Baader Digital Solar Filter 3.8 OD - 80-280mm

• NOT suitable for visual solar observation - permanent eye injury will result from any visual use, including use of optical viewfinders on DSLR cameras. Only use for digital imaging with all high-end telescopes and extreme tele-lenses (lucky imaging technique). Suitable for highest magnifications and detailed imaging of individual sunspots
• AstroSolar PHOTO Film OD 3.8, mounted stress free in temperature compensated cell
• No astigmatism during winter observation or with temperature changes in summer
• Scope of Supply: BDSF (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, mounting instructions.

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!

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.

ASTF/BDSF (AstroSolar Telescope Filter) - Baader DIGITAL Solar Filter for high-end Telescopes

This family of solar filters is made in the most elaborate way. AstroSolar must not be put under stress, neither during mounting the film, nor during any temperature change. For this reason the ASTF-Filter features a temperature compensated cell. The film itself is repeatably cemented onto an injection molded ring, whereas the substrate of that ring has the same thermal expansion like the Astro Solar Filter material itself. This free floating film-carrier ring is held onto the aluminum frame with the help of another holding ring made of fiber reinforced plastic – for a maximum of security against breaking of the cell. This temperature compensated cell enables the AstroSolar filter material to retain its excellent optical quality at any temperature – be it -30°C or +50°C.

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
• 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 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/BDSF-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

Safety Information

Safety Warning-How to Protect Your Eyes(link to Safety Information)

Safety Precautions - How to Prevent Accidents(link to Safety Precautions)

Baader Solar Filters Clamping Range

Testreview - The Baader ASTF Solar Whitelight Filter - W. Paolini

Testreview ATT-Magazine: Baader Solar Filters (BSF)