A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Astronomy and Astrophysics » Amateur Astronomy
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Lat/Long and timekeeping system for Mars



 
 
Thread Tools Display Modes
  #31  
Old December 5th 18, 06:28 AM posted to sci.astro.amateur
Quadibloc
external usenet poster
 
Posts: 7,018
Default Lat/Long and timekeeping system for Mars

On Tuesday, December 4, 2018 at 11:39:31 AM UTC-7, Gerald Kelleher wrote:
I am sure the ISIS branch of astronomy would find 'sidereal vs solar'
convictions acceptable


We have not come to destroy, but to fulfill.

John Savard
  #32  
Old December 5th 18, 06:37 AM posted to sci.astro.amateur
Chris L Peterson
external usenet poster
 
Posts: 10,007
Default Lat/Long and timekeeping system for Mars

On Tue, 4 Dec 2018 21:27:54 -0800 (PST), Quadibloc
wrote:

But I'm talking about trying to be understood by people who are not astronomers.

And to ordinary people, a "day" is a unit of time between successive periods of
light or of dark, without rotation even entering into their thoughts.


I don't disagree. But the page you were complaining about was
specifically written to educate people about an astronomical concept!
  #33  
Old December 5th 18, 06:39 AM posted to sci.astro.amateur
Quadibloc
external usenet poster
 
Posts: 7,018
Default Lat/Long and timekeeping system for Mars

On Tuesday, December 4, 2018 at 10:37:17 PM UTC-7, Chris L Peterson wrote:

I don't disagree. But the page you were complaining about was
specifically written to educate people about an astronomical concept!


That's true. But if they *need* educating, then they aren't already educated when
they start reading it. So, in order that they can understand what the page says,
so they can learn something from it, it should be written in language that makes
sense to them.

John Savard
  #34  
Old December 5th 18, 08:18 AM posted to sci.astro.amateur
Gerald Kelleher
external usenet poster
 
Posts: 1,551
Default Lat/Long and timekeeping system for Mars

Mars will have its own distinct hours minutes and seconds values where the Equatorial speed will be 889.3 km per Martian hour just as the Earth's Equatorial speed is 1,669.8 km per Earth hour.

Only a small subculture prevents a system being applied to Mars and more importantly, the stranglehold of an RA/Dec system which by itself is fine for certain tasks but useless for timekeeping, planetary geometry and rotation just as it is for this planet.

"The application of a Timekeeper to this discovery is founded upon the
following principles: the earth's surface is divided into 360 equal
parts (by imaginary lines drawn from North to South) which are called
Degrees of Longitude; and its daily revolution Eastward round its own
axis is performed in 24 hours; consequently in that period, each of
those imaginary lines or degrees, becomes successively opposite to the
Sun (which makes the noon or precise middle of the day at each of
those degrees and it must follow, that from the time any one of
those lines passes the Sun, till the next passes, must be just four
minutes, for 24 hours being divided by 360 will give that quantity; so
that for every degree of Longitude we sail Westward, it will be noon
with us four minutes the later, and for every degree Eastward four
minutes the sooner, and so on in proportion for any greater or less
quantity. Now, the exact time of the day at the place where we are,
can be ascertained by well known and easy observations of the Sun if
visible for a few minutes at any time from his being ten degrees high
until within an hour of noon, or from an hour after noon until he is
only 10 degrees high in the afternoon; if therefore, at any time when
such observation is made, a Timekeeper tells us at the same moment
what o'clock it is at the place we sailed from, our Longitude is
clearly discovered." John Harrison



  #35  
Old December 5th 18, 08:43 AM posted to sci.astro.amateur
Paul Schlyter[_3_]
external usenet poster
 
Posts: 1,344
Default Lat/Long and timekeeping system for Mars

On Tue, 04 Dec 2018 13:03:36 -0500, Davoud wrote:
I must confess that I have never heard of a "sidereal hour;"


Then you haven't computed the local altitude or azimuth for a
celestial object either, or it's rise and set time. When doing so,
sidereal time is useful. When doing so for the Sun, you can avoid
sidereal time by using the Equation of Time instead.

https://en.wikipedia.org/wiki/Sidereal_time

Nowadays planetarium software takes care of these details for most
stargazers, who are happily unaware of the software's use of sidereal
time.


no such
interval exists in the Système international. An hour is an hour is

an
hour, 3600 seconds. It is the second that is the base unit of time

in
SI units, not the hour, which is too broad a brush.


True. Solar time does not exist in SI either. Only atomic time is
defined in the SI system of units.

And if you want to strictly follow SI, you should avoid using
minutes, hours, days, months, years and instead use KS, Ms, Gs, Ts,
etc etc.

One day = 86.4 ks
One year = ca 31.56 Ms
One human lifetime = ca 2.6 Gs
The age of the universe = ca 0.43 Ps

Sidereal and solar hours aren't the only non-SI units used by
astronomers. We also have the stellar magnitude (apparent, absolute
and bolometric) , the light year and the parsec, solar masses, Earth
masses and the Astronomical Unit. There are probably more non-SI
units used by astronomers.

What about giving a stars apparent brightness in nanolux instead of
its visual magnitude? Or it's absolute brightness in Petalumens? Or
it's bolometric brightness in PW? That's whar we would have to do if
we were to strictly use only SI units.
  #36  
Old December 5th 18, 09:04 AM posted to sci.astro.amateur
Gerald Kelleher
external usenet poster
 
Posts: 1,551
Default Lat/Long and timekeeping system for Mars

The system of equal hours,minutes and seconds is anchored in the creation of the 24 hour day which in turn is anchored to the noon cycle (day/night). The mean value relies on the mathematical principle that when different amounts are combined and divided equally they give an average or mean value, in this case what would be different hours,minutes and seconds for each noon cycle is reduced to an average or constant value.

The deficient observers launches into impressive values with multiples decimal places with first identifying where the 24 hour day comes from, what references are used and how it relates timekeeping to geometry/geography via longitude and Latitude.

To create a geostationary satellite system for Mars requires the planet have its own timekeeping system constructed around the planet's Lat/Long system and although the latter is easy enough to construct, the Martian hour is not.

Considering the hapless go out of their way to promote the idea that the Earth has more rotations than 24 hour days (day/night cycles) as their system demands it, there is every reason to put our planet's timekeeping evolution in historical and technical context.

  #37  
Old December 5th 18, 01:56 PM posted to sci.astro.amateur
Gerald Kelleher
external usenet poster
 
Posts: 1,551
Default Lat/Long and timekeeping system for Mars

On Wednesday, December 5, 2018 at 7:44:02 AM UTC, Paul Schlyter wrote:
On Tue, 04 Dec 2018 13:03:36 -0500, Davoud wrote:
I must confess that I have never heard of a "sidereal hour;"


Then you haven't computed the local altitude or azimuth for a
celestial object either, or it's rise and set time. When doing so,
sidereal time is useful. When doing so for the Sun, you can avoid
sidereal time by using the Equation of Time instead.

https://en.wikipedia.org/wiki/Sidereal_time


Even after two decades, it is remarkable how the hapless still try to justify a direct link between the planet's rotation with celestial sphere rotation and then attempt to paste in a 24 noon cycle as an afterthought.

The Lat/Long system for both the Earth and Mars is based on the average 24 hour noon cycle as no two cycles are alike. The background stars only form the basis of a calendar framework and even then it is strictly the transition from evening to morning appearance parallel to the orbital plane and minus celestial sphere rotation.

All this thread has shown is nobody is up to the job which correlates one Martian hour with 15 degrees of rotation for that planet, something a GPS system requires to make sense of location on the planet.



  #38  
Old December 5th 18, 03:40 PM posted to sci.astro.amateur
Quadibloc
external usenet poster
 
Posts: 7,018
Default Lat/Long and timekeeping system for Mars

On Wednesday, December 5, 2018 at 5:56:49 AM UTC-7, Gerald Kelleher wrote:

Even after two decades, it is remarkable how the hapless still try to justify a
direct link between the planet's rotation with celestial sphere rotation and
then attempt to paste in a 24 noon cycle as an afterthought.


The only thing that's remarkable is that even after two decades, you haven't
realized there's nothing wrong with this, and you're the one who is mistaken.

John Savard
  #39  
Old December 5th 18, 05:03 PM posted to sci.astro.amateur
Gerald Kelleher
external usenet poster
 
Posts: 1,551
Default Lat/Long and timekeeping system for Mars

Clearly the other contributors to this thread are neither mathematicians nor astronomers. The sample mean for variations in the natural noon cycle amount to 24 hours as each cycle when the Sun crosses the observer's meridian is not 24 hours.

https://en.wikipedia.org/wiki/Arithmetic_mean

The average 24 hour day for Mars will also be derived from the same inequalities in the natural noon cycle but a Martian hour, Martian minute and Martian second within that average will be entirely different yet will mesh with the planet's 360 degree Latitude and Longitude system organised around the planet's Equator. This will be the structure of a GPS system for vehicles on Mars or other purposes.

You guys continue with theoretical stuff that nobody can admire but this great endeavour is for those who actually appreciate how the system on Earth was put together.

  #40  
Old December 5th 18, 07:00 PM posted to sci.astro.amateur
Davoud[_1_]
external usenet poster
 
Posts: 1,989
Default Lat/Long and timekeeping system for Mars

Davoud:
I must confess that I have never heard of a "sidereal hour;"


Paul Schlyter:
Then you haven't computed the local altitude or azimuth for a
celestial object either, or it's rise and set time. When doing so,
sidereal time is useful. When doing so for the Sun, you can avoid
sidereal time by using the Equation of Time instead.

https://en.wikipedia.org/wiki/Sidereal_time

Nowadays planetarium software takes care of these details for most
stargazers, who are happily unaware of the software's use of sidereal
time.


I have done all of that. Perhaps I used the wrong nomenclature?
Sidereal Hour Angle. I am happily aware of TheSkyX Pro's use of
sidereal time, but I am also happy to let TheSkyX Pro take care of the
math while I enjoy the view.*

no such interval exists in the Système international...
It is the second that is the base unit of time
in SI units, not the hour, which is too broad a brush.


And if you want to strictly follow SI, you should avoid using
minutes, hours, days, months, years and instead use KS, Ms, Gs, Ts,
etc etc.

One day = 86.4 ks
One year = ca 31.56 Ms
One human lifetime = ca 2.6 Gs
The age of the universe = ca 0.43 Ps


In this case I interpret "strictly" as "dogmatically" I can't bring
myself to tell my neighbor "I'm taking a short vacation; I'll be back
in about 604.8 ks."

*Figuratively speaking. Due to macular degeneration I do not look
through telescopes any more. I can still focus on a laptop display,
however https://www.flickr.com/photos/primeval/30364292358,
https://www.flickr.com/photos/primeval/29296501697.

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Timekeeping architecture oriel36[_2_] Amateur Astronomy 7 February 25th 14 12:27 PM
Lat/Long and AM/PM system for Mars oriel36[_2_] Amateur Astronomy 0 August 15th 12 04:59 PM
Timekeeping in Genesis oriel36[_2_] Amateur Astronomy 2 November 11th 11 08:38 PM
Long socks and pride, marching in the boardwalk, Ceausescu's private police, system, Boogle-bush gb6726 Astronomy Misc 31 October 22nd 07 07:04 AM
Looking for software compute lat and long of features on solar system bodies canopus56 Amateur Astronomy 2 August 20th 06 06:04 PM


All times are GMT +1. The time now is 05:46 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.