1.1 Image quality:
FD-TXI: The optical train (primary mirror, secondary mirror, TXI flat mirrors,
entrance aperture and focal plane filters) shall
have a 90% encircled energy of <2" and a FWHM
n.t.e. TBD".
HR-TXI: The optical train (primary mirror, secondary mirror, TXI flat mirrors,
entrance aperture and focal plane filters) shall
have a 90% encircled energy of <0.02" and a FWHM
n.t.e. TBD".
(NB: Pixel sizes for the instruments are approximately
1, 0.01'' respectively)
1.2 Multilayer coatings:
1.2.1 Bandpass: Primary and secondary mirrors to have broad-band
(170-220A, TBR) coatings.
1.2.2 Reflectivity: Primary and secondary mirrors to have a peak reflectivity
>25% at TBD lambda.
1.2.3 Uniformity:
1.2.4 TXI mirrors to have..??
1.3 Spectroscopy:
1.3.1 Mechanism Times (all include settling times):
1.3.1.1 Changeover time, TXI-broadband: 5 minute (TBR), including settling
1.3.1.2 TXI small-lambda (0.5A ~ 0.045 radians) motions: 1 second (TBR)
1.3.1.3 TXI large-lambda (from any lambda to any other, approx. 0.15rad):
5 seconds (TBR)
1.3.2 Mechanism Accuracy: TXI smallest steps are 0.1A (~ 0.009rad).
1.3.3 Mechanism Repeatability: TXI lambda repeatablity to within 0.1A.
1.3.4 Mechanism range: TXI range is 170-220A (TBR) ~ 8degrees, or 0.15 rads
1.3.5 Mechanism directionality: TXI must be capable of slewing up and down
in wavelength.
1.4 Telescope co-alignments (see note below on required offsets):
FD-TXI to MR-TXI: 100'' on orbit
MR-TXI to HR-TXI: 10'' on orbit
Magnetograph to FD-TXI: 30'' [TBR] on orbit
offsets: The telescopes are not strictly co-aligned. There is an
offset imposed by the requirement that the gaps in the CCDs caused
by butting them do not overlap. Thus, the MR-TXI CCD image falls
250 +/- 100 FD-TXI pixels above the FD-TXI butt line. Likewise,
the HR-TXI image falls 200+/- 200 MR-TXI pixels above the MR-TXI
butt line.
1.5 Optical Alignments:
1.5.1: Each telescope's optical system must be capable of achieving final
alignment in orbit consistent with the required image quality as
defined in 1.1.
1.6 Focus Requirements:
1.6.1: Each telescope's optical system must be capable of achieving final
focus in orbit consistent with the required image quality as
defined in 1.1. Both coarse and fine focus must be provided for.
2. FILTERS:
2.1 Focal Plane Filters: Shall transmit not less than 80% of the incident
x-ray flux, over the range of 170-220A.
3. LIGHT REJECTION
4.1 Visible light rejection at
the focal plane: variable from 10*4 to 10*14 by using
different focal plane filter combinations (requires 2 filter
wheels with at least one open position on each).
4. EXTENDABLE BENCH:
4.1 The bench must be capable of extending to a final length of 30m, and
must be capable of fitting inside a Delta-2 shroud at launch. The bench
must be of sufficient stiffness to enable the focus and alignment
of the telescopes to be maintained over periods of not less than 30 days.
5. CCD REQUIREMENTS
5.1 Minimum integration time: 0.1s
5.2 Maximum integration time: 200s
5.3 Detector size: 4Kx4K (or 2Kx4K, buttable)
5.4 Read noise requirement: TBD
5.5 Dark count requirement: TBD
5.6 Simultaneous start times: Any combination of science CCDs
must be capable of simultaneous start times
(to within 0.1 TBR seconds).
6. CALIBRATIONS
6.1 Ground Calibrations:
6.2 In-flight Calibrations:
6.2.1 CCD Dark frames
6.2.2 CCD Flat fields
6.2.3 Throughput vs. time
6.2.3.1 Filter throughput vs. time
6.2.3.2 Mirror reflectivity vs. time
6.2.3.3 CCD sensitivity vs. time
7. ISPI REQUIREMENTS
8. MAGNETOGRAPH REQUIREMENTS
9. POINTING REQUIREMENTS:
9.1 Absolute knowledge:
9.2 Relative:
9.3 Max. offset from Sun Center:
9.4 Separate Telescope Offsets: there are no requirements that the
three telescopes be capable of viewing different FOVS.
9.5 Focal plane must be capable of following a feature at the solar
equator for exposures between 1-200 seconds.
(2km/sec at solar eq => 0.3 pixel/second
in HR-TXI, 0.03 pixel/second in MR-TXI, and 0.003 pixel/second
in FD-TXI, assuming 12 micron pixels ).
10. TIMING REQUIREMENTS:
10.1 Absolute timing: to within 1 TBR second
10.2 Relative timing: to within 0.1 TBR second
B. HIREX DERIVED ENGINEERING REQUIREMENTS
C. HIREX ENGINEERING DESIGN DRIVERS
1. All optics must be easily accessible/replaceable. Replacement
includes alignment/focus.
2. Weight reduction is a primary consideration.
Questions, comments pcheimets@cfa.harvard.edu