Size: 4 InchesA good astronomer wants to use his telescope at night AND day. For this you need a high quality solar filter. Sunspots, eclipses and transiting satellites, all can be seen clearly and safely when using a silver-black polymer filter. The sun will appear in a natural orange color through your telescope. Buying the sheet and making the filter on your own will also save you a lot of money. have been producing high quality solar filters for the past 30 years and we are an authorized distributor of theirs. Worldwide shipping available.