WHAT SIZE DO I ORDER?
The application table below lists sizes by clear aperture (filter size) and outer cell wall inside diameter (I.D.) The I.D. of the cell slips over and around the O.D. of the telescope tube or lens holder. If you do not see your brand and model, simply choose the closest outer cell I.D. size larger than the outside diameter measurement of your instrument.
ARE THE FILTERS COMPLETELY SAFE?
Black Polymer filters are completely safe for unlimited visual use. If handled with care and common sense, all will last a minimum of 20 years to life.
CAN THE TELESCOPE OPTICS GET HOT OR DAMAGED?
No, all the heat and intense light is blocked before it can enter the telescope. Your telescope may get warm from sunlight shining on it, not from the small amount of visible light transmitted through the filter.
WHAT DETAIL IS VISIBLE?
Sunspots and surface granulation are the two main features.
The only detail that cannot be seen with a standard filter (commonly called white light filter) are prominence and flares which require our highly specialized H-Alpha filter system.
the central axis and out of view.