Javascript Ephemeris

For those who use or have copied my ephemeris pages I've made a small
correction so it gets daylight saving time right for those states of the
USA that use it. Most places change on the last Sunday of the month but
America decided to be different.

Pete H

http://www.aphayes.pwp.blueyonder.co...ris/index.html

In article ,
Peter Hayes wrote:
For those who use or have copied my ephemeris pages I've made a small
correction so it gets daylight saving time right for those states of the
USA that use it. Most places change on the last Sunday of the month but
America decided to be different.

Pete H

http://www.aphayes.pwp.blueyonder.co...ris/index.html

Perhaps you could correct your ephemeris pages further, so that you
give RA and Decl to approximately the same accuracy? As your Javascript
ephemeris is now, you give the declination some ten times more accurate
than the accuracy of the RA you give.

Yes, I know it's a common error - people seem to fail to realize that
one minute of time (in RA) is really the same as 15 minutes of arc.

--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stjarnhimlen dot se
WWW: http://stjarnhimlen.se/

In uk.sci.astronomy message , Wed, 11
Mar 2009 21:54:14, Peter Hayes posted:
For those who use or have copied my ephemeris pages I've made a small
correction so it gets daylight saving time right for those states of
the USA that use it. Most places change on the last Sunday of the month
but America decided to be different.


My Web site includes JavaScript which, given the TZ string for a place,
will convert between GMT and local time. Also Delphi. It does M-type
rules, and perhaps J-type.

Almost all places with Summer Time use M-type rules. Mauritius and
Morocco may have J-type Summer Time rules. Iran is incompatible, being
non-Gregorian J-type. The Israeli Summer Time Rules currently (2008)
defeat the code, as neither start nor finish is TZ-compatible ; but
a Rule can be written for each individual year. There may be other
exceptions.

URL:http://www.merlyn.demon.co.uk/js-date5.htm & js-date2.htm .

--
(c) John Stockton, nr London UK. IE7 FF3 Op9 Sf3
news:comp.lang.javascript FAQ URL:http://www.jibbering.com/faq/index.html.
URL:http://www.merlyn.demon.co.uk/js-index.htm jscr maths, dates, sources.
URL:http://www.merlyn.demon.co.uk/ TP/BP/Delphi/jscr/&c, FAQ items, links.

Paul Schlyter wrote:
In article ,
Peter Hayes wrote:
For those who use or have copied my ephemeris pages I've made a small
correction so it gets daylight saving time right for those states of the
USA that use it. Most places change on the last Sunday of the month but
America decided to be different.

Pete H

http://www.aphayes.pwp.blueyonder.co...ris/index.html

Perhaps you could correct your ephemeris pages further, so that you
give RA and Decl to approximately the same accuracy? As your Javascript
ephemeris is now, you give the declination some ten times more accurate
than the accuracy of the RA you give.

Yes, I know it's a common error - people seem to fail to realize that
one minute of time (in RA) is really the same as 15 minutes of arc.


Hi Paul, thanks for your web pages that inspired some of my code. Of
course you are right. I'll add it to the to do list for when it's quiet
at work; the advantage of doing super computer support is there are long
quiet times interspersed with 'what the F is going on' periods ;)

Pete

In article ,
Peter Hayes wrote:
Paul Schlyter wrote:
In article ,
Peter Hayes wrote:
For those who use or have copied my ephemeris pages I've made a small
correction so it gets daylight saving time right for those states of the
USA that use it. Most places change on the last Sunday of the month but
America decided to be different.

Pete H

http://www.aphayes.pwp.blueyonder.co...ris/index.html

Perhaps you could correct your ephemeris pages further, so that you
give RA and Decl to approximately the same accuracy? As your Javascript
ephemeris is now, you give the declination some ten times more accurate
than the accuracy of the RA you give.

Yes, I know it's a common error - people seem to fail to realize that
one minute of time (in RA) is really the same as 15 minutes of arc.


Hi Paul, thanks for your web pages that inspired some of my code. Of
course you are right. I'll add it to the to do list for when it's quiet
at work; the advantage of doing super computer support is there are long
quiet times interspersed with 'what the F is going on' periods ;)

Pete

Regarding supercomputes: today's laptops are more powerful than the
supercomputers of the late 1970's, e.g. the Cray-1 ....

--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stjarnhimlen dot se
WWW: http://stjarnhimlen.se/

Paul Schlyter wrote:
In article ,
Peter Hayes wrote:



Hi Paul, thanks for your web pages that inspired some of my code. Of
course you are right. I'll add it to the to do list for when it's quiet
at work; the advantage of doing super computer support is there are long
quiet times interspersed with 'what the F is going on' periods ;)

Pete

Regarding supercomputes: today's laptops are more powerful than the
supercomputers of the late 1970's, e.g. the Cray-1 ....

I worked on serial 1 the original Cray for a time. We used to call it
the 'Cray on wheels' because it went to so many sites as a temporary
measure whilst the customers machine was being built. There's a picture
on my home page, I'm the one standing on the left, now looking a lot
older and not wearing that horribly dated tie. There's probably more
memory in the average in car computer than serial 1 had ;(

Pete H

In article ,
Peter Hayes wrote:
Paul Schlyter wrote:
In article ,
Peter Hayes wrote:



Hi Paul, thanks for your web pages that inspired some of my code. Of
course you are right. I'll add it to the to do list for when it's quiet
at work; the advantage of doing super computer support is there are long
quiet times interspersed with 'what the F is going on' periods ;)

Pete

Regarding supercomputes: today's laptops are more powerful than the
supercomputers of the late 1970's, e.g. the Cray-1 ....

I worked on serial 1 the original Cray for a time. We used to call it
the 'Cray on wheels' because it went to so many sites as a temporary
measure whilst the customers machine was being built. There's a picture
on my home page, I'm the one standing on the left, now looking a lot
older and not wearing that horribly dated tie. There's probably more
memory in the average in car computer than serial 1 had ;(

Pete H

Yup, there it is! The world's most expensive sofa.... :-)


--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stjarnhimlen dot se
WWW: http://stjarnhimlen.se/

Paul Schlyter wrote:
In article ,
Peter Hayes wrote:
For those who use or have copied my ephemeris pages I've made a small
correction so it gets daylight saving time right for those states of the
USA that use it. Most places change on the last Sunday of the month but
America decided to be different.

Pete H

http://www.aphayes.pwp.blueyonder.co...ris/index.html

Perhaps you could correct your ephemeris pages further, so that you
give RA and Decl to approximately the same accuracy? As your Javascript
ephemeris is now, you give the declination some ten times more accurate
than the accuracy of the RA you give.

Yes, I know it's a common error - people seem to fail to realize that
one minute of time (in RA) is really the same as 15 minutes of arc.

Fixed, the code now prints minutes of RA as mm.m I've also added
references to your planetary web pages for the gravitational
perturbations between the outer planets. I'm not planning to add the
corrections any time soon but a least users know of the potential errors.

Pete H

In article ,
Peter Hayes wrote:
Paul Schlyter wrote:
In article ,
Peter Hayes wrote:
For those who use or have copied my ephemeris pages I've made a small
correction so it gets daylight saving time right for those states of the
USA that use it. Most places change on the last Sunday of the month but
America decided to be different.

Pete H

http://www.aphayes.pwp.blueyonder.co...ris/index.html

Perhaps you could correct your ephemeris pages further, so that you
give RA and Decl to approximately the same accuracy? As your Javascript
ephemeris is now, you give the declination some ten times more accurate
than the accuracy of the RA you give.

Yes, I know it's a common error - people seem to fail to realize that
one minute of time (in RA) is really the same as 15 minutes of arc.

Fixed, the code now prints minutes of RA as mm.m I've also added
references to your planetary web pages for the gravitational
perturbations between the outer planets. I'm not planning to add the
corrections any time soon but a least users know of the potential errors.

Pete H

Great!

But you forgot the Moon - its RA is still displayed as hh:mm



--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stjarnhimlen dot se
WWW: http://stjarnhimlen.se/

Paul Schlyter wrote:
In article ,
Peter Hayes wrote:
Paul Schlyter wrote:
In article ,
Peter Hayes wrote:
For those who use or have copied my ephemeris pages I've made a small
correction so it gets daylight saving time right for those states of the
USA that use it. Most places change on the last Sunday of the month but
America decided to be different.

Pete H

http://www.aphayes.pwp.blueyonder.co...ris/index.html
Perhaps you could correct your ephemeris pages further, so that you
give RA and Decl to approximately the same accuracy? As your Javascript
ephemeris is now, you give the declination some ten times more accurate
than the accuracy of the RA you give.

Yes, I know it's a common error - people seem to fail to realize that
one minute of time (in RA) is really the same as 15 minutes of arc.

Fixed, the code now prints minutes of RA as mm.m I've also added
references to your planetary web pages for the gravitational
perturbations between the outer planets. I'm not planning to add the
corrections any time soon but a least users know of the potential errors.

Pete H

Great!

But you forgot the Moon - its RA is still displayed as hh:mm


OK tomorrow, some of this code is 5 years old and I'm in the over 60
memory failing zone ;(