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Image Orientation

The star diagonal reverses the image from left-to-right. This rever-
sal is hardly noticeable when viewing the night sky. If you are 
printing star maps on your computer, you may want to have your 
program flip the star map to match your eyepiece’s reversed view 
through the diagonal.

Use of Filters

The 1.25" diagonal is threaded to accept Orion 1.25" filters on its 
barrel. If you use filters directly on the star diagonal, it will prevent 
having to remove and reinstall filters when switching eyepieces. 

The 2" diagonal will also accept filters (Orion 2" size only), either 
on the barrel of the diagonal itself or on the bottom of the 1.25" 
eyepiece adapter.

Care and Maintenance

Although the star diagonal is quite durable, it should avoid pro-
longed, unnecessary exposure to the elements. Keep the diago-
nal capped on both ends when not in use, preferably in a foam-
lined eyepiece case. It is also recommended to leave the diagonal 
in a dry place with caps off overnight to let it completely dry out 
after use. Store the instrument in a cool, dry place; storage in a 
humid environment can result in degradation of the optical coat-
ings on the mirror. This is not covered by the warranty.

Cleaning the Diagonal

The mirror of the star diagonal is coated with high-reflectivity 
coatings which can be damaged with careless handling. Avoid 
touching mirror surfaces with your fingers or any coarse material. 
Clean the mirrors only if they get noticeably dirty. Always use lens 

cleaning tissue and fluid specifically designed for telescope opti-
cal coatings. Do not use regular tissue or fluids made for eyeglass 
or household use.
To properly clean the star diagonal’s mirror, the mirror must be 
removed from its housing.  To do this, first remove the four Phillips 
head screws from the bottom of the diagonal. For 2" models, you 
will also need to remove the two button head cap screws from the 
side of the diagonal (requires a 2mm or 5/64" hex key). The mir-
ror is gently supported by foam padding and can be removed by 
simply sliding it out of the diagonal housing. 
Once the mirror is removed from its housing, blow compressed 
air over the surface to remove dust particles and debris, then 
gently wipe away smudges with telescope optical cleaning fluid 
and tissue. Apply some fluid to a tissue and gently wipe the mirror 
surface. Use another clean, dry piece of tissue to gently wipe up 
any fluid remaining. Repeat if necessary. Use caution; wiping with 
too much applied pressure may cause scratches.

Specifications

Enhanced aluminum coating: 97% reflectivity 
Dielectric coating: 99% reflectivity

Corporate Offices:

 89 Hangar Way, Watsonville CA 95076 - USA

Toll Free USA & Canada:

 (800) 447-1001 

International:

 +1(831) 763-7000

Customer Support:

 support@telescope.com

Copyright © 2021 Orion Telescopes & Binoculars. All Rights Reserved. No part of this product instruction or any of its contents 

may be reproduced, copied, modified or adapted, without the prior written consent of Orion Telescopes & Binoculars.

A N   E M P L O Y E E - O W N E D   C O M P A N Y

One-Year Limited Warranty

This Orion product is warranted against defects in materials or workmanship for a peri-
od of one year from the date of purchase. This warranty is for the benefit of the original 
retail purchaser only. During this warranty period Orion Telescopes & Binoculars will 
repair or replace, at Orion’s option, any warranted instrument that proves to be defec-
tive, provided it is returned postage paid. Proof of purchase (such as a copy of the origi-
nal receipt) is required. This warranty is only valid in the country of purchase.
This warranty does not apply if, in Orion’s judgment, the instrument has been abused, 
mishandled, or modified, nor does it apply to normal wear and tear. This warranty gives 
you specific legal rights. It is not intended to remove or restrict your other legal rights 
under applicable local consumer law; your state or national statutory consumer rights 
governing the sale of consumer goods remain fully applicable. 
For further warranty information, please visit www.OrionTelescopes.com/warranty.

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