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Thank you for visiting Siebert Optics!
Serving Large Observatories and the Amateur Astronomy Community alike.

200 Short Johnson Road
Clayton, NC 
USA  27520


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Eyepieces .965" / 1.25" / 2.0" / 2.7" / 3.0" / 4.0" / 4.3"


Large and Small Binocular Cleaning and Alignment services $99 Call or Email for details.


BT70 RA88 / Miyauchi / Kowa eyepieces


Binoviewer Alignment and Supercharge Services


Advanced Barlow Lenses including: Modular and 4 element Telecentric magnification multipliers


1.25" and 2" Advanced Binoviewers From $649-$1999


 Binoviewer OCA's and Accessories


Adapters - Meade Scopes and ETX


Binoculars - Quality Modified


Large and Small Non Illuminated and Illuminated Cross haired eyepieces.






Camera Focus Adaptors


Camera Adapters - Universal


H-Alpha Focus Accessories



Special binoviewer services and products you cant get anywhere else 

ICP's Image Correction Prisms for Newts




Extension Tubes


Large refractor modular OTA's


Eyepiece Comparisons


Focal Length Reducers




Planetary Fleece Blanket 


PST Accessories


Telecentric Barlow Lenses


Zero Magnification Adapter





Ladies Corner

Saturn Earrings  

Astronomy themed totes/purses


Free Domain Pictures

Astronomy Accessory Links of 

       products not offered 

       by Siebert Optics


Useful Astronomy Links


International Dealers


Astro photos


Non-Astronomy Items










End Cap solutions for many applications 

Including T - 2 and T thread applications 


Delrin 1.25" or 2" ID (Female) caps for diagonal inlet $15

Delrin 1.25" or 2" OD (Male) for top eyepiece holder $15 

0r both ID and OD Delrin caps for $15 

The above is for all 1.25" and 2" cap applications both male and female


Delrin Binoviewer Cap set with bottom cap and top male plugs  all 1.25" $30  

Delrin Binoviewer Cap set with 2" bottom cap and top 1.25" male plugs $30  

The above is for all binoviewers with 1.25" or 2" cap applications.


Baader T - 2 Male or Female Caps $15 each

Baader Binoviewer Cap set T - 2 Female and 2 Male 1.25" eyepiece plugs $40

The above are for Baader diagonals and binoviewers


Camera T thread Male or Female Caps $15 each

The above is for all camera T - thread applications both male and female.

SCT male end cap $15 each

The above is for Celestron SCT diagonals










































All listed products come with a 30-day money-back guarantee* unless otherwise stated.

Specialty order items are not refundable (items made specifically for you).

We welcome
International orders!.

We accept Visa, Mastercard,


  American Express. U.S. Money Orders, and Personal Checks (held 10 working days for clearing)Online payments may be made securely through



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