Page 2 of 2

Re: Galactic centre (APOD 2009/11/11)

Posted: Tue Nov 17, 2009 9:58 pm
by kjardine
Hi Martin,

I've tracked down a NICMOS plate at this location:

http://archive.stsci.edu/cgi-bin/mastpr ... =NA134R070

The coordinates turn out to be 17:45:28.75 -29:04:21.5

Unfortunately, the object does not appear on the plate at all, even though all of the surrounding stars do.

So it looks like it is an artifact after all, introduced when creating the mosaic mentioned in my previous post.

Cheers,
Kevin

Kevin Jardine
Galaxy Map
http://galaxymap.org

Re: Galactic centre (APOD 2009/11/11)

Posted: Wed Nov 18, 2009 3:11 am
by Martin
Thank you for your reply. Unfortunately, I cannot view what you have linked to -with any significant detail. So I cannot see what you are talikng about. Perhaps, your coordinates are not correct. You suggested that the object appears only in infrared?

Re: Galactic centre (APOD 2009/11/11)

Posted: Wed Nov 18, 2009 6:58 am
by kjardine
Hi Martin,

Yes, the link is correct. You can download the FITS file and use a FITS viewer to look at it.

The preview image they provide at the link is too dark to be usable, which is why you need to download the full FITS file.

There are many FITS viewers available. One popular one is Aladin, which you can download here.

One advantage of most FITS files, including that one, is that they are calibrated so that you can read the coordinates off directly in Aladin.

Kevin

Kevin Jardine
Galaxy Map
http://galaxymap.org

Re: Galactic centre (APOD 2009/11/11)

Posted: Wed Nov 18, 2009 7:29 am
by kjardine
Osmo wrote:there is interesting "Saturn-like" object.
To add some more information, this object is visible in this Hubble NICMOS (near infrared) data here:

http://archive.stsci.edu/cgi-bin/mastpr ... =NA132G060

(you have to view the FITS file to see it)

at the exact coordinates

17:46:03.01 -28:52:46.0

Even in this data it looks extended on either side.

The closest object in SIMBAD to this location is the radio source [HJB85] Sgr A-N1 .

Update: a 2008 paper here:

http://cdsads.u-strasbg.fr/cgi-bin/nph- ... .174..481L

confirms that there is a compact radio source, 2LC 000.098-0.051, in this direction with an angular diameter of 7.1 arcseconds. That doesn't explain what it is, but does suggest that it is real.

Cheers,
Kevin

Kevin Jardine
Galaxy Map
http://galaxymap.org

Re: Galactic centre (APOD 2009/11/11)

Posted: Wed Nov 18, 2009 2:35 pm
by geckzilla
Hey Kevin, you should go here and update your signature so that it's automatically appended to your posts. Unless you just like typing it manually every time.

I was hoping to figure something out about both the saturn-like object and the weird faint ring but couldn't figure out either. It's also really hard to tell from all these pictures exactly which are obscured by dust lanes and whatnot. It'd be really neat if Google Sky were updated with these extreme closeups and all these data were on various layers that could be toggled on and off but as I understand it would be a painstaking task at best to get them lined up accurately enough or it may have already been done. Their infrared layer is disappointingly low resolution.