TPO 2" SCT Quartz Dielectric Diagonal

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  • Regular price $138.95
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  • Quartz offers greater thermal stability, resulting in minimal thermal expansion & contraction.
  • The TPO 2-inch SCT Quartz Dielectric Diagonal features a deluxe 1/10th wave mirror diagonal with 99-percent reflectivity and dielectric coatings.
  • Attaches to rear cell thread of Schmidt-Cassegrain/Maksutov-Cassegrain telescopes.
  • The Third Planet Optics 2-inch SCT Quartz Dielectric Diagonal has a fully CNC machined housing and includes 1.25-inch adapter.
  • Brass compression rings on both diagonal and adapter assure gentle treatment of your eyepieces.


TPO 2" SCT Quartz Dielectric Diagonal

The Third Planet Optics 2-inch quartz dielectric mirror diagonal features 99-percent reflectivity, dielectric coatings to maximize light output of your telescope system. Our custom made diagonal uses a quartz mirror polished to 10th wave accuracy (or better) for best possible image quality.

TPO's quartz dielectric diagonal provides greater thermal stability than comparable glass diagonals, resulting in minimal thermal expansion and contraction. This quartz diagonal, therefore, minimizes focus position change due to variations in temperature.

The TPO 2-inch quartz dielectric diagonal also features a CNC machined housing. The CNC machined aluminum housing will provide outstanding results for years of use. This housing is designed to retain the optimal collimation of the mirror and assure the best optical performance.

This diagonal also includes brass compression rings on both diagonal and the included 2-inch to 1.25-inch adapter, assuring gentle treatment of your eyepieces. Some other brands use set screw locking mechanisms that can mar the barrel surface of your favorite eyepieces. Avoid scratches and gouges by using the OPT dielectric series diagonals.

TPO quartz dielectric diagonals provide outstanding performance with low prices to provide amateur astronomers with excellent value! OPT backs this diagonal with a full 2 year warranty against manufacturer defects.

This diagonal attaches to the rear cell of SCT's. It is not meant for SC telescopes that have an electric focuser attached to the rear cell. In these instances, we recommend the OPT 2 inch Quartz Dielectric Diagonal.


OPT Product Number: OS-D2SCTDIQ

Additional Information

Accessory TypeDiagonals
Free ShippingYes
Warranty2 Year Warranty

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  • I'm considering upgrading my Celestron C11-XLT to this 2" diagonal. Is this diagonal compatible without additional adapters? I'm aware that there may be at least two sizes of rear cell threads used in some Schmidt-Cassegrain telescopes, depending on the m

    This will fit the 2" visual back thread on your C11-XLT with no additional adapters needed.

  • will this work on a meade lz80 6 inch SC>

    Yes, this diagonal will thread to the rear 2" SCT thread on the back cell of the LX80 6" SC.

  • I have a celestron 8se Is this product compaitble with my telescope?

    Hello and thanks for your question. Yes this will fit all Schmidt Cassegrain telescopes. Especially yours!!! :) Please contact us with any questions.