Orion 8671 Instruction Manual

Orion® 3" Field Flattener for

EON 115 & 130 f/7 Triplet

Refractors

#86 71

INSTRUCTION MANUAL

Providing Exceptional Consumer Optical Products Since 1975

IN 560 Rev. A 10/15

Customer Support:

www.OrionTelescopes.com/contactus

Corporate Offices:

89 Hangar Way, Watsonville CA 95076 - USA

Copyright © 2015 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.

2

This large-format field flattener, designed for photography with the Orion EON
115mm and 130mm f/7 triplet refractors, flattens the focal plane for astro-imaging
without affecting the focal length of the telescope. When imaging with a CCD or
DSLR camera, the far edges of the field of view will appear sharper when using
the field flattener with your EON telescope.

Connection to Telescope

The 3" Field Flattener threads directly onto the 3" dual-speed Crayford focuser of
the Orion EON 115 and 130 f/7 triplet refractors, for a rock-solid connection. The
Field Flattener has M92x1.0 male threads, which mate with the female threads
on the focuser. First remove the accessory collar from the focuser by turning the
knurled ring counterclockwise, as shown in Figure 1. Then screw the flattener
into the focuser.

The optimal backfocus distance (distance from the rear flange of the flattener,
excluding the M48 thread, to the camera sensor) is 51.5mm. However the flat­tener is known to provide sharp images at up to 5mm either side of this distance.

Connection to a DSLR Camera

The 3" Field Flattener features M48x0.75 threads on the camera side, wider than
the typical T-mount (M42), to minimize vignetting and provide better illumina­tion of full-frame camera sensors. Thus, for DSLRs you will need an M48 DSLR
adapter – a wider version of the standard T-ring.

Connection to a CCD Camera

Most CCD cameras require less backfocus than a DSLR camera. That means
you will need to add spacing as needed to fill the 51.5mm of required distance
to the Field Flattener. M48 (2") spacers are available from third party vendors.

Figure 1. To install the field flattener, A) remove the accessory collar as shown, then B)
thread on the field flattener until tight.

Accessory collar knurled ring

A

B

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Specifications

Optics 2-element, fully-multicoated

Backfocus length (optimal) 51.5mm

Threads, telescope side 92x1.0mm, male

Threads, camera side 48x0.75mm, male

Mechanical length when attached 88.8mm

Focal reduction None (1x)

Weight 17.9 oz (507g)

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One-Year Limited Warranty

This Orion product is warranted against defects in materials or workmanship for a
period 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
defective, provided it is returned postage paid. Proof of purchase (such as a copy of
the original 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.

Orion Telescopes & Binoculars

Corporate Offices: 89 Hangar Way, Watsonville CA 95076 - USA

Customer Support: www.OrionTelescopes.com/contactus

Copyright © 2015 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.