One of the major objectives of the society is to
promote the science of Astronomy through scientific
programs in observational astronomy and other fields.
These programs enable professional and nonprofessional
astronomers to engage in research studies in collaborative effort.
I. Philippine Solar Index Program
As the center for astronomical data
archiving and requisition in the country, the
Astronomical League of the Philippines is responsible
for producing the Philippine Sunspot Number (Rp)
and Group Sunspot Number (Rg) with the assistance of astronomers sending
sunspot data to the society.
The relative sunspot number or Wolf Number is computed
using the equation Rp = k(10g +s), where:
Rp corresponds to the Philippine Sunspot Number;
g = number of visible sunspot groups; and s
= total number of individual sunspots. The k-coefficient
used is unity or 1.
The group sunspot number is computed by averaging
monthly group counts by individual observers.
The current coordinator of the Philippine Solar Index
Program is Raymund John Ang.
- Observers are requested to make observations of
sunspots using direct or projection method. Full
aperture filter must be placed over the objective for
direct viewing. Note that the use of eyepiece solar
filters is extremely hazardous and can cause
irreversible blindness. Although the projection method
yields lower resolution, it is recommended for beginning
solar observers. Remember to cover the finder scope to
avoid accidents and injuries. Use of cheap eyepiece
models for projection is advised since the setup may
result to damage to the eyepieces, especially in
- Telescopes with clear aperture of 50 - 80mm
should be used when monitoring sunspots. If using medium
to large aperture equipments, use an aperture stop to
reduce effective aperture to about 80mm. Useful
magnification for sunspot observations is from 40 - 100x.
Low and high magnification scanning of solar surface is
- Be sure to count all visible groups and spots. The
relative sunspot number devised Wolf is adopted in
computing for the Philippine Sunspot Number (Rp) with
k-coefficient set to unity or 1.
- For the Group Sunspot Number (Rg), individual group count
should be made.
- Sunspot data must be sent to the Coordinator on or before the 10th day of the
proceeding month for inclusion in the Solar Bulletin
section of the Philippine Journal of Astronomy.