Palomar 200-inch Telescope:

LFC - Large Format Camera

Camera Parameters

• Mosaic of six 2048 x 4096 pixel SITe SI-002 thinned, backside illuminated, AR coated CCD located at Hale Telescope's Prime Focus (f/3.3)

  

• Field Diameter: 24 arcminutes

• Pixel size: 15 microns

• Pixel Scale:
  
  

  • 0.18"/pixel binned 1x1
  
  
  • 0.36"/pixel binned 2x2

• Minimum Exposure time: 0.6 sec

• Gap between CCD chips: ~ 15 arcsec

• Readout (Mosaic) Options:

  
  

Mode (mosaic command)	Chip Numbers Used	Binning Value (pixels)	Field Size (arcmin)	Readout Time (sec)
lfc / lfc2 lfc2bin lfcfour lfczero lfczerobin lfcfind	0, 1, 2, 3, 4, 5 0, 1, 2, 3, 4, 5 0, 1, 2, 3 (center 4) chip 0 only chip 0 only chip 0 only	1 x 1 2 x 2 1 x 1 1 x 1 2 x 2 2 x 2	25.3' x 24.8' 25.3' x 24.8' 12.5' x 24.8' 6' x 12.3' 6' x 12.3' 6' x 6'(1k x 1k)	115 56 111 105 45 31




• Image File Size: ~ 17 Mb per CCD at 1 x 1 binning

• LFC Guider: partially vignetted 512 x 512 SITe chip located in the open area between chips 3 and 5. See focal plane schematic. Capable of guiding down to mV ~ 18

CCD Specs

• 2048 x 4096 pixel SITe SI-002 thinned, backside illuminated, AR coated CCD




CCD Chip #	Bias	Gain (e-/DN)	Read Noise (e-)	Saturation (DN)
0	650	2	11	59100
1	1700	1.9	9	53400
2	1100	2.1	9	40800
3	2600	2	8	44000
4	1700	2.1	8	21700
5	4100	1.8	6	61400

LFC Filter Specs

• Filter wheel has slots for 4 filters




Filter	Central (A)	Width (A)	Thickness (mm)	Focus Offset (mm from r')	Domeflats *	Transmissions, Text Files & Plots (see below)
r'	6255	1470	3.05	-	5	r'.txt
i'	7680	1540	3.05	-	3	i'.txt
z'	~9000	~1800 (w/qe)	3.05	-	5	z'.txt
g'	4660	1400	8.02	+1.5	40	g'.txt
u'	3540	590	8.38	+1.6	120 (HIGHLAMP)	u'.txt
Rs	6930	1220	10.26	+2.0	8	Rs.txt
Is	8190	1670	10.26	+2.0	5	Is.txt
B-bess	4400	1000	7.0	+1.3	2 (HIGHLAMP)	B.txt
V-bess	5500	900	7.0	+1.3	40	V.txt
R-bess	6300	1200	7.0	+1.3	10	R.txt
I-bess	9000	3000	7.0	+1.3		I.txt
Broad-RI	7670	2940	6.0			RI.txt
H-alpha	6570	100	11.68	+2.8	120	see plots below
S-II	6730	90	11.68	+2.8	120	see plots below
6610/100	6610	100	7.06	+1.3	120	6610
6650/100	6650	100	7.06	+1.3	120	6650
6700/100	6700	100	6.93	+1.3	120	6700
3800/200	3800	200	7.67	+1.4	60(highlamp)	3800
4010/90	4010	90	12.19	+2.9?		not yet on record
5200/70	5200	70	4.90	?		not yet on record
5085/70	5085	70	5.13	?		not yet on record


* Seconds to 10,000 DN(unbinned)




Figure: Sloan filters convolved with ccd quantum efficiency





Figure: Newest (2006) LFC Bessell and custom RI filters

Rs transmission curve (without Q.E.)

Is transmission curve (without Q.E.)

New (Nov. 2007) Narrow Band Filters, Courtesy of Karl Stapelfeldt.

H-alpha transmission curve (without Q.E.)

S-II transmission curve (without Q.E.)

Custom LFC Filters

• 6.1 inches square

• Thickness: ~3 mm (min); 10 mm (max), but < 6 mm preferred due to weight considerations.

• Contact: Jeff Hickey about non-observatory filter mounting. Also see Rob Simcoe's LFC Page for more information.

Latest LFC News

• MCDCOM Program Update (February 20, 2007):

  • Added logic to filter wheel movement so that the filter wheel will correctly move to the requested position in both extreme cold and extreme hot ambient temperatures.

  • Created two new backup MCDCOM programs in case the hot/cold logic fails:

    • mcdcom_hot to be used in hot temperatures
    • mcdcom_cold to be used in cold temperatures

  • When mcdcom is started, 3 scripts are automatically copied to the user's working directory (if none exist):

    • focus_coarse
    • focus_fine
    • dither5

  • A test version of the lfcguider (lfcguide_ns) is now available which attempts to guide at non- sidereal rates. Target rates are entered in the File/BlackBelt menu popup window

  
  
• MCDCOM Program Update (April 28, 2005):

  • The iraf command now works. When toggled ON, files are written as signed integer FITS.

  • The istat command now works correctly, displaying the mean of chip 0.

  • A new command fs has been added. This adds a filename suffix (eg: .fits). To clear this at any time, issue fs "".

  • New commands have been added to turn lamps on and off from the command line, useful in domeflat scripts:

    • telescope lowlamp
    • telescope highlamp
    • telescope arclamp
    • telescope lampsoff

  • Fixed the header bug in the guider program. All fits files should now have proper telescope header information, regardless of when a "go" is issued.

  
  
• Added Narrow Band Filters (Nov. 2007)

  • Karl Stapelfeldt has supplied two new Narrow Band filters from Asahi Spectra. The filter plots are linked above, and are named H-alpha and S-II.

• More Narrow Band Filters (2008 & 2009)

  • Ted Wyder and Brian Siana have added the following filters which are listed and linked above;6610/100,6650/100,6700/100,3800/200. All are available to the public.