Hubble Space Telescope Primer for Cycle 11

A.3 NICMOS

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Suppose that you wish to use the NICMOS to observe a target at a declination of -50 degrees, so that there are 56 minutes of visibility time per orbit (see Table 6.1). Your desired exposures are listed in Table A.7, and the associated overheads are listed in Table A.8. In Table A.9 you can see how the observations fit into a total of 1 orbit.

Table A.7: NICMOS Example: Planned Exposures

Config	Mode	Spectral Element	Number of Exp	Time per Exp [m]	Notes
NIC2	IMAGING	F110W	4	2.1	Pattern (see Section 5.4) of MULTIACCUM exposures with an offset of 1" between dither positions
NIC2	IMAGING	F160W	4	4	Pattern (see Section 5.4) of MULTIACCUM exposures with an offset of 1" between dither positions
NIC2	IMAGING	F222M	4	4	Pattern (see Section 5.4) of MULTIACCUM exposures with an offset of 1" between dither positions

 
Table A.8: NICMOS Example: Incurred Overheads

Overhead	Overhead Time [m]	Notes	see Table
Guide star acquisition	6	First orbit in new visit	6.2
MULTIACCUM exposure	0.07		6.9
Instrument Setup	0.3	Beginning of each orbit	6.10
Filter change	0.3		6.10
SAM of 1"	0.33	Small Angle Maneuver between positions in the pattern	6.14

 
Table A.9: NICMOS Example: Orbit Planning

Activity	Duration [m]	Elapsed Time [m]
Orbit 1
Guide star acquisition	6	6
Instrument Setup	0.3	6.3
F110W Exp Time	2.1	8.4
F160W Exp Time	4	12.4
F222M Exp Time	4	16.4
Overhead	(3x0.07) + (2x0.3) + (1x0.33)	17.4
F110W Exp Time	2.1	19.5
F160W Exp Time	4	23.5
F222M Exp Time	4	27.5
Overhead	(3x0.07) + (3x0.3) + (1x0.33)	28.9
F110W Exp Time	2.1	31.0
F160W Exp Time	4	35.0
F222M Exp Time	4	39.0
Overhead	(3x0.07) + (3x0.3) + (1x0.33)	40.4
F110W Exp Time	2.1	42.5
F160W Exp Time	4	46.5
F222M Exp Time	4	50.5
Overhead	(3x0.07) + (3x0.3) + (1x0.33)	51.9
Unused	4.1	56