:09 -0600
                              Re: Young People Read Old SFF: Nightfall by Isaac Asimov Dimensional Traveler <dtravel@sonic.net> - 2016-09-01 20:47 -0700
                              Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-02 03:13 -0700
                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-02 03:25 +0000
                            Re: Young People Read Old SFF: Nightfall by Isaac Asimov hamish.laws@gmail.com - 2016-09-01 20:48 -0700
                              Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-02 04:34 +0000
                                Re: Young People Read Old SFF: Nightfall by Isaac Asimov Robert Woodward <robertaw@drizzle.com> - 2016-09-01 22:16 -0700
                                  Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-02 07:32 -0700
                                  Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-02 07:33 -0700
                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-03 00:22 +0000
                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-02 21:39 -0500
                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov "Brian M. Scott" <b.scott@csuohio.edu> - 2016-09-02 22:57 -0400
                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-02 21:28 -0700
                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> - 2016-09-03 05:33 +0200
                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-02 23:39 -0500
                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-02 21:25 -0700
                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov Paul Colquhoun <newsposter@andor.dropbear.id.au> - 2016-09-03 18:22 +1000
                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-03 10:10 -0500
                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-04 00:38 +0000
                                            Re: Young People Read Old SFF: Nightfall by Isaac Asimov tsbrueni@gmail.com - 2016-09-03 20:23 -0700
                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-03 08:31 -0400
                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-03 10:14 -0500
                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-03 08:25 -0700
                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-03 08:31 -0700
                                  Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-02 16:21 +0000
                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-02 10:39 -0700
                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-02 13:17 -0500
                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov Jaimie Vandenbergh <jaimie@sometimes.sessile.org> - 2016-09-02 23:03 +0100
                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-02 17:54 -0500
                                            Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-03 00:03 +0000
                                              Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-02 21:35 -0500
                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov tsbrueni@gmail.com - 2016-09-02 16:08 -0700
                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov David DeLaney <daviddelaney@earthlink.net> - 2016-09-02 21:16 -0500
                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov 103134.3516@compuserve.com - 2016-09-07 12:56 -0700
                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Robert Carnegie <rja.carnegie@excite.com> - 2016-09-07 19:05 -0700
                                            Re: Young People Read Old SFF: Nightfall by Isaac Asimov "Brian M. Scott" <b.scott@csuohio.edu> - 2016-09-07 22:21 -0400
                                              Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-08 04:53 +0000
                                            Re: Young People Read Old SFF: Nightfall by Isaac Asimov Jaimie Vandenbergh <jaimie@sometimes.sessile.org> - 2016-09-09 00:12 +0100
                                              Re: Young People Read Old SFF: Nightfall by Isaac Asimov Dimensional Traveler <dtravel@sonic.net> - 2016-09-08 17:00 -0700
                                              Re: Young People Read Old SFF: Nightfall by Isaac Asimov Greg Goss <gossg@gossg.org> - 2016-09-08 22:36 -0600
                                                Re: Young People Read Old SFF: Nightfall by Isaac Asimov Jaimie Vandenbergh <jaimie@sometimes.sessile.org> - 2016-09-09 08:34 +0100
                                                  Re: Young People Read Old SFF: Nightfall by Isaac Asimov David DeLaney <daviddelaney@earthlink.net> - 2016-09-09 04:41 -0500
                                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov tsbrueni@gmail.com - 2016-09-09 03:31 -0700
                                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov Jaimie Vandenbergh <jaimie@sometimes.sessile.org> - 2016-09-09 16:36 +0100
                                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov Peter Trei <petertrei@gmail.com> - 2016-09-09 09:11 -0700
                                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov Joe Bernstein <joe@sfbooks.com> - 2016-09-09 09:45 -0700
                                              Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-09 09:52 -0700
                                                Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-09 11:18 -0600
                                                Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-09 10:29 -0700
                                                  Re: Young People Read Old SFF: Nightfall by Isaac Asimov Peter Trei <petertrei@gmail.com> - 2016-09-09 12:17 -0700
                                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov Peter Trei <petertrei@gmail.com> - 2016-09-09 12:20 -0700
                                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov scott@slp53.sl.home (Scott Lurndal) - 2016-09-09 19:59 +0000
                                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-09 14:14 -0700
                                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-09 14:44 -0700
                                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-09 15:35 -0700
                                                            Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-09 16:00 -0700
                                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-09 14:34 -0700
                                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov Robert Carnegie <rja.carnegie@excite.com> - 2016-09-09 19:19 -0700
                                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-10 04:40 -0700
                                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-10 08:21 -0400
                                                            Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-10 07:09 -0700
                                                              Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-10 10:49 -0400
                                                                Re: Young People Read Old SFF: Nightfall by Isaac Asimov Dimensional Traveler <dtravel@sonic.net> - 2016-09-10 08:19 -0700
                                                                  Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-10 12:27 -0400
                                                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov Greg Goss <gossg@gossg.org> - 2016-09-10 10:47 -0600
                                                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-10 12:49 -0700
                                                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-10 17:15 -0400
                                                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov Dimensional Traveler <dtravel@sonic.net> - 2016-09-10 14:20 -0700
                                                                Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-10 10:29 -0500
                                                                  Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-10 12:47 -0400
                                                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-10 10:55 -0600
                                                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-10 12:51 -0700
                                                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-10 17:18 -0400
                                                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-11 05:45 -0700
                                                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-12 00:06 +0000
                                                                  Re: Young People Read Old SFF: Nightfall by Isaac Asimov Robert Carnegie <rja.carnegie@excite.com> - 2016-09-10 11:22 -0700
                                                              Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-10 10:33 -0600
                                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-09 14:33 -0700
                                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov Kevrob <kevrob@my-deja.com> - 2016-09-09 15:13 -0700
                                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-09 16:00 -0700
                                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-09 16:08 -0700
                                                            Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-10 10:36 -0500
                                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-09 16:06 -0700
                                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-09 16:10 -0700
                                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov "Brian M. Scott" <b.scott@csuohio.edu> - 2016-09-10 12:49 -0400
                                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov Charles Bishop <ctbishop@earthlink.net> - 2016-09-10 14:43 -0700
                                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov "Brian M. Scott" <b.scott@csuohio.edu> - 2016-09-10 17:57 -0400
                                                      Re: Young People Read Old SFF: Nightfall by Isaac Asimov Tom Kratman <tomkratman@gmail.com> - 2016-09-10 20:20 -0700
                                                        Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-10 20:27 -0700
                                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Tom Kratman <tomkratman@gmail.com> - 2016-09-11 19:51 -0700
                                                            Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-11 21:16 -0700
                                                              Re: Young People Read Old SFF: Nightfall by Isaac Asimov Tom Kratman <tomkratman@gmail.com> - 2016-09-12 18:08 -0700
                                                                Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-12 19:40 -0700
                                                                  Re: Young People Read Old SFF: Nightfall by Isaac Asimov Tom Kratman <tomkratman@gmail.com> - 2016-09-14 17:31 -0700
                                                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-14 18:16 -0700
                                                                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-14 22:26 -0700
                                              Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-11 05:38 -0700
                                                Re: Young People Read Old SFF: Nightfall by Isaac Asimov Greg Goss <gossg@gossg.org> - 2016-09-12 21:55 -0600
                                            Re: Young People Read Old SFF: Nightfall by Isaac Asimov 103134.3516@compuserve.com - 2016-09-16 12:06 -0700
                                          Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-11 05:30 -0700
                                Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-02 00:12 -0600
                                Re: Young People Read Old SFF: Nightfall by Isaac Asimov David DeLaney <daviddelaney@earthlink.net> - 2016-09-02 08:53 -0500
                    Re: Young People Read Old SFF: Nightfall by Isaac Asimov jdnicoll@panix.com (James Nicoll) - 2016-09-02 01:33 +0000
                  Re: Young People Read Old SFF: Nightfall by Isaac Asimov Greg Goss <gossg@gossg.org> - 2016-09-01 21:53 -0600
                Re: Young People Read Old SFF: Nightfall by Isaac Asimov wdstarr@panix.com (William December Starr) - 2016-09-01 20:11 -0400
                Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-02 07:50 -0700

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#451038

On Saturday, September 10, 2016 at 6:21:26 AM UTC-6, J. Clarke wrote:
> In article <5ede8bfa-83c1-4d22-918c-02101c5b74b2@googlegroups.com>, 
> jsavard@ecn.ab.ca says...

> > (Telescopes only make stars brighter by making 
> > them bigger - they can't make things brighter per unit area, it's a law of 
> > optics.)

> What law of optics would that be?

> <makes popcorn>

"Radiance is conserved through a loss-less optical system."

Now, this applies to "things" you look at with your eye. You can make a 
projected image brighter per unit area by using a bigger lens to create the 
image, which is why you don't have to expose film for as long with an f/1.4 
lens as with an f/16 lens. But if you're looking through a lens at an image, or 
looking at an image in a mirror, it can't be brighter than the original.

John Savard

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#451039

In article <eda510d3-4280-4eb6-bd52-a15721705a94@googlegroups.com>, 
jsavard@ecn.ab.ca says...
> 
> On Saturday, September 10, 2016 at 6:21:26 AM UTC-6, J. Clarke wrote:
> > In article <5ede8bfa-83c1-4d22-918c-02101c5b74b2@googlegroups.com>, 
> > jsavard@ecn.ab.ca says...
> 
> > > (Telescopes only make stars brighter by making 
> > > them bigger - they can't make things brighter per unit area, it's a law of 
> > > optics.)
> 
> > What law of optics would that be?
> 
> > <makes popcorn>
> 
> "Radiance is conserved through a loss-less optical system."
> 
> Now, this applies to "things" you look at with your eye. You can make a 
> projected image brighter per unit area by using a bigger lens to create the 
> image, which is why you don't have to expose film for as long with an f/1.4 
> lens as with an f/16 lens. But if you're looking through a lens at an image, or 
> looking at an image in a mirror, it can't be brighter than the original.
> 
> John Savard

So by your logic Gran Canaris, Palomar, Wison, a pair of binoculars, and 
a pinhole all have the same limiting magnitude as the naked eye.

What's wrong with this picture?

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#451042

On 9/10/2016 7:49 AM, J. Clarke wrote:
> In article <eda510d3-4280-4eb6-bd52-a15721705a94@googlegroups.com>,
> jsavard@ecn.ab.ca says...
>>
>> On Saturday, September 10, 2016 at 6:21:26 AM UTC-6, J. Clarke wrote:
>>> In article <5ede8bfa-83c1-4d22-918c-02101c5b74b2@googlegroups.com>,
>>> jsavard@ecn.ab.ca says...
>>
>>>> (Telescopes only make stars brighter by making
>>>> them bigger - they can't make things brighter per unit area, it's a law of
>>>> optics.)
>>
>>> What law of optics would that be?
>>
>>> <makes popcorn>
>>
>> "Radiance is conserved through a loss-less optical system."
>>
>> Now, this applies to "things" you look at with your eye. You can make a
>> projected image brighter per unit area by using a bigger lens to create the
>> image, which is why you don't have to expose film for as long with an f/1.4
>> lens as with an f/16 lens. But if you're looking through a lens at an image, or
>> looking at an image in a mirror, it can't be brighter than the original.
>>
>> John Savard
>
> So by your logic Gran Canaris, Palomar, Wison, a pair of binoculars, and
> a pinhole all have the same limiting magnitude as the naked eye.
>
> What's wrong with this picture?
>
Size and time.

-- 
Now taking submissions for the rec.arts.TV Channels Watched Survey for 
Summer 2016

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#451048

In article <nr1897$34s$1@dont-email.me>, dtravel@sonic.net says...
> 
> On 9/10/2016 7:49 AM, J. Clarke wrote:
> > In article <eda510d3-4280-4eb6-bd52-a15721705a94@googlegroups.com>,
> > jsavard@ecn.ab.ca says...
> >>
> >> On Saturday, September 10, 2016 at 6:21:26 AM UTC-6, J. Clarke wrote:
> >>> In article <5ede8bfa-83c1-4d22-918c-02101c5b74b2@googlegroups.com>,
> >>> jsavard@ecn.ab.ca says...
> >>
> >>>> (Telescopes only make stars brighter by making
> >>>> them bigger - they can't make things brighter per unit area, it's a law of
> >>>> optics.)
> >>
> >>> What law of optics would that be?
> >>
> >>> <makes popcorn>
> >>
> >> "Radiance is conserved through a loss-less optical system."
> >>
> >> Now, this applies to "things" you look at with your eye. You can make a
> >> projected image brighter per unit area by using a bigger lens to create the
> >> image, which is why you don't have to expose film for as long with an f/1.4
> >> lens as with an f/16 lens. But if you're looking through a lens at an image, or
> >> looking at an image in a mirror, it can't be brighter than the original.
> >>
> >> John Savard
> >
> > So by your logic Gran Canaris, Palomar, Wison, a pair of binoculars, and
> > a pinhole all have the same limiting magnitude as the naked eye.
> >
> > What's wrong with this picture?
> >
> Size and time.

How does "time" enter into a visual observation?  And if telescopes "can 
only make stars brighter by making them bigger, they can't stars 
brighter per unit area" how does size help?

Hint--I know how a telescope works, I'm not asking because I want some 
genius to enlighten me.  I want to see quadi examing his assumptions.

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#451051

"J. Clarke" <j.clarke.873638@gmail.com> wrote:
>In article <nr1897$34s$1@dont-email.me>, dtravel@sonic.net says...

>> >>>> (Telescopes only make stars brighter by making
>> >>>> them bigger - they can't make things brighter per unit area, it's a law of
>> >>>> optics.)
>> >>
>> >>> What law of optics would that be?
>> >>
>> >>> <makes popcorn>
>> >>
>> >> "Radiance is conserved through a loss-less optical system."
>> >>
>> >> Now, this applies to "things" you look at with your eye. You can make a
>> >> projected image brighter per unit area by using a bigger lens to create the
>> >> image, which is why you don't have to expose film for as long with an f/1.4
>> >> lens as with an f/16 lens. But if you're looking through a lens at an image, or
>> >> looking at an image in a mirror, it can't be brighter than the original.

>> > So by your logic Gran Canaris, Palomar, Wison, a pair of binoculars, and
>> > a pinhole all have the same limiting magnitude as the naked eye.

"You can make an image brighter"

>> > What's wrong with this picture?
>> >
>> Size and time.
>
>How does "time" enter into a visual observation? 

You expose a photograph or other photon-gathering system for a long
time and then look at THAT.

> And if telescopes "can 
>only make stars brighter by making them bigger, they can't stars 
>brighter per unit area" how does size help?

-- 
We are geeks.  Resistance is voltage over current.

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#451057

On Saturday, September 10, 2016 at 10:27:53 AM UTC-6, J. Clarke wrote:

> How does "time" enter into a visual observation?  And if telescopes "can 
> only make stars brighter by making them bigger, they can't stars 
> brighter per unit area" how does size help?

Well, if a star can't be made brighter per unit area, but a star can be made 
bigger, then at the *same brightness per unit area*, a star that is twice as 
big gives you four times as much light.

If the star is still so small that it looks like a point, the point has become 
brighter.

John Savard

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#451061

In article <f1aa6dec-5a5b-45f1-9e47-908f2d0ae5c0@googlegroups.com>, 
jsavard@ecn.ab.ca says...
> 
> On Saturday, September 10, 2016 at 10:27:53 AM UTC-6, J. Clarke wrote:
> 
> > How does "time" enter into a visual observation?  And if telescopes "can 
> > only make stars brighter by making them bigger, they can't stars 
> > brighter per unit area" how does size help?
> 
> Well, if a star can't be made brighter per unit area, but a star can be made 
> bigger, then at the *same brightness per unit area*, a star that is twice as 
> big gives you four times as much light.

Spread over four times as much area so where's the gain?
 
> If the star is still so small that it looks like a point, the point has become 
> brighter.

You keep using this word . . .

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#451063

On 9/10/2016 9:27 AM, J. Clarke wrote:
> In article <nr1897$34s$1@dont-email.me>, dtravel@sonic.net says...
>>
>> On 9/10/2016 7:49 AM, J. Clarke wrote:
>>> In article <eda510d3-4280-4eb6-bd52-a15721705a94@googlegroups.com>,
>>> jsavard@ecn.ab.ca says...
>>>>
>>>> On Saturday, September 10, 2016 at 6:21:26 AM UTC-6, J. Clarke wrote:
>>>>> In article <5ede8bfa-83c1-4d22-918c-02101c5b74b2@googlegroups.com>,
>>>>> jsavard@ecn.ab.ca says...
>>>>
>>>>>> (Telescopes only make stars brighter by making
>>>>>> them bigger - they can't make things brighter per unit area, it's a law of
>>>>>> optics.)
>>>>
>>>>> What law of optics would that be?
>>>>
>>>>> <makes popcorn>
>>>>
>>>> "Radiance is conserved through a loss-less optical system."
>>>>
>>>> Now, this applies to "things" you look at with your eye. You can make a
>>>> projected image brighter per unit area by using a bigger lens to create the
>>>> image, which is why you don't have to expose film for as long with an f/1.4
>>>> lens as with an f/16 lens. But if you're looking through a lens at an image, or
>>>> looking at an image in a mirror, it can't be brighter than the original.
>>>>
>>>> John Savard
>>>
>>> So by your logic Gran Canaris, Palomar, Wison, a pair of binoculars, and
>>> a pinhole all have the same limiting magnitude as the naked eye.
>>>
>>> What's wrong with this picture?
>>>
>> Size and time.
>
> How does "time" enter into a visual observation?  And if telescopes "can
> only make stars brighter by making them bigger, they can't stars
> brighter per unit area" how does size help?
>
> Hint--I know how a telescope works, I'm not asking because I want some
> genius to enlighten me.  I want to see quadi examing his assumptions.
>
I was thinking "Time" as in time-lapse.

-- 
Running the rec.arts.TV Channels Watched Survey.
Fall 2016 survey began Sep 01; still accepting responses for Summer 2016

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#451043

"J. Clarke" <j.clarke.873638@gmail.com> wrote in
news:MPG.323de7732a83683098a536@news.eternal-september.org: 

> In article <eda510d3-4280-4eb6-bd52-a15721705a94@googlegroups.com>, 
> jsavard@ecn.ab.ca says...
>> 
>> On Saturday, September 10, 2016 at 6:21:26 AM UTC-6, J. Clarke wrote:
>> > In article <5ede8bfa-83c1-4d22-918c-02101c5b74b2@googlegroups.com>,
>> > jsavard@ecn.ab.ca says...
>> 
>> > > (Telescopes only make stars brighter by making 
>> > > them bigger - they can't make things brighter per unit area, it's
>> > > a law of optics.)
>> 
>> > What law of optics would that be?
>> 
>> > <makes popcorn>
>> 
>> "Radiance is conserved through a loss-less optical system."
>> 
>> Now, this applies to "things" you look at with your eye. You can make
>> a projected image brighter per unit area by using a bigger lens to
>> create the image, which is why you don't have to expose film for as
>> long with an f/1.4 lens as with an f/16 lens. But if you're looking
>> through a lens at an image, or looking at an image in a mirror, it
>> can't be brighter than the original. 
>> 
>> John Savard
> 
> So by your logic Gran Canaris, Palomar, Wison, a pair of binoculars,
> and a pinhole all have the same limiting magnitude as the naked eye.
> 
> What's wrong with this picture?

You're looking at the wrong thing. The limit Quaddie is talking about is
how bright something can be made to look. It seems that an optical system
can't make something appear brighter than it does at zero range.

I strongly suggest you take a look at this, which goes to a lot of
trouble to make the same point.

http://what-if.xkcd.com/145/

That said, I don't find it entirely convincing myself.

pt

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#451050

In article <XnsA67F74E0CE11Emelchizedek@216.166.97.131>, 
treifamily@gmail.com says...
> 
> "J. Clarke" <j.clarke.873638@gmail.com> wrote in
> news:MPG.323de7732a83683098a536@news.eternal-september.org: 
> 
> > In article <eda510d3-4280-4eb6-bd52-a15721705a94@googlegroups.com>, 
> > jsavard@ecn.ab.ca says...
> >> 
> >> On Saturday, September 10, 2016 at 6:21:26 AM UTC-6, J. Clarke wrote:
> >> > In article <5ede8bfa-83c1-4d22-918c-02101c5b74b2@googlegroups.com>,
> >> > jsavard@ecn.ab.ca says...
> >> 
> >> > > (Telescopes only make stars brighter by making 
> >> > > them bigger - they can't make things brighter per unit area, it's
> >> > > a law of optics.)
> >> 
> >> > What law of optics would that be?
> >> 
> >> > <makes popcorn>
> >> 
> >> "Radiance is conserved through a loss-less optical system."
> >> 
> >> Now, this applies to "things" you look at with your eye. You can make
> >> a projected image brighter per unit area by using a bigger lens to
> >> create the image, which is why you don't have to expose film for as
> >> long with an f/1.4 lens as with an f/16 lens. But if you're looking
> >> through a lens at an image, or looking at an image in a mirror, it
> >> can't be brighter than the original. 
> >> 
> >> John Savard
> > 
> > So by your logic Gran Canaris, Palomar, Wison, a pair of binoculars,
> > and a pinhole all have the same limiting magnitude as the naked eye.
> > 
> > What's wrong with this picture?
> 
> You're looking at the wrong thing. The limit Quaddie is talking about is
> how bright something can be made to look. It seems that an optical system
> can't make something appear brighter than it does at zero range.
> 
> I strongly suggest you take a look at this, which goes to a lot of
> trouble to make the same point.
> 
> http://what-if.xkcd.com/145/
> 
> That said, I don't find it entirely convincing myself.

I'm not even going to start on what's wrong with it.

He's right that you can't make the surface of a star brighter from a 
hundred light years away than it is when you are sitting in its 
photosphere, but that's really not an argument that makes much practical 
sense.

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#451054

On 9/10/2016 10:47 AM, J. Clarke wrote:
> In article <XnsA67F74E0CE11Emelchizedek@216.166.97.131>,
> treifamily@gmail.com says...
>>
>> "J. Clarke" <j.clarke.873638@gmail.com> wrote in
>> news:MPG.323de7732a83683098a536@news.eternal-september.org:
>>
>>> In article <eda510d3-4280-4eb6-bd52-a15721705a94@googlegroups.com>,
>>> jsavard@ecn.ab.ca says...
>>>>
>>>> On Saturday, September 10, 2016 at 6:21:26 AM UTC-6, J. Clarke wrote:
>>>>> In article <5ede8bfa-83c1-4d22-918c-02101c5b74b2@googlegroups.com>,
>>>>> jsavard@ecn.ab.ca says...
>>>>
>>>>>> (Telescopes only make stars brighter by making
>>>>>> them bigger - they can't make things brighter per unit area, it's
>>>>>> a law of optics.)
>>>>
>>>>> What law of optics would that be?
>>>>
>>>>> <makes popcorn>
>>>>
>>>> "Radiance is conserved through a loss-less optical system."
>>>>
>>>> Now, this applies to "things" you look at with your eye. You can make
>>>> a projected image brighter per unit area by using a bigger lens to
>>>> create the image, which is why you don't have to expose film for as
>>>> long with an f/1.4 lens as with an f/16 lens. But if you're looking
>>>> through a lens at an image, or looking at an image in a mirror, it
>>>> can't be brighter than the original.
>>>>
>>>> John Savard
>>>
>>> So by your logic Gran Canaris, Palomar, Wison, a pair of binoculars,
>>> and a pinhole all have the same limiting magnitude as the naked eye.
>>>
>>> What's wrong with this picture?
>>
>> You're looking at the wrong thing. The limit Quaddie is talking about is
>> how bright something can be made to look. It seems that an optical system
>> can't make something appear brighter than it does at zero range.
>>
>> I strongly suggest you take a look at this, which goes to a lot of
>> trouble to make the same point.
>>
>> http://what-if.xkcd.com/145/
>>
>> That said, I don't find it entirely convincing myself.
>
> I'm not even going to start on what's wrong with it.
>
> He's right that you can't make the surface of a star brighter from a
> hundred light years away than it is when you are sitting in its
> photosphere, but that's really not an argument that makes much practical
> sense.
>

Wasn't he talking about moonlight not starlight?

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#451058

On Saturday, September 10, 2016 at 10:47:38 AM UTC-6, J. Clarke wrote:

> He's right that you can't make the surface of a star brighter from a 
> hundred light years away than it is when you are sitting in its 
> photosphere, but that's really not an argument that makes much practical 
> sense.

But if one is pointing one's telescope at the *moon* - or at Jupiter - then it 
makes very much practical sense. I look at Jupiter in my telescope, and see 
colors; Jupiter is farther away from the Sun than the Moon, enough so that this 
would compensate for the Moon's lower albedo.

And it is that case about which there was a dispute.

John Savard

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#451062

In article <ec25c51b-fd01-4e27-b450-d3c203f25005@googlegroups.com>, 
jsavard@ecn.ab.ca says...
> 
> On Saturday, September 10, 2016 at 10:47:38 AM UTC-6, J. Clarke wrote:
> 
> > He's right that you can't make the surface of a star brighter from a 
> > hundred light years away than it is when you are sitting in its 
> > photosphere, but that's really not an argument that makes much practical 
> > sense.
> 
> But if one is pointing one's telescope at the *moon* - or at Jupiter - then it 
> makes very much practical sense. I look at Jupiter in my telescope, and see 
> colors; Jupiter is farther away from the Sun than the Moon, enough so that this 
> would compensate for the Moon's lower albedo.
> 
> And it is that case about which there was a dispute.

But why do you care about brightness when observing the Moon?  The moon 
gets more sunlight than Miami Beach, insufficient illumination is not in 
general an issue when observing the Moon.

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#451108

On Saturday, September 10, 2016 at 3:18:38 PM UTC-6, J. Clarke wrote:
 
> But why do you care about brightness when observing the Moon?  The moon 
> gets more sunlight than Miami Beach, insufficient illumination is not in 
> general an issue when observing the Moon.

Someone claimed that Rayleigh scattering makes the air blue, so that the Moon 
would look blue when you looked at it.

Then there was a reply to the effect that the Moon is so dim that we see it 
with night vision, and so the Moon *is* blue, but we can't see its blueness.

So I was replying to *half* of that nonsense - the derailment of the issue - by 
noting that, no, the Moon is quite bright enough to see its own color when we 
look *at* it, even if it's not bright enough to illuminate *other* things 
brilliantly enough to see their color.

The other half of that nonsense, though, I neglected until now.

Rayleigh scattering makes the sky blue by scattering sunlight *away* from the 
visible Sun itself in our sky to the *rest* of the sky.

And thus a harvest Moon, full and low on the horizon... is bright enough to 
trigger cones, and it looks _yellow_.

And with something brighter, where cones aren't the issue, we note twice each 
day what the Earth's atmosphere - when you are looking through an extra 
thickness of it at an object in the sky low on the horizon - does to its color.

https://www.youtube.com/watch?v=pp8GEytgdZA

John Savard

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#451151

Quadibloc <jsavard@ecn.ab.ca> wrote:
> On Saturday, September 10, 2016 at 3:18:38 PM UTC-6, J. Clarke wrote:
>
>> But why do you care about brightness when observing the Moon?  The moon
>> gets more sunlight than Miami Beach, insufficient illumination is not in
>> general an issue when observing the Moon.
>
> Someone claimed that Rayleigh scattering makes the air blue, so that the Moon
> would look blue when you looked at it.
>
> Then there was a reply to the effect that the Moon is so dim that we see it
> with night vision, and so the Moon *is* blue, but we can't see its blueness.
>
> So I was replying to *half* of that nonsense - the derailment of the issue - by
> noting that, no, the Moon is quite bright enough to see its own color when we
> look *at* it, even if it's not bright enough to illuminate *other* things
> brilliantly enough to see their color.
>
> The other half of that nonsense, though, I neglected until now.
>
> Rayleigh scattering makes the sky blue by scattering sunlight *away* from the
> visible Sun itself in our sky to the *rest* of the sky.
>
> And thus a harvest Moon, full and low on the horizon... is bright enough to
> trigger cones, and it looks _yellow_.
>
> And with something brighter, where cones aren't the issue, we note twice each
> day what the Earth's atmosphere - when you are looking through an extra
> thickness of it at an object in the sky low on the horizon - does to its color.
>
> https://www.youtube.com/watch?v=pp8GEytgdZA

Thank you for an interesting thread John. You won't get any argument
from me as it's been too long since my last classroom lecture on
Rayleigh scattering.

Under certain circumstances the moon appears blue during *daylight*
hours. Here's a photo of the moon from earlier today:

http://crcomp.net/Diary/BlueMoon/bluemoon.jpg

Thank you,

--
Don Kuenz KB7RPU

    The moon shines bright: in such a night as this... - Shakespeare

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#451056

On Saturday, 10 September 2016 16:29:14 UTC+1, Cryptoengineer  wrote:
> "J. Clarke" <j.clarke.873638@gmail.com> wrote in
> news:MPG.323de7732a83683098a536@news.eternal-september.org: 
> 
> > In article <eda510d3-4280-4eb6-bd52-a15721705a94@googlegroups.com>, 
> > jsavard@ecn.ab.ca says...
> >> 
> >> On Saturday, September 10, 2016 at 6:21:26 AM UTC-6, J. Clarke wrote:
> >> > In article <5ede8bfa-83c1-4d22-918c-02101c5b74b2@googlegroups.com>,
> >> > jsavard@ecn.ab.ca says...
> >> 
> >> > > (Telescopes only make stars brighter by making 
> >> > > them bigger - they can't make things brighter per unit area, it's
> >> > > a law of optics.)
> >> 
> >> > What law of optics would that be?
> >> 
> >> > <makes popcorn>
> >> 
> >> "Radiance is conserved through a loss-less optical system."
> >> 
> >> Now, this applies to "things" you look at with your eye. You can make
> >> a projected image brighter per unit area by using a bigger lens to
> >> create the image, which is why you don't have to expose film for as
> >> long with an f/1.4 lens as with an f/16 lens. But if you're looking
> >> through a lens at an image, or looking at an image in a mirror, it
> >> can't be brighter than the original. 
> >> 
> >> John Savard
> > 
> > So by your logic Gran Canaris, Palomar, Wison, a pair of binoculars,
> > and a pinhole all have the same limiting magnitude as the naked eye.
> > 
> > What's wrong with this picture?
> 
> You're looking at the wrong thing. The limit Quaddie is talking about is
> how bright something can be made to look. It seems that an optical system
> can't make something appear brighter than it does at zero range.
> 
> I strongly suggest you take a look at this, which goes to a lot of
> trouble to make the same point.
> 
> http://what-if.xkcd.com/145/
> 
> That said, I don't find it entirely convincing myself.

Arguing with Mister XKCD is tougher, though.

Before I clicked on the link, I was about to ask
the question myself - for those who haven't, it 
involves a /really/ big magnifying glass -

Presumably though if you take a large number 
of /mirrors/ outdoors, at night, - - ?

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#451049

On 9/10/2016 8:09 AM, Quadibloc wrote:
> On Saturday, September 10, 2016 at 6:21:26 AM UTC-6, J. Clarke wrote:
>> In article <5ede8bfa-83c1-4d22-918c-02101c5b74b2@googlegroups.com>,
>> jsavard@ecn.ab.ca says...
>
>>> (Telescopes only make stars brighter by making
>>> them bigger - they can't make things brighter per unit area, it's a law of
>>> optics.)
>
>> What law of optics would that be?
>
>> <makes popcorn>
>
> "Radiance is conserved through a loss-less optical system."
>
> Now, this applies to "things" you look at with your eye. You can make a
> projected image brighter per unit area by using a bigger lens to create the
> image, which is why you don't have to expose film for as long with an f/1.4
> lens as with an f/16 lens. But if you're looking through a lens at an image, or
> looking at an image in a mirror, it can't be brighter than the original.

It can't be brighter than the original _at point blank range_.  It can 
be significantly brighter than it is to the naked eye.

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#451011

Peter Trei <petertrei@gmail.com> wrote in
news:b4e086b0-f385-48ea-aa31-45adcf711ac3@googlegroups.com: 

> On Friday, September 9, 2016 at 1:29:19 PM UTC-4, Gutless
> Umbrella Carrying Sissy wrote: 
>> Quadibloc <jsavard@ecn.ab.ca> wrote in
>> news:b8149602-669b-4ede-9fde-81de10110859@googlegroups.com: 
>> 
>> > On Thursday, September 8, 2016 at 5:12:29 PM UTC-6, Jaimie
>> > Vandenbergh wrote: 
>> >> On Wed, 7 Sep 2016 19:05:33 -0700 (PDT), Robert Carnegie
>> >> <rja.carnegie@excite.com> wrote:
>> > 
>> >> >If air was naturally coloured blue then the moon would 
>> >> >appear blue.
>> >> 
>> >> It probably would, if the light at night wasn't generally
>> >> too faint to be triggering your retinal cones - the colour
>> >> receptors. It's only in the very brightest of full moons
>> >> that you can see any colour under moonlight at all. 
>> > 
>> > Except that the moon *itself* isn't illuminated by moonlight;
>> > it's illuminated by direct sunlight. Looking at a light
>> > source and looking at the objects it illuminates are two
>> > different things. 
>> > 
>> But in both cases, and all others, if the level of illumination
>> is too low to trigger the cones, you're still seeing in black
>> and white. 
>> 
>> In short, you didn't reply to what Jaimie said. At all.
>> 
>> (No surprises there, of course.)
> 
> I live in a dark area. On nights with a full moon, if the sky is
> clear, I can see some color by the moonlight - bright reds in
> particular. But even then the moon does not appear blue.

Well, the speculation was what color the moon would apepar *if* the 
air was blue.
> 
> The moon, at that point, is a hell of a lot brighter than
> (forex) traffic lights - it lights up the landscape, and I can
> see a long way. Traffic lights, though obviously colored, are a
> lot dimmer, but remain obviously colored.

The moon illuminates more because it is bigger. It is not brighter 
than traffic lights. If it were, traffic lights would be completely 
invisible in daylight. It is the difference between a point source 
and a big, bright source far away, whose light is dispersed across 
the landscape.
> 
> I have seen a blue moon, but by the usual method of there being
> distant forest fires spreading smoke.
> 
And, of course, an actual "blue moon," i.e., second new moon in a 
month.

-- 
Terry Austin

Tom "The Crap Man" Kratman is my bitch.

"Terry Austin: like the polio vaccine, only with more asshole."
    -- David Bilek

Jesus forgives sinners, not criminals.

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#451014

On Friday, September 9, 2016 at 5:33:50 PM UTC-4, Gutless Umbrella Carrying Sissy wrote:
> Peter Trei <petertrei@gmail.com> wrote in
> news:b4e086b0-f385-48ea-aa31-45adcf711ac3@googlegroups.com: 
> 
> > On Friday, September 9, 2016 at 1:29:19 PM UTC-4, Gutless
> > Umbrella Carrying Sissy wrote: 
> >> Quadibloc <jsavard@ecn.ab.ca> wrote in
> >> news:b8149602-669b-4ede-9fde-81de10110859@googlegroups.com: 
> >> 
> >> > On Thursday, September 8, 2016 at 5:12:29 PM UTC-6, Jaimie
> >> > Vandenbergh wrote: 
> >> >> On Wed, 7 Sep 2016 19:05:33 -0700 (PDT), Robert Carnegie
> >> >> <rja.carnegie@excite.com> wrote:
> >> > 
> >> >> >If air was naturally coloured blue then the moon would 
> >> >> >appear blue.
> >> >> 
> >> >> It probably would, if the light at night wasn't generally
> >> >> too faint to be triggering your retinal cones - the colour
> >> >> receptors. It's only in the very brightest of full moons
> >> >> that you can see any colour under moonlight at all. 
> >> > 
> >> > Except that the moon *itself* isn't illuminated by moonlight;
> >> > it's illuminated by direct sunlight. Looking at a light
> >> > source and looking at the objects it illuminates are two
> >> > different things. 
> >> > 
> >> But in both cases, and all others, if the level of illumination
> >> is too low to trigger the cones, you're still seeing in black
> >> and white. 
> >> 
> >> In short, you didn't reply to what Jaimie said. At all.
> >> 
> >> (No surprises there, of course.)
> > 
> > I live in a dark area. On nights with a full moon, if the sky is
> > clear, I can see some color by the moonlight - bright reds in
> > particular. But even then the moon does not appear blue.
> 
> Well, the speculation was what color the moon would apepar *if* the 
> air was blue.
> > 
> > The moon, at that point, is a hell of a lot brighter than
> > (forex) traffic lights - it lights up the landscape, and I can
> > see a long way. Traffic lights, though obviously colored, are a
> > lot dimmer, but remain obviously colored.
> 
> The moon illuminates more because it is bigger. It is not brighter 
> than traffic lights. If it were, traffic lights would be completely 
> invisible in daylight. It is the difference between a point source 
> and a big, bright source far away, whose light is dispersed across 
> the landscape.
> > 
> > I have seen a blue moon, but by the usual method of there being
> > distant forest fires spreading smoke.
> > 
> And, of course, an actual "blue moon," i.e., second new moon in a 
> month.
> 

I've _heard_ a Blue Moon...

"Bom ba ba bom ba bom ba bom bom ba ba bom ba ba bom ba ba dang a dang dang
Ba ba ding a dong ding...............Blue moon " - The Marcels
(gilding Rogers' and Hart's lily)

.. and I've drunk a Blue Moon.

But I've never seen a blue colored moon.

Kevin R

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#451016

Kevrob <kevrob@my-deja.com> wrote in
news:adb29484-7ebc-4bc0-bd44-42600059ec8b@googlegroups.com: 

> On Friday, September 9, 2016 at 5:33:50 PM UTC-4, Gutless
> Umbrella Carrying Sissy wrote: 
>> Peter Trei <petertrei@gmail.com> wrote in
>> news:b4e086b0-f385-48ea-aa31-45adcf711ac3@googlegroups.com: 
>> 
>> > On Friday, September 9, 2016 at 1:29:19 PM UTC-4, Gutless
>> > Umbrella Carrying Sissy wrote: 
>> >> Quadibloc <jsavard@ecn.ab.ca> wrote in
>> >> news:b8149602-669b-4ede-9fde-81de10110859@googlegroups.com: 
>> >> 
>> >> > On Thursday, September 8, 2016 at 5:12:29 PM UTC-6, Jaimie
>> >> > Vandenbergh wrote: 
>> >> >> On Wed, 7 Sep 2016 19:05:33 -0700 (PDT), Robert Carnegie
>> >> >> <rja.carnegie@excite.com> wrote:
>> >> > 
>> >> >> >If air was naturally coloured blue then the moon would 
>> >> >> >appear blue.
>> >> >> 
>> >> >> It probably would, if the light at night wasn't generally
>> >> >> too faint to be triggering your retinal cones - the
>> >> >> colour receptors. It's only in the very brightest of full
>> >> >> moons that you can see any colour under moonlight at all.
>> >> > 
>> >> > Except that the moon *itself* isn't illuminated by
>> >> > moonlight; it's illuminated by direct sunlight. Looking at
>> >> > a light source and looking at the objects it illuminates
>> >> > are two different things. 
>> >> > 
>> >> But in both cases, and all others, if the level of
>> >> illumination is too low to trigger the cones, you're still
>> >> seeing in black and white. 
>> >> 
>> >> In short, you didn't reply to what Jaimie said. At all.
>> >> 
>> >> (No surprises there, of course.)
>> > 
>> > I live in a dark area. On nights with a full moon, if the sky
>> > is clear, I can see some color by the moonlight - bright reds
>> > in particular. But even then the moon does not appear blue.
>> 
>> Well, the speculation was what color the moon would apepar *if*
>> the air was blue.
>> > 
>> > The moon, at that point, is a hell of a lot brighter than
>> > (forex) traffic lights - it lights up the landscape, and I
>> > can see a long way. Traffic lights, though obviously colored,
>> > are a lot dimmer, but remain obviously colored.
>> 
>> The moon illuminates more because it is bigger. It is not
>> brighter than traffic lights. If it were, traffic lights would
>> be completely invisible in daylight. It is the difference
>> between a point source and a big, bright source far away, whose
>> light is dispersed across the landscape.
>> > 
>> > I have seen a blue moon, but by the usual method of there
>> > being distant forest fires spreading smoke.
>> > 
>> And, of course, an actual "blue moon," i.e., second new moon in
>> a month.
>> 
> 
> I've _heard_ a Blue Moon...
> 
> "Bom ba ba bom ba bom ba bom bom ba ba bom ba ba bom ba ba dang
> a dang dang Ba ba ding a dong ding...............Blue moon " -
> The Marcels (gilding Rogers' and Hart's lily)
> 
> .. and I've drunk a Blue Moon.
> 
> But I've never seen a blue colored moon.
> 
Blue moons aren't blue. As noted above, it refers to the second new 
moon in the same month (at least where I come from - I have no idea 
if it's universal usage).

-- 
Terry Austin

Tom "The Crap Man" Kratman is my bitch.

"Terry Austin: like the polio vaccine, only with more asshole."
    -- David Bilek

Jesus forgives sinners, not criminals.

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