The Great American Eclipse!
August 21, 2017

Get Ready!

1991 Eclipse, San Jose del Cabo, Mexico, Copyright Roland and Marj Christen
Click image for larger version and additional details
The magnificent corona of the sun is only visible during totality of a solar eclipse when the moon completely covers the sun. Don't miss your opportunity to experience this unique natural phenomenon on August 21st. The last total eclipse to traverse the continental U.S. was in 1979 - 38 years ago!

On eclipse day, the path follows a diagonal course from the coasts of Oregon to South Carolina. You must be within the path of totality, which is only 68 miles wide, in order to experience totality and see the corona. However, the entire U.S. outside of the path will enjoy the partial eclipse, including Alaska and Hawaii. Our neighbors Canada, Mexico and the Caribbean islands will also enjoy partial phases.

In order to enjoy the partial phases of the eclipse, whether or not you are on the center line, you must protect your eyes. Even when the sun is partially covered, the harmful rays can cause severe damage if you look at it directly without appropriate eye protection. Be sure to use a solar filter for the front of your telescope, binocular or telephoto lens for visual observation or photography.. The AstroSolar Safety Film from Baader Planetarium is very economical and of exceptional quality whether you purchase a pre-made filter or make one yourself from the sheets tht we offer. If you enjoy observing the sun with a refractor on a regular basis, you may wish to invest in a Baader Cool-Ceramic Safety Herschel Prism.

For more information about eclipses and the eclipse path, check out these resources. Then, come back and stock up on solar accessories for a safe observing experience. Remember to order early before prices increase or we run out.

The Solar Eclipse Experience **Be sure to read this!**
Sky and Telescope magazine
Astronomy magazine

Baader Planetarium Solar Products

Kendrick Solar Products

AstroSolar™ Safety Film from Baader Planetarium

Who Should Order AstroSolar Safety Film??

Everyone in the continental U.S., Hawaii, Mexico, Central America, the Caribbean and parts of Alaska, Canada and South America will experience partial phases of the eclipse. If you plan to use a telescope, binoculars or your camera, you must use a proper solar filter on the front of your objective lens to protect your eyes. DO NOT use an eyepiece filter since it is likely to crack under intense heat from the sun.

AstroSolar Safety Film is a very cost-effective and very high quality material to make your own solar filter. Be sure to order early for the best pricing and availability so that you can safely enjoy watching the partial phases as the moon covers the sun.

Optical Quality

Astro-Physics is synonymous with optical quality so you know we are very particular about the solar filters that we recommend. AstroSolar Safety film from Baader Planetarium produces the highest contrast and sharpness possible in your visual or photographic image, thus preserving the performance of your telescope. As you observe the partial phases before and after totality, you will see sunspots and surface granulation in fine detail.

The solar image is a very pleasing natural white without false blue or orange color. Other films and most glass filters produce a blurry bluish or reddish solar image, thereby cutting part of the spectrum. Especially with a falsely-colored orange sun, it is difficult to see faculae regions which are visible predominantly in the blue region of the spectrum.

Due to its neutral color balance, AstroSolar enables the use of various color or interference filters, which allow the observer to concentrate on certain spectral passbands for investigations of different layers within the solar "astmosphere".

Eye Safety

AstroSolar is essentially free of pinholes. The patented, high-density coatings are deposited on both sides. As a result, the chance of two pinholes overlapping each other is extremely low. Baader AstroSolar safety film has been approved by the National Bureau of Standards for eye safety in Germany and is CE tested and approved. All processes connected to this product have been thoroughly tested. Coatings are inspected constantly for consistency to ensure your eye safety!

Important note: AstroSolar 5.0 is not designed to work as an "eclipse shade" or handheld solar filter and is not suitable for naked eye solar observation.

AstroSolar film was designed to serve as a precision optical window for telescopic and photographic solar observation without deteriorating the optical wavefront. AstroSolar film must be used in front of the optical element of an astronomical telescope, telephoto lens or binocular. For visual observation, you must view through an eyepiece. Do not make a handheld solar filter and hold it directly in front of your eyes.

If AstroSolar 5.0 is being tested for visual observation ISO-specification, all tests must be performed with a telescope and eyepiece (or other optical instrument) added into the testing apparatus.

History and Goal of AstroSolar

The development of AstroSolar was only possible due to the incredible demand during the 1999 eclipse in Europe. Dozens of miles of film were destroyed during tests to produce the tooling and process techniques necessary to develop an absolutely uniform molecular structure for the substrate. Not to mention the related treatments, annealing and dual side coating that the film undergoes until it has attained the desired properties. The goal was to provide an inexpensive filter material that would preserve the optical quality of telescopes and binoculars throughout Europe. Since that time, observers around the world have used AstroSolar for daily solar viewing as well as special events like solar eclipses and the Venus Transit in 2012.

Additional Considerations

You may also wish to add the Baader Solar Continuum Filter to your Solar observing arsenal. This filter, when combined with the AstroSolar Filter Material gives increased contrast for finer detail in surface features.

Order Information

AstroSolar™ is available in sheet form in two sizes: 200 x 290mm (7.9" x 11.4") or 500 x 1000mm (19.7" x 39.4") so that you can make your own filters very inexpensively. It is also available in premade filters from Kendrick Astro Instruments for your telescope or binocular.

Each order will come with these instructions:
"Making an Inexpensive Filter Cell for BAADER AstroSolar™ Material"
"Construction A Solar Filter for Binoculars with Baader AstroSolar Film"
"Baader Planetarium - Technical and Safety Information"

*** Special Pricing Through July 14 ***
The eclipse provides a perfect opportunity for clubs, schools, colleges and other groups to order several sheets or rolls of AstroSolar film and host filter-making parties.

Plan an outreach...Alert your local media...Create public interest.

We provide discount pricing for multiple sheet orders through July 14th.

BAADER AstroSolar™ Density 5 - Visual, A4 size, 200 x 290mm (7.9" x 11.4")
All filters packaged individually with instructions. Each filter includes: 9.25" x 11.75" 0.040 chipboard and 9.75" x 12.25" rigid corrugated mailer, which can be used to construct your filter.
AS50A4$37.00 in stockAdd AS50A4 To My Cart

AS50A4-5$175.00 in stock Add AS50A4-5 To My Cart

AS50A4-10$326.00 in stockAdd AS50A4-10 To My Cart

BAADER AstroSolar™ Density 5 - Visual, 1/2 Meter size, 500 x 1000mm (19.7" x 39.4")
All filters packaged individually with instructions..
AS50HM$86.00 in stockAdd AS50HM To My Cart

AS50HM-5$410.00 in stockAdd AS50HM-5 To My Cart

AS50HM-10$757.00 in stockAdd AS50HM-10 To My Cart

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Solar Continuum Filter - 1.25" (BPSC125) and 2" (BPSC2)

Unsurpassed contrast of photospheric details is achieved by an extremely narrow half bandwidth of only 8nm. Functions like a monochrometer, suppressing the effects of atmospheric turbulence to provide images that appear markedly more stable.

Focus "Sweet Spot Generator" - completely eliminates the usual focusing guesswork - the image snaps to a razor sharp focus at the exact focal position. Image the sun the way professionals do!

IMPORTANT: The Solar Continuum Filter MUST be used in conjunction with a visual density white-light solar filter or Herschel Prism (with ND3.0 filter) in front of the lens. We suggest Astro-Solar ND 5.0 Visual Filter material, also from Baader Planetarium. DO NOT attempt to use this filter without a white-light filter in front of your main telescope optics. Serious damage to your eyes could result.

BPSC125$88.00 in stockAdd BPSC125 To My Cart
BPSC2$136.00 in stockAdd BPSC2 To My Cart

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Baader Cool-Ceramic Safety Herschel Prism (BPHERP) - for Refractors Only (see caution note below)

We are pleased to announce that we offer Baader Planetarium’s 2" Cool-Ceramic Safety Herschel Prism. This Herschel prism affords the finest detail possible in solar viewing.  The contrast and sharpness that it provides when observing surface detail will leave you breathless. No solar filter can compare! Additionally, it reveals the sun in a true white-light, uncolored by filters.

A Herschel prism is a unique prism that is angled at 23 degrees. It passes 95.4% of the sun’s light and heat through the prism and out the back side. The 4.6% of the light that is directed to the eyepiece requires the use of a 3.0 neutral density filter. This filter must always be used when visually observing and, therefore, is permanently installed.


This new generation Herschel Prism incorporates some unique features that add to its safety and ease of use. A layered, perforated-metal heat cage traps the excess energy transmitted through the prism, rendering it harmless. What little light and heat that remains is finally absorbed by a translucent ceramic tile. This translucent tile displays the image of the sun, serving as a solar finder. Simply move your telescope about until you see the sun appear on the translucent tile and you are all set. It is much quicker and more accurate than watching the scope's shadow on the ground.

We are offering the “photographic version" of the Baader Herschel Prism. This version comes complete with a full compliment of 2" neutral density filters (ND-1.8, ND-0.9, ND-0.6 and permanently mounted ND-3.0) and a 2" Solar Continuum filter. The Solar Continuum filter helps to further boost contrast, revealing sunspot and surface granularity detail (it does have a green colorization). A foam-lined metal carry case is provided for convenience and protection. The Baader Herschel Prism is compatible with Baader's Astro T-2 System. Please follow this link to view a copy of the manual.

Note: Baader lists the light path distance as being 114 mm measured from the nosepiece flange (not the insertion depth) to the top flange of the eyepiece holder. The position of eyepiece optical centers will reduce this spacing by 5 to 10 mm since the eyepiece will sit down into the eyepiece holder. When using the Herschel Prism for imaging, the eyepiece holder can be replaced with the Baader 2" to 42 mm adapter (BP27) so that a camera can be directly attached using a camera T-ring. This configuration will have a spacing distance of 67 mm flange to flange, plus the T-ring and camera. Please see the above link to the Baader manual for more information.

A question that is always asked is, "Does it damage my telescope to have it looking at the sun for long periods of time?" No! The lens passes the infrared (heat) part of the spectrum as efficiently as the visible part of the spectrum. Since the lens does not absorb or retain the infrared light, it does not heat up.

CAUTION - Important Limitation of Use: It is important to know that a Herschel Prism can only be used with refracting telescopes. It can not be used on any style reflecting telescope. If you own a Petzval-style refractor, or any design which puts elements to the rear of the scope where excessive heat build-up can occur, it is best to check with the manufacturer regarding their specific scope. [Note that Al Nagler of TeleVue has stated that the rear elements of the TeleVue Petzval scopes are sufficiently forward that no damage will occur to their scopes.] Regarding visual use, Baader has tested the prism for safety in refractors up to 8" apertures. They do note that you will want to add an additional neutral density filter for viewing comfort with the larger scopes.

CAUTION - Secondary optics, such as flatteners, telecompressors, barlows, and filters need to be placed after the Herschel Prism, not in front of it.

BPHERP$710.00 in stockAdd BPHERP To My Cart

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Kendrick Sun Finder (KSF6000)

The Kendrick Sun Finder makes locating the sun and centering it in your eyepiece a cinch…no more trying to line up the shadow of the scope on the ground.  It will work with all your solar accessories and dedicated solar scopes. 

The Sun Finder projects a solar dot onto the white target which can be viewed either from the front of the finder or through the cut out on the back.  The finder comes with a double sided adhesive foam tape for easy adhesion to a solar filter ring or other surface.

Put one on each of your solar filters!

KSF6000$31.00 in stockAdd KSF6000 To My Cart

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Kendrick Solar Filters Using Baader AstroSolar™ Filter Material

If you would rather not make your solar filter, you may prefer to purchase a ready-made filter. Kendrick Astro Instruments anticipated this need and has an economical solution!

Using the Baader AstroSolar™ material, Kendrick manufactures aluminum filter cells in a variety of apertures. With three long nylon screws placed on tabs at 120° intervals, this filter cell enables you to safely attach the filter to your lens cell or dew shield for a variety of telescope apertures.

Please use the following chart to determine which is the proper filter for your telescope.

AP Telescope or Binoculars Dew Shield O.D.

Visual Filter Part #

Fits Tube
PB105X70, PB15X70 (need 2) 87mm KDRA70V 85mm to 95mm
107mm KDRA90V 98mm to 108mm
105EDFS, 105EDT


117mm to 127mm
Star12ED 137mm KDRA120V 130mm to 140mm
130EDFGT, 130GTX
155mm KDRA130GTV 150mm to 160mm
130EDFS, 130EDT, STAR130ED
164mm KDRA130V 157mm to 167mm
140EDF27, 140EDF4
184mm KDRA155V 182mm to 192mm
155EDF, 155EDFS, 155EDT
189mm KDRA155V 182mm to 192mm
194mm KDRA180V 191mm to 201mm
175EDF, 180EDF, 180EDT
226mm KDRA206V 223mm to 233mm
280mm N/A N/A

Additional Considerations

You may also wish to add the Baader Solar Continuum Filter to your Solar observing arsenal. This filter, when combined with the Kendrick Solar Filters gives increased contrast for finer detail in surface features.

Those who want the photograhic density filter material might also consider purchasing the Baader Neutral Density Filter. The neutral density filter performs double duty, turning your Kendrick Photographic Filter into a safe visual filter system, and then also acting as a primo moon filter to avoid the eye burn that can come from moon observation through medium to large aperture instruments.

Please click here for Kendrick Solar Filter pricing.

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This page was last modified: October 13, 2017

Astro-Physics, Inc.
11250 Forest Hills Road, Machesney Park, IL  61115, U.S.A.
Phone: 815-282-1513   Fax: 815-282-9847