How to install tfinder?

[ping]

Hello,

I have CCD images from CTIO Yalo-1m telescope. They only have telescope pointing but no astrometry solution for the image itself. Can tfinder make the astrometry solution for the images? If so, where do I get the tfinder?

Thanks,

Ping

[valdes]

I'm not sure about the availability of tfinder. However, there is a somewhat easier to use task called msctpeak which derived from tfinder. This task is in the mscfinder package of either mscred or nfextern.msctools. Both of these package are readily available for current versions of IRAF. With V2.15 you can use the simplified dynamic installation option (see extern$README). For earlier versions of IRAF you find things at the ftp:/iraf.noao.edu site or iraf.net.

You might find the link:

http://iraf.noao.edu/projects/ccdmosaic/astrometry/astrom.html

while the msc packages and tasks and this link talk about multi-extension files like mosaic cameras, everything works with single images as well.

Frank Valdes

[ping]

Hi Frank,

Thank you for your reply.

I think in order for msctpeak to work. The image itself should have at least some sort of WCS, even it's off. But the images from yalo1m has no WCS at all. If you display it with ds9, the WCS block is blank. The image header does have telescope pointing:

RA = '16:54:16.70' / Telescope RA at EQUINOX
DEC = '-39:52:29.1' / Telescope DEC at EQUINOX

Is there something I can add to the header to make WCS appear in the image?

Thanks!

Ping

[valdes]

Hi Ping,

Check out the task "mkcwcs". You have the ra and dec already. You need to figure out the scale and the orientaion on the sky. In case it isn't clear, the rapix and decpix specify a point in the image to which the ra and dec apply.

Frank

[ping]

Hi Frank,

Thank you for your very quick reply.

I just tried "mkcwcs". It works!

Thank you very much!

Best,
Ping