By Mike Mugavero Quite simply put, Hydrogen Alpha filters are designed to transmit a narrow section of the solar spectrum while reflecting or absorbing undesirable light. To accomplish this, the filter must break down white light into its constituent form to produce a rainbow of colors. Providing optical filtration in this order of dimension is most demanding. In my opinion, DayStar makes the best filters. Remember, the narrower the filter bandpass, the higher the contrast of solar features.
Temperature affects the wavelength, which in turn affects the contrast of the filter.
Observers using the filter during the summer months should not run into any problems with contrast, as long as you protect the filter from direct sunlight by placing a shield of some sort over it. In order to accomplish this, DayStar offers a filter temperature regulator, called the Filter Temperature Regulator Oven. It is found that fast optical systems create a heavy heat load and broaden the systems bandpass. Both high heat and UV light will shorten the life span of your filter. It must be noted here that only a refractor or Catadioptric telescope should be used.