XRT Stray Light Study 3 -- Measurement and Correction.
Link to the 2nd test page.
Link to the 4th test page.
(29 May, 2014 by Aki Takeda)
1. Stray light correction project -- the 3rd test.
1.1 Purposes of the 3rd test.
- collect more light curves of the XRT eclipses.
- first trial to obtain Al-poly and C-poly stray-light images.
1.2 Test sequence.
The second test was performed on 27-May-2014, 20:25 -- 20:50UT.
- 20:22:00 -- s/c pointing to disk center (0,0)
- 20:25:00 -- 9-filter synoptic program (to take Al-poly and C-poly composites).
- 20:41:00 -- test sequence started (until ~20:50).
- -----------------------------------------------------------------------------------------------------------------------------------------------
- 250x250 pix, 1" resol., every 10 sec on AR12073, Ti-poly + G-band(VLS close).
- 1024x1024 pix, 2" resol., every 60 sec, Full-Sun, Al-poly + C-poly.
- detailed parameters of the sequence (XOB#1A25).
- -----------------------------------------------------------------------------------------------------------------------------------------------
- 20:41:30 ------ XRT entering twilight zone.
- 20:47:30 ------ XRT s/c night entry.
- 21:00:00 ------ XRT SAA entry.
- 21:04:30 ------ XRT s/c night exit.
- 21:10:00 ------ XRT exiting from twilight.
- 21:23:30 ------ XRT SAA exit.
2. Result of the test observation.
2.1 Solar condition
2.2 Sunset light curves
2.3 Stray light images
Al-poly stray light images obtained (movie).
No significant stray light detected.
C-poly stray light images obtained (movie).
2.4 Image correction.
Correction of the synoptic composite image (C-poly) taken 16 minutes before the 3rd test.
| BEFORE [synoptic (double) composite image] |
AFTER [stray light image (prep-ed) subtracted] |
 |
 |
[memo] Synoptic Composite Image Archive :
1) the May-2014 page updated with corrected Ti-poly images.
2) Ti-poly images in the Apr-2014 page also re-processed for correction with
the same terminator image taken on 20140515.
3) Ti-poly (1024x1024) images in the May-2012 page (the stray-light problem
started this month), are tried to correct, using the 20140515 terminator
image. It turned out that simple subtraction causes over-correction.
A fudge factor of 0.5 is effective to get desent Ti-poly images.
