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Orion Telescopes
Coronado SolarMax III 90mm RichView Filter with BF30
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Pre-Order Now! Expected Ship Date: 08/13/2024
  • Hydrogen-alpha filter set including the 90mm SolarMax III Etalon with 30mm Blocking filter (BF)
  • Narrow 0.7 Angstrom bandpass ideal for viewing prominences on the solar limb
  • External front mounted etalon for use on your high-quality telescope
  • Padded hard case included to protect your investment
  • Requires third-party adapter to connect etalon to front of your scope.

Learn more
Item #  55903b
Mfg Model #  624013

This Coronado SolarMax III 90mm Solar Filter set with RichView tuning system includes a 90mm diameter primary Hydrogen-alpha etalon filter with sub 0.7 angstrom bandwidth and 30mm Blocking Filter. The filter set is packed in a hard case to protect your investment.

The 90mm etalon includes Meade's patented RichView tuning which allows direct tuning of the etalon filter. The RichView tuning system adjusts the distance between the etalons parallel glass plates in order to achieve the perfect wavelength bandpass for the feature you are observing, all while maintaining precise optical alignment. Coronado's patented technology allows the etalon to be used at high altitude observing locations. The RichView system simply allows for better control over your H-a bandpass window. In addition to RichView tuning, the included T-Max Tuner allows you to tune in the brightest image and remove any internal reflections. Combined, the RichView and T-Max together offer unparalleled image tuning to get the best possible view of solar details!

Solar Disk Detail Image

The Sun in hydrogen-alpha light showing some of the different features visible around the solar disk.

The kit also includes a Coronado 30mm right angle (diagonal) type Hydrogen-alpha blocking filter, now in the SolarMax III design. This updated design includes a long 2" diameter nosepiece with 1.25" eyepiece holder and t-thread connection. The blocking filter is the second element in any Coronado H-alpha system, and is just as crucial to your safety and the system's performance as the primary SolarMax etalon filter. This blocking filter CANNOT be used without a SolarMax etalon. Secondary interference filter for full disc image of the Sun for telescopes up to 3,000mm focal length. The BF30 provides a larger unvignetted field of view over the smaller BF15/10 sizes.

This 30mm blocking filter is a convertible design and ideal for imaging the sun! Convert from the 1.25" right angle configuration to a 2" straight design with the included straight-thru adapter. Also includes Coronado's zero-length 2" to 1.25" adapter so you can use all your favorite 1.25" accessories.

Note: Cannot be used with the #624018 Coronado 1.25" nosepiece adapter as BF30 filters are in the 2" nosepiece. Do not attempt to use only the diagonal portion of this blocking filter — the straight through 2" nosepiece must be used at all times.

Coronado filters are used around the world by serious solar enthusiasts and professional research facilities alike. When properly and safely mounted on your high-quality refractor or other suitable telescope this filter set allows observation and imaging of the amazing and ever-changing surface detail and prominences on the Sun in hydrogen-alpha light. Not for use on truss-tube telescopes with open sides as unfiltered sunlight may be transmitted through the optical tube. Custom mounting of the etalon to your optical tube will be required. End-users will be required to contract a third party company to machine any necessary adapters (adapters not included).

90mm Etalon Drawing

The dimensions of the 90mm front etalon filter. Use the thread specification for building your custom mounting adapter.

The stunning bright red views through a Coronado Ha telescope display astounding surface and limb detail. Features such as prominence, filaments, plages, and surface granulation are fascinating to observe, and many of these features can change shape over the course of days or even just hours in the case of flares and edge prominences.

Designed and Manufactured in North America.

Product Support
Visit our product support section for instruction manuals and more

90mm SolarMax III Etalon
BF30 blocking filter
2" straight through adapter
Zero length 2"-1.25" adapter
Hard case
SolarMax III Instruction Manual

When an item is not in-stock we will ship it as soon as it becomes available. Typically in-stock items will ship first and backordered items will follow as soon as they are available.

A per-item shipping charge (in addition to the standard shipping and handling charge) applies to this product due to its size and weight. This charge varies based on the shipping method.

Standard Delivery: $0.00

Standard Delivery to Canada: $50.00
3 Day Delivery: $70.00
2 Day Delivery: $70.00
Next Day Delivery: $85.00

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