In doing sunspot observations, there are a host of things to take note as well to be careful of. After consulting INTER-SOL Programme, here is the list of the questions most probably asked by the amateur sunspots observer.

Q: What are the things to take note when using a telescope with solar filter to do sunspot observations?
A: If you plan to use a telescope with a solar filter, make sure it is put in front of the telescope's lens. We do not recommend solar filters which are put on the eyepiece at all, as they indeed may crack, resulting in significant injuries to the observer's eyes. Good solar filters are either made of glass or of a special foil (e.g. AstroSolar). Do not use anything else as a solar filter.
If a proper solar filter is put in front of the telescope lens, the full heat and energy of the sun will never get into your telescope, so it (and you!) can't be hurt. Good solar filters block some 99.999% of the visual light plus IR, UV etc.
Q: What are the things to take note when using the projection method to do sunspot observations?
A: For the projection method, it is essential to use eyepieces with are not puttied. Otherwise you risk ruining the eyepiece. Usually, the most inexpensive eyepieces (e.g. the Huygens or Mittenzwey types) are not puttied.
Q: What are puttied eyepieces?
A: In puttied eyepieces, some or all of the lenses that make up the eyepiece are combined with putty. If you are not familiar with the word, putty similar to adhesive or cement.
Q: If the eyepieces are puttied, how long can they last in the projection method without being damaged?
A: We do not have any experience with the use of puttied eyepieces for solar observations in projection method, and we do not recommend using them at all for solar observations unless a solar filter is used.
Q: What model of telescope’s eyepiece is puttied?
A: It is unfortunately not possible to comment on this as virtually all available eyepieces may be used with any telescope.
Q: Will the projection method burn the paper we are trying to project the sun's image on? How to prevent it if so?
A: First of all if you project the sun onto a sheet of paper, you place the paper far off the focal point so it is highly unlikely that the paper may catch fire. Also, we recommend using a white-painted piece of e.g. plywood instead of paper, as this e.g. also offers you the possibility of fixing a graduation line template on the screen.

For more information on the projection method, go to:

If you are interested in the INTER-SOL Programme or wish to learn more from them, you might want to visit their website for additional information.

Resources: INTER-SOL programme   

Page © of GEM1506K, Group 2 (