As for not being very smart…join the club. I’m to the point where I wear slip-on shoes because the ones you tie are too confusing. The wife checks each morning to make sure I have the correct shoe on the correct foot. She does come in handy. Dave On Sep 5, 2014, at 17:07, Ryan Simpkins <astro@ryansimpkins.com> wrote:
I am not very smart...
Is the answer because it is easier not having to deal with negative degrees? Subtracting relative degrees from 180 will never get you in to negative territory like subtracting from 0 will. By basing all relative calculations from 180 you can't ever get in to those situations (unless you start spinning in circles I suppose). It also means you don't have to be worried about 0 being equal to 360 except in the case when it is.
How this makes trigonometry easier I have no clue. Trigonometry is already in the 'super-advanced' category in my opinion. I don't think there is a way to make it easier other than to avoid it entirely... Which I gather might be a problem if you want to launch a rocket or change orbits.
-Ryan
On Fri, September 5, 2014 13:13, Chuck Hards wrote:
Schooled!
;-)
On Fri, Sep 5, 2014 at 12:55 PM, daniel turner via Utah-Astronomy < utah-astronomy@mailman.xmission.com> wrote:
It's for a very good reason. Astronomers and surveyors who actually do the trigonometry that converts RA/DEC coordinates to ALT/AZ have found that pointing zero to the south makes for a much easier math conversion. So the South as zero has been a convention for these "hard core" science types for a very long time.
Another example is Seiichi Yoshida's excellent comet website.
http://www.aerith.net/comet/weekly/current.html
But of course this frightens some of the supposed gatekeepers of knowledge who insist on rigid conformity and relentless dumbing down. Like in our reoccurring debates about kilometers and kilograms
it's just a colorful fact of life. It won't hurt you and if you ever try to "do the math" with celestial coordinates, you will quickly see why it's done that way.
And you will be running with the big dogs.
DT
BTW, for some reason (can anyone here explain?) MPC's idea of azimuth is 180 degrees off what I think most of us use. So subtract 180 for the azimuth numbers listed to get ones most of us are more used to (i.e. where is says 330, subtract 180 to get 150 in the SE).
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