[APML] OT: M17 in near-IR

[Wei-Hao Wang <whwang@gmail.com>]

Hi list,

Just for fun.  This is a near-IR picture of M17 I took in June:
http://www.ifa.hawaii.edu/~wang/misc/M17_ULB_2MASS.jpg

The image was made using LRGB mode.  L image is taken by our
2m telescope and a near IR camera called ULBCAM.  ULBCAM is
a prototype of the camera that will be used in the 6m Next Generation
Space Telescope.  It has four 2k by 2k near-IR chips (16 Mega pixels
in total) that is more like CMOS but unlike CCDs.  It's also the 
largest near-IR camera on large telescopes.  To advertise this camera,
I was asked to take some pretty images during my observation.

The L image is taken through J filter, whose central wavelength is about 
1.2 um, twice longer than that of visible red light.  Because this camera 
is only a prototype and doesn't have a proper aperture stop, it will see
the thermal emission from itself and from the telescope.  For this reason,
we don't operate it at wavelengths longer than 1.8 um where thermal
emission starts to be strong.  With only one image taken at 1.2 um,
I cannot make a color picture.  I downloaded 2MASS 1.2, 1.6, 1.9 um
images from the internet and use them as RGB channels.  The 2MASS
data don't have the resolution and depth that ULBCAM has but they
provide reasonable color information.

The blue color in this picture comes from hydrogen, I believe.  It's just
the IR version of H-alpha line.  The yellow and red color may come from
hot dust around young stars.

Enjoy.

Wei-Hao

-- 
________________________________________________________________
Wei-Hao Wang  :)

Institute for Astronomy at University of Hawaii

Address:                       
2680 Woodlawn Drive         Personal Website:
Honolulu, HI 96822             http://www.ifa.hawaii.edu/~wang
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