Viewing Misc/10124
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Notification:

Date: Thu, 05 Feb 2004 13:53:54 -0600
To: xmmhelp@xmm.vilspa.esa.es
From: Mel Ulmer <m-ulmer2@northwestern.edu>
Subject: time

HI,

I have data with a time stamp of 171762597.071947, can you tell me please 
the Julian day conversion and/or how to get from there to a a UT and date?

I tried taking the begin time of the space craft (1999 Dec) and subtracting 
that in days from my observation date (2003 Oct). but I didn't get close, 
even after converting the time difference to seconds. It seems the clock 
time zero started about 1997 in May. But maybe I should be assuming the 
units are in seconds in the first place.

Thanks in advance,

Regards,

Mel Ulmer 

Reply 1

From: Norbert Schartel <xmmhelp@xmm.vilspa.esa.es>
To: m-ulmer2@northwestern.edu
Subject: Re: time (PR#10124)
Date: Fri Feb  6 10:19:49 2004

Dear Mel,

the time stamp are seconds since
1997-12-31:23:58:56.816.

The stamp you are giving corresponds
to 2003-06-11T23:48:44

With best regards
Norbert

Followup 1

Date: Fri, 6 Feb 2004 07:02:53 -0600 (CST)
From: Mel Ulmer <ulmer@marie.astro.northwestern.edu>
To: Norbert Schartel <xmmhelp@xmm.vilspa.esa.es>
Subject: Re: time (PR#10124)

Dear Norbert,

Thanks very much.

Regards,

Mel
On Fri, 6 Feb 2004, Norbert Schartel wrote:

> Dear Mel,
> 
> the time stamp are seconds since
> 1997-12-31:23:58:56.816.
> 
> The stamp you are giving corresponds
> to 2003-06-11T23:48:44
> 
> With best regards
> Norbert
> 

-- 
========================================================================
Mel Ulmer              mailing address: Prof. Melville P. Ulmer
mailto:m-ulmer2@northwestern.edu        Dept. of Physics & Astronomy
voice 847-491-5633                      Dearborn Observatory
fax 847 491 3135                        2131 Tech Drive
secretary phones 491-7650               Northwestern University
                 491-3685               Evanston, IL 60208-2900
www.astro.northwestern.edu/~ulmer/
========================================================================

Followup 2

Date: Fri, 6 Feb 2004 07:58:11 -0600 (CST)
From: Mel Ulmer <ulmer@marie.astro.northwestern.edu>
To: Norbert Schartel <xmmhelp@xmm.vilspa.esa.es>
Subject: Re: time (PR#10124)

Dear Norbert,

If I take your time stamp and then convert to number of seconds since the 
time stamp , I get the time should have been
 
2003,06,11,23:48:53.88 to yield 171762597.071947 (acutally with my juilan
day converter in IDL etc the closest I could get due to round off error
was 171762597.0719486474990845); the calculation I did was
(julian1-julian)*3600.d0*24.

Where julian1 = the julian day of the observation
(2452802.4922903566621244) and julian = the julian day of the time stamp
(2450814.4992686905898154).
 
Did I do something wrong? I'm off by about 9 seconds.
 
Regards,

Mel
> Dear Mel,
> 
> the time stamp are seconds since
> 1997-12-31:23:58:56.816.
> 
> The stamp you are giving corresponds
> to 2003-06-11T23:48:44
> 
> With best regards
> Norbert
> 

-- 
========================================================================
Mel Ulmer              mailing address: Prof. Melville P. Ulmer
mailto:m-ulmer2@northwestern.edu        Dept. of Physics & Astronomy
voice 847-491-5633                      Dearborn Observatory
fax 847 491 3135                        2131 Tech Drive
secretary phones 491-7650               Northwestern University
                 491-3685               Evanston, IL 60208-2900
www.astro.northwestern.edu/~ulmer/
========================================================================

Reply 2

From: Norbert Schartel <xmmhelp@xmm.vilspa.esa.es>
To: m-ulmer2@northwestern.edu
Subject: Re: time (PR#10124)
Date: Fri Feb  6 16:08:21 2004

Dear Mel,

sorry, I can not reproduced what I did
to calculate the time which I sent in
the previous message. Re-doing it, I 
came to exactly the same time which
you are giving in your last e-mail.

With best regards
Norbert