FLAMINGOS --- Distortion Maps Over FLAMINGOS's Lifetime

FLAMINGOS's optics were designed to have good image quality (in terms of spot size and encircled energy) and low distortion when used with the KPNO Mayall 4-m telescope (10.7 arcminute FOV). Unfortunately, some aspect of the as-built optics is not quite correct and we have noticable coma/astigmatism at the corners of the array which we have not had sufficient time to resolve.

For distortion, however, is possible to attempt a correction. It is based either on images of astrometric fields or by some other source with known image scale, such as a pinhole grid located at the MOS focal plane.

For example, the two UF teams who are running NOAO KPNO surveys have dedicated image and spectroscopy IRAF pipeline routines. These pipelines use an IRAF geomap/geotran solution that has been generated by Richard, from images I took of a pinhole grid array taken with two Hartmann masks (simple on/off pairs). These data have been taken any time we disturbed the position of the detector array or installed new filters (w/o disturbing the array position). The geomap/geotran solutions as a function of time are provided here (the ones that I can find, that is).

DISCLAIMER: Feel free to use these solutions, but at your own risk. We are only liable for results obtained with them when used for our survey data projects.

WARNING: Large Table Ahead:

Major Operations on the FLAMINGOS Camera Dewar Which Would Affect Distortion A Timeline of Where, When, and What Was Done
Timeline of Major Events				Available Geomap/Geotran Solution and Applicable Dates Note some maps may be missing!
Location of Dewar During Date Period	Date Camera Dewar Opened and Array Position Disturbed	Location During Surgery	What Surgery Was Performed	KPNO 2.1-m	KPNO 4-m	MMT	Gemini
Fall 2000 through Late June 2000 --------------------- Gainesville and Arizona	Fall 2000	Gainesville	Initial installation of Engineering Grade Array.
Mid-July 2001 through Mic-October 2001 --------------------- Cerro Pachon	Late July through mid-September 2001	Gemini South - Cerro Pachon	Instrument damaged during shipment to Chile, for first season at Gemini South. Borrowed BaF2 lens from Ron Probst's CITO instrunment ISPI (Thanks Ron!). Wire bond on lower left quadrant of array came loose at one end. Array sent to Rockwell for re-attachment of wirebond Installed 1-mm thick PK-50 behind ZnSe Asphere (last lens before detector); bad for K-band, but just temporary solution to background problems.	Should have re-measured pinhole grid; data missing. (When did we install Hartmann masks?) No map file to be found.	Should have re-measured pinhole grid; data missing. (When did we first install the Hartmann masks?) No map file to be found.	Should have re-measured pinhole grid; data missing. (When did we first install the Harmann masks?) No map file to be found.	geminipin.jun2002.map = Gemini01.map Pinhole data taken when? Map created Thu 16:35:04 26-Sep-2002 UF teams using it for 2001 Gemini Data (which doesn't match first file's naming convention).
November 2001 through May 2002 --------------------- Arizona	November 2001	NOAO - Tucson & KPNO 4-m	Move PK-50 to location with HK Filter (was behind last lens - bad for K-band).	2mpin.dec01.map UF team not using this map, not certain why. Contains 3 polynomial solutions. Pinhole data taken Dec 2001. Map created Tue 17:28:14 29-Jan-2002	4mpin.dec01.map = KP4m01.map Pinhole data taken Dec 2001 Map created Fri 17:12:01 15-Nov-2002 Currently using it for all data up to May 2002. Probably should only be used for Nov 2001 to May 2002 data.	mmtpin.feb2002.map Pinhole data probably taken Dec 2001. Map created Thu 08:07:36 21-Feb-2002 Uses Chebyshev polynomial fit.
	March 2002 through April 2002	NOAO - Tucson	Squeezed ZnSe lens too hard during lab tests. Borrowed duplicate ZnSe lens from ISPI, again!	KP2m01.map Pinhole data taken when - cannot find it? Map created Mon 14:28:27 15-Jul-2002 Contains 1 Legendre polynomial solution. Currently using it for all data up to May 2002, but this may not be correct for data prior to Dec 2001.		Cannot find pinhole data. It should have been taken. Cannot find a map file, either.
June 2002 through November 2002 --------------------- Cerro Pachon	10 June 2002	Gemini South, Cerro Pachon	Installed replacement ZnSe lens. Installed JH Grism.	Probably didn't measure pinhole grid for 2.1-m, 4-m, or MMT, as science array installation would occur before return to USA.			Gemini03.map Cannot find this file, or pinhole data. Don't know if map for Engineering array or Science array.
	September through October 2002	Gemini South - Cerro Pachon	Installed Science Grade Array while at Gemini South. Dewar opened several times; problems with filter wheel box.	2mpin.dec02.map = KP2m03.map Pinhole data taken 05 Dec 2002, after September/October surgeries. Map created Mon 14:28:27 15-Jul-2002 UF using for data taken between June 2002 and July 2003.	4mpin.dec02.map = KP4m03.map Pinhole data taken 05 Dec 2002, after September/October surgeries. Map created Thu 15:22:55 24-Apr-2003 UF using for data taken between June 2002 and July 2003.	mmtpin.dec2002.map = MMT03.map Pinhole data taken 05 Dec 2002, after September/October surgeries. Map created Thu 15:22:27 24-Apr-2003 (suspiciously close in time to 4m map?) UF using for data taken after June 2002.	Gemini03.map Cannot find this file, or pinhole data. Don't know if map for Engineering array or Science array.
December 2002 through June 2003 --------------------- Arizona	December 2002	NOAO - Tucson	02 Dec: Installed new filter wheel sapphire bearings. (Array position disturbed).
July 2003 --------------------- Gainesville	July 2003* * Array not actually disturbed, but filters are 5 mm thick and the old ones were 3 mm thick.	UF - Gainesville	Installed J, H, and Ks filters from BARR. Filters installed through access port, so array position not removed. Pinhole map remeasured in September, anyways.	2mpin.26sep2003.map Contains 3 Legendre polynomial solutions; UF uses the first solution (see KP2m04.map). Pinhole data taken 26 Sep 2003. Map created Fri 17:32:36 09-Jan-2004 Should use for all data after July 2003.	4mpin.26sep2003.map = KP4m03b.map Pinhole data taken 26 Sep 2003. Map created Sun 14:00:45 02-Nov-2003 Should use for all data after July 2003.	Might not have remeasured pinhole grid. Final MMT observing run was late October / early November 2003.
August 2003 through Present Day --------------------- Arizona

Last updated 2004 August 19, Thursday
S. Nicholas Raines