Astrozap: How to Choose the Right Solar Filter

To ensure you order the correct size, please refer to the sizing chart and measurement instructions provided in the product description. Sizing is generally based on the outside diameter of your telescope or dew shield where the filter will fit, not the diameter of the lens or mirror.

Please note that if a solar filter is not in stock, it may need to be custom-built. In such cases, please allow an additional 2 to 3 weeks for production and delivery.

How to Choose the Right Astrozap Solar Filter

The sun is a fascinating, dynamic object. Its surface is surprisingly detailed and changes frequently. The observing hours are more convenient. However, there are a few rules to follow before using your telescope on the sun. The first rule of solar observing is never point your telescope at the sun without a proper filter. The second rule of solar observing is always inspect the filter before placing it on your telescope prior to observing to ensure that there are no defects (scratches or pinholes) that could damage your eyes or equipment. IF YOU DISCOVER ANY DEFECTS, DO NOT USE THE FILTER—IRREVOCABLE EYE DAMAGE COULD RESULT FROM THE USE OF A DAMAGED SOLAR FILTER ALSO, NEVER MOUNT A SOLAR FILTER ON ANYTHING OTHER THAN DIRECTLY TO THE OPTICAL TUBE.

If you have a finderscope or similar device on your telescope, remember to cover it or or install a solar filter on it before using your solar-filter-equipped telescope to observe or image the sun.

All Astrozap Solar Filters use only high quality and safe materials. Astrozap offers 4 different types of solar filters. For pre-made solar filters, one size does not fit all!
Here are the variables you need to consider in choosing the right Astrozap solar filter for your particular telescope or binocular needs.

A. For pre-made Astrozap Solar Filters you need at least 1 inch of clear/unobstructed surface on the outside front of the optical tube(s) where the solar filter will slide on. Never mount a solar filter on anything other than directly to the optical tube. We do not recommend placing Astrozap pre-made Solar filters on telescopes or binoculars that have any obstructions on the 1-inch outside-front area of the optical tube (obstructions such as beveled plastic trim or mount fixture hardware can prevent safe mounting). It is especially important for Solar Filters to not leak sunlight – via stray light entering the optics or falling off altogether. Your equipment or more importantly, your eyes, could be harmed.

B. Telescopes need to be closed-tube type. Truss tube telescopes, even with cloth light shrouds, can leak sunlight and harm equipment or eyes. To be sure, check with your telescope manufacturer to see if your model is suitable for an accessory solar filter.

A. Astrozap offers Pre-Made solar filters, made to fit specific sizes (accommodating various makes and models) of telescopes or astronomy binoculars (meeting the basic requirements in #1 above), securely and safely. Pre-Made solar filters come with one or more plastic retaining screws, depending on the filter's size, that do not mar or scratch the finish on the optical tube. Astrozap Pre-Made Solar Filters are proudly made in the USA. Pre-Made solar filters from Astrozap come in three types:

B. Astrozap also offers Build-your-Own solar filters that come in one type: Baader AstroSolar™ Material. This is the same material as in the Pre-Made Baader Full Aperture AstroSolar™ Solar Filters. Baader Solar Filter material is for visual observing.

3. FINDING YOUR SOLAR FILTER ON ASTROZAP.COM

A. Measure the front outside diameter, where the Astrozap Solar Filter will slide onto the outside front of the tube. The easiest and best way is to simply measure across the outside front of the tube in mm as shown below. Most of our measurements are in mm.


 
B. Measure the unobstructed distance on the front of the tube where the dew shield will slide on for a snug fit. Make sure you have at least 1 inch or 25mm unobstructed.




C. Under the SOLAR FILTERS main navigation button, click on the button link that goes to the type of solar filter you want to purchase and select the correct size. As an additional help for you, the glass solar filter product pages also show a table with sizes and some of the telescopes that each filter will fit. Not all telescope makes and models are included, but if you follow the “How to Choose the Right Astrozap Solar Filter” instructions, you will be able to find the right product.

D. Your choices under SOLAR FILTERS Astrozap home page link are grouped under the following button links:
- Telescope Pre-Made Solar Filters

E. If you still need help, simply contact us at info@astronomyplus.com and let us know what make and model telescope or binocular you are trying to fit. We are here to help!