ASTF – Baader Solar Filters for All Telescopes (Refractor, Reflector, and Catadioptric)
Baader's ASTF line of solar filters permit safe visual observation and solar photography with all types of telescopes. These telescope filters feature a temperature-compensated cell design to provide high-resolution views or images and are recommended for use with high-end amateur telescopes.
This family of solar filters is made in the most elaborate way, and its construction and design is superior to that of the ASBF and ASSF line of Baader filters. Ideally, AstroSolar film must not be put under stress, either during mounting of the film or during any temperature change. For this reason the ASTF filter features a temperature compensated cell. The film itself is cemented onto an injection molded ring, and the substrate of that ring has the same thermal expansion properties as the AstroSolar 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 to provide maximum security against breakage 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 (-22°F or +122°F).
As a result, this filter is suitable for high magnifications and detailed observation of individual sunspots. You will experience no astigmatism during winter observations or with temperature changes in the summer. The filter comes with two 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.
Important Note: SCT Users must only mount the filter to the outside of the tube (the limited depth of the SCT front ID prevents adequate engagement of the centering bolts).
ASTF-180 Solar Filter Specifications
- Item number: ASTF-180 or 2459315
- AstroSolar film aperture: 180mm (7.08")
- Outside diameter clamping range (with included 10mm bolts): 210 - 240mm (8.26 - 9.44")
- Inside diameter clamping range (with included 10mm bolts): 230 - 260mm (9.05 - 10.23"). See additional info below.
- Outside diameter clamping range (with included 20mm bolts): 200 - 230mm (7.87 - 9.05")
- Inside diameter clamping range (with included 20mm bolts): 240 - 270mm (9.44 - 10.62"). See additional info below.
- Suited for aperture range: 170 - 190mm (6.69 - 7.48")
- Outside diameter of filter cell: 270mm (10.62")
- Weight: 6.9oz / 195g
Additional Filter Details and Features
- Made of original Baader AstroSolar Safety Visual Film (ND 5.0), cell mounted, and quality inspected by skilled members of Baader's staff.
- The AstroSolar filter material is mounted onto a plastic ring where the plastic ring itself works as stabilizing element for the filter cell. This still plastic ring is mounted onto the aluminum front frame. The thermal expansion coefficient of the plastic and the film are similar.
- 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.
- Includes two sets of 3 injection molded centering-bolts with threaded brass inserts to center the filter-cell in front of the tube opening (10mm and 20mm diameter; 38mm length). This fastening system keeps the filter snugly in place and centers the filter. Each bolt features injection molded rubber grip-faces, shaped to easily slide onto any telescope tube but hard to come off.
- No tool mounting and adjustment of the centering bolts to fit a wide variety of mechanical tube diameters. Bolts are made to contact the outside of the optical instrument tube for most applications.
- For some optical items (such as refractor and Newtonian reflector telescopes), you may be able to attach the bolts on the inside of the instrument tube. However, this requires a clear depth of about 20mm on the inside for adequate engagement of the centering bolts which many instruments (like binoculars, camera lenses, and SCT/Mak-Cass telescopes) do not have.
- Includes non-rotating sliding fasteners made from aluminum that hold the centering bolts.
- 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.
- ASTF filters come with rubber plugs to be used as a 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 virtually all circumstances.
- Securely packed in a cardboard box with stiff cardboard inlay for safely shipping the filter; Instruction booklet included.
About Baader AstroSolar Film and Solar Filters
The world's finest objective solar filter material - Baader Planetarium's AstroSolar Safety Film - is now available in a complete range of high-quality mounted Baader Solar Filters. Their innovative design and construction enables each filter to fit a wide range of instruments - from high end telescopes, to spotting scopes, camera lenses, and even special versions to fit binoculars. Each filter is precisely mounted at Baader onto special cells, guaranteeing a stress-free mounting that preserves the full optical quality of the AstroSolar film.
Baader Solar Filters provide a professional and secure solution to observe and image the Sun using AstroSolar Safety Film. Many ready-made filters stretch the filter material like a drumhead in order to make it look like a piece of glass. However, this absolutely destroys the image quality, rendering the film useless for high magnification work. AstroSolar is mounted entirely stress free onto Baader's filters in order to perform like a high precision plane-optical window. Even though it may seem counterintuitive, Baader AstroSolar film must show slight ripples! When the film is put under stress by an improper cell mount, its optical quality is degraded and it performs just like a common coated glass-filter made of untreated float glass.
In its September 2000 issue, Sky & Telescope magazine proclaimed Baader Planetarium's AstroSolar Safety Film to be "the new standard in solar filters." AstroSolar Safety Film delivers white light views of the Sun that are unmatched by any other objective solar filter or material. The views through AstroSolar display fine solar details, including fine penumbral detail, solar granulation, and lighter colored faculae. The disk is set against a dark background, free of the haze and scatter that is common in typical 'mylar' films or inexpensive glass filters. The performance of Astro Solar Filter Film is even more remarkable when considering its very low cost.
What is even more important - with AstroSolar Film the Sun appears in its real color - neutral white (with only a slight bluish tinge). Other films and glass filters produce a blurry bluish or reddish/orange/yellow Solar image, thereby cutting part of the spectrum. Especially with an orange sun, it is very hard to see faculae regions which are visible predominantly in the blue portion of the spectrum.
Due to its neutral color balance, AstroSolar Film enables the use of various color (or interference) filters which allows the observer to concentrate on certain spectral passbands for investigations of different layers within the solar "atmosphere". It is also possible to further improve the stability and sharpness of the solar image through the use of the Baader Solar Continuum Filter (sold separately). Views of granulation and faculae are particularly enhanced through the use of this continuum filter, in combination with AstroSolar film.
Please note that you cannot see solar prominences with white light solar filters such as this - that requires the use of sophisticated and significantly more expensive narrowband solar filters or telescopes. Solar filters made with AstroSolar Film with a neutral density (ND) of 5.0 can be used for visual and photographic, imaging and video applications.
Jan 28, 2018
Excellent qualityPros: Cons: Comments:
The filter works great on a CPC800. The radially adjustable studs and Velcro straps insure a snug, secure fit. The detail seen us FAR superior to float glass or polymer filters!
This review was provided courtesy of AgenaAstro.comAug 22, 2017
Excellent and easy to set upPros: Cons: Comments:
I bought one large enough to match the objective diameter, which meant that the three support screws were slightly too far apart for the tube. I took up the slack with adhesive-backed foam so the the filter would not slide and had a solid friction fit to supplement the Velcro strap support. I modified the box to hold the filter safety with the screws attached. Both of these minor enhancements could be incorporated into the design.
This review was provided courtesy of AgenaAstro.comApr 14, 2017
Great resolution of sunspotsPros: Cons: Comments:
It offers great resolution of sunspots and granulation when the seeing is good. I use it on my C8 with a Baader orange filter. The view with an uhc-c filter is also interesting as it boost contrast.
This review was provided courtesy of AgenaAstro.comSep 30, 2016
Solar with Baader is awsomePros:
Strong Construction,Compact,Easy to Use,Lightweight,Accurate,Quality LensesCons: Comments:
When you order measure you scope dew shield and get the one that fits. Easy to set up and a dream to use. I will buy another for my other scope. Using this filter with a 102mm apreture this filter allows tact sharp imaging of the solar surface. Turned my night time viewing into a day time wonder.
This review was provided courtesy of AgenaAstro.comJul 21, 2016
Excellent Solar FilterPros:
Accurate,Strong Construction,Compact,Lightweight,Easy to UseCons: Comments:
WARNING: Viewing the Sun through a Telescope without proper Solar Filters will definitely cause permanent blindness to your eyes. Take all the precaution that is necessary to avoid looking at the Sun directly with your naked eyes.
This is an excellent Solar Filter and fits on my Meade Infinity 102mm Refractor Telescope. I recently purchased this item right here and am very pleased with its performance. I've looked at the Sun with much details seeing the Sunspots and how it displays the Sun white as snow.
Setting up the Solar filter was very easy as long as you follow all the instructions that is provided in the small booklet which comes with the Solar filter. All the necessary parts are included in the package.
Finding the Sun with your Telescope is not an easy task especially if you are not using the...in this case my Red Dot viewfinder. However I did use my Red Dot Viewfinder covering it with a piece of Baader Solar Filter, which I had a long time ago to locate the Sun and then removed the Red Dot viewfinder from the Telescope as soon as I was able to locate the Sun. Exposing the Red Dot Viewfinder to the Sun will damage the instrument so you need to be very cautious when or if using the viewfinder to locate the Sun.
I'm quite pleased with this Solar Filter and will recommend it to anyone who's interested in viewing the Sun through a telescope, binoculars etc.
This review was provided courtesy of AgenaAstro.comSort by
Manufacturer Baader Planetarium