EOVSA Data Products

Welcome to the EOVSA data products documentation. EOVSA observes the full disk of the Sun at all times when the Sun is >10 degrees above the local horizon, which is season dependent and ranges from 7-12 hours duration centered on 20 UT. During January, coverage will be 16-24 UT daily, 7 days/week. EOVSA will provide microwave spectra and imaging at up to 451 frequencies between 1 and 18 GHz. We deliver the radio interferometry data on three levels.

Brief description of the data products:

Our working definition is that Level 0 is the raw visibility data from the instrument, whereas Level 1 corresponds to the calibrated visibility data, which have all of the required content to produce Level 2 images and spectrogram data in standard FITS format. All of these data products are archived and available online, accessed from the EOVSA server.

Level 0

Raw visibility data from the instrument

Level 1

Level 1 data is the calibrated visibility data in a widely used open-standard format called a CASA measurement set (or “ms”; CASA is the Common Astronomy Software Applications package used by many modern interferometer arrays). Many different CASA ms’s can be created from the raw visibility data by selecting time ranges, frequencies, integration times,polarizations, and so on. We provide standard ms for each day (red boxes in Figure 1), for use by researchers who wish to start with visibility data, while the full-resolution, raw visibility data are made available through links (TBD) to our server. Level 1 data have all of the required content to produce Level 2 data products.

CASA 1-min averaged ms

EOVSA 1-min averaged visibility data in CASA ms format can be retrieved from the following page:

http://www.ovsa.njit.edu/fits/UDBms_slfcaled

CASA Event ms

TBD

Level 2 - Images and spectrogram data in standard FITS format

Getting level 2 data

EOVSA Level 2 data products can be retrieved from the "synoptic data" page:

http://www.ovsa.njit.edu/fits/synoptic

Example - get the synoptic data on December 25, 2019

• go to EOVSA browser page.
• Browse to December 25, 2019.
• Click "synoptic fits" button next to the calendar tool.
• Select the data product you want to download based on the name in the following list.

List of Level 2 data products

category	data product	name
Dynamic Spectrum	All-day TP spectrum	EOVSA_TPall_yyyymmdd.fts
	All-day XP spectrum	EOVSA_XPall_yyyymmdd.fts
Image
	Synoptic 1.4 GHz image	eovsa_20191225.spw00-01.tb.disk.fits
	Synoptic 3.0 GHz image	eovsa_20191225.spw02-05.tb.disk.fits
	Synoptic 4.5 GHz image	eovsa_20191225.spw06-10.tb.disk.fits
	Synoptic 6.8 GHz image	eovsa_20191225.spw11-20.tb.disk.fits
	Synoptic 10.2 GHz image	eovsa_20191225.spw21-30.tb.disk.fits
	Synoptic 13.9 GHz image	eovsa_20191225.spw31-43.tb.disk.fits

Reading level 2 data

Software

suncasa

All-day TP spectrum

Daily total power full-Sun-integrated spectrogram calibrated in solar flux units are provided at 451 frequencies and 1 s time resolution.

from suncasa.eovsa import eovsa_dspec as ds
## define the dynamic spectrum file.
tpfits = 'EOVSA_TPall_20191225.fts'
## display the dynamic spectrum. 
ds.dspec(tpfits)

All-day XP spectrum

Daily cross power spectrogram (mean flux from baselines with "intermediate" lengths) calibrated in solar flux units are provided at 451 frequencies and 1 s time resolution. XP spectrogram has much better sensitivity to weak bursts.

from suncasa.eovsa import eovsa_dspec as ds
## define the dynamic spectrum file.
tpfits = 'EOVSA_XPall_20191225.fts'
## display the dynamic spectrum. 
ds.dspec(tpfits)

Synoptic 6-band Images

Full disk images at 6 selected frequency bands centered at 1.4, 3.0, 4.5, 6.8, 10.2, and 13.9 GHz are provided once per day, calibrated in brightness temperature.