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From: rlofilho@gmail.com
Subject: Time correction to the HJD
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5 replies: 1 2 3 4 5
3 followups: 1 2 3

Private message: yes  no

Notes:

Notification:


Date: Fri, 20 Dec 2013 16:23:58 GMT
From: rlofilho@gmail.com
To: xmmhelp@sciops.esa.int
CC: rlofilho@gmail.com
Subject: Time correction to the HJD
Full_Name: Raimundo Lopes
Submission from: (NULL) (189.71.181.170)


Dear Colleague:

Is there some task on SAS, ftools, etc, to convert the XMM's time in seconds
(after have applied to it the barycen task) to HJD?

Thanks in advance,
 - Raimundo.


Reply 1

Resend
From: Pedro M. Rodriguez Pascual <xmmhelp@sciops.esa.int>
To: rlofilho@gmail.com
Subject: Re: Time correction to the HJD (PR#73411)
Date: Fri Dec 20 16:46:47 2013
Dear Raimundo,

Unfortunately, there is no such task in latest SAS13.5 release.

Sincerely,

Pedro

> Full_Name: Raimundo Lopes
> Submission from: (NULL) (189.71.181.170)
> 
> 
> Dear Colleague:
> 
> Is there some task on SAS, ftools, etc, to convert the XMM's time in
seconds
> (after have applied to it the barycen task) to HJD?
> 
> Thanks in advance,
>  - Raimundo.
> 
> 


Followup 1

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From: Raimundo Lopes <rlofilho@gmail.com>
Date: Fri, 20 Dec 2013 14:54:40 -0200
Subject: Re: Time correction to the HJD (PR#73411)
To: "Pedro M. Rodriguez Pascual" <xmmhelp@sciops.esa.int>
--047d7b41ccbcb3cb6104edfa247e
Content-Type: text/plain; charset=ISO-8859-1

Dear Pedro:

Thank you so much for your prompt reply.

In this case I suppose that the first step to do is - after to do the
barycen correction - change the initial time of a given light curve to JD
and the only task I know to do this is xTime. Next, change from JD to HJD.
Right?

Is there some recommendation of task to convert from JD to HJD, for
example, in Python?

Thanks again,
 - R.



2013/12/20 Pedro M. Rodriguez Pascual <xmmhelp@sciops.esa.int>

> Dear Raimundo,
>
> Unfortunately, there is no such task in latest SAS13.5 release.
>
> Sincerely,
>
> Pedro
>
> > Full_Name: Raimundo Lopes
> > Submission from: (NULL) (189.71.181.170)
> >
> >
> > Dear Colleague:
> >
> > Is there some task on SAS, ftools, etc, to convert the XMM's time in
> seconds
> > (after have applied to it the barycen task) to HJD?
> >
> > Thanks in advance,
> >  - Raimundo.
> >
> >
>
> This message and any attachments are intended for the use of the addressee
> or addressees only. The unauthorised disclosure, use, dissemination or
> copying (either in whole or in part) of its content is not permitted. If
> you received this message in error, please notify the sender and delete it
> from your system. Emails can be altered and their integrity cannot be
> guaranteed by the sender.
>
> Please consider the environment before printing this email.
>
>

--047d7b41ccbcb3cb6104edfa247e
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr">Dear
Pedro:<div><br></div><div>Thank you so much for your =
prompt reply.</div><div><br></div><div>In this
case I suppose that the firs=
t step to do is - after to do the barycen correction - change the initial t=
ime of a given light curve to JD and the only task I know to do this is xTi=
me. Next, change from JD to HJD. Right?=A0</div>

<div><br></div><div>Is there some recommendation of task
to convert from JD=
 to HJD, for example, in
Python?</div><div><br></div><div>Thanks
again,</di=
v><div>=A0-
R.</div><div><br></div></div><div
class=3D"gmail_extra"><br><br=
>

<div class=3D"gmail_quote">2013/12/20 Pedro M. Rodriguez Pascual <span
dir=
=3D"ltr">&lt;<a href=3D"mailto:xmmhelp@sciops.esa.int"
target=3D"_blank">xm=
mhelp@sciops.esa.int</a>&gt;</span><br><blockquote
class=3D"gmail_quote" st=
yle=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">

Dear Raimundo,<br>
<br>
Unfortunately, there is no such task in latest SAS13.5 release.<br>
<br>
Sincerely,<br>
<br>
Pedro<br>
<br>
&gt; Full_Name: Raimundo Lopes<br>
&gt; Submission from: (NULL) (189.71.181.170)<br>
&gt;<br>
&gt;<br>
&gt; Dear Colleague:<br>
&gt;<br>
&gt; Is there some task on SAS, ftools, etc, to convert the XMM&#39;s
time =
in seconds<br>
&gt; (after have applied to it the barycen task) to HJD?<br>
&gt;<br>
&gt; Thanks in advance,<br>
&gt; =A0- Raimundo.<br>
<div class=3D"HOEnZb"><div class=3D"h5">&gt;<br>
&gt;<br>
<br>
This message and any attachments are intended for the use of the addressee =
or addressees only. The unauthorised disclosure, use, dissemination or copy=
ing (either in whole or in part) of its content is not permitted. If you re=
ceived this message in error, please notify the sender and delete it from y=
our system. Emails can be altered and their integrity cannot be guaranteed =
by the sender.<br>


<br>
Please consider the environment before printing this email.<br>
<br>
</div></div></blockquote></div><br></div>

--047d7b41ccbcb3cb6104edfa247e--



Reply 2

Resend
From: Pedro M. Rodriguez Pascual <xmmhelp@sciops.esa.int>
To: rlofilho@gmail.com
Subject: Re: Time correction to the HJD (PR#73411)
Date: Fri Dec 20 17:21:28 2013
Dear Raimundo, 

Note that the conversion to TDB does not affect the actual time system in use,
i.e., all times keep being referred to the fixed mission reference time
1998-01-01T00:00:00 TT (1997-12-31T23-58-56.816 TAI)

Pedro



Followup 2

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Subject: Re: Time correction to the HJD (PR#73411)
From: rlofilho@gmail.com
Date: Sat, 21 Dec 2013 05:33:22 -0300
To: "Pedro M. Rodriguez Pascual" <xmmhelp@sciops.esa.int>
Dear Pedro:

Ok. But what is the proper way to convert the time from seconds in the XMM time
already corrected by the barycen task to HJD?

Cheers,
Raimundo.

On 20/12/2013, at 17:21, "Pedro M. Rodriguez Pascual"
<xmmhelp@sciops.esa.int> wrote:

> Dear Raimundo, 
> 
> Note that the conversion to TDB does not affect the actual time system in
use,
> i.e., all times keep being referred to the fixed mission reference time
> 1998-01-01T00:00:00 TT (1997-12-31T23-58-56.816 TAI)
> 
> Pedro
> 
> 
> 
> This message and any attachments are intended for the use of the addressee
or addressees only. The unauthorised disclosure, use, dissemination or copying
(either in whole or in part) of its content is not permitted. If you received
this message in error, please notify the sender and delete it from your system.
Emails can be altered and their integrity cannot be guaranteed by the sender.
> 
> Please consider the environment before printing this email.
> 



Reply 3

Resend
From: Pedro M. Rodriguez Pascual <xmmhelp@sciops.esa.int>
To: rlofilho@gmail.com
Subject: Re: Time correction to the HJD (PR#73411)
Date: Sat Dec 21 11:59:39 2013
Dear Raimundo,

XMM seconds correspond to seconds elapsed since 1998-01-01T00:00:00 TT  (== JD
2450814.4992687 UT). Although there are SAS internal functions for different
time conversion, there is not a public especific SAS task to do it. 

For practical purposes and after barycentric correction,

HJD(TDB)=XMMTIME(seconds)/86400+2450814.5000

note that for HJD in UTC system, the reference number for XMMTIME=0seconds is
245084.4992687 and the leapseconds introuced by the International Earth Rotation
and Reference Systems Service (IERS) should be properly included.

Pedro

> Dear Pedro:
> 
> Ok. But what is the proper way to convert the time from seconds in the XMM
time
> already corrected by the barycen task to HJD?
> 
> Cheers,
> Raimundo.
> 
> On 20/12/2013, at 17:21, "Pedro M. Rodriguez Pascual"
<xmmhelp@sciops.esa.int>
> wrote:
> 
>> Dear Raimundo, 
>> 
>> Note that the conversion to TDB does not affect the actual time system
in
use,
>> i.e., all times keep being referred to the fixed mission reference
time
>> 1998-01-01T00:00:00 TT (1997-12-31T23-58-56.816 TAI)
>> 
>> Pedro
>> 
>> 
>> 
>> This message and any attachments are intended for the use of the
addressee
or
> addressees only. The unauthorised disclosure, use, dissemination or
copying
> (either in whole or in part) of its content is not permitted. If you
received
> this message in error, please notify the sender and delete it from your
system.
> Emails can be altered and their integrity cannot be guaranteed by the
sender.
>> 
>> Please consider the environment before printing this email.
>> 
> 
> 


Followup 3

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From: Raimundo Lopes <rlofilho@gmail.com>
Date: Sat, 21 Dec 2013 10:42:48 -0200
Subject: Re: Time correction to the HJD (PR#73411)
To: "Pedro M. Rodriguez Pascual" <xmmhelp@sciops.esa.int>
--089e013c6fa0d4728604ee0abd6d
Content-Type: text/plain; charset=ISO-8859-1

Dear Pedro:

I am finishing a timing analysis in which the correction for HJD is crucial
and it has the potential to change all conclusions. So to be on the safe
side, please confirm:

from your response I understand that the HJD from the data in seconds which
were corrected by the barycen task *is equal* to the JD derived from the
data in seconds without correction by the barycen. Right?

Cheers,
 - Raimundo.


2013/12/21 Pedro M. Rodriguez Pascual <xmmhelp@sciops.esa.int>

> Dear Raimundo,
>
> XMM seconds correspond to seconds elapsed since 1998-01-01T00:00:00 TT
>  (== JD
> 2450814.4992687 UT). Although there are SAS internal functions for
> different
> time conversion, there is not a public especific SAS task to do it.
>
> For practical purposes and after barycentric correction,
>
> HJD(TDB)=XMMTIME(seconds)/86400+2450814.5000
>
> note that for HJD in UTC system, the reference number for XMMTIME=0seconds
> is
> 245084.4992687 and the leapseconds introuced by the International Earth
> Rotation
> and Reference Systems Service (IERS) should be properly included.
>
> Pedro
>
> > Dear Pedro:
> >
> > Ok. But what is the proper way to convert the time from seconds in the
> XMM
> time
> > already corrected by the barycen task to HJD?
> >
> > Cheers,
> > Raimundo.
> >
> > On 20/12/2013, at 17:21, "Pedro M. Rodriguez Pascual"
> <xmmhelp@sciops.esa.int>
> > wrote:
> >
> >> Dear Raimundo,
> >>
> >> Note that the conversion to TDB does not affect the actual time
system
> in
> use,
> >> i.e., all times keep being referred to the fixed mission reference
time
> >> 1998-01-01T00:00:00 TT (1997-12-31T23-58-56.816 TAI)
> >>
> >> Pedro
> >>
> >>
> >>
> >> This message and any attachments are intended for the use of the
> addressee
> or
> > addressees only. The unauthorised disclosure, use, dissemination or
> copying
> > (either in whole or in part) of its content is not permitted. If you
> received
> > this message in error, please notify the sender and delete it from
your
> system.
> > Emails can be altered and their integrity cannot be guaranteed by the
> sender.
> >>
> >> Please consider the environment before printing this email.
> >>
> >
> >
>
> This message and any attachments are intended for the use of the addressee
> or addressees only. The unauthorised disclosure, use, dissemination or
> copying (either in whole or in part) of its content is not permitted. If
> you received this message in error, please notify the sender and delete it
> from your system. Emails can be altered and their integrity cannot be
> guaranteed by the sender.
>
> Please consider the environment before printing this email.
>
>

--089e013c6fa0d4728604ee0abd6d
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr">Dear Pedro:<div><br></div><div>I
am finishing a timing ana=
lysis in which the correction for HJD is crucial and it has the potential t=
o change all conclusions. So to be on the safe side, please confirm:</div>

<div><br></div><div>from your response I understand that
the HJD from the d=
ata in seconds which were corrected by the barycen task <b><u>is
equal</u><=
/b> to the JD derived from the data in seconds without correction by the ba=
rycen. Right?</div>

<div><br></div><div>Cheers,</div><div>=A0-
Raimundo.</div></div><div class=
=3D"gmail_extra"><br><br><div
class=3D"gmail_quote">2013/12/21 Pedro M. Rod=
riguez Pascual <span dir=3D"ltr">&lt;<a
href=3D"mailto:xmmhelp@sciops.esa.i=
nt" target=3D"_blank">xmmhelp@sciops.esa.int</a>&gt;</span><br>

<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">Dear Raimundo,<br>
<br>
XMM seconds correspond to seconds elapsed since 1998-01-01T00:00:00 TT =A0(=
=3D=3D JD<br>
2450814.4992687 UT). Although there are SAS internal functions for differen=
t<br>
time conversion, there is not a public especific SAS task to do it.<br>
<br>
For practical purposes and after barycentric correction,<br>
<br>
HJD(TDB)=3DXMMTIME(seconds)/86400+2450814.5000<br>
<br>
note that for HJD in UTC system, the reference number for XMMTIME=3D0second=
s is<br>
245084.4992687 and the leapseconds introuced by the International Earth Rot=
ation<br>
and Reference Systems Service (IERS) should be properly includ

Message of length 7508 truncated


Reply 4

Resend
From: Pedro M. Rodriguez Pascual <xmmhelp@sciops.esa.int>
To: rlofilho@gmail.com
Subject: Re: Time correction to the HJD (PR#73411)
Date: Thu Dec 26 17:36:47 2013
Dear Raimundo, 

I am affraid that my responses are confusing rather than clarifying. My
apologies. 

By default, XMM times are referred to the center of the Earth (JD). After SAS
barycentric correction the times are referred to the barycenter of the Solar
System (BJD). As far as I understand, HJD are referred to the center of the Sun
and the difference with respect to BJD can be as large as several seconds.

In view of the critical role that the conversion to HJD plays into the results
of your analysis, your question is being forwarded to SAS developers for
confirmation that barycentric correction correctly uses the Solar System
Barycenter as reference location. 

Sincerely,

Pedro


> 
> Dear Pedro:
> 
> I am finishing a timing analysis in which the correction for HJD is
crucial
> and it has the potential to change all conclusions. So to be on the safe
> side, please confirm:
> 
> from your response I understand that the HJD from the data in seconds
which
> were corrected by the barycen task *is equal* to the JD derived from the
> data in seconds without correction by the barycen. Right?
> 
> Cheers,
>  - Raimundo.
> 
> 
> 2013/12/21 Pedro M. Rodriguez Pascual <xmmhelp@sciops.esa.int>
> 
>> Dear Raimundo,
>>
>> XMM seconds correspond to seconds elapsed since 1998-01-01T00:00:00 TT
>>  (== JD
>> 2450814.4992687 UT). Although there are SAS internal functions for
>> different
>> time conversion, there is not a public especific SAS task to do it.
>>
>> For practical purposes and after barycentric correction,
>>
>> HJD(TDB)=XMMTIME(seconds)/86400+2450814.5000
>>
>> note that for HJD in UTC system, the reference number for
XMMTIME=0seconds
>> is
>> 245084.4992687 and the leapseconds introuced by the International
Earth
>> Rotation
>> and Reference Systems Service (IERS) should be properly included.
>>
>> Pedro
>>
>> > Dear Pedro:
>> >
>> > Ok. But what is the proper way to convert the time from seconds in
the
>> XMM
>> time
>> > already corrected by the barycen task to HJD?
>> >
>> > Cheers,
>> > Raimundo.
>> >
>> > On 20/12/2013, at 17:21, "Pedro M. Rodriguez Pascual"
>> <xmmhelp@sciops.esa.int>
>> > wrote:
>> >
>> >> Dear Raimundo,
>> >>
>> >> Note that the conversion to TDB does not affect the actual
time system
>> in
>> use,
>> >> i.e., all times keep being referred to the fixed mission
reference time
>> >> 1998-01-01T00:00:00 TT (1997-12-31T23-58-56.816 TAI)
>> >>
>> >> Pedro
>> >>
>> >>
>> >>
>> >> This message and any attachments are intended for the use of
the
>> addressee
>> or
>> > addressees only. The unauthorised disclosure, use, dissemination
or
>> copying
>> > (either in whole or in part) of its content is not permitted. If
you
>> received
>> > this message in error, please notify the sender and delete it from
your
>> system.
>> > Emails can be altered and their integrity cannot be guaranteed by
the
>> sender.
>> >>
>> >> Please consider the environment before printing this email.
>> >>
>> >
>> >
>>
>> This message and any attachments are intended for the use of the
addressee
>> or addressees only. The unauthorised disclosure, use, dissemination or
>> copying (either in whole or in part) of its content is not permitted.
If
>> you received this message in error, please notify the sender and delete
it
>> from your system. Emails can be altered and their integrity cannot be
>> guaranteed by the sender.
>>
>> Please consider the environment before printing this email.
>>
>>
> 
> --089e013c6fa0d4728604ee0abd6d
> Content-Type: text/html; charset=ISO-8859-1
> Content-Transfer-Encoding: quoted-printable
> 
> <div dir=3D"ltr">Dear
Pedro:<div><br></div><div>I am finishing a timing ana=
> lysis in which the correction for HJD is crucial and it has the potential
t=
> o change all conclusions. So to be on the safe side, please
confirm:</div>
> 
> <div><br></div><div>from your response I understand
that the HJD from the d=
> ata in seconds which were corrected by the barycen task
<b><u>is equal</u><=
> /b> to the JD derived from the data in seconds without correction by the
ba=
> rycen. Right?</div>
> 
> <div><br></div><

Message of length 9004 truncated


Reply 5

Resend
From: Pedro M. Rodriguez Pascual <xmmhelp@sciops.esa.int>
To: rlofilho@gmail.com
Subject: Re: Time correction to the HJD (PR#73411)
Date: Thu Jan  2 10:02:17 2014
Dear Raimundo,

The barycen task converts times expressed in the local satellite frame (as
seconds since Mission Reference Time 1998-01-01T00:00:00 TT) to Barycentric
Dynamical Time (TDB) whose spatial origin lies at the solar system barycenter. 

Unfortunately, further conversion to Heliocentric Julian Date (HJD), whose
spatial origin is the center of the Sun, is not supported by the SAS system. 

Sincerely,

Pedro


> 
> Dear Pedro:
> 
> I am finishing a timing analysis in which the correction for HJD is
crucial
> and it has the potential to change all conclusions. So to be on the safe
> side, please confirm:
> 
> from your response I understand that the HJD from the data in seconds
which
> were corrected by the barycen task *is equal* to the JD derived from the
> data in seconds without correction by the barycen. Right?
> 
> Cheers,
>  - Raimundo.
> 
> 

Up to top level
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