iOptron 6001, 6002 Finding Objects With the Setting Circles, Calculating the Power

Dec. setting circle

R.A. setting circle

Dec. mark

R.A. mark

for the object

Finding Objects With the Setting Circles

Now that both setting circles are calibrated, look up in a star atlas the coordinates of an object you wish to view. Loosen the Dec. lock knob (12) and rotate the telescope until the Dec. value from the star atlas matches the reading on the Dec. setting circle (13). Remember that values of the Dec. setting circle are positive when the telescope is pointing north of the celestial equator (Dec. = 0°), and negative when the telescope is pointing south of the celestial equator. Retighten the lock knob.

The mount’s R.A. setting circle (16) is scaled in	Loosen the R.A. lock knob (14) and rotate the
hours, from 1 through 24, with small marks in	telescope until the R.A. value from the star atlas
between representing 6-minute increments. The	matches the reading on the R.A. setting circle (16).
numbers closest to the R.A. axis gear apply to	Remember to use the upper set of numbers on the
viewing in the Southern Hemisphere, while the	R.A. setting circle. Retighten the lock knob.
numbers above them apply to viewing in the
Northern Hemisphere.	Most setting circles are not accurate enough to put
The Dec. setting circle (13) is scaled in degrees,	an object dead-center in the telescope’s eyepiece,
	but they should place the object somewhere within
with each mark representing 2° increments. Values	the field of view of the finderscope, assuming the
of Dec. coordinates range from +90° to -90°. The 0°	equatorial mount is accurately polar aligned. Use
mark indicates the celestial equator. When the	the R.A. and Dec control cables to center the object
telescope is pointed north of the celestial equator,	in the finderscope, and it should appear in the
values of the Dec. setting circle are positive, while	telescope’s field of view.
when the telescope is pointed south of the celestial
equator, values of the Dec. setting circle are	The R.A. setting circle must be re-calibrated every
negative.	time you wish to locate a new object. Do so by
Before you can use the setting circles to locate	calibrating the setting circle for the centered object
	before moving on to the next one.
objects, the mount must be correctly polar aligned,
and the R.A. setting circle must be calibrated. The	4.5. Calculating the Power
Dec. setting circle has been permanently calibrated
at the factory, and should read 90° whenever the	The power or magnification offered by a telescope
telescope optical tube is parallel with the R.A. axis.
	is determined by two factors: the optical or focal
Calibrating the Right Ascension Setting Circle	length of the telescope's lens and the eyepiece's
	focal length. This telescope's focal length is 900
1. Identify a bright star in the sky near the celestial	mm. To calculate the magnification factor, divide
	the lens' focal length by that of the eyepiece. The
equator (Dec. = 0°) and look up its coordinates in a
	resulting value represents the magnification factor
star atlas.
	offered by the telescope when it is used with this
2. Loosen the R.A. and Dec. lock knobs (14, 12) on	eyepiece. For example, using a 20 mm eyepiece
	provides a magnification factor of:
the equatorial mount, so the telescope optical tube
can move freely.	Magnification = 900 mm/20 mm = 45X
3. Point the telescope at the bright star whose
coordinates you know. Lock the R.A. and Dec. lock
knobs. Center the star in the telescope’s field of
view with the R.A. and Dec control cables.
4. Rotate the setting circle until the metal arrow
indicates the R.A. coordinate listed in the star atlas

Having trouble setting up or making it work? Email us at 900X70@ioptron.com We’ll be glad to help!

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