XRT Stray Light Study 2015 -- Phase 2 (after 14-June-2015).

Link to the 2014 summary page.
Link to the 2015 phase 1 summary.
Link to the 2016 summary.

(22 June, 2015 by Aki Takeda)
(27 July, 2015 revised.)
(3 August, 2015, non-DC correction added.)

0. Motivation.

On 14-June-2015, around 12UT, there was another jump-up of the stray light intensity, probably caused by the rupture of another sector of pre-filter. G-band intensity monitor at SAO

1. Purposes of the project 2015, phase 2.

2. Summary of Results.

3. Measurements 2015 (phase 2) at a glance.

ID No. date & time (UT) XOB purposes (link: obtained plots & images) memo
12 18-Jun-2015, 17:51:30 1A92 light curve, T-poly(1.4s) and Al-mesh(1s) at DC. prev. bakeout + 16 days.
13 20-Jun-2015, 17:23:00 1A97 light curve, Al-poly (1s), Thin-Be (5.6s) at DC prev. bakeout + 18 days.
14 20-Jun-2015, 19:03:30 1A98 light curve, Ti-poly (2s), C-poly (2s) at DC prev. bakeout + 18 days.
15 30-Jun-2015, 18:23:30 1AA3 light curve, Ti-poly (1.4s), C-poly (2s) at DC *** Data lost ***
16 1-Jul-2015, 17:25:00 1AA4 light curve, Ti-poly (1.4s), Al-mesh (1s) at W-limb prev. bakeout + 1 day.
17 2-Jul-2015, 17:22:30 1AA5 light curve, Ti-poly (1.4s), Al-mesh (1s) at S-pole prev. bakeout + 2 days.
18 3-Jul-2015, 18:36:30 1AA6 light curve, Ti-poly (1.4s), C-poly (2s) at N-pole prev. bakeout + 3 days.
19 3-Jul-2015, 23:32:00 1AA7 light curve, Ti-poly (1.4s), C-poly (2s) at E-limb prev. bakeout + 3 days.
20 18-Jul-2015, 16:05:00 1AB4 light curve, Ti-poly (1.4s), Al-mesh (1s) at DC prev. bakeout + 1 day.
21 19-Jul-2015, 18:19:00 1AB4 light curve, Ti-poly (1.4s), Al-mesh (1s) at DC prev. bakeout + 2 days.
22 11-Aug-2015, 17:18:30 1ABF light curve, C-poly (2s) at DC *** Data partialy lost. (+6days)
23 16-Aug-2015, 18:40:00 1ABF light curve, C-poly (2s) at DC not enough X-ray extinction.

4. Stray light images 2015, at a glance.

Ti-poly, 20150518 DC Ti-poly, 20150618 DC Ti-poly, 20150620 DC Ti-poly, 20150718 DC Ti-poly, 20150719 DC

difference image [2015/06/18]-[2015/07/18]
difference image [2015/07/19]-[2015/07/18]

C-poly, 20150518 DC C-poly, 20150620 DC C-poly, 20150811 DC

Al-mesh, 20150509 DC Al-mesh, 20150618 DC Al-mesh, 20150718 DC Al-mesh, 20150719 DC

Al-poly, 20150507 DC Al-poly, 20150620 DC

thin-Be, 20150507 DC thin-Be, 20150620 DC

Ti-poly, 20150701 WL Ti-poly, 20150702 SP Ti-poly, 20150703 NP Ti-poly, 20150703 EL

Al-mesh, 20150701 WL Al-mesh, 20150702 SP C-poly, 20150703 NP C-poly, 20150703 EL

5. Correction of the images.

5.1 Ti-poly composite images (at DC pointing)

2015/06/18: correction is imperfect because of strong scattered light due to M3.0 flare from the AR12371.

2015/06/18, Before corr. After correction

2015/06/20: stray light image taken with 2sec was too long to be used for quantitative treatment (center portion exceeds 2500 DN). So the stray light image from other date (with proper exposure) should be used for correction.
Three problems in the corrected image:

2015/06/20, Before corr. Corr. by 6/18 stray light img. Corr. by 7/18 stray light img.

2015/07/18 and 2015/07/19: Stray light image taken soon after CCD bakeout, with right exposure (1.4.sec). Synoptic images taken right before (assure same pointing). In the corrected image, stripes gone, while diagonal band edges still seen. Spots were removed by XRT_SPOTCOR.

2015/07/18, Before corr. After correction
1024x1024 image movie
[Before, SL-img & After]

some more attempt
to get better correction.
2015/07/19, Before corr. After correction Corr. with 7/18 stray-light img.

5.2 Ti-poly composite images (at non-DC pointings)

The edges of diagonal band are hard to correct, even with the stray light image taken within 10 minutes.

2015/07/01, Before corr. After corr.
2015/07/02, Before corr. After corr.
2015/07/03, Before corr. After corr.
2015/07/03, Before corr. After corr.

5.3 C-poly composite images (at DC pointing)

2015/08/16, Before corr. Corr. with 8/11 stray-light img.

5.4 Al-mesh composite images (at DC pointing)

No noticable changes.

2015/07/18, Before corr. After corr.

6. Light curves 2015, collection.

moved to the phase 1 page.

7. G-band images analysis.