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 5 of 20 
Orion Telescopes
Coronado Adapter Ring for 40mm Double Stack Filter
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In Stock
  • Adapter ring for original first generation SM40 etalon
  • When coupled to the second etalon, reduces original 0.7 angstrom bandpass of the Hydrogen-Alpha telescope to 0.5 angstrom
  • Designed for older SM40 Etalon - not needed for newer SME-40, SMIII, or PST systems
  • Threads components solidly together, ensuring a tilt free connection
  • Designed and Manufactured in North America

Learn more
Item #  55738
Mfg Model #  AP185

This adapter ring is required to double stack an SM40 external primary etalon, double stacking an original 40mm Coronado telescope such as an SMT40.

Double stacking reduces the original 0.7 angstrom bandpass of the Hydrogen-Alpha telescope to 0.5 angstrom, dramatically increasing visibility of surface detail such as granularity and active regions on the surface of the Sun.

Note, this adapter ring is only required to stack an additional etalon onto the original SM40. It is not required if you have the newer SME-40, SMIII, or PST system. Telescope and double stacking filter sold separately.

Designed and Manufactured in North America.


Limited Warranty against defects in materials or workmanship for two years from date of purchase. This warranty is provided by Meade for the benefit of the original retail purchaser only. For complete warranty details contact Meade at 800-626-3233.

  • User level
  • Design
  • Barrel size
  • Barrel security recess
  • Body material
  • Additional included accessories
  • Other features
  • Warranty
    Two year

Orders received by 1pm Eastern Standard Time for in-stock items ship the same business day. Order received after noon will ship the next business day. 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. You have the option in check out to request that your order ship complete, if you'd prefer.


This product is available to ship Standard delivery US except for delivery to Alaska and Hawaii. Delivery is available to APO/DPO/FPO addresses. Delivery is not available to US territories/protectorates. Delivery is available to Canada.

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