1SOFIA
Stratospheric Observatory for Infrared
Astronomy
Flight Planning for 1st Light
Allan Meyer and Eric Becklin
SSSC 29 Sept 2009
2SOFIA
Stratospheric Observatory for Infrared
Astronomy
Flight Planning for “TA charact., 1st light”
• TA characterization: pointing stability, other performance & functionality aspects potentially affected by flight environment
• “first light” image from FORCAST: not science, for demonstration purposes only. Will not drive any new requirements or schedule delays
• Development phase constraints on the aircraft, and the character of the “IR Sky” dictate & severely limit the content of feasible flight plans. (Probably also true for TA characterization without FORCAST)
• Aircraft Constraints:– Door fully open but fixed at 23° elevation for TA char., 1st light
– 200 nautical mile radius limit from DAOF*
– Offshore limit ~50 miles
– No Mexico overflight => Dec. > -35°
– ~ 6 hour flight duration
– Sun at least ~10° below horizon
– 35K observing altitude, winter / spring, 2010
*late note: Platform Project is considering an increase of the radius limit
3SOFIA
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Location of Geographic Limits
• 200 nm radius limit
• Off-shore limit
Mexico border
4SOFIA
Stratospheric Observatory for Infrared
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Flight Plan Science Constraints
• TA characterization– Pointing stability
– Image quality (i.e. confirm diffraction limit from HIPO Shack-Hartmann)
– Chopping performance
– 5 - 25 µm fast imaging (50 - 500 Hz) of IR bright stars (M <+2)
• “First light”: – demonstration of science capability:
Point source okay; one extended source could be attempted.
– TBD s, 5 - 40 µm
• IR bright stars for setup, fast imaging (TA char.), & demonstration of FORCAST performance.
• FIR bright extended source(s) (H II/SFRs, planet) for science demonstration.
• Trackable with current FPI, mag. limit ~12 (offset tracking or FFI tracking if needed)
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Getting a List of Appropriate IR Stars
• The appropriate list of visible & mid-IR bright stars is the first step
• FORCAST sensitivity at ~500 Hz readout rate– J. Adams (Cornell, Dec. ‘08) calculation for 16 MIRAC stds.
– At 508 Hz readout rate, S/N = 50 for 56 Jy at 5.35 µm
– Vega ( Lyr, M = 0, 158 Jy) S/N = 140
• Lists from several online sources have been downloaded for trial use
• The best list appears to be based on the IRAS Point Source Catalog (PSC), with limits on 12 µm flux, 12µm/25µm flux ratio, & appropriate ID.SIMBAD ident.
typeR.A.
(2000)Dec. Gal.
long.244.4
Gal. lat.
V Kspec. type
F12 / F25
l Pup
Em*
7 43 48.47 -28 57 17.4 -2.54 4.0 2.5A3Iab:
1.8
12 Lib
Star
14 54 20.13 -24 38 31.9 335.5 30.35 5.3 2.2K2/K3III
4.1
13 PsA
Star
22 4 23.84 -29 54 59.5 18.5 -53.40 6.5 2.0K5III
4.9
24 Cap
*in**
21 7 7.67 -25 0 21.1 22.0 -40.01 4.5 0.5K7III
3.8
27 Sco
Star
16 57 11.18 -33 15 34.2 350.5 6.07 5.5 1.6K5III
4.2
36 Lib
Star
15 34 37.32 -28 2 49.1 341.5 22.35 5.1 1.9K4III
3.7
43 Oph
Star
17 23 21.59 -28 8 34.2 358.0 4.54 5.3 1.5K5III
4.4
49 Hya
Star
14 6 22.30 -26 40 56.5 323.0 33.25 3.3 0.8K1III-IV
4.5
50 Hya
Star
14 12 46.02 -27 15 40.3 324.3 32.21 5.1 2.4K3III
4.1
52 Eri
Star
4 35 33.04 -30 33 44.4 231.0 -41.31 3.8 1.6G8IIIa
3.8
AF For
PulsV*
3 8 37.52 -26 26 46.9 219.6 -59.47 8.6 2.1M5III
3.5
AH Sco
semi-regV*
17 11 17.02 -32 19 30.7 353.1 4.27 7.5 0.4M4III:
1.8
AI For
V*
3 19 34.91 -24 7 22.4 216.2 -56.59 5.7 1.1M1III
3.7
AK Pyx
Irregular_V*
8 48 14.63 -28 38 19.7 252.0 9.35 6.5 0.5M5III
2.7
AL Pyx
Irregular_V*
9 1 6.28 -27 30 56.7 252.9 12.27 7.2 2.4M1III
3.9
alf Sco
semi-regV*
16 29 24.46 -26 25 55.2 351.9 15.06 1.1 ~M1.5Iab-b
4.6
Alpha PsA
V*
22 57 39.05 -29 37 20.1 20.5 -64.91 1.2 ~A4V
3.8
AM For
semi-regV*
3 43 10.03 -31 1 9.4 229.4 -52.51 7.2 1.4M4III
3.7
AO Pyx
Irregular_V*
9 14 47.65 -33 40 56.5 259.6 10.41 8.8 2.1M5/M6III
3.5
6SOFIA
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Astronomy
Candidate Targets for Feasibility Trials
• FORCAST 2006 “Design Reference Mission”:– ~100 assorted galactic & extragalactic targets– 28 calibration stars: Boo, Tau, CMa, etc. N mag. ~0 to -4
• NOAO list + UKIRT stds. + Cat. IR Obs. (Gezari)– M<+1, > -35° => N = 288
• IRAS PSC (using CDS Vizier) + SIMBAD idents– 12 µm flux > 25 µm flux for stellar sources– Dec. strip for ~23° elevation west heading: -34° to -24°– N ~ 250 to 310 depending on 12µm flux cutoff (e.g. 10 Jy, or gal. b modulated)
• Catalog of Pstns. of IR Stellar Sources (CPIRSS, Hindsley et al. 1994)– IRAS PSC sources confidently identified as stars (Tycho, Hipparcos, etc.)
– Dec. -34° to -24°, F(12µm) > 5 Jy, & F(12µm) > F(25µm) => N = 263
7SOFIA
Stratospheric Observatory for Infrared
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CPIRSS F(12 µm) > 5 Jy, -34° < Dec. < -24°
-36°
-34°
-32°
-30°
-28°
-26°
-24°
-22°
-20°
024681012141618202224Right Ascension (hrs, J2000)
Decli
nati
on
(J2
00
0)
Sky Distribution
QuickTime™ and a decompressor
are needed to see this picture.
FORCAST DRM (green), NOAO + UKIRT + CIO bright IR stars (M < +1), Dec. >-35°
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Stratospheric Observatory for Infrared
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Feasibility: example TA char. Flight plan
ETD: 0320Z Mar. 15, 2010
ETE: 06+50
9SOFIA
Stratospheric Observatory for Infrared
Astronomy
Summary of Observing Legs
Leg no. Object V M F(12µm)Leg
DurationObject elevation
range
4 Saturn 0 30 m 19° - 25°
5 S Cep 7.5 -1.7 383 Jy 24 m 23°
7 HIP 43093 7.2 +1.8 20 Jy 45 m 24° - 23°
9 NGC 6543 9 +7 8 Jy 35 m 22° - 25°
10 NSV 4862 4.3 +1 20 Jy 45 m 23°
12 Gamma Cep 4.2 ~+0.7 21 Jy 37 m 23°
14 W Hya 7.5 - 3.9 4200 Jy 35 m 22° - 24.5°
16 HIP 11978 6,8 +1.1 12 Jy 30 m 23° - 22°
Sum of observing leg durations = 4.7 h
Net time with objects in 22° - 24° elev. range ~4.1 h
10SOFIA
Stratospheric Observatory for Infrared
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“1st Light” & Short Science: availability of M42, Sgr A (winter / spring )
M 42, Sgr A Max. Leg Duration vs. Date( TA Elev. Range 23° - 30° )
0
10
20
30
40
50
60
70
80
90
1-Jan 15-Jan 29-Jan 12-Feb 26-Feb 12-Mar 26-Mar 9-Apr 23-Apr 7-May
Date
Max.
Leg D
ura
tion (
23°
- 30°)
M 42 setting
M 42 rising
M 42 rsing & setting
Sgr A (rising)
• M 42 available both rising & setting thru end of Jan. (8-hr flight can catch both.)
• After that only one leg possible, limited by 23°- 30° elev. range to 40 minutes until ~Apr. 20.
• Sgr A starts to become available in mid-March. (Leg duration limited to 50 min. by 200 nautical mile radius range limit.)
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