TPO 2" Quartz Dielectric Diagonal

  • Quartz offers greater thermal stability, resulting in minimal thermal expansion and contraction.
  • The Third Planet Optics 2 inch Quartz Dielectric Diagonal is a deluxe 1/10th wave mirror diagonal with 99% reflectivity, dielectric coatings.
  • Fully CNC machined housing and includes 2 inch to 1.25 inch adapter.
  • The TPO 2 inch Quartz Dielectric Diagonal features brass compression rings on both the diagonal and adapter assure gentle treatment of your eyepieces.
  • Fully machine threaded to accept 2 inch filters.
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  • Regular price $128.95

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TPO 2" Quartz Dielectric Diagonal

The TPO 2 inch quartz dielectric mirror diagonal features 99% 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 Third Planet Optics 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.

TPO Product Number: OS-D2DIQ


Angle90 degree
Diagonal Barrel Size2"
Free ShippingYes
Warranty2 Year Warranty
Customer Reviews
5.0 Based on 3 Reviews
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Ron O.
A bargain!

Simply awesome performance for the price. The only reason I didn't give this gem a five star rating, was that I wish the screw had a bigger head. Awesome...worth every penny.

Robert T. Romanelli
Customer review

OPT has a real winner here branded under its own label. For quality and value, this diagonal cannot be beat. I was impressed by the solid construction, admirable fit and finish but most of all by its superb optical performance. I highly recommend this fine accessory.

ralph g.

i gave this diag.4.5 stars only becouse the mir. surface had a tiny spec on it but as far as viewing?it was a very fine piece that i would buy again as it was built like a work horse no cheep junk.