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Solar Observation and Imaging


          HOME | Product Listing | Order Info


 >  AstroSolar Safety Film Solar Filter Material   


 > 2" Cool-Ceramic Herschel Safety Wedge Solar Prism  NEW Version!

           (and accessories)


 >  Calcium K-Line  Filter , (1¼"  


 >  Solar Continuum Filter , (1¼" and 2")


 >  Solar Spectrum H-Alpha Systems and Baader H-Alpha Accessories New Baader D-ERF!



 ♦ AstroSolar™ Safety Film, White Light Solar Filter Material




Baader AstroSolar™ Safety Film
(Patent pending in all European States - voted for "Astro-Product of the Decade" in the USA, and Sky and Telescope's Sept 2000 Review "A New Standard in Solar Filters") Baader Planetarium's  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 AstroSolar is even more remarkable when considering its very low cost - only $36 for telescopes up to 8".  We even have sizes large enough for producing full-aperture filters for very large telescopes (see the huge 40" filter as shown above!).   When combined with Baader's tips for a simple do-it-yourself filter mount, anyone can construct a complete low cost - High Quality - white light solar filter for any telescope.

It is possible to further improve the stability and sharpness of the solar image through the use of the Baader Solar Continuum Filter.  Views of granulation and faculae are particularly enhanced through the use of this filter, in combination with AstroSolar.  Users of achromatic refractors will be particularly pleased with the performance using this additional filter.

Optical quality:
For a full interferometric report on the optical quality of AstroSolar, please click on this link:

AstroSolar and TurboFilm Interferometric Report

This highest precision film consistently produces strehl ratios of 94 to 96 percent in interferometric tests - thus it performs optically as well as a high quality Fluorite Triplet Lens by Carl Zeiss (per interferometric test results). Baader even had a hard time themselves seeing any difference in performance between AstroSolar™ and 1/20 wave precision optical windows which they stocked from Zeiss. Their stock of precision polished plates runs into tens of thousands of $ - all stocked for the 1999 eclipse - but AstroSolar™ was so good in fact, that these plates were hard to sell. Baader AstroSolar Safety Film shows notably more sharpness and contrast than any competitive objective filter we know of, especially including the affordable Glass Objective Filters and Mylar filters.  We have found that only our own superb Baader Herschel Safety Wedge is able to noticeably exceed the performance of AstroSolar.

What is even more important - with AstroSolar™ the Sun appears in it' s 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 wing of the spectrum.

Due to it's neutral color balance, AstroSolar 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".

Eye safety:
AstroSolar™ is essentially free from pinholes, since - unlike even the most expensive glass filters - it is coated on both sides, so that the chance of two pinholes overlapping each other is extremely faint. Pinholes do appear, but to 1 out of 10000 only, in optical density 2.5! Baader AstroSolar™ safety film has been approved for eye safety by the National Bureau of Standards in Germany, the PTB. Unlike any other Solar Filter on the market, AstroSolar™ is CE-tested according to EG-Norm 89/686 and EN 169/92 ( notified body 0196). All processes connected to this product have been thoroughly tested. Coatings are inspected constantly for consistency to ensure your eye safety!

History and goal of AstroSolar ™:
Baader Planetarium delivered solar safety film for 19 million eclipse viewers that were used throughout Europe for the August 11 Eclipse. Not one user of their films suffered from eye damage. Baader has produced solar safety films for over 17 years and has reason to claim a high degree of competence for all aspects of solar observation. With Baader AstroSolar™ we are set out to show you the Sun' s hidden grandeur at a fraction of the cost for comparable equipment. Real professional solar work has typically been restricted to a few die hard amateurs who would put up the $1000,- or more for a real precision 1/20 wave glass filter. Now you can get an equally precise AstroSolar™ filter to fit an 8" aperture for $36 (or much less even, if a whole group of people share a larger roll of film). No longer will solar observation be a "ho hum" experience, where you look into your telescope through an "economy priced" glass or mylar filter and wonder what this kind of amateur activity is all about. Many of our customers have pushed out the glass or mylar from their older filters only to use their filter cell for AstroSolar™ - and experience a completely new, crisp, and incredibly esthetic sun. All of a sudden, the telescope has the same performance during the day that it has at night, and now they realize that the consistently 'poor seeing' at their site was really just a consistently poor solar filter..  We are always amazed how easily some amateurs accept mediocre sharpness during observation of our nearest star, while they can be extremely critical if their telescope does not perform perfect on other stars (or planets).

Production secrets / products:
The development of AstroSolar™ was only possible due to the incredible demand during the 1999 eclipse. Dozens of miles of film were destroyed during tests to produce the tooling and process techniques to produce an absolutely uniform molecular structure for the substrate. Not to speak of the related treatments, annealing and dual side coating that the film undergoes until it has attained the desired properties. As a result of this material breakthrough, Baader is able to offer two film products which do not at all distort the performance of your telescope;
1. AstroSolar™ for solar observation and photography,
2. TurboFilm™ , an optically clear precision film for night time protection of your valuable optical equipment; to shield it against dirt, scratches, coating defects, humidity inside open tubes and on mirror surfaces - and last not least, to stop air currents (tube-seeing).

Please Note:  Before mounting the AstroSolar, be sure to peel off the removable clear protective film that is present on one side of the film.

For construction of a simple do-it-yourself cell for AstroSolar, please click on this link: simple do-it-yourself filter mount


- Baader AstroSolar Safety Film, Visual (ND5), Small, A4 Sheet (7.9"x11.8"), (#ASOLV-S)

- Baader AstroSolar Safety Film, Visual (ND5), Medium Roll (39.4"x19.7"), (#ASOLV-M)

- Baader AstroSolar Safety Film, Visual (ND5), Extra-Large Roll (46"x46"), (#ASOLV-L)


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                       ♦ Baader 2" Cool-Ceramic Safety Herschel Prism



Images taken with the Herschel Safety Wedge           

The New Baader Planetarium 2" Cool-Caramic Safety Herschel Prism delivers the finest white-light solar views obtainable, and is the only white light filter that we have found to noticeably exceed the performance of Baader AstroSolar Film.  The Herschel wedge prism provides safe full-aperture solar views without absolutely no image degradation.  Views are noticeably superior in resolution and contrast to even the very finest and most expensive glass objective solar filters and films.  The amount of Sunspot detail and surface granulation will surprise even the most experienced solar observer.  Penumbra resolve into a staggering range of contrasts and fine wispy details.  The solar disc is set against a jet-black sky, like observing the full moon at night!  With our Herschel Wedge Prism, it becomes obvious that the lack of detail and contrast experienced with most other white-light filters  was not so much due to the atmospheric seeing as you had thought...   A further benefit is the true unfiltered nature of the spectrum passed by the filter.  Unlike all objective solar filters, the Baader Herschel Wedge does not selectively filter any of the visual wavelengths.  This provides a true white-light view, and permits the use of additional eyepiece filters to selectively study any bands desired, without the compounding effects of a pre-filter.

The NEW Baader 2" Cool-Caramic Safety Herschel Prism is the finest solar wedge ever produced for amateur use.   It is the culmination of Baader's many years of experience in the design and production of Herschel Wedges.   Utilizing a precision 2" ultra-smooth wedge prism and optimized optical design for stray light elimination, the Baader Safety Herschel Wedge maximizes image contrast and sharpness.  The large first-surface prism has high surface quality and smoothness over its entire surface, which  will not break down at magnifications well over 100x, permitting full-disc photography and imaging with no resolution or contrast loss across the full field.  Efficient internal baffling and prism rear-face multicoatings further reduce scatter and maximize contrast.

As supplied, a special precision polished and coated Baader ND=3.0 filter is permanently pre-installed within the wedge housing (it  MUST be present for any and all visual observation).  This critical safety feature ensures that the ND filter will always be present, with no chance of accidentally viewing the unfiltered light as with some other herschel wedges.  The genuine Baader ND filters have been designed and produced specifically for Herschel usage, and are the only ND filters ever to be produced with both surfaces fineoptically polished and anti-reflection multicoated.   These additional steps provide the highest image quality across the entire field, preventing any image breakdown and scattered light which are inherent in standard ND filters. 

The modular design of the Baader Herschel Wedge incorporates a removable 2" nosepiece and Baader 2" Clicklock Eyepiece Clamp.  The threaded machined aluminum body permits attachment of a full range of Baader accessories, as well as for close-coupling of cameras and Baader binoviewers.  A full system chart can be found by clicking this More Info link. 


  • Our latest version incorporates an innovative internal Light Trap and Ceramic Tile backplate developed by Baader Planetarium.  This development takes the Herschel Wedge into the 21st Century, by rendering the output energy cool and diffused, while completely sealing the prism body!    In all other herschel designs, the waste energy is simply deflected out of the rear face of the prism by an angled mirror, also leaving openings for accidental or prying fingers to discover...  Thanks to Baader Planetarium, this concern has now been completely removed.  In place of the typical output mirror is a coated multi-layered perforated steel screen.  The bright light and heat energy are harmlessly diffused.  The special die-cast magnesium body also conducts away the heat more efficiently than aluminum.  The remaining light is passed into a special translucent ceramic back plate. 

  • Integrated Solar Finder.  Another unique aspect of the new Cool-Ceramic Safety Herschel Prism is the integrated solar finder.  The sun's defocused image can be readily seen projected onto the translucent ceramic backplate, permitting fast and easy aiming.

  • Each Baader Safety Herschel Wedge also includes a pre-installed 2" Solar Continuum Filter!  With the Solar Continuum, the contrast and image stability is further enhanced in all telescopes (APOs as well as Achromats).  Users of Achromats will find the Solar Continuum is indispensible, providing an image that rivals the sharpness and contrast of an Apochromat (with the Solar Continuum the image is presented in a deep lime green color).  The combination of the Herschel Wedge and Solar Continuum Filter delivers the finest solar views obtainable with any white-light telescope.  The Solar Continuum filter may be removed by the user for pure white light views, if desired (but the ND=3.0 must not be removed).

  • We offer two versions of the Herschel Wedge: The lower priced Version-V (visual) comes with the pre-installed ND=3.0/1:1000 (required for safe viewing), and a pre-installed 2" Solar Continuum Filter.  The Version-P (photographic) starts with the Version-V and adds 3 additional Baader ND filters (ND1.8/1:64, ND0.9/1:8, ND0.6/1:4 ).  The additional ND filters are handy for further dimming the image by using in place of the Continuum filter for white light viewing, or attaching to eyepieces or a  T2-15 Reducer, and are particularly useful for imaging.  Please refer to the More Info page for additional information.

  • All of the fine-optically polished genuine Baader ND filters incorporate special anti-reflection multi-coatings, to further eliminate light scatter and ghosting for maximum image contrast.  The result is image quality unachievable with any other ND filter.

  • NEW:  Each Safety Herschel Wedge now includes a custom foam lined carrying case that holds the Herschel Wedge along with storage area for all of the filters provided in the V and P versions.

(carrying case shown with HERSCH-P model)

Please Note: 

  • The Herschel Wedge is only recommended for use with refracting telescopes, NOT Schmidt-Cassegrain, Maksutov, or any other Reflecting Telescopes.  This is a professional-quality white light (not H-Alpha) solar filtration system, whose basic design concept has existed for almost as long as the telescope itself.  Like glass or mylar film objective solar filters, it is completely safe if used properly and common sense precautions always observed.  Please click on the More Info link for additional safety information. 

  • Similar in length to any 2" diagonal, the Baader Cool-Ceramic Safety Herschel Prism requires more back-focus than a 1.25" accessory.   The optical path length of the Herschel is approximately 128mm, as measured from it's front face to the top of the 2" eyepiece holder.  Since most 2" eyepieces have their field stops well below the main eyepiece body, most telescopes will need less than 128mm of back focus to accommodate the Herschel.  Most telescopes with 2" focusers will have no problem providing this amount of back-focus (in-travel).  However, some telescopes provide limited back-focus that may require a shorter path length for some eyepieces.  For these scopes the path length of the Herschel may be reduced to 108mm for 1.25" eyepieces by the attachment of a T2-27 adapter and T2-08 1.25" Clicklock eyepiece clamp.

(click on image for additional information, 722kB pdf)


For a recent full review of the Cool-Caramic Safety Herschel Prism by Ted Wolfe, please click on the following Cloudy Nights link:


"I received the Herschel prism Tuesday afternoon. Thanks for shipping it so securely.   I have read the additional safety information and I will be sure to check that the D=3.0 ND filter is always installed correctly. I absolutely love the views through it with my AP 4" f/10 . It is better than I expected. Thank you again."  Stan Jung

"I recently bought a Baader Herschel wedge from you and would like you to know that I am 101% happy and contented with its performance, optical quality, as well as fit and finish. I would unhesitatingly recommend it to anyone interested in the finest available white light solar filter. Several of the images I took with the wedge have already been featured in ."  John Nassr, Philippines


 - Baader Herschel Wedge Solar Prism 2", including fitted carrying case (#HERSCH-V)

 - Baader Herschel Wedge Solar Prism 2", including fitted carrying case (#HERSCH-P)


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Herschel Wedge Accessories: Polarizing Filters

A particularly handy attribute of the Herschel Wedge is it's partial polarizing effect on the solar image.  This permits a very convenient means of variably adjusting the image brightness, simply by using a single polarizing filter between the Herschel and Eyepiece.   The filter/eyepiece combo can then be rotated, and the image is variably dimmed.  We use a Baader polarizer in our own observations, finding this very useful to easily achieve the optimum brightness for maximum visual contrast at any magnification. 


We sell two sizes of Polarizing filters for visual use with the Herschel (both are produced in Japan for Baader Planetarium).  The 1¼" version can be threaded onto an eyepiece directly.  The 2" can, of course, be attached to a 2" eyepiece.  For the ultimate in convenience, we recommend the 2" Polarizer attached to a T2-15 (2"/1¼" reducer).  This allows you to conveniently switch between 1¼" eyepieces without removing the filter, and still maintaining a close position between the eyepiece and filter.  Use of a T2-15 also gives you a very convenient means of attaching and removing the Solar Continuum filter. 


Please Note:  Polarizing filters are intended for visual use and must only be used in conjunction with the existing internal ND=3.0 filter.  A polarizing filter does not provide sufficient blocking by itself, nor is it able to block IR wavelengths as completely as an ND filter.  Also, the polarizing filter must be used on the eyepiece or eyepiece reducer, never ahead of the ND3.0 filter (the polarizing filter must be located after the ND3.0 filter to prevent damage to the delicate internal layers of the polarizing filter).


- Baader Polarizing Filter,  1¼”  (#FPOL-1)


- Baader Polarizing Filter,  2”  (#FPOL-2)




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Herschel Wedge Accessories: Adapter 2"/T-2 Filterholder T2-27

The Herschel Wedge housing incorporates internal 2" threading on the output.  As supplied, the Herschel Wedge includes a  2" filter holder and 2" Clicklock Eyepiece Clamp on the output of the wedge.  The T2-27 2"/T-2 Filterholder may be used to convert the output of the Herschel Wedge to an external T-2 thread.  This allows closer direct attachment of cameras, T2-08 Clicklock Eyepiece Clamp 1¼”/T-2  , or Maxbright Binoviewer (use a T-2 Quick Change Ring for the Baader MkV).  Please Note:  The ND=3.0 filter supplied with the Herschel MUST be transferred to the T2-27 for visual use (or other ND filters for photographic use)


- Adapter 2"e/T-2e,  2”  (#T2-27)



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Herschel Wedge Accessories: Fitted Foam-Lined Carrying Case

Custom foam lined carrying case holds the 2" Cool-Ceramic Safety Herschel Prism, with storage area for all of the filters provided in the V and P version.


- Carrying Case for 2" Cool-Ceramic Herschel Prism, available separately (#HERSCH-CASE)


(carrying case shown with HERSCH-P model)



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Calcium K-Line Filter



                                                                                                                            © M. Weigand

The New Baader Planetarium Calcium K-Line Filter makes imaging of the sun in K-Line accessible to anyone with a telescope and digital camera or webcam.  Baader's innovative double-stacked filter uses sophisticated coatings to produce a sharp 8nm wide bandpass, centered at 395nm.  This bandpass provides ample contrast for high-resolution imaging of super granulation, flares, and other features that are prominent in CaK.   Unlike small, dedicated, and expensive CaK telescopes, the Baader K-Line filter works with with your existing telescope - at a small fraction of the cost.  The Baader CaK may be used with virtually any telescope, of any aperture - Newtonian, SCT, Refractor, etc. 

The Baader K-Line Filter is simply used just like any standard 1.25" thread-on eyepiece filter.  It may be attached to an eyepiece for projection imaging (see Digital Photography for camera projection adapters and Digital T-Rings), or directly to a camera's nosepiece (ie, T2-14) for prime-focus .  In addition, an objective pre-filter must be used at the telescope's entrance to reduce the energy that reaches the filter.  For this purpose, a 200mm x 290mm (8x11inch) sheet of Baader's renowned AstroSolar Photo Film (Photo ND=3.8) is provided with each K-Line filter.  This material may be easily mounted to any telescope using instructions provided (see AstroSolar and TurboFilm Mounting ). 

The Herschel Safety Wedge Solar Prism may also be used as the energy rejection filter (in place of the AstroSolar Photo Film).  This will provide the absolute highest quality solar  images possible in CaK.

Please note:  The Baader K-Line filter is intended Only for imaging.  It is not suitable for safe visual observation (the UV levels may pose an eye safety risk from prolonged observations).   Due to the eye's low sensitivity and very poor resolving ability at 395nm, solar features in CaK are generally invisible for most observers - even through multi-thousand dollar sub-angstrom dedicated CaK etalons and telescopes.   All of these instruments are intended primarily for imaging.


* Image Venus! *


In addition to imaging the sun in CaK, the Baader K-Line filter opens up another exciting possibility - imaging of Venus!  The narrow bandpass @ 395nm enables imagers to record cloud structures, with results similar to the dedicated Baader Venus Filter.

 © M. Weigand


 - Baader K-Line Filter, 1.25"(including 200x290mm AstroSolar ND-3.8), (#CAK-1)


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Solar Continuum Filter


The new Baader Solar Continuum filter is designed to enhance the visibility of solar granulation and sunspot details.  By transmitting a specific spectral region around 540nm, free of emission and absorption lines, the Solar Continuum filter is able to boost contrast and reduce the effects of atmospheric turbulence.   With the Solar Continuum filter in place, images snap to focus, and granulation becomes regularly visible.  Details at the limit of visibility become easier to hold, and image motion reduced.

The Solar Continuum filter works well in all types of telescopes, for both visual and imaging.  Users of SCTs and achromatic refractors will find it particularly beneficial, as it completely excludes the red and blue wavelengths, and centers on the peak visual wavelengths where the telescope optics are sharpest and free from chromatic aberrations.  For digital imaging, we also recommend the Continuum filter be combined with our UV/IR Cut Filter (to completely cut the defocused far infrared wavelengths). 

The  Solar Continuum filter also makes the perfect star test filter.  It's narrow bandpass and complete blockage of longer and shorter wavelengths make it superior to standard green colored filters for testing refractors at their center design wavelength (and peak visual wavelength).  With this filter, more accurate appraisals of optical quality can be made, without the effects of spherochromatism or secondary color error.   Due to the narrow 10nm bandpass, star testing through the Solar Continuum filter will require a bright test star.

As with all Baader Planetarium Filters, the Solar Continuum possesses all the trademark Baader filter qualities.  Optical, Physical, and Mechanical quality are superb.  For a summary of filter features, please see the Filters page.

Please Note:  For safe use, the Solar Continuum filter must be used in conjunction with a primary solar filter (ie, Herschel Wedge Prism, or Baader AstroSolar Film).  It must be placed After the primary filter, and cannot be used alone, or permanent eye and equipment damage will result.

Please click on the image below for a typical transmission curve:

Solar Continuum Filter Transmission Curve


- Baader Solar Continuum Filter,  1¼”  (#FSOL-1)


- Baader Solar Continuum Filter,  2”  (#FSOL-2)



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Solar Spectrum H-Alpha Systems and Baader Accessories



We are excited to offer a full selection of advanced products for H-Alpha Solar Observation!   These truly professional grade products have been selected to deliver the absolute highest resolution and contrast views of Hydrogen Alpha features.  The views through this equipment rival the best photographs.  Surface and prominence details become shockingly crisp and high contrast, able to withstand high magnifications for detailed study of individual features. The amount of detail visible through these narrowband rear-etalon systems rivals the Moon in its variety and observability.   Smaller aperture objective-based systems deliver convenient full disk views for quick looks, but at a heavy penalty in the resolution and contrast needed to detect and study the rich H-alpha solar features in full detail at high magnifications.  As with our Herschel Wedge Prism, it becomes obvious that the lack of detail and contrast in other systems was not so much due to the atmospheric seeing as you had thought... 


Another surprise is the relative affordability of Solar Spectrum filters.  A completely configured SO-1 0.5A system with 85mm clear (and unobstructed!) aperture costs about $2,800.  Compared to the wider band single or double stacked objective etalon systems, the Solar Spectrum filters offer greatly improved performance at significantly  lower prices.



Solar Spectrum H-Alpha Filter Systems

Solar Spectrum produces what we have found to be the ultimate in high resolution H-Alpha filter systems.  With over 20 years of experience in making filter systems for professionals as well as amateurs, Solar Spectrum brings an unmatched level of expertise to bear in producing filters at prices accessible to amateurs.  This experience uniquely enables them to deliver a high level of quality and consistency in very narrow filters (< 0.3A) which are extremely demanding to produce. 


These rear-mounted etalons deliver high-quality narrowband filtration that can be used with apertures from as small as 40mm up to 180mm!  Unlike front objective etalons, the telescope aperture is not limited by the diameter of the etalon.  Every Solar Spectrum filter can be flexibly configured to match any desired telescope and aperture desired, without any loss in resolution.  Each Solar Spectrum filter system includes the rear mounted etalon assembly (which includes an  integrated thermoelectric heater/cooler),  programmable temperature control box with digital temperature readout, and AC power cable.  The control box accepts 90-256 VAC 50/60Hz.  For DC use, any inexpensive inverter can be used.  A complete system consists of a Solar Spectrum Filter and Front-Mounted Energy Rejection Filter.  Telescopes with focal ratios faster than f/20 will also require a telecentric lens to produce the desired f/25 - f/30 beam.  Currently, Telecentric lenses are available in 2X and 4X amplifications.


Availability:  Currently, we offer Solar Spectrum filters on a special order basis.  Typical delivery times range from 16-24 weeks, depending on filter size and bandpass.  Occasionally we will have a system available from stock.  Please contact us for specifics.  Narrower bandpasses available on request (primarily for imaging use).  Calcium K-Line and custom filters are also available upon request. 


Payment:  Deposit of 50% required at time of order, remainder due when filter is completed and ready to ship.   Payments by check or money order only (sorry, no paypal or credit cards for Solar Spectrum Products).


Solar Observer Series 1:  Our lowest cost system.  19mm clear aperture enables solar full disk views with focal lengths below 2000mm (60-80mm aperture).  Of course, larger telescope apertures may be used to deliver increasingly detailed views.  Available in the following bandpasses - 0.65A, 0.5A, <0.3A.


- Solar Observer 1, 0.65A +/- 0.05 Bandpass (#SS-SO1.65)

- Solar Observer 1, 0.5A +/- 0.05 Bandpass (#SS-SO1.5)

- Solar Observer 1, <0.3A Bandpass (#SS-SO1.3)


Solar Observer Series 1.5:  Our best value.  Larger 25mm clear aperture enables solar full disk views with focal lengths below 2400mm (80-95mm aperture).  Of course, larger telescope apertures may be used to deliver increasingly detailed views.  Available in the following bandpasses - 0.65A, 0.5A, <0.3A.


- Solar Observer 1.5, 0.5A +/- 0.05 Bandpass (#SS-SO15.5)

- Solar Observer 1.5, <0.3A Bandpass (#SS-SO15.3)


Advanced Solar Observer:  Large 32mm clear aperture, enables visual use with 2" eyepieces and larger format imaging.   Enables full disk views with focal lengths below 3000mm.  Available in the following bandpasses - 0.8A, 0.65A, 0.5A, <0.3A.


- Advanced Solar Observer, 0.5A +/- 0.05 Bandpass (#SS-ASO1.5)

- Advanced Solar Observer, <0.3A Bandpass (#SS-ASO1.3)


Research Grade Solar Observer:  32mm clear aperture, extreme filter uniformity for research applications.  Available in the following bandpasses - 0.5A, 0.3A, 0.2A.


"I used the solar filter today.  WOW!!!!!!  The level of detail is incredible.  Using a Televue Panoptic 35 I can see the entire disk.  Using a BinoViewer with 26mm Meade eyepieces, the field of view is smaller but the image looks almost 3D and is far more pleasing.  I am more than satisfied with this equipment.  Well worth the cost and the wait."  Tony Van Heugten  (SO-1.5, 0.3A on a Meade 10" SCT with 90 C-ERF)


Baader D-ERF, Energy Rejection Filters

Baader planetarium has introduced a new evolution in their premium energy rejection filters, from 70mm up to 180mm!  These filters incorporate a new all-dielectric IR rejection coating that eliminates the heating from IR energy to produce a truly cold focus (hence, "Cool ERF").  As a result, the telescope and etalon remain cool and safe from excessive heating.   The result is longer filter life, and freedom from tube currents caused by heating.  Users with compound telescopes (SCTs, Cassegrains, Maks) will really appreciate the D-ERF, due to its reduced heat load on the mirrors and the reduction in tube currents caused by internal heating.


Unlike every other ERF produced up until now, the Baader D-ERF are produced from a high quality optical clear glass, ensuring freedom from the internal impurities that caused so much headache in producing the older red-glass ERFs.  The red glass used in producing the older generation of ERFs is of very poor and variable internal quality.  In order to produce ERFs from red glass, Baader had to complete and polish each ERF, then interferometrically inspect every one  for internal defects, resulting in having to dispose of far more ERFs than they were able to keep.  Its no wonder why other red glass ERFs have such a poor reputation, particularly in sizes over 3" in aperture.


The energy rejection is now accomplished using ultra-hard dielectric coatings on both sides of the glass substrate, and also serve to protect the glass, making it highly resistant to scratches.  D-ERF filters are made from high grade optical glass which is free of any internal defects.  The thick substrates are polished plane-parallel, smooth, and flat to an amazing 1/10 wave p-v over the entire surface.  Only by using thick substrates can a high surface accuracy be achieved and held in use (for example, the 90mm ERF is 5.5mm thick.  Thinner substrates are not capable of holding such high surface accuracy).  The special dielectric filter stacks are precisely balanced on opposite sides to maintain the superb optical flatness after coating.


For further information, please see:  D-ERF Use   (150 kB)    The D-ERF transmission curve can also be found by clicking the link below

D-ERF Transmission Curve


D-ERF filters are sold un-mounted and are available in the following diameters: 70mm, 90mm, 110mm, 135mm, 160mm, 180mm.   We occasionally have a  limited stock in the smaller sizes (larger sizes on request).  Please contact us for further specifics and availability.


- Baader D-ERF, 70mm Diameter (unmounted) (#DERF-70)

- Baader D-ERF, 90mm Diameter (unmounted) (#DERF-90)

- Baader D-ERF, 110mm Diameter (unmounted) (#DERF-110)


Please Note:  Custom spun-Aluminum filter cells are also available to fit any telescope, on special order.  Please contact us for pricing and availability.   Prices typically range from $100-$125.


Baader 2X/4X Telecentric Lens Systems

Baader Planetarium has designed a new optimized telecentric system for use with Solar Spectrum H-Alpha systems.  A telecentric system is used to convert shorter focal ratio telescopes to the desired f/25 or greater beam needed by the rear mounted Solar Spectrum filter.  More than a barlow lens or barlow lens based system, the Baader telecentric ensures that the output beam maintains a consistent normal incident angle across the full filter width.  The result is a consistent bandwidth and high image contrast across the field of view.  This lens system has been optimized to maintain an exceedingly high optical quality for dedicated solar use (>99% strehl at 656.3nm).  Simpler barlow or barlow-based systems are not able to produce this level of accuracy or telecentricity.  Hard Dielectric IR coatings further help to reject IR energy and protect the rear etalon from excessive heat energy. 


2X                4X


For further information, please see:  Telecentric System (150 kB)


Telecentric systems are available in a 2X and a 4X version.  Please contact us for further specifics and availability.


- Baader Telecentric Lens System, 2X (#TZ-2)

- Baader Telecentric Lens System, 4X (#TZ-4)




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Last Update 08/11/12


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