NIRI SV observation 20

	Status: observations complete Data link: Public data page Assessment: complete.

Mode:	Wide-field Imaging
Additional instrument verification:	Test NIRI wide-field imaging mode. Test ability to image high-contrast, extended objects in multiple filters. Test for image persistence from very bright sources. Test NIRI reduction software on bright point sources and extended low-surface brightness features. Check NIRI image quality under excellent seeing conditions.
Telescope verification:	Tests preliminary version of telescope offset sequencer. Test PWFS guiding under excellent seeing conditions.
Proposed observing sequence:	Telescope offset sequence files created manually
OT program file:	not available
Science background:	AFGL 2591 was targeted to test our ability to image extended objects with bright point sources. A "pretty" target was also desired for PR purposes. This data were also important for testing the data reduction software. This dramatic infrared image sheds new light on the early stages of the formation of giant stars in our galaxy. This image reveals remarkable details in a nebula of gas and dust expelled from AFGL 2591. This expulsion is a common feature in the formation of stars similar in size to the Sun, but it is far less common in their massive counterparts. The resolution of this image is 0.4 arcseconds. Please see the press release for more information.
Target(s):
	Object	RA (2000)	dec (2000)
	AFGL 2591	20 29 24.9	40 11 21.0
Observing conditions:	image quality: 50%-ile (0.3 at Kp to 0.4 arcsec at J) sky transparency (clouds): 50%-ile (photometric) sky transparency (water vapour): Any sky background: 80%-ile max air mass: 1.1
Observing time achieved:	2 min on-source at J, 1 min at H and Kprime).
Data release date:	October 11, 2001
SV team member(s) responsible for assessment:	Colin Aspin, Tracy Beck

Last update October 12, 2001; Joe Jensen