TABLE1.REV -- POLAR HOLES 1970-JULY 1995
TABLE2.REV -- EQUATORIAL HOLES 1970-JULY 1995
TABLE3.REV -- LONG DURATION POLAR HOLES 1970-JULY 1995
TABLE4.REV -- LONG DURATION EQUATORIAL HOLES 1970-JULY 1995
TABLE5     -- ALL HOLES AUGUST 1995 TO PRESENT



Revised 26 October 1995 -- new text for data starting August 1995 (TABLE5)


SOLAR CORONAL HOLE DATA

Antonio Sanchez-Ibarra
Centro de Investigacion en Fisica/EOS
Universidad de Sonora
Hermosillo Sonora, Mexico

and

Marcela Barraza-Paredes
Centro de Investigacion en Astronomia Solar, CIAS
Hermosillo Sonora, Mexico

Since August 1, 1995, Coronal Holes are measured on a daily basis from images 
taken from the Soft X-ray Telescope on board the YOHKOH Japanese spacecraft 
instead of the previous method of reducing the data solely from Kitt Peak 
Vacuum Telescope He 1083 nm images. 

Daily YOHKOH Soft X-ray Telescope combined images with a grid overlay are used 
to determine heliocentric coordinates of coronal holes. A daily synoptic chart 
is used to help in the identification of both equatorial (isolated) and polar 
(polar extension) holes. Images are calibrated using as a reference the level 
of brightness from holes at the poles to identify the lower densities of the 
corona. Preliminary identification and measurements of positions and 
extensions of the holes are done daily with the uncertainty level remarked.  
These data are on-line after 1900 UT daily at our World Wide Web Internet 
site (http://www.uson.mx/unison/eos/eos.htm). An extended revision is done 
every month before publishing the data. Identification of the coronal hole's 
main polarity is made using magnetograms from the National Solar Observatory 
Kitt Peak Vacuum Telescope.

These coronal hole data are still under revision.  We are trying to determine 
how the extended emission of active regions affects the perspective of coronal 
holes far from the central meridian. Also, comparisons are now made with the 
identification of coronal holes on Kitt Peak He I 1083 nm images.

Continuing with the Catalogue of Coronal Holes 1970-1991 (Report UAG-102), and 
with the purpose of following the original identification number, an extended 
section of data based on the analysis of Helium I 1083 nm synoptic charts from 
the National Solar Observatory's Kitt Peak Vacuum Telescope was added to the 
original Catalogue. These data cover the years 1991-1995 (Carrington rotations 
1850 to 1898) and the identification method, classification, and measuring 
procedures used are the same as the original Catalogue.  These revised archive 
data are available on-line via ftp anonymous (ftp ftp.ngdc.noaa.gov, cd STP, 
cd SOLAR_DATA, cd CORONA), or via the Word Wide Web (http://www.ngdc.noaa.gov).




SOLAR CORONAL HOLE DATA LEGEND



CH:
Coronal Hole identification number and type: 
E=equatorial, P=polar.


SHAPE:
Polar coronal hole shapes are divided into several classifications:

B=booted,
C=conic,
D=dumbell,
E=elongated
I=irregular,
P=pointed,
R=ramified,
S=square


Equatorial coronal holes are classified as: 

C=circular,
E=elongated,
D=elliptic
I=irregular,
R=ramified


UNCERTAINTY:
Certainty in measurements: 1=high, 1=medium, 3=poor.


REMARKS:
C=connected, 
D=disconnected
PI=provisional identification, 
R=related to (hole identification number)