Thousand Oaks Optical
Thousand Oaks Optical has been supplying safe solar filtration to the amateur and professional solar astronomy community for decades and makes three different types of white light solar filters as described below:
Optical Film Solar Filters
After years of R&D we have developed a new solar film that has the optical quality of glass with the advantages of impregnated polymer. Will never develop pinholes or scratches that can let in light and ruin a filter. Other advantages: lightweight and does not require rebalancing tube assembly, will not break, consistent yellow-orange solar image, even density with any aperture, flat surface compared to other thing film filters that have wrinkles and creases. Will not tear or puncture. Stronger than any other solar film on the market. Also available in sheets. Guaranteed 15 years.
Type 2+ Glass Solar Filters
Made with high quality hand select glass coated with Thousand Oaks’ exclusive Solar II Plus. The most durable glass filter on the market. Guaranteed fifteen years, and properly cared for should last a lifetime. These filters are the most popular because of their excellent resolving qualities and because of their durability, many choose Type 2+ Glass over other types.
Frequently Asked Questions
WHICH TYPE OF FILTER IS THE BEST OPTICALLY; R-G, BLACK POLYMER, OR TYPE 2+ GLASS?
The RG film offers the highest resolution with high magnification. The glass is a very close second. Under low to moderate magnification, it's difficult see the difference between RG, Glass or Black Polymer.
ARE THE FILTERS COMPLETELY SAFE?
All of Thousand Oaks Glass 2+, RG-Solar Film & 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.
WHAT IS THE TRANSMISSION OF THOUSAND OAKS OPTICAL FILTERS?
Solarlite: 1/1,000th of 1% (Optical Density 5). Great for both visual and photographic use.
DO THE ALUMINUM CELLS COME WITH THUMB SCREWS?
Thumb screws may seem like a good idea, however, Thousand Oaks extensive testing found that in most cases it's actually less secure than a felt lining which covers a lot more surface area for a secure friction fit. If the tolerance is within a few thousands of an inch such as with eyepiece holders, it would be fine, but this is rarely the case. Thumb screws can also dent and scratch the tube and put strain on the filter glass. Thumb screws are simply a "one size fits many" manufacturing shortcut and provide a false security.
WILL 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.
HOW MUCH DETAIL CAN I SEE?
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 specialized H-Alpha filter systems.