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Serving Large Observatories and the Amateur Astronomy Community alike.

200 Short Johnson Road
Clayton, NC 
USA  27520

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         Products:

Telescopes for sale

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

BT70 RA88 / Miyauchi / Kowa eyepieces

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

Binoviewer Alignment and Supercharge Services

Adapters - Meade Scopes and ETX

Binoculars - Quality Modified

Large and Small Non Illuminated and Illuminated Cross haired eyepieces.

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

Camera Focus Adaptors

Camera Adapters - Universal

H-Alpha Focus Accessories

Converters

Special binoviewer services and products you cant get anywhere else 

ICP's Image Correction Prisms for Newts

Diagonals

Extension Tubes

Large refractor modular OTA's

Eyepiece Comparisons

Focal Length Reducers

Miscellaneous

Observers Hood - light blocking 

Planetary Fleece Blanket 

PST Accessories

Telecentric Barlow Lenses

Zero Magnification Adapter

Ladies Corner

Saturn Earrings  

Astronomy Themed  Fleece Blanket 

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

      Fabrics

      Purses

Once you get into the Diagonal calculator, use the below provided specs for the values.  The scope set at f4.5 and the binoviewers for CA. and OP. You must double the off axis value to get your diameter spot of full illumination at the eyepieces. The ink is under the specs. Play with the f-ratios and see what happens.

   Baader specs below

Primary mirror diameter:     200 mm     ---scope primary size

Primary mirror focal length: 900 mm  ---scopes focal length

Diagonal size - m.a.:              28mm      ---binoviewer bottom Clear aperture

Diagonal to focal plane:        114mm    ---distance from bottom of binoviewer to eyepiece focal plane.

 You have 1 mm of Full illumination without an OCA.

New Black Night  specs below

Primary mirror diameter:     200 mm     ---scope primary size

Primary mirror focal length: 900 mm  ---scopes focal length

Diagonal size - m.a.:              25mm      ---binoviewer bottom Clear aperture

Diagonal to focal plane:        100mm    ---distance from bottom of binoviewer to eyepiece focal plane.

 You have 1 mm of Full illumination without an OCA.

       Mel Bartel Diagonal Calculator

Try All these Dielectric binoviewers below.

  Baader             BN25               TV                  Denk 

  CA 28 x OP 114mm                     CA 25 x OP 100mm                   CA 28 x OP 130mm                       CA 26 x OP 116mm

     $1600                        $450                     $900                        $900