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 wrote:

> Ha! As soon as I can get it online, we will have a NavList-specific 
> version of "bbcode" available. So you'll be able to add most any sort 
> of formatting you like including professional-looking LaTeX equations. 

Hot dang! The NavList is being dragged (hopefully not kicking and screaming..  
;-)) into the 21st century. Huge thanks for that. :-)

> Meanwhile, somebody please send Paul Hirose a plain vanilla email and 
> explain to him that filtering out all messages with HTML in them is 
> pointless. 

Been there, done that with other lists that I've either moderated or helped to 
moderate. For some weird reason, some people are adamantly opposed to HTML of 
any form in e-mail (some even go so far to promote a "blue-ribbon campaign" 
against it). Getting them all on-board (and dragged into the "modern age") 
might be a bit problematic, but good luck with that one.

> These alternate views are NORMAL in email in the year 2009

100% correct.

> I should get paid for this.

You should, but we probably couldn't afford you....  ;-)

--
GregR



--- On Tue, 12/15/09, frankreed@HistoricalAtlas.com  wrote:

> From: frankreed@HistoricalAtlas.com 
> Subject: Re: [NavList 11184] Re: Historical Lunars : take in account 'delta-T'  or ignore it ?
> To: NavList@fer3.com
> Date: Tuesday, December 15, 2009, 6:42 PM
> Antoine, you wrote:
> "To recap, lower and lower altitude refraction random
> errors do render Lunar distances more and more inaccurate
> .... So, why should we bother with the (subtle ?)
> distinction between the Great Circle joining the refracted
> centers and the shortest Great Circle joining refracted
> limbs ? Well, this still remains an interesting subject to
> study and play with ..."There's a
> calculation of this in one of the old 19th century nautical
> astronomy textbooks. I can't recall exactly where right
> now but it's probably Chauvenet. It's an exceedingly
> small correction (note for anyone following along: this is
> NOT the correction for refractional flattening but a more
> subtle alignment issue). The next largest correction that we
> do not take into account in lunars calculations done by the
> standard methods is the correction for the actual shape of
> the Moon's limb. There are mountain ranges and impact
> basins along the limb that change the diameter by as much as
> a couple of seconds of arc. These are just below the
> 0.1' threshold so they can be ignored except if
> we're trying for that next step in accuracy. The lunar
> limb's outline varies with time due to the lunar
> librations. This is all calculable...You wrote:
> "A possible explanation for the
> "discrepancy" you mentioned between the NAL and
> AAL refraction values might come from the fact that AAL
> values are given for a single given CONSTANT wavelenght,
> while NAL gives values for the observed average wavelenghts
> - i.e. INCREASING WAVELENGHTS when heights decrease - since
> all bodies apparent colors start moving towards
> "red" when height decrease. This MIGHT be a
> resonable explanation. Any other explanations from NavList
> Members ?"That's an interesting idea, but
> there are plenty of other possibilities. But the point you
> make here is important. Refraction varies with wavelength,
> and all common celestial objects have spectra which are
> nearly flat in the visible spectrum, even when they're
> low in the sky and reddened by scattering. There's still
> plenty of blue in the solar spectrum when the Sun is low.
> Likewise for the Moon (the lunar spectrum, of course, looks
> just like the solar spectrum, complete with all the
> absorption lines, since its light is reflected sunlight).
> Since refraction varies with wavelength, astronomical
> objects are "smeared" into little "French
> flags" (and yes, that's how we describe it over
> here, too): blue at the top, more or less white in the
> middle and red at the bottom. This is a physical
> "smearing" of the apparent position of an
> astronomical object, and no amount of calculation or
> clearing can eliminate it. That's the real problem with
> shooting sights at extremely low altitudes from, say, 3 to 6
> degrees. The refraction tables are reliable in that range.
> But they apply only to one color in the objects'
> extended images (below 3 degrees, the refraction is variable
> depending on the structure of the atmospheric layers and
> should not be trusted to better than half a minute of
> arc).And you added, regarding special signs and
> formatting:
> "Sorry about that ... But maybe should I (we ???)
> harshly complain to our Forum Moderator ... ( Silence on
> board !, don't let him know for now !!! )
> :-)))"Ha! As soon as I can get it online, we
> will have a NavList-specific version of "bbcode"
> available. So you'll be able to add most any sort of
> formatting you like including professional-looking LaTeX
> equations. Which would you like first: threaded message
> views? Or nicely formatted messages with beautiful inline
> equations?-FER
> PS: Meanwhile, somebody please send Paul Hirose a plain
> vanilla email and explain to him that filtering out all
> messages with HTML in them is pointless. About half of
> NavList messages now include "plain text" and
> "html text" alternate views which means he's
> trashing about half of the message traffic. These alternate
> views are NORMAL in email in the year 2009, and the
> percentages are probably much higher in all email.
> Furthermore, the vast majority of email senders have no idea
> that they are sending an html view nor do they have any idea
> how to turn it off, if it's even possible in their email
> setup. It is possibly reasonable to filter out messages that
> include ONLY an html view and in fact most spam filters add
> a couple of points to their spam tally when they find a
> message with no plain text view at all.I should get
> paid for this. 
> 
> 
> 
> -- 
> 
> NavList message boards: www.fer3.com/arc
> 
> Or post by email to: NavList@fer3.com
> 
> To , email
> NavList+@fer3.com

-- 
NavList message boards: www.fer3.com/arc
Or post by email to: NavList@fer3.com
To , email NavList+@fer3.com

   

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