XRT’s Observational Parameters R. Kano (NAOJ)

Contents FOV & Full Disk Imaging Time Cadence & Observation Table New Items as Solar X-ray Telescopes –Pre-flare Buffer –Focus Mechanism Camera Performances

Field of View (FOV) 10 different size: 64, 128, 192, 256, 384, 512, 768, 1024, 1536, & 2048 (arcsec). A rectangular FOV is also available. (64arcsec is only for a square FOV.) 2048 arcsec

Full Disk observation is rare. The size of the largest FOV (2048”) is larger than the solar diameter. However, it is rare to observe the full disk, because Solar-B usually pointing a feature on the solar disk for SOT. This is an example of AR observation.

For Full Disk Observation... To take a full disk solar image regularly, it is necessary to change the Solar-B pointing. I propose that we take the full disk solar image several times in a day. It takes about 5(TBR)min to change and stabilize the S/C pointing.

typical data rate = about 300k pixel / min example-1 : AR observation = 294k pixel / min 384”x384”, 1”-res., 2-filter images & 1min interval example-2 : high speed AR obs. = 294k pixel / min 384”x384”, 1”-res., 2-filter images & 10sec interval 10min observation and 50min non-observation. example-3 : AR & FFI observation = 287k pixel / min 384”x 384”, 1”-res., 2-filter images & 80sec interval 2048”x2048”, 4”-res., 2-filter images & 8min interval Time Cadence

typical data rate = about 300k pixel / min example-1 : AR observation = 294k pixel / min example-2 : high speed AR obs. = 294k pixel / min example-3 : AR & FFI observation = 287k pixel / min 1min 10min 50min 80sec 8min AR FFI AR

Observation Table Subroutine-1 Subroutine-2 Subroutine-3 Sub.- max8 Main routine Sequence-1 Sequence-2 Sequence-3 Seq.- max8 Subroutine-1 Exposure-1 Exposure-2 Exposure-3 Exp.- max8 Sequence-1 Obs. Program 20 programs for XRT100 sequences for XRT

Exp.-1: FOV=384”x384”, Res.=1”, Fil.=Thin Al poly Exp.-2: FOV=384”x384”, Res.=1”, Fil.=Medium Al Sequence-1: temperature analysis of active regions Exp.-1: FOV=2048”x2048”, Res.=4”, Fil.=Thin Al mesh Exp.-2: FOV=2048”x2048”, Res.=4”, Fil.=Thin Al poly Sequence-2: temperature analysis of full frame images Sequence tables are Building blocks. 100 Seqence tables for XRT are stored in MDP.

An Example of Obs. Table Sequence-1: T-ana. of AR Sequence-2: T-ana. of FFI 1 time 8 times Sequence-1: T-ana. of AR Sequence-3: Dark images 1 time 8 times Subroutine-1: 2 times Subroutine-2: 1 time Main routine-1 AR FFI Dark

Pre-flare Observation FOV: 512x256 arcsec, 1”-res. –(You should predict the location of flare site.) 13min Pre-flare images can be kept. Time resolution before the flare onset(X) –X-780sec – X-260sec:60sec interval –X-260sec – X-110sec:20sec interval –X-110sec – X :10sec interval (This is a typical example. You can adjust the duration and interval of pre-flare data.)

Focus Mechanism Focus Range: +/– 1mm We can use this mechanism not only for the engineering purpose (to cancel the focus shift by the launch env. etc.), but also for the observational purpose: –Better resolution only near the CCD center vs. –Moderate resolution over the whole CCD. The usage rate is lower than 15 times in a day.

Aberration at Different Focus Pos. φ512’’φ1024’’ RMS=φ1’’ Distance from the Center (Only Geometrical Optics)

Camera Performances Dark Free –CCD temperature will be lower than –43 C. –0.1 – 1 e/pixel/sec –<<1DN/pixel, if the exposure <<1min Low Noise –20 electron (= 0.4 DN) cf.) 1DN(Data Number)=50e