Information - Revision history

Bchen: /* Self-calibration Strategies */

2018-01-02T21:14:31Z

Self-calibration Strategies

← Older revision		Revision as of 21:14, 2 January 2018
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	==Flare Imaging==		==Flare Imaging==
	===Self-calibration Strategies===		===Self-calibration Strategies===
	(Bin) Currently I am using a sliding window of five bands (band_to_selfcal +- 2 bands) to create ~~an image via~~ multi-frequency ~~synthesis~~ as the input model for self-calibration.		(Bin) Currently I am using a sliding window of five bands (band_to_selfcal +- 2 bands) to create multi-frequency synthesized image as the input model for self-calibration at the band in question. Any alternative strategies? How about channel-by-channel selfcal?

	===Imaging Strategies===		===Imaging Strategies===

Bchen: /* Possible Topics */

2018-01-02T21:11:55Z

Possible Topics

← Older revision		Revision as of 21:11, 2 January 2018
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	===Imaging Strategies===		===Imaging Strategies===

	==Software==		==Software Development==
	Currently we are using Python for analyzing calibration data and CASA for script-based imaging.		Currently we are using Python for analyzing calibration data and CASA for script-based imaging.
	# What is the best approach to make an interactive imaging tool to serve the community (for both experts and non-experts)?		# What is the best approach to make an interactive imaging tool to serve the community (for both experts and non-experts)?
	# How about the tool to visualize/analyze/make use of the resulted 4-D dynamic spectral imaging data?		# How about the tool to visualize/analyze/make use of the resulted 4-D dynamic spectral imaging data?

Bchen: /* Software */

2018-01-02T21:11:18Z

Software

← Older revision		Revision as of 21:11, 2 January 2018
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	==Software==		==Software==
	Currently we are using Python for analyzing calibration data and CASA for script-based imaging. What is the best approach to make an interactive imaging tool to serve the community (for both experts and non-experts)? How about the tool to visualize/analyze/make use of the 4-D dynamic spectral imaging data?		Currently we are using Python for analyzing calibration data and CASA for script-based imaging.
			# What is the best approach to make an interactive imaging tool to serve the community (for both experts and non-experts)?
			# How about the tool to visualize/analyze/make use of the resulted 4-D dynamic spectral imaging data?

Bchen: /* Possible Topics */

2018-01-02T21:10:36Z

Possible Topics

← Older revision		Revision as of 21:10, 2 January 2018
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	===Imaging Strategies===		===Imaging Strategies===
			Clean? MEM? Optimum way to do spectral imaging? Here is [https://web.njit.edu/~binchen/download/eovsa/20170910_x8flare/movie_spec_v4/eovsa_spec_20170910.html an example] made for the Sep 10 flare (Bin).

	==Quiet Sun and Active Region Imaging==		==Quiet Sun and Active Region Imaging==
			===Self-calibration Strategies===
			===Imaging Strategies===

			==Software==
			Currently we are using Python for analyzing calibration data and CASA for script-based imaging. What is the best approach to make an interactive imaging tool to serve the community (for both experts and non-experts)? How about the tool to visualize/analyze/make use of the 4-D dynamic spectral imaging data?

Bchen: /* Self-calibration */

2018-01-02T21:01:10Z

Self-calibration

← Older revision		Revision as of 21:01, 2 January 2018
Line 31:		Line 31:

	==Flare Imaging==		==Flare Imaging==
	===Self-calibration===		===Self-calibration Strategies===
			(Bin) Currently I am using a sliding window of five bands (band_to_selfcal +- 2 bands) to create an image via multi-frequency synthesis as the input model for self-calibration.

	===Imaging Strategies===		===Imaging Strategies===

	==Quiet Sun and Active Region Imaging==		==Quiet Sun and Active Region Imaging==

Bchen: /* Strategies to achieve optimum imaging fidelity/resolution for all frequencies */

2018-01-02T20:58:19Z

Strategies to achieve optimum imaging fidelity/resolution for all frequencies

← Older revision		Revision as of 20:58, 2 January 2018
Line 32:		Line 32:
	==Flare Imaging==		==Flare Imaging==
	===Self-calibration===		===Self-calibration===
	===Strategies ~~to achieve optimum imaging fidelity/resolution for all frequencies~~===		===Imaging Strategies===

	==Quiet Sun and Active Region Imaging==		==Quiet Sun and Active Region Imaging==

Bchen: /* Flare Imaging */

2018-01-02T20:57:56Z

Flare Imaging

← Older revision		Revision as of 20:57, 2 January 2018
Line 31:		Line 31:

	==Flare Imaging==		==Flare Imaging==
			===Self-calibration===
			===Strategies to achieve optimum imaging fidelity/resolution for all frequencies===

	==Quiet Sun and Active Region Imaging==		==Quiet Sun and Active Region Imaging==

Bchen: /* Calibration */

2018-01-02T20:55:16Z

Calibration

← Older revision		Revision as of 20:55, 2 January 2018
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	=Possible Topics=		=Possible Topics=
	==Calibration==		==Calibration==
	The ~~"standard",~~ (semi-)automatic calibrations we have done so far:		The (semi-)automatic calibrations we have done so far:
	# Antenna-based amplitude calibration:		# Gain corrections: To account for changes of the attenuation settings (esp. during flares). See [http://www.ovsa.njit.edu/wiki/index.php/System_Gain_Calibration this page] for details.
	# Reference phase calibration: antenna-based, band-averaged phases derived from "reference" observations of strong celestial radio sources every night		# Antenna-based amplitude calibration: made by referencing total power and auto-correlation amplitudes to RSTN/Penticton total solar flux density measurements. See [http://www.ovsa.njit.edu/wiki/index.php/Total_Power_Calibration this page] for details.
	# Daily phase calibration: antenna-based multi-band delays ~~derived~~ from		# Reference phase calibration: antenna-based, band-averaged phases derived from "reference" observations of strong celestial radio sources every night. See [http://www.ovsa.njit.edu/wiki/index.php/Reference_Gain_Calibration this page] for details]
			# Daily phase calibration: antenna-based multi-band delays resulted from the phase difference as a function from frequency between the phase calibrators (observed 3 times during the day) and the reference phases. See [http://www.ovsa.njit.edu/wiki/index.php/Daily_Gain_Calibration this page] for details.
			# Correcting for polarization mixing due to feed rotation: See [http://www.ovsa.njit.edu/wiki/index.php/Polarization_Mixing_Due_to_Feed_Rotation this page] for details.

			More calibrations:
			# Polarization calibration: To calibrate absolute degree of circular polarization. Procedures need to be worked out.
			# Per-channel bandpass calibration within individual bands: To calibrate the phase/amplitude variations from channel to channel. Procedures need to be worked out.

	==Flare Imaging==		==Flare Imaging==

	==Quiet Sun and Active Region Imaging==		==Quiet Sun and Active Region Imaging==

Bchen at 19:43, 2 January 2018

2018-01-02T19:43:11Z

← Older revision		Revision as of 19:43, 2 January 2018
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	* In principle, circular polarization should be valid and meaningful, but no polarization calibration has been done (yet) so no non-ideal behavior (leakage terms, etc.) have been accounted for.		* In principle, circular polarization should be valid and meaningful, but no polarization calibration has been done (yet) so no non-ideal behavior (leakage terms, etc.) have been accounted for.

	==Flare Data==		===Flare Data===
	Folder [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/ Flare_20170910] contains two measurement sets at full 1-s time resolution, each with 10-min duration:		Folder [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/ Flare_20170910] contains two measurement sets at full 1-s time resolution, each with 10-min duration:
	# IDB20170910154625.corrected.ms (171 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910154625.corrected.ms.tar.gz] containing the first 10 minutes of the flare (15:46:25-15:56:25 UT), calibrated but no self-calibration		# IDB20170910154625.corrected.ms (171 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910154625.corrected.ms.tar.gz] containing the first 10 minutes of the flare (15:46:25-15:56:25 UT), calibrated but no self-calibration
Line 11:		Line 11:
	# IDB20170910155625.corrected.ms (232 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910155625.corrected.ms.tar.gz] containing the second 10 minutes of the flare (15:56:25-16:06:25 UT)		# IDB20170910155625.corrected.ms (232 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910155625.corrected.ms.tar.gz] containing the second 10 minutes of the flare (15:56:25-16:06:25 UT)
	# IDB20170910155625.corrected.ms.xx.selfcaled (77 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910155625.corrected.ms.xx.slfcaled.tar.gz] self-calibrated data for polarization XX		# IDB20170910155625.corrected.ms.xx.selfcaled (77 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910155625.corrected.ms.xx.slfcaled.tar.gz] self-calibrated data for polarization XX
	==All Day Quiet Sun/Active Region Data==		===All Day Quiet Sun/Active Region Data===
	Folder [http://ovsa.njit.edu/imaging_workshop/AR_20170710/ AR_20170710] contains 8 calibrated measurements sets at 60-s time resolution.		Folder [http://ovsa.njit.edu/imaging_workshop/AR_20170710/ AR_20170710] contains 8 calibrated measurements sets at 60-s time resolution.
	# The seven UDB20170710*.corrected.ms are files for each scan separately, ranging in size from 7 - 150 MB depending on the length of the scan.		# The seven UDB20170710*.corrected.ms are files for each scan separately, ranging in size from 7 - 150 MB depending on the length of the scan.
	# UDB20170710_allday.ms (268 MB) [http://ovsa.njit.edu/imaging_workshop/AR_20170710/UDB20170710_allday.ms.tar.gz] is the same data concatenated into a single file. However, each scan has a separate source ID.		# UDB20170710_allday.ms (268 MB) [http://ovsa.njit.edu/imaging_workshop/AR_20170710/UDB20170710_allday.ms.tar.gz] is the same data concatenated into a single file. However, each scan has a separate source ID.
	The AR data are also calibrated but not self-calibrated. In fact, we need to create a strategy for self-calibration of such data. You can get an overview of the AR coverage on that day by looking at the plot at http://ovsa.njit.edu/flaremon/daily/2017/XSP20170710.png. The separate scan files above are labeled with the time of the start of the scan, and each scan covers the time of continuous solar data between each calibration scan.		The AR data are also calibrated but not self-calibrated. In fact, we need to create a strategy for self-calibration of such data. You can get an overview of the AR coverage on that day by looking at the plot at http://ovsa.njit.edu/flaremon/daily/2017/XSP20170710.png. The separate scan files above are labeled with the time of the start of the scan, and each scan covers the time of continuous solar data between each calibration scan.

			=Possible Topics=
			==Calibration==
			The "standard", (semi-)automatic calibrations we have done so far:
			# Antenna-based amplitude calibration:
			# Reference phase calibration: antenna-based, band-averaged phases derived from "reference" observations of strong celestial radio sources every night
			# Daily phase calibration: antenna-based multi-band delays derived from

			==Flare Imaging==

			==Quiet Sun and Active Region Imaging==

Bchen at 19:23, 2 January 2018

2018-01-02T19:23:55Z

← Older revision		Revision as of 19:23, 2 January 2018
Line 1:		Line 1:
	Data are [http://ovsa.njit.edu/~~imaging_workshopIDB20170910154625.corrected.ms~~/ here]. ~~Folder~~ ''Flare_20170910'' contains two measurement sets at full 1-s time resolution:		=Sample EOVSA Data=
	# IDB20170910154625.corrected.ms (171 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910154625.corrected.ms.tar.gz] containing the first 10 minutes of the flare, calibrated but no self-calibration		Data are [http://ovsa.njit.edu/imaging_workshop/ here]. Here are some things to consider when working with the data:
			* Antennas 1-8 and 12 have a wide sky coverage, while antennas 9-11 and 13 are the older equatorial mounts that can only cover +/- 55 degrees from the meridian. All antennas were tracking for the flare, but for portions of the all-day scan (roughly before 1600 UT or after 2400 UT) only 9 antennas will be tracking. Data for non-tracking antennas is NOT flagged, so if you try to image these periods, you'll need to manually omit ants 9-11 and 13.
			* Because of the 2.5 GHz high-pass filters, data are taken only for bands 4-34. These will be labeled spectral window (spw) 0-31 in the measurement sets. However, band 4 (spw 0) is currently not calibrated, so only the 30 spectral windows 1-31 (bands 5-34, or frequencies 3-18 GHz) are valid data. You'll need to omit spw 0 when making images.
			* In principle, circular polarization should be valid and meaningful, but no polarization calibration has been done (yet) so no non-ideal behavior (leakage terms, etc.) have been accounted for.

			==Flare Data==
			Folder [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/ Flare_20170910] contains two measurement sets at full 1-s time resolution, each with 10-min duration:
			# IDB20170910154625.corrected.ms (171 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910154625.corrected.ms.tar.gz] containing the first 10 minutes of the flare (15:46:25-15:56:25 UT), calibrated but no self-calibration
	# IDB20170910154625.corrected.ms.xx.selfcaled (66 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910154625.corrected.ms.xx.slfcaled.tar.gz] self-calibrated data for polarization XX		# IDB20170910154625.corrected.ms.xx.selfcaled (66 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910154625.corrected.ms.xx.slfcaled.tar.gz] self-calibrated data for polarization XX
	# IDB20170910155625.corrected.ms (232 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910155625.corrected.ms.tar.gz] containing the second 10 minutes of the flare		# IDB20170910155625.corrected.ms (232 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910155625.corrected.ms.tar.gz] containing the second 10 minutes of the flare (15:56:25-16:06:25 UT)
	# IDB20170910155625.corrected.ms.xx.selfcaled (77 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910155625.corrected.ms.xx.slfcaled.tar.gz] self-calibrated data for polarization XX		# IDB20170910155625.corrected.ms.xx.selfcaled (77 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910155625.corrected.ms.xx.slfcaled.tar.gz] self-calibrated data for polarization XX
			==All Day Quiet Sun/Active Region Data==
	Folder ''AR_20170710'' contains 8 measurements sets at 60-s time resolution.		Folder [http://ovsa.njit.edu/imaging_workshop/AR_20170710/ AR_20170710] contains 8 calibrated measurements sets at 60-s time resolution.
	# The seven UDB20170710*.corrected.ms are files for each scan separately, ranging in size from 7 - 150 MB depending on the length of the scan.		# The seven UDB20170710*.corrected.ms are files for each scan separately, ranging in size from 7 - 150 MB depending on the length of the scan.
	# UDB20170710_allday.ms (~~595~~ MB) is the same data concatenated into a single file. However, each scan has a separate source ID.		# UDB20170710_allday.ms (268 MB) [http://ovsa.njit.edu/imaging_workshop/AR_20170710/UDB20170710_allday.ms.tar.gz] is the same data concatenated into a single file. However, each scan has a separate source ID.
	The AR data are also calibrated but not self-calibrated. In fact, we need to create a strategy for self-calibration of such data. You can get an overview of the AR coverage on that day by looking at the plot at http://ovsa.njit.edu/flaremon/daily/2017/XSP20170710.png. The separate scan files above are labeled with the time of the start of the scan, and each scan covers the time of continuous solar data between each calibration scan.		The AR data are also calibrated but not self-calibrated. In fact, we need to create a strategy for self-calibration of such data. You can get an overview of the AR coverage on that day by looking at the plot at http://ovsa.njit.edu/flaremon/daily/2017/XSP20170710.png. The separate scan files above are labeled with the time of the start of the scan, and each scan covers the time of continuous solar data between each calibration scan.

	~~Here are some things to consider when working with the data:~~
	* Antennas 1-8 and 12 have a wide sky coverage, while antennas 9-11 and 13 are the older equatorial mounts that can only cover +/- 55 degrees from the meridian. All antennas were tracking for the flare, but for portions of the all-day scan (roughly before 1600 UT or after 2400 UT) only 9 antennas will be tracking. Data for non-tracking antennas is NOT flagged, so if you try to image these periods, you'll need to manually omit ants 9-11 and 13.
	* Because of the 2.5 GHz high-pass filters, data are taken only for bands 4-34. These will be labeled spectral window (spw) 0-31 in the measurement sets. However, band 4 (spw 0) is currently not calibrated, so only the 30 spectral windows 1-31 (bands 5-34, or frequencies 3-18 GHz) are valid data. You'll need to omit spw 0 when making images.
	* In principle, circular polarization should be valid and meaningful, but no polarization calibration has been done (yet) so no non-ideal behavior (leakage terms, etc.) have been accounted for.