Orion Optics OD150, OD200, OD250, OD300, OD350 Owner's Manual

Orion Optics UK Ltd

Owners manual for models:

OD150, OD200, OD250, OD300, OD350 and OD400

Contents
1 Introduction
2 Main parts of telescope

3. Model differences

4. Assembly

5. Checking things

6. Collimation

7. Using the telescope

8. Care and Maintenance

9. Accessories and upgrades

Introduction

Main Telescope parts

Thank you for buying one of our Dobsonian range of telescopes. The following will give you all the
information you need to allow you to assemble, use and, maintain your telescope. If you carry out the
procedures correctly the telescope will give you many years of faultless usage. Please take note in
particular of the details on care of optics, if these notes are ignored or not carried out properly, damage
to the optical coatings could result. Please read through this document before commencing assembly
of the telescope, familiarise yourself with the names of the major components. And finally, when
assembled, above all, enjoy it.

This section will show you the main parts of the telescope and their function within the telescope.
Nearly all the parts on all the range have the same name and function but, because of differing model
sizes, the actual shape of the part often varies.

Shown here is a typical model with most external components labelled. Certain items are shown in
greater detail.

TYPICAL DOBSONIAN MODEL

Fig 1

Model differences

Apart from the obvious difference of aperture and physical size and shape, all the telescopes from the
OD150 up to and including the OD400, are remarkably similar. Differences occur mainly in the
technical specifications between the standard models and the de-luxe models.

The main areas of ‘visible’ differences are:

Finder scope. Standard are supplied with a 30mm aperture finder, De-Luxe with a 50mm finder

but both work off exactly the same principle.

Focuser. Standard are fitted with a rack and pinion 2” focuser (150mm models use a

31.7mm focuser) The De-Luxe utilises a 2” precision Crayford focuser.

Both the above two items are covered in more detail later.

Differences which cannot be readily seen until you begin to use the telescope:

Optics. Standard models are supplied with our normal coatings, De-Luxe models have our

hi-tech Hilux high reflectivity coatings applied to both mirrors. This typically
transmits around 25% more light to your eye than standard telescope optical
coatings. 1/4PV wavefront optics are fitted to the standard models and 1/6 PV to
De-Luxe models. With the De-Luxe models, you should also have a Zygo print out
of data of the telescope on optical test.

You may have requested and had some additional equipment added to your telescope, this is not
covered in this manual.

Assembly

DOBSONIAN BASE SECTIONS UNASSEMBLED

Fig 2

To assemble the base choose a hard, flat surface. Do not try to assemble on a carpeted or similar
surface as the mount will not fit squarely together. First of all, fix the back panel to the base assembly
with one of the assembly screws, use the supplied Allen key. DO NOT TIGHTEN the screw at this
stage. See Fig 3.