A Proposal of Standard Observations: AR, Flare, and PreFlare

2009/06/22 XRT Team Meeting 1

A Proposal of Standard Observations:AR, Flare, and PreFlare

R. Kano (NAOJ)


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.


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

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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 CoreAR Border

AR Env. FL CoreFL Border

FL Env.


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


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


30sec 1 min


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 modetime

time

Different colors mean different filters.


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


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:


Compression Rate median values derived in the test AR observation on May 23.

Appendix-2:

G3: thin Be G2: Ti/poly. G1: Al/meshCore384”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.


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.

A Proposal of Standard Observations: AR, Flare, and PreFlare

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