Zetas RIGHT Again!
In Article <3BEDF805.D434C2E8@home.com> Jim wrote:
> One way to try to make Zetatalk RIGHT (wouldn't
> that be unusual) is to change it.
And one way to try to make ZetaTalk WRONG is to confuse the issue! As
in the magnification discussion which went on endlessly here on
sci.astro during April through the end of May, and again in September,
during which is became evident that there are SEVERAL ways to measure
magnitude, while the hard line ZetaTalk bashers were claiming and
insisting there were only ONE. See next post for the Zeta argument
against all this DOUBLE STANDARD.
In Article <3mdL6.firstname.lastname@example.org>
> Why all the BS about the difference between ABSOLUTE
> magnitude and APPARENT magnitude? Our own sun has an
> ABSOLUTE magnitude of +4.85 (if viewed from 10
> parsecs distance from earth, standard definition).
In Article <3B12E9D8.BD3AC493@zetatalk.com> Nancy Lieder wrote:
> Magnus Nyborg wrote:
>> In Article <3B1261B3.90C0B686@zetatalk.com> Nancy Lieder wrote:
>>> given that the Sun is considered to be magnitude 4.85
>> You are only about 32.85 magnitudes off, with the Sun
>> actually being magnitude -28, a factor of almost 14000
>> billion times... close, but no cigar!
> Gee, S. Welknelk stated it was 4.85, and no one objected.
> Can we all get on the same page here?
In Article <3B129F2B.EAB48C90@navix.net> David Knisely wrote:
> Absolute Magnitude is defined as the magnitude a
> light-emitting object would show if it were 10 parsecs
> (32.6 light years) away from the observer. The only
> solar-system object which would be visible at 10 parsecs
> (at least to the eye) would be the sun, and it would be
> magnitude 4.82 at that distance. Some comets or
> asteroids can be given a sort of "1-AU" magnitude
> (the brightness as seen at 1 astronomical unit away
> from the sun and the observer), but the term Absolute
> Magnitude is generally reserved for the 10 parsec
In Article <3B3C7FC6.8F9E57@zetatalk.com> Nancy Lieder wrote:
> there are SEVERAL types of magnitudes,
> depending upon how close an object is - absolute
> (10 parsecs away), apparent (closer), apparent
> heliocentric (within the solar system), and
> some others yet I think.
In Article <3B812097.336950E3@zetatalk.com> Nancy Lieder wrote:
> Michael L Cunningham wrote:
>>> The thing I don't understand is why M31 (with a 3.7
>>> Magnitude) is not visible to the naked eye? Stars with
>>> this magnitude are very bright.
>> It's called "surface brightness" and the total magnitude
>> is equivalent to its light coming from a point source
>> such as a single star. ... Since M31 is spread out over
>> a full half degree of area (full moon covers a half
>> degree of sky) it is actually much fainter without
>> optical aid than a 3.7 magnitude point source.
In Article <email@example.com> Bob Officer wrote:
> Use a little averted vision and There it [M31} is...
> Faint, but it is there.
Bill Nelson wrote:
> if a point source is spread over two pixels on a CCD,
> where it would normally hit only one - you have just
> lost over a magnitude of detectability.
In Article <96wj7.3135$W52.firstname.lastname@example.org> Greg Neill wrote:
> Stars don't shine from their centers. They shine from their
> *diffuse* (to use your term) photosphere, surrounding their
> entire bulk. ... Diffuse objects are indistinguishible from
> "sharp" objects at any distance that renders them effective
> point sources.