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Baader Planetarium UV/IR Cut Filter

Baader Trademark (19,559 bytes) Baader 2 inch UV / IR filter (68,093 bytes) The Baader UV/IR Cut filter is designed to reflect infrared energy to protect sensitive equipment and is a good choice for use with heat sensitive accessories including the DayStar Hydrogen Alpha filters. And it will provide improved results when used for CCD imaging particularly when combined with another filter such as the Contrast Booster or Solar Continuum filters. This filter is not in itself helpful for night time visual astronomy.

Right: Baader 2 inch UV / IR Cut Filter P/N BPUVIR2 shown as provided with plastic case and box.
This filter is also available in 1.25 inch diameter shown lower left on this page (70,432 bytes).
Click on image for enlarged view (144.945 bytes).

    Filters take away but they can not add - diminishing some parts of the spectrum
    so that we might resolve what is otherwise obscured...

How Are These Constructed?

The filter is made with a disc of transparent optical glass that has been ground plane parallel to within thirty seconds of arc, and then polished until very smooth. The glass undergoes a vacuum deposition coating process where numerous micron-thin coatings of various elements are applied one upon another in a precise order and thicknesses. The coatings are calculated to transmit desired wavelengths (portions of the visible spectrum), while simultaneously rejecting other wavelengths.

When looking through this filter while holding it parallel to the human eye the filter element appears completely transparent. When tilted, depending on the angle of tilt and lighting, it will then appear to have a greenish or magenta toned antireflection coating.

Baader 1.25 inch UV / IR filter (15,963 bytes) The filter element is housed in a machined aluminum cell, and held in place by a thread-in retaining ring. The filter name, size and part number are in silver, and this mirror like print when combined with the small print size make this information difficult to read in low light or under dim red lighting. Company Seven recommends our customers keep these filters in well organized accessory cases, so one can know which filter is which. It helps to become familiar with how the elements appear too (read descriptions below).

Left: Baader 1.25 inch UV / IR Cut filter (15,963 bytes).

The Baader UV / IR Cut filter is made available in diameters of 1.25 (31.7 mm) and 2 inch (50.8 mm) so that it can be installed in line onto many accessories, or directly onto most popular eyepieces.

What Does This Do For Me?

Protect sensitive equipment from heating during solar applications.

Stays cool and will not shatter if subjected to great thermal stress, since even intensive radiation is not absorbed as with ordinary "heat protective Filters" such as KG-3 or KG-5. Energy is reflected due to an elaborate interference system of twenty three dielectric coating layers.

For for daytime or astronomical digital or film imaging it improves the quality of star images.

Because of it's high ninety eight percent average transmission across the visible spectrum, this filter can be used with with any size or design of amateur telescope with no perceptible loss of brightness.

UV / IR Filter Graph (134,597 bytes) Right: Baader UV / IR filter transmission curves. Notice how little effect it has in the visual spectrum of 400 to 700 nm, while blocking the UV and IR light (132,179 bytes).

Features Of The Baader Filter:

  • The glass elements used to make the Baader Filters are free of striae, optically finely polished plane parallel to within 30 seconds of arc. This eliminates any double images or ghosting due to wedge errors in the glass. These filters tend to far supersede the quality of common color filter elements which are flame polished. The combination of their fine optical craftsmanship and a comparatively thin 2 mm profile allows these filters to be inserted anywhere into the optical path without introducing astigmatism or other noticeable defects into the image. For instance they can be installed in the front of a Binocular Viewer without degrading the image in any way.

  • Filters will thread into conventional slip fit eyepieces or accessories with the common 1.25 inch diameter x 42 tpi (28.5 x 0.6 mm) or 2 inch (50.8 mm) threading. These thread patterns have been tested and optimized to fit allmost all eyepieces on the market.

  • Stackable filters: each filter cell incorporates both a male and a female thread to allow stacking the filters to obtain even narrower passbands or special effects.

  • The filter cells features the largest clear aperture of any 1-¼ and 2 inch filters on the market - for complete freedom from vignetting at any focal length. The front crown of the cell incorporates milled notches which makes handling and threading the filter an easy operation in the dark.

  • For protection, each filter is provided with its own transparent plastic case. We are astonished however, that as outstanding as the filters are, plastic case latch tend to fail sometimes even when new. Company Seven therefore offer optional third party cases. And for the most discriminating clients, we even offer a custom made wood accessory case described below.

    Examples of Imaging with the UV / IR Filter:

    Consider the following three picture which were taken by Mr. Oliver Grattepanche. He explains the instrument and accessories employed:

      "TSC 225 Schmidt Cassegrain from TAKAHASHI, NJP160 mount, F/40 with 2X Big Barlow TeleVue, NGFs more focuser, and OF course your incredible Baader astro+solarly filter D:3.8, IR CUT filter and Continuum filter".

    Above Left to Right: Sunspot taken with VestaPro with 1/3 inch diagonal black and white CCD sensor,
    Surface granulation shown with 800 CCD frames stacked with IRIS astronomical images processing software.
    The colors were added afterward basic image compiling and processing for aesthetic purposes.
    Click on images to see enlarged view

    Optional Wood Case
    optional wood case for Questar Color Filter Set. (52,803 bytes).

    The optional wood case is foam lined with cutaway spaces for filters, eyepieces and other small accessories for your telescope. Please refer to our price list for current prices for the filter set and the optional case or contact Company Seven for more information.

    Right: optional wood box for Color Filter Set (52,803 bytes)
    Click on the image to see enlarged view (190,049 bytes).



    1. It is best to protect the filter from sharp edges or any item that could cause a scratch or abrade the glass.

    2. When not in use, store the filter in a its provided rigid container, and it may help you to keep them organized in a fitted carrying case.

    3. Dew may form on the filters, if this happens do not store a wet filter into its airtight container for long periods of time; whenever possible let the filter "dry out" in order to reduce the potential for problems developing associated with Fungus, etc.

    4. Draw any large, loose bits of foreign matter from the surface of the glass with an air bulb or small vacuum. Stubborn particles can be removed with a soft camel's hair brush. Throughout the year, but especially in cold climates when static become more of a problem we particularly recommend the use of a Staticmaster brush.

    5. Place a few drops of an approved lens cleaning solution (by Carl Zeiss or Kodak) or mild soap solution of clear dish washing liquid diluted with distilled water onto a cotton swab. Then gently wipe in a circular motion with little or no pressure. The filter can be damaged if there are tiny abrasive particles on the surface which are pressed in by rubbing hard.

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