Viewing Calibration/8877
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Private message: yes  no

Notes:
see XMM-SOC-CAL-TN-0032
Notification:

Date: Fri, 1 Aug 2003 14:06:44 -0400 (EDT)
From: nichol <nichol@cmu.edu>
To: xmmhelp@xmm.vilspa.esa.es
cc: Bob Nichol <nichol@cmu.edu>, Kathy Romer <romer@cmu.edu>
Subject: XMM pointing accuracy

Hi XMM-Newton,

Is there any in-flight calibration of the AMA, i.e., the average error on
the boresight of the EPIC/MOS?

I ask because I have just matched sources from 42 XMM pointings with
quasars from the SDSS DR1 database, and find ~2 arcsecond rms between the
quoted boresight and the "true" boresight from the SDSS quasars (which are
tied to the radio frame). Is that consistent with your expectations and
other in-flight tests?

Cheers

Bob Nichol


-- 
Bob Nichol
5000 Forbes Ave.
Carnegie Mellon
412-268-8068
nichol@cmu.edu

Reply 1

From: Matthias Ehle <xmmhelp@xmm.vilspa.esa.es>
To: nichol@cmu.edu
Subject: Re: XMM pointing accuracy (PR#8877)
Date: Mon Aug  4 08:15:14 2003

Dear Bob Nichol,

I have sent you a technical note on the absolute astrometry of XMM-Newton
from my private account (as the helpdesk system does not allow me
to attach files).

You will see in this note that the XMM-Newton absolute atrometry accuracy is
1.0" at 1 sigma, or 2" at 90% confidence level.

Cheers,
Matthias

PS: Please, continue to use the helpdesk (not my private address) in case
of further communications. 

Matthias Ehle 
XMM-Newton SOC 
User Support Group