ABOUT US 2018-06-01T14:20:35+00:00

​Astrodon has been purchased by Optical Structures Incorporated (OSI). The web store has transitioned to the OSI store at

Your source for the highest performing, most durable filters for astrophotography and research

It all started out as a hobby to take pictures through telescopes using high-resolution monochrome CCD cameras and red, green and blue filters to produce a color image of a galaxy or nebula. The RGB filters of the day were not color-balanced, which meant that you could not simply combine them in the computer equally. The blue filters were not very efficient, produced noisy data and required higher weights when combined with green and red data.  It was because of this that I began designing a set of RGB filters that were “balanced” to simplify the overall imaging task. I knew I had a product that was useful and saved a lot of time for astrophotographers like myself.

With my concept and design, I approached several suppliers of astrophotography filters to make my filters, but was turned down each time. Confident in the fact that there were no astrophotography filters for sale that could match my RGB filters, I found a coater and started manufacturing my own brand in 2003.  It caught on with friends and early distributors.

The business name combines my name, Don, with Astronomy which became Astrodon. The company mission became “simplify your imaging” because it was what the products are intended to do. The RGB sets, consistent with the “balancing” idea became “Tru-Balance”. These filters are now sold worldwide, and are widely considered to have the best performance and quality with a “step up to Astrodon” image.  Ask any distributor who makes the best filters.  Along the way, we added the highest performing narrowband filters used for certain types of astronomical objects, such as those used by NASA for its iconic “Pillars of Creation” image from the Hubble Space Telescope. In the early days, the narrowband and RGB filters were different thicknesses requiring the user to refocus the telescope.  Again, to simplify the process, ALL Astrodon filters are made from single substrates of high quality fused silica of the same 3 mm thickness to minimize or eliminate the need for significant refocusing.

During this time the most popular CCD cameras had a guide sensor next to the imaging sensor inside the camera.  This meant that you had to guide behind a blue filter or even worse, a narrowband filter.  So, Astrodon created what became our MonsterMOAG off-axis guider, which is a hardware part that allows you to guide your telescope system IN FRONT of your filters, making guiding so much easier.

Lastly, along the way, we acquired Schuler Astro-Imaging UVBRI filters to enter the research market.  They were made with up to three different colored glasses epoxied together – the traditional way such photometric filters were made for decades.  The limitations became quickly obvious leading us to develop the next generation of photometric filters for research.  They are now made similar to our other filters with a single high-quality fused silica substrate and are 100% coated using hard oxide sputtered coatings.  As a result, our photometric V filter no longer fogs.  We started with UVBRI filters and added Sloan (SDSS) filters that all have the highest throughputs available anywhere, along with great durability so important for long-term, consistent research.

The term “performance” and “simplify”  permeate the descriptions our products lines.  We are the high price leader for astronomy filters, with the understanding that you will receive the highest performing most durable and easy-to-use filters for sale on the market.

In January, 2018, Astrodon was acquired by Optical Structures, Inc. of Rancho Cordova, CA, the owners of Farpoint, JMI and Lumicon.  I will stay on-board as a consultant.  I wish to thank all of you for your support and use of Astrodon products over the years.

Clear Skies,

Don Goldman, Ph.D,

Optical Structures, Inc.
Rancho Cordova, CA