A. Information About Our Ready-To-Use Solar Filters
Why mess around with trying to make your own filter cell when you can have a ready-made, high quality Baader solar filter at a great price? Agena's visual solar filters are available in several sizes to fit virtually any finder, binocular, or telescope OTA/dewshield between 40mm and 225mm in diameter. They are made from the famous white light Baader AstroSolar safety film made by Baader Planetarium in Germany. The filter aperture and axis design varies by size (see specifications below). The filter cells are made of tough ABS plastic (sizes up to 140mm) or cast aluminum (sizes larger than 140mm) and are fitted with nylon thumbscrews for a secure fit. Optional screws are available (see "Accessories" section on this page) to increase the range over which each filter cell can fit. We offer Baader AstroSolar filters in visual density, ND 5 (0.00001 transmission) for direct visual use only. This can also be used for photography.
B. Baader AstroSolar Safety Film - Brief Overview
In its September 2000 issue, Sky & Telescope magazine proclaimed Baader Planetarium's AstroSolarâ¢ 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 AstroSolar is even more remarkable when considering its very low cost. When combined with Baader's tips for a simple do-it-yourself filter mount (see below), anyone can construct a complete low cost, high quality, white light solar filter for any telescope.
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 wing 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. Users of achromatic refractors will be particularly pleased with the performance using this additional filter.
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.
C. Appearance of Baader AstroSolar Film and Solar Filter Cell
At first glance, Baader AstroSolar Film appear to be like ordinary aluminum foil. You will often notice streaks or bends on the Baader film you receive. Sometimes, it also appear that the film might be slightly "warped." This is perfectly normal and natural and does not imply that the filter film is defective or used. The optical and mechanical properties of the film are not compromised. Please also note that the "flashlight test" is not a good way of inspecting this film. Putting it right against a very bright light will show a very mottled and non-uniform appearance, but again, this is normal and does not indicate a problem with the film piece.
Also, the Baader film is mounted a bit loosely on the filter cell. Hence, it may appear slightly stretched or even loose and "billowy" and may flutter a bit in a strong breeze. Again, this is normal.
Our filter cells are hand-produced in small lots and may have a slightly rough finish or minor cosmetic blemishes in parts. They may also have casting imperfections that look very much like cracks, but are not. However, these are all cosmetic and have no impact on the performance of the filter.
D. Tips on Selecting a Solar Filter for your Telescope
- Do NOT buy a filter that is the same size as your telescope aperture. For example, a 90mm telescope requires a filter cell LARGER than 90mm.
- Measure the outside diameter of your telescope tube/dewshield. Pick a solar filter with a Cell ID ("B" = Inside Diameter in specifications below) that is slightly larger than this. Do not select a filter cell that is exactly the same size as your tube/dewshield diameter - it won't slide on.
- Make sure that the included screws are long enough to clamp down on your tube/dewshield. Longer screws are sold separately if you need them. See specification "C" below.
- Make sure that the filter you select is deep enough to securely sit over your tube/dewshield. Use the Inside Depth ("D") specification below to determine this. Some telescopes have a beveled/slanted dew shield - our filter cells are probably not deep enough for a secure fit on these telescopes.
- Our on-axis design filters are perfect for refractor telescopes, but are not suitable for most reflector telescopes (Newtonian/SCT/Mak/etc.). If you use these with reflector designs, a significant portion of the filter aperture will overlap with your secondary and will effectively be wasted. Use simple geometry to calculate what portion of the filter aperture will be blocked by your secondary and whether the remaining clear filter aperture is adequate for your needs.
- Our off-axis design filters may work with some reflector telescopes, but you should compare your telescope's primary/secondary schematic to our filter specifications. Your scope's secondary may overlap with the Baader film rendering a portion of it ineffective. Similarly, a portion of the film may lie outside the edge of your primary mirror. You can use the detailed diagram and specifications provided below to see what portion of the filter aperture can be used with your reflector or catadioptric telescope.
E. Product Reviews/Testimonials
"The solar filter mounted easily using the supplied thumb screws and, well, looked good on [my] scopes. I can say I felt "smart" for having bought the filter. Thanks for the quality product, good price, and excellent service."
- B. Pugh, Oakland, California
"The integrity of your filters put me at ease. I am very pleased with the views, and feel confident observing with your filter. The thumbscrews grip nice and tight to the front of my scope, and they don't chew up the finish. I know this filter will not just come off. These are a great value!"
- B. Chellis, Seymour, Connecticut
"No joke: last week, my dog took the filter off the shelf, ate the box, and ripped out the Baader solar film! Fortunately, the way your filter is set up, I was able to unscrew it and replace the film with [another piece]. I doubt you could do that with any other style of filter."
- S. Azmus, Kenosha, Wisconsin
Sep 23, 2012
Agena Baafer solar filterPros:
Cheap Plastic ContainerComments:
Another well made Agena product.
The cell is well made and is NOT plastic.
One should note,if your not familiar with Baader film,never lay the cell flat to allow the film to contact *anything* rough,it will scrath *very* easily ruining the film,but Agena makes it easy to replace the film - thanks Agena.
This review was provided courtesy of AgenaAstro.comJul 13, 2012
Great Price; Solid Construction!Pros:
Easy to Use,Strong ConstructionCons: Comments:
I bought the 160mm filter, prior to June's Venus transit, for use on my 4.5" reflector and it fits great. The 150mm filter might have fit a little bit better, but since it was sold-out at the time, I bought the 160mm and got some additional 1.75" long nylon screws to make sure the filter would attach to my telescope. The 70mm of filter aperture is more than sufficient for my 4.5" mirror, and as a result, images of Venus and sunspots were bright and crisp. The filter is not as light as other plastic-framed, Baader solar filters I have used in the past. That being said, it's NOT heavy enough to screw-up the balance of my telescope's EQ mount. Frame construction is solid (milled aluminum) and well done. I did notice that the frame gets quite warm after being in the sun for more than 15 minutes, but it's nothing that will burn your hands when removing it from your telescope. Overall, I'm very satisfied with my purchase and would recommend this product without hesitation.
This review was provided courtesy of AgenaAstro.comJul 13, 2012
Good Product, timely deliveryPros:
Easy to Use,Lightweight,Strong ConstructionCons: Comments:
I used the Agena Baader Solar Filter to observe the transit of Venus. The filter was well-made, thoughtfully packaged, and fit securely on the telescope. I placed the order less than a week before the transit, and it arrived in time!
I am very happy with the quality of the filter and the timely delivery.
This review was provided courtesy of AgenaAstro.comJul 7, 2012
Good Potential, but not perfectPros:
Strong Construction,Very Heavy Aluminum Cell,Excellent Baader FilmCons:
Sharp Pointed Screws,No Felt on Inside of CellComments:
First I want to say this a review of the ITEM not Agena Astro. Agena is EXCELLENT in their customer service and follow up. They shipped this out so quickly I was able to use it in time for the Venus Transit! I highly recommend doing business with them.
How I used it: On the end of my AstroTech AT106LE APO refractor for safe observation of the sun.
Great: Its very heavy. This is good because with a solar filter, you dont want there to be any possibility the filter will come off the end of the tube from a strong wind. There is no way this is going anywhere and that increases my confidence in using the product. I also think the Baader Astrosolar film does a good job of showing detail on sunspots and faculae. Optically it works very well.
Things not so great: The biggest flaw on this design is the screws used to hold the film cell to the aluminum cell actually are pointy (wood screws???) and extend through the back of the aluminum cell. In my excitement to use the product I didn't inspect this as I should have and tried to put it on the scope as carefully as I could. This wound up scratching the front of my anodized lens shade which really was dissapointing to me. How the manufacturer would use pointy screws is beyond me and how they allowed them to extend beyond the aluminum cell is also poor manufacturing. I was very careful and it still scratched it in a few places. Also the flat black paint on the inside of the aluminum cell easily flakes off, exposing the aluminum underneath. The inside of the alumium cell should also be lined with felt and it is not. I also noticed a flaw in the alumium cell where it had a small pitted area. It didn't pose any saftey concern, but was an aesthetic flaw. I filled it with some glue.
Overall, this unit has potential, but my example wasn't excecuted to the level I expect.
This review was provided courtesy of AgenaAstro.comJun 30, 2012
Transit of Venus Success!!Pros:
Strong Construction,Accurate,Sturdy,Lightweight,Easy to UseCons: Comments:
This filter made watching the TOV a memorable experience for hundreds of sidewalk viewers of this momentous event.
This review was provided courtesy of AgenaAstro.comSort by