1 / 14

XRT’s Observational Parameters

This article provides information about the observational parameters of the X-ray Telescope (XRT) and its capability for full disk imaging. It also discusses the focus mechanism and camera performances of the XRT.

daviddelgado
Télécharger la présentation

XRT’s Observational Parameters

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. XRT’s Observational Parameters R. Kano (NAOJ)

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

  3. 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.) 768 1024 1536 2048 arcsec

  4. 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.

  5. 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.

  6. Time Cadence • 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

  7. 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 AR 10min 50min AR 80sec AR FFI 8min

  8. Observation Table Obs. Program Main routine Subroutine-1 Sequence-1 Subroutine-1 Sequence-1 Exposure-1 Subroutine-2 Sequence-2 Exposure-2 Subroutine-3 Sequence-3 Exposure-3 Sub.- max8 Seq.- max8 Exp.- max8 20 programs for XRT 100 sequences for XRT

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

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

  11. 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.)

  12. Focus Mechanism • Focus Range: +/– 1mm • We can use this mechanism not onlyfor 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.

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

  14. 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

More Related