Baader Planetarium

BAADER ASTF240 AstroSolar Telescope Filter 240mm

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Your Price: $209.99

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Product Overview

Baader Solar Filters provide a professional and secure solution to observe and image the Sun using AstroSolar Safety Film. Many ready made filters do stretch the filter material like a drumhead in order to make it look like a piece of glass – this absolutely does destroy the image quality, rendering the film useless for high magnification work. AstroSolar must be mounted entirely stress free in order to perform like a high precision planeoptical window. It sounds like a contradiction with traditional perception of quality, but AstroSolar must show slight ripples! Only when the film is being put under stress by an improper cell mount it performs just like any single side coated glass-filter made of untreated floatglass.

All Baader Solar Filters feature:

  • original Baader AstroSolar® Safety Film (OD 5.0), cell mounted and quality inspected by skilled members of our staff
  • clear white IR-rejecting front ring with reinforcing raised edges along the outer and inner circumference, designed to protect the solar filter material from contact with any sharp metal edge
  • 3 injection molded centering-bolts with threaded brass inserts to center the filter-cell in front of the tube opening. These bolts come in three different diameters, depending on the filter category (ASTF/ASSF/ASBF). Each bolt features injection molded rubber grip-faces, shaped to easily slide onto any telescope tube – but are very hard to come off
  • no tool mounting and adjustment of the centering bolts to fit a wide variety of mechanical tube diameters. Bolts made to contact the outside or optional (if appropriate) the inside of the optical instrument tube
  • non-rotating sliding fasteners made from aluminum that hold the centering bolts. These metal sliders are equipped with a machined indicator to point towards the adjustment index
  • additional Phillips screws are integrated into the sliding fasteners, so that the centering bolts can be firmly fastened with a screw driver if preferred by the user
  • index scale provided beside each adjustment slot – adjacent to each sliding fastener, for fast and repeatable adjustment of the filter cell onto different telescope tubes
  • 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
  • (only for ASTF-filters) rubber plugs supplied as cover for closing unused adjustment slots in the aluminum frame
  • 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 circumstances (gust of wind asf)
  • warning text printed onto the front side of each filter cell: Read the Instructions before use
  • cardboard gift box fit for safely shipping the filter

Baader ASTF 240 mm Solar Filter Specifications

  • Best for Telescope Apertures: 230 mm -250 mm
  • Filter Aperture: 240 mm or 9.45”
  • Outer Cell Diameter: 330 mm
  • Net Weight: 230 grams or 8.1 ounces
  • ID Clamping Range with 10 mm Bolt: 290 mm - 320 mm
  • ID Clamping Range with 20 mm Bolt: 300 mm - 330 mm
  • OD Clamping Range with 10 mm Bolt: 270 mm - 300 mm
  • OD Clamping Range with 20 mm Bolt: 260 mm - 290 mm


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