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From: nathansecrest@msn.com
Subject: Astrometry questions
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2 followups: 1 2

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Date: Tue, 23 Jul 2013 01:40:57 GMT
From: nathansecrest@msn.com
To: xmmhelp@sciops.esa.int
Cc: nathansecrest@msn.com
Subject: Astrometry questions
Full_Name: Nathan Secrest
Submission from: (NULL) (72.75.68.182)


Hello,

I am confused about the astrometric accuracy of my XMM-Newton MOS/PN data.  The
OM data header says that 'POSCOROK' = T, but by comparing my data to SDSS
images, it appears that there is a systematic offset between the X-ray sources
and candidate SDSS sources, of about 5 arcseconds.  I carefully examined my data
headers, but I could not find any information about an astrometric correction
being applied.  

Most of the material I find online seems to apply to astrometric correction of
the OM data, but I have not been able to find anything about confirming the
astrometry of my MOS/PN data. 

Thanks,

Nathan Secrest


Reply 1

Resend
From: Ignacio de la Calle <xmmhelp@sciops.esa.int>
To: nathansecrest@msn.com
Subject: Re: Astrometry questions (PR#52546)
Date: Tue Jul 23 15:46:18 2013
Dear Nathan,

I will get a more detailed answer to you tomorrow, but the short answer to
your question is that you should install SAS 13 where there has been a lot 
of improvement in astrometric corrections, and the errors you comment have
been reduced to the order of 1 arcsec.

Regards,

Ignacio de la Calle
XMM-Newton SOC


> Hello,
> 
> I am confused about the astrometric accuracy of my XMM-Newton MOS/PN data. 
The
> OM data header says that 'POSCOROK' = T, but by comparing my data to SDSS
> images, it appears that there is a systematic offset between the X-ray
sources
> and candidate SDSS sources, of about 5 arcseconds.  I carefully examined my
data
> headers, but I could not find any information about an astrometric
correction
> being applied.  
> 
> Most of the material I find online seems to apply to astrometric correction
of
> the OM data, but I have not been able to find anything about confirming
the
> astrometry of my MOS/PN data. 
> 
> Thanks,
> 
> Nathan Secrest
> 
> 


Followup 1

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From: Nathan Secrest <nathansecrest@msn.com>
To: Ignacio de la Calle <xmmhelp@sciops.esa.int>
Subject: RE: Astrometry questions (PR#52546)
Date: Thu, 1 Aug 2013 16:49:54 -0400
--_e34f1528-9baf-4b0f-9726-84338cec333f_
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

Hi Ignacio=2C
I had 13.0.0 installed already=2C and I went ahead and installed the 13.0.1=
 patch (although when I start sas it still says 13.0.0).  This doesn't seem=
 to have made any difference with the astrometry.  Yet I am fairly certain =
that there is an offset=2C because everything lines up nicely if that appar=
ent offset is corrected for.  How should I proceed?  Isn't there some way t=
o manually fix the astrometry?
Thanks=2C
Nathan=20

> Date: Tue=2C 23 Jul 2013 15:46:17 +0000
> From: xmmhelp@sciops.esa.int
> To: nathansecrest@msn.com
> Subject: Re: Astrometry questions (PR#52546)
>=20
> Dear Nathan=2C
>=20
> I will get a more detailed answer to you tomorrow=2C but the short answer=
 to
> your question is that you should install SAS 13 where there has been a lo=
t=20
> of improvement in astrometric corrections=2C and the errors you comment h=
ave
> been reduced to the order of 1 arcsec.
>=20
> Regards=2C
>=20
> Ignacio de la Calle
> XMM-Newton SOC
>=20
>=20
> > Hello=2C
> >=20
> > I am confused about the astrometric accuracy of my XMM-Newton MOS/PN
da=
ta.=20
> The
> > OM data header says that 'POSCOROK' =3D T=2C but by comparing my data
t=
o SDSS
> > images=2C it appears that there is a systematic offset between the
X-ra=
y
> sources
> > and candidate SDSS sources=2C of about 5 arcseconds.  I carefully
exami=
ned my
> data
> > headers=2C but I could not find any information about an astrometric
co=
rrection
> > being applied. =20
> >=20
> > Most of the material I find online seems to apply to astrometric
correc=
tion
> of
> > the OM data=2C but I have not been able to find anything about
confirmi=
ng the
> > astrometry of my MOS/PN data.=20
> >=20
> > Thanks=2C
> >=20
> > Nathan Secrest
> >=20
> >=20
>=20
> This message and any attachments are intended for the use of the addresse=
e or addressees only. The unauthorised disclosure=2C use=2C dissemination o=
r copying (either in whole or in part) of its content is not permitted. If =
you received this message in error=2C please notify the sender and delete i=
t from your system. Emails can be altered and their integrity cannot be gua=
ranteed by the sender.
>=20
> Please consider the environment before printing this email.
>=20
 		 	   		  =

--_e34f1528-9baf-4b0f-9726-84338cec333f_
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Content-Transfer-Encoding: quoted-printable

<html>
<head>
<style><!--
.hmmessage P
{
margin:0px=3B
padding:0px
}
body.hmmessage
{
font-size: 12pt=3B
font-family:Calibri
}
--></style></head>
<body class=3D'hmmessage'><div dir=3D'ltr'>Hi
Ignacio=2C<div><br></div><div=
>I had 13.0.0 installed already=2C and I went ahead and installed the 13.0.=
1 patch (although when I start sas it still says 13.0.0). &nbsp=3BThis does=
n't seem to have made any difference with the astrometry. &nbsp=3BYet I am =
fairly certain that there is an offset=2C because everything lines up nicel=
y if that apparent offset is corrected for. &nbsp=3BHow should I proceed?
&=
nbsp=3BIsn't there some way to manually fix the
astrometry?</div><div><br><=
/div><div>Thanks=2C</div><div><br></div><div>Nathan&nbsp=3B<br><br><div>&gt=
=3B Date: Tue=2C 23 Jul 2013 15:46:17 +0000<br>&gt=3B From:
xmmhelp@sciops.=
esa.int<br>&gt=3B To: nathansecrest@msn.com<br>&gt=3B
Subject: Re: Astromet=
ry questions (PR#52546)<br>&gt=3B <br>&gt=3B Dear
Nathan=2C<br>&gt=3B <br>&=
gt=3B I will get a more detailed answer to you tomorrow=2C but the short an=
swer to<br>&gt=3B your question is that you should install SAS 13
where the=
re has been a lot <br>&gt=3B of improvement in astrometric
corrections=2C a=
nd the errors you comment have<br>&gt=3B been reduced to the order of
1 arc=
sec.<br>&gt=3B <br>&gt=3B Regards=2C<br>&gt=3B
<br>&gt=3B Ignacio de la Cal=
le<br>&gt=3B XMM-Newton SOC<br>&gt=3B <br>&gt=3B
<br>&gt=3B &gt=3B Hello=2C=
<br>&gt=3B &gt=3B <br>&gt=3B &gt=3B I am confused
about the astrometric acc=
uracy of my XMM-Newton MOS/PN data. <br>&gt=3B The<br>&gt=3B
&gt=3B OM data=
 header says that 'POSCOROK' =3D T=2C but by comparing my data to
SDSS<br>&=
gt=3B &gt=3B images=2C it appears that there is a systematic offset between=
 the X-ray<br>&gt=3B sources<br>&gt=3B &gt=3B and
candidate SDSS sources=2C=
 of about 5 arcs

Message of length 6485 truncated


Reply 2

Resend
From: Ignacio de la Calle <xmmhelp@sciops.esa.int>
To: nathansecrest@msn.com
Subject: Re: Astrometry questions (PR#52546)
Date: Mon Aug  5 09:39:31 2013
Dear Nathan,

The installation of SAS 13.0.1 still says 13.0.0, but you should have the right
version if you have just downloaded it.

Could you tell me which obsid you are working with ? 

Regards,

Ignacio de la Calle
XMM-Newton SOC

> Hi Ignacio=2C
> I had 13.0.0 installed already=2C and I went ahead and installed the
13.0.1=
>  patch (although when I start sas it still says 13.0.0).  This doesn't
seem=
>  to have made any difference with the astrometry.  Yet I am fairly certain
=
> that there is an offset=2C because everything lines up nicely if that
appar=
> ent offset is corrected for.  How should I proceed?  Isn't there some way
t=
> o manually fix the astrometry?
> Thanks=2C
> Nathan=20
> 
>> Date: Tue=2C 23 Jul 2013 15:46:17 +0000
>> From: xmmhelp@sciops.esa.int
>> To: nathansecrest@msn.com
>> Subject: Re: Astrometry questions (PR#52546)
>>=20
>> Dear Nathan=2C
>>=20
>> I will get a more detailed answer to you tomorrow=2C but the short
answer=
>  to
>> your question is that you should install SAS 13 where there has been a
lo=
> t=20
>> of improvement in astrometric corrections=2C and the errors you comment
h=
> ave
>> been reduced to the order of 1 arcsec.
>>=20
>> Regards=2C
>>=20
>> Ignacio de la Calle
>> XMM-Newton SOC
>>=20
>>=20
>> > Hello=2C
>> >=20
>> > I am confused about the astrometric accuracy of my XMM-Newton
MOS/PN da=
> ta.=20
>> The
>> > OM data header says that 'POSCOROK' =3D T=2C but by comparing my
data t=
> o SDSS
>> > images=2C it appears that there is a systematic offset between the
X-ra=
> y
>> sources
>> > and candidate SDSS sources=2C of about 5 arcseconds.  I carefully
exami=
> ned my
>> data
>> > headers=2C but I could not find any information about an
astrometric co=
> rrection
>> > being applied. =20
>> >=20
>> > Most of the material I find online seems to apply to astrometric
correc=
> tion
>> of
>> > the OM data=2C but I have not been able to find anything about
confirmi=
> ng the
>> > astrometry of my MOS/PN data.=20
>> >=20
>> > Thanks=2C
>> >=20
>> > Nathan Secrest
>> >=20
>> >=20
>>=20
>> This message and any attachments are intended for the use of the
addresse=
> e or addressees only. The unauthorised disclosure=2C use=2C dissemination
o=
> r copying (either in whole or in part) of its content is not permitted. If
=
> you received this message in error=2C please notify the sender and delete
i=
> t from your system. Emails can be altered and their integrity cannot be
gua=
> ranteed by the sender.
>>=20
>> Please consider the environment before printing this email.
>>=20
>  		 	   		  =
> 
> --_e34f1528-9baf-4b0f-9726-84338cec333f_
> Content-Type: text/html; charset="iso-8859-1"
> Content-Transfer-Encoding: quoted-printable
> 
> <html>
> <head>
> <style><!--
> .hmmessage P
> {
> margin:0px=3B
> padding:0px
> }
> body.hmmessage
> {
> font-size: 12pt=3B
> font-family:Calibri
> }
> --></style></head>
> <body class=3D'hmmessage'><div dir=3D'ltr'>Hi
Ignacio=2C<div><br></div><div=
>>I had 13.0.0 installed already=2C and I went ahead and installed the
13.0.=
> 1 patch (although when I start sas it still says 13.0.0). .=3BThis does=
> n't seem to have made any difference with the astrometry. .=3BYet I am =
> fairly certain that there is an offset=2C because everything lines up
nicel=
> y if that apparent offset is corrected for. .=3BHow should I proceed?
&=
> nbsp=3BIsn't there some way to manually fix the
astrometry?</div><div><br><=
> /div><div>Thanks=2C</div><div><br></div><div>Nathan.=3B<br><br><div>>=
> =3B Date: Tue=2C 23 Jul 2013 15:46:17 +0000<br>>=3B From:
xmmhelp@sciops.=
> esa.int<br>>=3B To: nathansecrest@msn.com<br>>=3B
Subject: Re: Astromet=
> ry questions (PR#52546)<br>>=3B <br>>=3B Dear
Nathan=2C<br>>=3B <br>&=
> gt=3B I will get a more detailed answer to you tomorrow=2C but the short
an=
> swer to<br>>=3B your question is that you should install SAS 13
where the=
> re has been a lot <br>>=3B of improvement in astrometric
corrections=2C a=
> nd the errors you comment have<br>>=3B been reduced to the order
of 1 arc=
> sec.<br>>=3B <br>>=3B Regards=2C<br>>=3B
<br>>=3B I

Message of length 7142 truncated


Followup 2

Compose reply
Download message
From: Nathan Secrest <nathansecrest@msn.com>
To: Ignacio de la Calle <xmmhelp@sciops.esa.int>
Subject: RE: Astrometry questions (PR#52546)
Date: Mon, 5 Aug 2013 05:48:07 -0400
--_8491bc42-1258-49b9-a14b-6f83a3af075b_
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

Hi Ignacio=2C
The observation ID is 0721900201.  I'm almost positive there is about a 4''=
 offset in the image=2C but I don't know how to address it correctly. =20
Thanks again=2C
Nathan

> Date: Mon=2C 5 Aug 2013 09:39:30 +0000
> From: xmmhelp@sciops.esa.int
> To: nathansecrest@msn.com
> Subject: Re: Astrometry questions (PR#52546)
>=20
> Dear Nathan=2C
>=20
> The installation of SAS 13.0.1 still says 13.0.0=2C but you should have t=
he right
> version if you have just downloaded it.
>=20
> Could you tell me which obsid you are working with ?=20
>=20
> Regards=2C
>=20
> Ignacio de la Calle
> XMM-Newton SOC
>=20
> > Hi Ignacio=3D2C
> > I had 13.0.0 installed already=3D2C and I went ahead and installed the
=
13.0.1=3D
> >  patch (although when I start sas it still says 13.0.0).  This doesn't
=
seem=3D
> >  to have made any difference with the astrometry.  Yet I am fairly
cert=
ain =3D
> > that there is an offset=3D2C because everything lines up nicely if
that=
 appar=3D
> > ent offset is corrected for.  How should I proceed?  Isn't there some
w=
ay t=3D
> > o manually fix the astrometry?
> > Thanks=3D2C
> > Nathan=3D20
> >=20
> >> Date: Tue=3D2C 23 Jul 2013 15:46:17 +0000
> >> From: xmmhelp@sciops.esa.int
> >> To: nathansecrest@msn.com
> >> Subject: Re: Astrometry questions (PR#52546)
> >>=3D20
> >> Dear Nathan=3D2C
> >>=3D20
> >> I will get a more detailed answer to you tomorrow=3D2C but the
short a=
nswer=3D
> >  to
> >> your question is that you should install SAS 13 where there has
been a=
 lo=3D
> > t=3D20
> >> of improvement in astrometric corrections=3D2C and the errors you
comm=
ent h=3D
> > ave
> >> been reduced to the order of 1 arcsec.
> >>=3D20
> >> Regards=3D2C
> >>=3D20
> >> Ignacio de la Calle
> >> XMM-Newton SOC
> >>=3D20
> >>=3D20
> >> > Hello=3D2C
> >> >=3D20
> >> > I am confused about the astrometric accuracy of my XMM-Newton
MOS/PN=
 da=3D
> > ta.=3D20
> >> The
> >> > OM data header says that 'POSCOROK' =3D3D T=3D2C but by
comparing my=
 data t=3D
> > o SDSS
> >> > images=3D2C it appears that there is a systematic offset
between the=
 X-ra=3D
> > y
> >> sources
> >> > and candidate SDSS sources=3D2C of about 5 arcseconds.  I
carefully =
exami=3D
> > ned my
> >> data
> >> > headers=3D2C but I could not find any information about an
astrometr=
ic co=3D
> > rrection
> >> > being applied. =3D20
> >> >=3D20
> >> > Most of the material I find online seems to apply to
astrometric cor=
rec=3D
> > tion
> >> of
> >> > the OM data=3D2C but I have not been able to find anything
about con=
firmi=3D
> > ng the
> >> > astrometry of my MOS/PN data.=3D20
> >> >=3D20
> >> > Thanks=3D2C
> >> >=3D20
> >> > Nathan Secrest
> >> >=3D20
> >> >=3D20
> >>=3D20
> >> This message and any attachments are intended for the use of the
addre=
sse=3D
> > e or addressees only. The unauthorised disclosure=3D2C use=3D2C
dissemi=
nation o=3D
> > r copying (either in whole or in part) of its content is not
permitted.=
 If =3D
> > you received this message in error=3D2C please notify the sender and
de=
lete i=3D
> > t from your system. Emails can be altered and their integrity cannot
be=
 gua=3D
> > ranteed by the sender.
> >>=3D20
> >> Please consider the environment before printing this email.
> >>=3D20
> >  		 	   		  =3D
> >=20
> > --_e34f1528-9baf-4b0f-9726-84338cec333f_
> > Content-Type: text/html=3B charset=3D"iso-8859-1"
> > Content-Transfer-Encoding: quoted-printable
> >=20
> > <html>
> > <head>
> > <style><!--
> > .hmmessage P
> > {
> > margin:0px=3D3B
> > padding:0px
> > }
> > body.hmmessage
> > {
> > font-size: 12pt=3D3B
> > font-family:Calibri
> > }
> > --></style></head>
> > <body class=3D3D'hmmessage'><div dir=3D3D'ltr'>Hi
Ignacio=3D2C<div><br>=
</div><div=3D
> >>I had 13.0.0 installed already=3D2C and I went ahead and installed
the =
13.0.=3D
> > 1 patch (although when I start sas it still says 13.0.0).  =3D3BThis
do=
es=3D
> > n't seem to have made any difference with the astrometry.  =3D3BYet I
a=
m =3D
> > fairly

Message of length 24031 truncated


Reply 3

Resend
From: Ignacio de la Calle <xmmhelp@sciops.esa.int>
To: nathansecrest@msn.com
Subject: Re: Astrometry questions (PR#52546)
Date: Wed Aug  7 09:43:54 2013
Dear Nathan,

Although the astronomic correction introduced in SAS13 should leave 
the offset on average to about 1arcsec, there are of course cases where
this offset could be up to about 4arcsec. This observations is one of those.

The exercise of crossmatching and correcting EPIC and OM coordinates is done 
independently. Once the offset is found, the corrections are reflected in both
the EPIC and OM source lists. While keywords are also added to the OM images
so that the position of the sources in the OM source list match the image,
the EPIC image is not corrected. This means that if you plot EPIC sources over
the EPIC image you will be able to see a displacement. For the same reason, 
there will be a displacement between the EPIC and OM image.

I hope this clarifies things. Otherwise please do not hesitate to let me 
know.

Regards,

Ignacio de la Calle
XMM-Newton SOC


> Hi Ignacio=2C
> The observation ID is 0721900201.  I'm almost positive there is about a
4''=
>  offset in the image=2C but I don't know how to address it correctly. =20
> Thanks again=2C
> Nathan
> 
>> Date: Mon=2C 5 Aug 2013 09:39:30 +0000
>> From: xmmhelp@sciops.esa.int
>> To: nathansecrest@msn.com
>> Subject: Re: Astrometry questions (PR#52546)
>>=20
>> Dear Nathan=2C
>>=20
>> The installation of SAS 13.0.1 still says 13.0.0=2C but you should have
t=
> he right
>> version if you have just downloaded it.
>>=20
>> Could you tell me which obsid you are working with ?=20
>>=20
>> Regards=2C
>>=20
>> Ignacio de la Calle
>> XMM-Newton SOC
>>=20
>> > Hi Ignacio=3D2C
>> > I had 13.0.0 installed already=3D2C and I went ahead and installed
the =
> 13.0.1=3D
>> >  patch (although when I start sas it still says 13.0.0).  This
doesn't =
> seem=3D
>> >  to have made any difference with the astrometry.  Yet I am fairly
cert=
> ain =3D
>> > that there is an offset=3D2C because everything lines up nicely if
that=
>  appar=3D
>> > ent offset is corrected for.  How should I proceed?  Isn't there
some w=
> ay t=3D
>> > o manually fix the astrometry?
>> > Thanks=3D2C
>> > Nathan=3D20
>> >=20
>> >> Date: Tue=3D2C 23 Jul 2013 15:46:17 +0000
>> >> From: xmmhelp@sciops.esa.int
>> >> To: nathansecrest@msn.com
>> >> Subject: Re: Astrometry questions (PR#52546)
>> >>=3D20
>> >> Dear Nathan=3D2C
>> >>=3D20
>> >> I will get a more detailed answer to you tomorrow=3D2C but the
short a=
> nswer=3D
>> >  to
>> >> your question is that you should install SAS 13 where there
has been a=
>  lo=3D
>> > t=3D20
>> >> of improvement in astrometric corrections=3D2C and the errors
you comm=
> ent h=3D
>> > ave
>> >> been reduced to the order of 1 arcsec.
>> >>=3D20
>> >> Regards=3D2C
>> >>=3D20
>> >> Ignacio de la Calle
>> >> XMM-Newton SOC
>> >>=3D20
>> >>=3D20
>> >> > Hello=3D2C
>> >> >=3D20
>> >> > I am confused about the astrometric accuracy of my
XMM-Newton MOS/PN=
>  da=3D
>> > ta.=3D20
>> >> The
>> >> > OM data header says that 'POSCOROK' =3D3D T=3D2C but by
comparing my=
>  data t=3D
>> > o SDSS
>> >> > images=3D2C it appears that there is a systematic offset
between the=
>  X-ra=3D
>> > y
>> >> sources
>> >> > and candidate SDSS sources=3D2C of about 5 arcseconds.  I
carefully =
> exami=3D
>> > ned my
>> >> data
>> >> > headers=3D2C but I could not find any information about
an astrometr=
> ic co=3D
>> > rrection
>> >> > being applied. =3D20
>> >> >=3D20
>> >> > Most of the material I find online seems to apply to
astrometric cor=
> rec=3D
>> > tion
>> >> of
>> >> > the OM data=3D2C but I have not been able to find
anything about con=
> firmi=3D
>> > ng the
>> >> > astrometry of my MOS/PN data.=3D20
>> >> >=3D20
>> >> > Thanks=3D2C
>> >> >=3D20
>> >> > Nathan Secrest
>> >> >=3D20
>> >> >=3D20
>> >>=3D20
>> >> This message and any attachments are intended for the use of
the addre=
> sse=3D
>> > e or addressees only. The unauthorised disclosure=3D2C use=3D2C
dissemi=
> nation o=3D
>> > r copying (either in whole or in part) of its c

Message of length 25277 truncated

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