Introduction
Sunspot Activity Notes
Solar Observing CD-ROM
Disk Drawings
Eclipses of the Sun
Glossary
Hydrogen Alpha
Sunspot Measurements
Observing the Sun
Parallactic Angle
Software
Solar Books
Stonyhurst Disks
The Sun as viewed from the Earth
Sunspot Area
Sunspot Location
Sunspot Numbers
Sunspot Trends
Transits
Useful Links

Three freeware Windows® 95/98/2000/ME/XP/NT programs are available for the calculation of sunspot locations and their area plus much more: Helio v3.2, Helio Viewer and Helio Creator. These programs are also available on the solar observing CD-ROM. Helio v1.0 featured in the May 2001 Sky & Telescope magazine (page 72).

Helio v3.2

The freeware Helio v3.2 program includes the following features:

  • Determine the solar position (RA, Dec, altitude and azimuth) and solar parameters (Bo, Lo, P, apparent diameter and Carrington rotation of the central meridian) for a given date and time, and observer latitude and longitude.
  • Select the orientation of the solar disk (including equatorial and altazimuth).
  • Display the central meridian, solar equator, latitude lines and longitude lines.
  • Input or select the position of a sunspot directly on the solar disk.
  • Calculate the sunspot latitude and longitude.
  • Input the sunspot size and calculate the sunspot area (in millionths of a solar hemisphere).
  • Display the Carrington Rotation number at the location of the sunspot.
  • Track a sunspot across the disk and from one rotation to the next (or previous) using either Carrington or differential rotation rates.
  • Produce a log file for sunspot measurements.
  • On-line help.

Helio v3.2 can be download as a zip file (845 kB) or a self extracting zip file (883 kB). The user guide is included in the zip files or it can be downloaded here (187 kB). If you have any problems with this program, please email me.

Helio Viewer

As a solar observer who makes full disk drawings and who wished to determine the latitude/longitude and area of spots groups, I wanted an easy way of measuring these parameters without the need for lots of hand calculations. Developed from Helio v2.0 (see above), Helio Viewer drastically reduces the time required to analyse my solar observations. There are two basic modes of operation of Helio Viewer: with the artificial Sun (as appears above) or a user full disk solar image (such as those on this web site). Helio Viewer has the following features:

  • Input of a user full disk image, such as those on this web site or those with the solar disk surrounded by a black background, in bitmap format.
  • Determine the solar position (RA, Dec, altitude and azimuth) and solar parameters (Bo, Lo, P, apparent diameter and Carrington rotation of the central meridian) for a given date and time, and observer latitude and longitude.
  • Select the diameter of the artificial Sun or display the user solar image at its full size.
  • Select the orientation of the solar disk (including equatorial and altazimuth).
  • Display the central meridian, solar equator, latitude lines and longitude lines.
  • Input or select the position of a sunspot by clicking directly on the solar disk.
  • Calculate the sunspot latitude and longitude.
  • Input the sunspot size and calculate the sunspot area (in millionths of a solar hemisphere).
  • Display the Carrington Rotation number at the location of the sunspot.
  • Track a sunspot across the disk and from one rotation to the next (or previous) using either Carrington or differential rotation rates (artificial Sun only).
  • Superimpose the Solar Environment Center (SEC) Solar Region Summary (SRS) report to show the location, region number, group type and area.
  • Measure the separation between two points on the solar disk or outside the solar disk.
  • Produce a log file for sunspot measurements.
  • On-line help.
  • User guide (PDF format).

Further information and screenshots for this program can be found here. Helio Viewer can be download as a zip file (919 kB). The user guide is included in the zip files or it can be downloaded here (222 kB). If you have any problems with this program, please email me.

Helio Image Creator

As I create electronic copies of disk drawings for display on this web site, I wanted an easy way of centering the images, adding annotation such as date & time, cropping to a given size and adding a border. Helio Image Creator performs these functions.

Thus Helio Image Creator has the following features:

  • Inputs a user full disk solar image (in bitmap format).
  • Determines the center of the solar image.
  • Changes the orientation of the image via a flip/mirror or rotation by any angle.
  • Creates a solar image of a specified size, adds annotation to top left, top right, bottom left and/or bottom right of the image and/or adds border.
  • Outputs the created image in bitmap format.
  • On-line help.
  • User guide (PDF format).

Helio Image Creator can be download as a zip file (344 kB). The user guide is included in the zip files or it can be downloaded here (105 kB). If you have any problems with this program, please email me.

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Last updated on 09 January 2007.