Please note that the shown ASTF Filter is an example image of ASTF 100 filter. Inner radius variies on other ASTF-Filters

BDSF – Baader Digital Solar Filter (OD 3.8) for high-end telescopes

Includes 19% VAT
Delivery Time: approx. 2-3 workdays
  • Attention: NOT suitable for visual solar observation. Only use for digital imaging with all high-end telescopes and extreme tele-lenses (lucky imaging technique)
  • AstroSolar PHOTO Film OD 3.8, mounted stress free in temperature compensated cell
  • suitable for highest magnifications and detailed imaging of individual sunspots
  • no astigmatism during winter observation or with temperature changes in summer

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Product Description

(…) I am extremely pleased with the performance of the ASTF. It exceeded my expectations and provided a white light solar view that was brighter and more detailed than the standard full aperture glass filter I have could provide. The primary and secondary mechanisms to secure the ASTF to the dew shield were both robust and provided completely safe operation, even in windy conditions. Best of all though was the performance, clearly besting my glass filter! Finally, all components of the product were very nicely engineered and showed a high level of quality and construction. An excellent product in performance, engineering, and construction, and now a permanent part of my equipment for white light solar observing! © William Paolini. Read the full review:


Review ASTF White Light Filter - William Paolini

Download baader-astf-whitelight-filter.pdf

ATTENTION: Baader Digital Solar Filter with AstroSolar® PHOTO Film OD 3.8

The Baader Digital Solar Filter with PHOTO-Film OD 3.8 is a development made possible after the product launch of our Baader Solar Filters OD 5.0 in spring 2015. The filter has the same cell and mechanical specifications as our ASTF-Filter with Safety Film OD 5.0, the only difference lies within the used AstroSolar® Film – our AstroSolar® PHOTO Film OD 3.8 which has proven itself over the years. This film allows shortest exposure times – mainly used for digital videography and the lucky imaging technique – and thus almost “freezes” turbulences in the earths atmosphere. AstroSolar® PHOTO Film OD 3.8 is NOT intended to observe the sun, only for digital imaging! Read more about the differences of our AstroSolar® Films here: lieferumfang-bdsf

Scope of Supply: ASTF Filter with apertures from 80 to 180mm (200 – 280mm not yet available) come with two sets of centering bolts in 38mm length. 3 bolts with 10mm diameter and 3 bolts with 20mm diameter, adjustable to the tube diameter of your telescope or dew cap. In addition three safety straps with glue-pads and three rubber plugs to cover the holes that are not used.

All Baader Solar Filters feature:

  • Only for BDSF-Filter: original Baader AstroSolar® PHOTO Film (OD 3.8), 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
  • 2 sets of 3 injection molded centering-bolts (length 38mm) with threaded brass inserts to center the filter-cell in front of the tube opening. These bolts come in two diameters, 10mm and 20mm. Each bolt features injection molded rubber grip-faces, shaped to easily slide onto any telescope tube – but to come off very hard
  • 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

More Information on AstroSolar® Safety Film:

Additional Information


80 mm, 100 mm, 120 mm, 140 mm, 160 mm, 180 mm, 200 mm, 240 mm, 280 mm

Optical Density

OD 3.8

Solar Film

AstroSolar Photo Film


Solar Photography, Whitelight

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What others are saying

  1. Konstantinos Tranganidas


    Would I be able to attach this to a camera lens of 80 mm outer diameter and if yes, which aperture would be suitable for it?

    (0) (0)

    Something wrong with this post? Thanks for letting us know. If you can point us in the right direction...

    • Team Baader

      Unfortunately the clamping range of the smallest BDSF filter – BDSF 80 – starts at 100mm outer diameter. You would need a large solar shade to attach this. We do recommend however that you use the ASBF 70 filter instead. You don´t need photofilm to make images with your camera. Photo-Film is mostly needed for CCD videography (lucky imaging) at high resolution. With AstroSolar Safety Film you will also get very good results.

      (0) (0)

      Something wrong with this post? Thanks for letting us know. If you can point us in the right direction...



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