Baader 100mm AstroSolar ASTF Filter for 120-160mm O.D. Telescopes

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Baader 100mm AstroSolar ASTF Filter for 120-160mm O.D. Telescopes
Item # BA-ASTF-100
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  • Baader's 100mm AstroSolar Filter fits telescopes with an outer diameter of 120mm to 160mm.
  • A unique temperature compensating Baader film mounting system allows Baader film to perform at it's absolute best.
  • Best suited for observing sun spots. Baader ASTF filters are uncommon in that they operate with no astigmatism and can be used with high magnification.
  • AstroSolar safety film is sandwiched between two precision designed rings. The front is IR rejecting with a reinforced edge on the outer and inner edges to help protect your solar film.
  • Totally color neutral, observe the Sun in it's true color - pure white light.
  • AstroSolar telescope filters attach to your telescope with three center bolts with sliding aluminum fasteners. These fasteners can be further locked into place with a standard Phillips head screwdriver.
  • Index marks next to each adjustment screw allow for quick and easy repeated adjustment each time you attach your Baader ASTF filter.
  • AstroSolar film is very delicate in nature. For this reason we cannot accept returns of this item once the box has been opened. Please measure your telescope carefully and when in doubt, give us a call or chat with us to make double sure the filter you're choosing will fit your telescope.


About Baader AstroSolar Filters...

Baader Solar Filters are designed to retain the real optical quality of the diffraction limited AstroSolar Safety Film in a precision mounted, temperature compensated cell. These professional quality Baader Solar Filters provide a secure and simple solution to observing and imaging the sun; utilizing AstroSolar Safety Film. Unlike most ready made filters- which stretch the filter material like a drumhead, destroying the image quality and rendering the film useless for any kind of high magnification work- AstroSolar works differently. By mounting the AstroSolar film in an entirely stress free fashion in a temperature compensated cell, it performs like a high precision planeoptical window.  Don't let ripples in the film fool you.  By not stretching the film tightly, it is permitted to act as it should without any image distortion. To acheive this highly controlled filter construction, the film is firmly adhered to an injection moulded ring.  The substrate of that centering ring has the same thermal expansion rate as the Baader film.  To complete the construction, this carrier ring is free floating within an aluminum frame, held in place with an additional holding ring made of fiber reinforced plastic.  This holding ring's job is to keep your filter safe from breakage.   Baader SolarFilter ASTF filters are highly temperature stable, operating perfectly in temperatures between -22F and 122F, nearly any observing conditions you might find yourself in. 

Often H-Alpha filters, which produce an image in a yellow-orange tone, are refered to as a "natural" colored image because we perceive the sun to be yellow and orange.  In truth, Baader solar film produced a natural color view of the Sun - pure, white light with a slight blue tint.  This permits visibility of the faculae regions of the Sun which are best seen in the blue portion of the visual spectrum.  And because the Baader ASTF filters have total neutral color balance you can use a variety of color filters on the eyepiece to bring out further detail on the solar surface.  The addition of a Baader Solar Continuum filter will further improve already excellent image stability and clarity.   Faculae or bright spots on the sun are further enhanced with the use of a Continuum filter as well.  

The end result is a white-light solar filter that exhibits no astigmatism during cold weather observing or on hot summer days, and is highly suitable for high magnification and detailed sun spot study. 


  • Skillfully constructed and assembled by Baader staff.  
  • Holding ring with raised edges helps to keep sharp edges away from the film.  
  • 3 centering bolts with threaded brass inserts to center the film to the center of your telescope optical tube.  Moulded rubber grips slide onto the telescope easily but provide a firm grip. 
  • Tool-free mounting and adjustment.  The centering bolts are made to make contact with the outside or inside of the telescope optical tube.  Inside mounting required a clear depth of at least 20mm on the inner ring of the optical tube.  
  • Aluminum sliding fasteners are non-rotating and have Phillips head screws so that they can be firmly tightened to the telescope. This prevents slight shifts in filter position and serves as an additional safety feature ensuring your filter stays in place at all times.   
  • A handy scale is next to each adjustment bolt for quick repeated adjustment with each use. 
  • Black sliding washers supplied to securely cover the full length of the adjustment slots in the aluminum frame for blocking sunlight from passing trough the filter cell beside the filter area.
  • Three security straps included, to secure the position of the filter cell with Velcro-adhesive pads. A safety feature to absolutely ensure a secure fit in front of the telescope under any circumstance.
  • Carefully packaged in a stiff cardboard box with special insert to keep your filter in tightly in place while shipping and transporting.  

AstroSolar film is delicate in nature.  For this reason we cannot accept returns of this item once the box has been opened. Please measure your telescope carefully and when in doubt, give us a call or chat with us to make double sure the filter you're choosing will fit your telescope. 

Additional Information

Additional Information

Manufacturer Baader
White Light Filter Material Baader Film
Glass, Film, or Herschel? Mylar or Film Filter
Filter OD Size in Inches 4.1" - 6"
Full Aperture or Off-Axis? Full Aperture
Filter Diameter 100mm
Filter Fits Telescope OD Range of... 120 - 160mm outer diameter or 150 - 190mm inner diameter
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