2009/06/22 XRT Team Meeting 1 A Proposal of Standard Observ ations: AR, Flare, and PreFlare R. Kano (NAOJ)
2009/06/22 XRT Team Meeting 1
A Proposal of Standard Observations:AR, Flare, and PreFlare
R. Kano (NAOJ)
2009/06/22 XRT Team Meeting 2
Concept of Standard Obs.
• Active Region (AR)– Take 2(or 3)-filter images with 3 different FOVs (Core, Border and
Environment) all day. • It is because events in active regions often affect (or are affected by) their environments.• This plan does not cover detail studies for multi-thermal (or DEM) structures. Special observations or coll
aborations with EIS will be needed for them.
– Take AR Core with the ~1 min cadence.• Because sound waves (~240km/s) take 5 min to travel along a loop (~100” = 73Mm), we can catch 5 pha
ses of motions with sound speed in a loop.
• AR with PreFlare observation– The same observation, but with a rapid cadence for Core- and Bor
der-FOVs by using preflare buffers.
• Flare (FL)– The same set of FOVs, but with a rapid cadence and thicker filters.
2009/06/22 XRT Team Meeting 3
A Baseline Plan for Standard AR Observation
Core- FOV: 384”x384”- Res.: 1”x1”- Filter: G2 & G3- Exp.: AEC3 (no sat.)- Cadence: 1 set / 1 min
Border- FOV: 768”x768”- Res.: 2”x2”- Filter: G1, G2 & G3- Exp.: AEC2 (small sat.)- Cadence: 1 set / 2 min
Environment- FOV: 1024”x1024”- Res.: 4”x4”- Filter: G1 & G2- Exp.: AEC2 (small sat.)- Cadence: 1 set / 2 min
(Images were taken in a dry run in May. )
The 1st dry run on May 23 revealed that we should reduce the data rate for continuous observations.
2009/06/22 XRT Team Meeting 4Com
posi
te I
mag
e of
3 F
OV
s t
aken
with
Ti/p
oly.
in th
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st o
n M
ay 2
3
(see
App
en
dix-
1) 384”x384”
1024”x1024”
2009/06/22 XRT Team Meeting 5
Filter Groups
G1• Al/mesh
G2• Ti/poly.• C/poly.• Al/poly.
G3• thin Be
G4• med Al• med Be
G5• thick Al• thick Be
• We classified the X-ray filters into 5 groups in this PPT, to simplify the proposal.
thinner thicker
AR Core
AR Border
AR Env. FL Core
FL Border
FL Env.
2009/06/22 XRT Team Meeting 6
What is different from AR Obs?
Core- FOV: 384”x384”=ROI-15- Res.: 1”x1”- Filter: G2 & G3- Exp.: AEC3 (no sat.)- Cadence: 1 set / 1 min
Border- FOV: 768”x768”=ROI-16- Res.: 2”x2”- Filter: G1, G2 & G3- Exp.: AEC2 (small sat.)- Cadence: 1 set / 2 min
Environment- FOV: 1024”x1024”- Res.: 4”x4”- Filter: G1 & G2- Exp.: AEC2 (small sat.)- Cadence: 1 set / 2 min
30sec 1 min 1 minG4 & G5 G2, G3 & G4
• Flare Observation
• AR with PreFlare ObservationCore- FOV: 384”x384”- Res.: 1”x1”- Filter: G2 & G3- Exp.: AEC3 (no sat.)- Cadence: 1 set / 1 min
Border- FOV: 768”x768”=ROI-5- Res.: 2”x2”- Filter: G1, G2 & G3- Exp.: AEC2 (small sat.)- Cadence: 1 set / 2 min
Environment- FOV: 1024”x1024”- Res.: 4”x4”- Filter: G1 & G2- Exp.: AEC2 (small sat.)- Cadence: 1 set / 2 min
30sec 1 min
2009/06/22 XRT Team Meeting 7
Schematic View of Time Cadences
Core
Border
Env.
Core
Border
Env.
From AR obs. to FL obs.
From AR+PreFlare obs. to FL obs.
Stored in Preflare BuffersOverwritten in Preflare Buffers
~ 1 min ~ 30 sec
~ 30 sec~ 30 sec
FL modeQT mode
FL modeQT mode
time
time
Different colors mean different filters.
2009/06/22 XRT Team Meeting 8
Estimated Data Rate• Based on the dry-run test using JPEG Q95 (see Appendix-2),
the data rate of the baseline AR obs. is estimated to 3,057 Mbits/day.It is much larger than the recent DR volume allocated to XRT (800~900 Mbits/day).
• We would like to keep the concept. But, some modifications are necessary. For examples:– Reduce the cadence from 1min to 2min for Core,
and from 2 min to 12min for Border & Env. 867Mbits/day
– Reduce the FOV size to 256”x256” but keep the 1min cadence for Core. Reduce the cadence to 10min for Border & Env.
873Mbits/day– Reduce the JPEG-Q from 95 to 85 for Core and to 92 for Border & Env.
For Border & Env., reduce the cadence to 5min also (see Appendix-3). 875Mbits/day
2009/06/22 XRT Team Meeting 9
Test Programs for AR(#16B4) & FL(#16B5)
AR Core
AR Border
AR Env.
G-band& Darks
FL Core
FL Border
FL Env.
G-band
Appendix-1:
2009/06/22 XRT Team Meeting 10
Compression Rate median values derived in the test AR observation on May 23.
Appendix-2:
G3: thin Be G2: Ti/poly. G1: Al/mesh
Core384”x384”, 1”-Res.
19.5%2.34bit/pix
24.6%2.95bit/pix
-----
Border768”x768”, 2”-Res.
21.1%2.53bit/pix
42.2%5.06bit/pix
54.9%6.59bit/pix
Env.1024”x1024”, 4”-Res.
----- 51.6%6.19bit/pix
50.0%6.00bit/pix
JPEG(Q=95) was used for all X-ray images.
• The data rate of the baseline AR obs. was estimated based on this compression rate and the parameters on slide 4.
2009/06/22 XRT Team Meeting 11
Smaller Q-values were tested on June 13.
XOB#16B4 thin Be Ti/poly. Al/mesh
Core 16.4% 20.7% -----
Border 23.5% 44.8% 54.5%
Env. ----- 53.2% 55.7%
XOB#16C5 thin Be Ti/poly. Al/mesh
Core 8.2% 11.2% -----
Border 17.2% 37.8% 46.8%
Env. ----- 45.7% 48.0%
Core: Q85
Env.: Q92
Border: Q92
Core: Q95
Env.: Q95
Border: Q95
Appendix-3:
It looks okey.