ORION TELESCOPES & BINOCULARS 8893 User manual

INSTRUCTION MANUAL
IN 421 Rev. B 06/19
Orion Field Flattener
for Short Refractors
#8893
Corporate Offices: 89 Hangar Way, Watsonville
CA 95076 - USA
Toll Free USA & Canada: [phone]
International: [phone]
Customer Support: [email protected]
Copyright © 2020 Orion Telescopes & Binoculars.All Rights Reserved. No part of this
product instruction or any of its contents may be reproduced, copied, modied or
adapted, without the prior written consent of Orion Telescopes & Binoculars.
AN EMPLOYEE-OWNED COMPANY

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Your Orion Field Flattener for Short Refractors corrects for Petzval field curva-
ture, which if uncorrected leaves the periphery of the image frame slightly out of
focus. This Field Flattener’s doublet optical lens configuration provides the correc-
tion necessary to yield sharp stars across the entire image frame – without affect-
ing the focal length of the refractor.
Results will be especially noticeable
when using cameras with APS-C and
full-size sensors.
The Field Flattener fits 2" focuser
drawtubes, and its barrel is internally
threaded to accept 2" Orion filters. It
has a 55mm backfocus distance, which
means that the camera’s sensor must
be set 55mm behind the Flattener’s
T-thread flange to achieve optimal
focus. The Field Flattener now comes
with interchangeable M42 (standard
T-thread) and M48 (“wide” T-thread)
male thread adapters (Figure 1). The
M48 adapter is recommended for use
with full frame camera sensors.
Attaching the Field Flattener to
a DSLR Camera
An appropriately sized T-ring (M42 or M48) for the make and model of your camera
is the only required accessory to attach the Field Flattener to your DSLR camera.
The distance from the camera’s sensor to the front plane of the T-ring will be 55mm
– a perfect match for the backfocus distance of the Field Flattener (Figure 2.1).
Attaching the Field Flattener to an Astronomical CCD/CMOS
Camera
Most astronomical CCD or CMOS cameras require less backfocus than a DSLR
camera. That means you will need to add spacers as needed to fill the 55mm of
required distance to the Field Flattener (Figure 2.2). T-thread spacers are avail-
able from several astronomical equipment dealers.
For example, if a camera has 20.1mm of backfocus – obtain this spec from your
camera’s manufacturer – you would need to add approximately 35mm of spacer
length between the camera and Field Flattener to achieve the proper distance (20.1
+ 35 = 55.1mm). Note that if you do not reach 55mm perfectly, the Field Flattener will
still work, but will gradually lose effectiveness the farther from 55mm (in either direc-
tion) your camera is positioned. Your CCD/CMOS camera must have compatible
female T-threads (usually M42) on the camera body to attach to the Field Flattener.
Remove the camera’s nosepiece (if equipped) and thread the camera body onto the
back of the Field Flattener or T-thread spacer.
M42 "T-Ring
Adapter"
M48 Adapter
Figure 1.

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Care & Maintenance
Care should be exercised when using all optical and mechanical telescope acces-
sories. Keep your Field Flattener in a protected environment when you’re not using
it, and place the dust cap and threaded metal cap on the Field Flattener for storage.
Avoid touching the glass lenses and coatings. If the lens should become dirty, you
may want to clean it. Blow off all loose dirt with a blower bulb. Use only optical lens
tissue and good-quality lens fluid. Wet a folded tissue and gently wipe the surface
of the lens. Immediately use a second piece of lens tissue to gently dry the lens off.
Do not rub or apply pressure, as this may scratch the lens if dust or grit is present.
Field
Flattener
DSLR
camera body
T-ring
2" focuser on
telescope
Field
Flattener
CCD/CMOS
Camera
55mm
Xmm
2" focuser on
telescope
Distance from CCD
chip to Field
Flattener Flange
should be 55mm
“X”mm of additional spacing may
be required to achieve 55mm,
depending on make and model
of camera.
Figure 2.1.
Figure
2.2.

Specifications
Optics 2-element, fully-multicoated
Clear Aperture 38mm
Focal Length 55mm
Mechanical Profile 51mm
Camera Attachment Male M42 and M48 interchangeable adapters
Weight 192g (6.8 oz)
Corporate Offices: 89 Hangar Way, Watsonville CA 95076 - USA
Toll Free USA & Canada: [phone]
International: [phone]
Customer Support: [email protected]
Copyright © 2020 Orion Telescopes & Binoculars.All Rights Reserved. No part of this product instruction or
any of its contents may be reproduced, copied, modied or adapted,without the prior written consent of Orion
Telescopes & Binoculars.
AN EMPLOYEE-OWNED COMPANY
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 benet 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 modied, nor does it apply to normal wear and tear. This
warranty gives you specic legal rights. It is not intended to remove or restrict your
other legal rights under applicable local consumer law; your state or national statu-
tory consumer rights governing the sale of consumer goods remain fully appli-
cable.
For further warranty information, please visit www.OrionTelescopes.com/warranty.