Ieq30 Pro Tm Mount Assembly; Introduction - iOptron iEQ30 Pro Instruction Manual

TM
3. iEQ30 Pro

3.1. Introduction

Congratulations! You have just purchased a new design of telescope mount that has a class
leading payload capacity for its weight and is capable of high precision tracking. This makes the iEQ30
Pro a superb choice for observational astronomy and astrophotography as part of a portable setup for
use in your backyard, at dark sky sites, and at star parties.
In order for you to get the optimum performance from the mount and your optical tube assembly
(OTA) combination, you must assemble and set up the mount correctly.
The following basic principles are included to help you understand the fundamental concepts of
telescope mounts before the specific details of the iEQ30 Pro mount are covered.
Telescope mounts are either equatorial or altitude-azimuth (Alt-Az). Both types of mount rotate
the OTA around two perpendicular axes to point to a desired object in the night sky.
An Alt-Az is a simple mount that has a horizontal axis to provide vertical (altitude) OTA
movement from the local horizon and a vertical axis to provide horizontal (azimuth) OTA movement and
is therefore able to point at any part of the sky. In order to track an object across the sky, an Alt-Az
mount has to continually move the OTA in both axes. This can provide tracking that is good enough for
visual observing and short exposure photography. However, the mechanics of this system are such
that an OTA carried by an Alt-Az mount will suffer from field rotation where stars will appear to rotate
about the point being tracked forming arcs. As such Alt-Az mounts are not suitable for long exposure
astrophotography which is needed to capture faint deep sky objects.
An equatorial mount has an axis, called the right ascension (R.A.) axis, aligned with the celestial
North Pole (CNP) in northern latitudes, or the celestial South Pole (CSP) in the Southern Hemisphere.
Equatorial mounts counteract the rotation of the Earth by driving the R.A. axis in the opposite direction
thus tracking celestial objects as they appear to move across the sky. Once the mount has been
accurately aligned to the celestial pole, only movement of the R.A. axis is required for accurate tracking
and this design does not suffer from field rotation .R.A. is the celestial equivalent of longitude and is the
angular distance measured eastward along the celestial equator as measured from a zero reference
point (the vernal equinox). A second axis perpendicular to the R.A., the declination axis (DEC),
provides elevation relative to the celestial equator.
As mentioned above, in order to track celestial objects the R.A. axis of an equatorial mount
must be accurately aligned with the celestial pole. Your new iOptron mount comes equipped with
features that make accurate alignment quick and easy. The iEQ30 Pro includes mechanical adjusters
that move the mount in altitude and azimuth in order to align the R.A. axis, also known as the mount's
Polar Axis, with the celestial pole. These adjustments do not involve any rotation of the mount's R.A. or
DEC axes and can be performed without the OTA installed. The first step is to make an approximate
azimuth alignment of the mount's Polar Axis by roughly aligning the R.A. axis to a reference point
toward True North (or True South if in the Southern Hemisphere). A compass can be used for this initial
azimuth alignment but you must allow for the variation between True and Magnetic North/South at your
location. Precise horizontal alignment of the Polar Axis is accomplished with the azimuth adjustment
bolts on the mount. The second step is to adjust the Polar Axis vertically (altitude) above the horizon by
setting the observer's latitude on the provided latitude scale. This procedure is based on the
fundamental geometry of the Earth's coordinate system in conjunction with the concept of the celestial
sphere. You can verify this by visualizing yourself at the North Pole (latitude N90°) in which case
Polaris will be 90° from the horizon, or directly overhead. These steps will place the Polar Axis very
close to the celestial pole. The accuracy of both of the above adjustments can be enhanced by the use
of the incorporated polar scope, which sits in an opening along the R.A. axis and allows direct viewing
of the pole. In order to get the most out of your equatorial mount it is essential to understand the
concept of polar alignment and how the equatorial mount helps you establish and maintain a true Polar
Axis alignment. Now you are ready to set up the GOTO functionality of the iEQ30 Pro mount – which
Mount Assembly
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