GotostarTM Users Manual
A quickstart guide to using a Gotostar-equipped EQ5 equatorial mount.
In an earlier guide we showed you how to attach the
motors, encoders and hand controller to an EQ5type mount and make any necessary adjustments to
the gear trains. Even if you have a pre-installed
Gotostar system, please ensure that you have read
through Install_Gotostar.pdf first.
Power Supplies
Fig. 1
Initial Setup
We also recommend that you familiarise yourself
with the operation of your Gotostar in the daytime.
For your first trial run you don’t need to install a
tube assembly or counterweights — just plug in ...
Fig. 2
Polar axis
Like any GoTo ‘scope, the motors place high
demands on any power supply that you are using
when slewing from one part of the sky to another.
We recommend that you use the mains transformer
provided (with an extension lead and a U.S. to U.K.
plug adaptor, if applicable) when using your
Gotostar at home. If you are observing away from
mains power, we suggest that you use the car cigarette lighter adaptor from your vehicle, or a heavyduty rechargeable 12V power source. A 12V power
pack derived from C or D-type alkaline batteries is
not suitable and can lead to erratic Gotostar performance.
the coiled cables and Gotostar hand control. Fig. 1
shows a view of an Astro-5 German equatorial
mount as seen from the north looking down the polar
axis (circled in red). The important detail is the position of the chromed declination axis counterweight
shaft: it is pointing straight down, in line with the
north-facing tripod leg. Slacken the polar axis clamp
(arrowed in blue) and rotate the mount about the
polar axis until your mount looks the same, then lock
the polar axis clamp. This procedure satisfies one
condition of the Gotostar Park Position and
must be performed every time you setup the mount.
Fig. 2 shows the same mount, but seen from the
south. In order to satisfy the final condition of the
Gotostar Park Position, you’ll need to unlock
the declination axis clamp (arrowed black in Figs. 1
& 2) and rotate the mount about the declination axis
until the edge of the Vixen-style dovetail bracket
(dashed red) lies closely parallel to the polar axis
(cyan arrow). The declination axis motor unit (outlined in yellow) must be on the right, or east, side —
this is very important! Once your mount looks like
Fig. 2, lock the declination axis clamp.
First Time Use
Now that you know how to position your equatorial
mount, this is the time to attach any counterweights
followed by the optical tube assembly. (It’s
assumed that you have previously determined the
balance point of the tube in the Vixen-style dovetail
Fig. 3
le ole
Po ial p
the est
is, cel
lar th
Po nor
To the
The version number of your software may be
slightly different from 070312 ENG, reflecting
updates to the built-in software. (The version number
is the date in year,
TR.A. 13h 6m36s
month, day
TDEC 90° 0’00”
format.) After a
1h 7m 6s
brief pause, the
64X display will revert
Alt. 51°21’29” Stop to something like
0° 0’ 0”
2007-05-23 16:23:40 N that shown left.
about what the figures mean at this stage as first you
will need to set the Gotostar’s internal clock to the
correct date and time.
What time is it? Where am I?
Unlike most GoTo systems, the Gotostar has a backup battery that remembers this information between
sessions. By referring to the red box (How do I
navigate my way around the Gotostar
menus?) on page 4, ensure that the correct
date and time is set for your location — use the
left and right arrows to get to the figures you
need to change, then type over them using the
numeric keys. Just as important is the Daylight
Time saving option: use the up or down arrow to
change this to a tick or a cross as appropriate. Be
sure to press ENTER once you have finished to
save the information.
bracket and of the counterweight(s) along the shaft.
We also assume that you have attempted to point the
polar axis of the mount in the close vicinity of Polaris,
the Pole Star.) Fig. 3 shows an 80mm Meade triplet
refractor in the Park Position as seen from the
west with the telescope pointing to the north celestial
pole ready to power-up the Gotostar.
Before connecting your 12V DC supply, ensure that
the grey power switch (see Install_Gotostar.pdf,
page two) is in the OFF (button out) position. Check
that both the polar axis and declination axis clamps
are locked. Press
the ON switch, the
Ver. 070312 ENG
beep, and the
power-up splash ©NANJING IDEA SCIENCE
screen (right) will & TECHNOLOGY CO. LTD.
be displayed.
Now that it has the correct local date and time,
the Gotostar also needs to know where you live
in order for it to create a mathematical model of
the sky above you. Prior to the next step, obtain
your precise latitude and longitude from an
Ordnance Survey map, atlas or online gazetteer.
Using the Gotostar Menu Tree on page 4,
select th e ‘ S etup
Set up site info:
site ’ o ption then
th e ‘ S etup lat. &
(you may
‘Select city’, but
000 Min.ahead of UT
it’s unlikely that
there is one close enough to get accurate results).
Above is
an example for Stonehenge in
Wiltshire, U.K. — 51°10 ’ 4 4 ” N, 1°49’35”W.
Always remember to press ENTER after modifying any screen entries to ensure that the new data
is saved.
Gotostar Alignment Basics
Now that Gotostar knows where you live, the
date and local time, the hand controller has all
the information it needs to locate any of the
objects in its vast database. But before it can find
anything for you it needs to establish that the
Park Position of your mount’s polar axis is
indeed pointing at the north celestial pole.
Furthermore, every mount’s accuracy of construction varies somewhat, so the optical axis of
the telescope may not be perpendicular to the
declination axis or, more rarely, the polar axis
may not be at right angles to the declination axis.
These small errors (known collectively as the
cone error) can make a big difference to the
GoTo performance of your mount, so it pays to
understand the implications. Fortunately,
Gotostar version 070312 ENG and later has a
‘ Three star align’ that can largely correct for cone
error and is therefore the preferred alignment mode.
Know Your Stars!
The align process requires you to accurately
point the telescope at one, two or three stars
(depending on the alignment mode you chose) in
turn. Gotostar will choose readily identifiable
alignment stars for you by name, since it already
knows which ones should be visible from the location and time yo u ’ ve specified. If you don’t
already know them, it obviously pays to first
learn the Arabic names of the brighter stars from
a star atlas or planisphere.
Your First Alignment
Assuming, then, that you have chosen th e ‘Three
star align’ option from th e ‘Align’ menu,
Gotostar will ask for confirmation that the mount
is in the Park Position before you press
ENTER. Gotostar will then present you with the
name of a suggested alignment star. If this star is
hidden by a tree or building, press the down
arrow to advance through the list in alphabetical
order until you find a star that is visible. Press
ENTER and the mount will spring into life, slewing
to where it thinks the star you have selected lies,
beeping once it has finished moving. Most likely,
the ‘scope won’t be pointing exactly at the
star, so use the up, down, left or right arrows to
centre the star — first in the finder, then in ...
the eyepiece. Once you are done, press
ENTER and the next alignment star will be selected. Don’t be surprised if the Gotostar slews the
telescope from one side of the mount to the other
during this procedure; it is establishing the
mount’s cone error by doing so. Repeat this
process until you have selected all three stars
whereupon Gotostar will compute the polar axis
positioning error of your mount and display it.
Press BACK and you will return to the display.
Select and Slew
You will hear that the polar axis motor is now
tracking the stars (pressing STOP will arrest the
motion, pressing it again will resume tracking)
and the altitude (Alt.) and azimuth (Azi.) figures
will change as the ‘scope follows an object
across the sky. Now that the mount is calibrated
and aligned the hard part is over, so you are free
to enjoy using the ‘Select and slew’ menu
options to find any one of the myriad objects listed in the hand controller’s database.
if you find that the GoTo accuracy of
your mount is poor for certain areas of the sky,
use the ‘Sync. to target ’ o ption on a readily
identifiable star in the region before slewing to a
fainter target nearby.
Tip 2: if you are able to leave the ‘scope
setup in an observatory, use th e ‘ Park Scope’
option for a pre-aligned startup next time.
Tip 1:
Advanced Techniques & Support
The Gotostar system is well supported by its
Chinese developer, Nanjing IDEA S&T Co. Ltd.
This ongoing development ensures that the hand
controller’s features and capabilities are continually being updated. Consequently, you are
encouraged to visit and join the Gotostar Yahoo
Group on the Internet where you will receive help
and advice from a dedicated team of enthusiasts
devoted to getting the most out of this product.
You can find out more at this address:
Everyone at Astronomica would like to thank you for
investing in Gotostar and look forward to hearing of
your experiences and observations while using it.
Above all, clear skies and enjoy!
GotostarTM Menu Tree
At-a-glance guide to the menu options available under software Ver. 070312 Eng.
Select and slew
Planets, sun, Moon
Deep sky objects
Sync. to target
Use "Arrow keys"
center the object in
the telescope's field
of view, then press
Electronic focuser
Set anti-backlash
PEC option
Set up Local Time
Set up site
Set N/S hemisphere
Set Display contrast
Set eyepiece light
Set Backlight
Set anti-backlash
Set Key Beep
Set Mount Type
Reset All
Upgrade firmware
One star align
Two star align
Three star align
Dis R.A. axis error
Test anti-backlash
PEC play back
Record PEC
Delete PEC record
Set up tracking
Sidereal speed
Solar speed
Lunar speed
User defined speed
User objects
Add a new record
Modify records
Delete one record
Erase all records
Auto guide
Park Scope
To Park Position
Manual or Auto guide
Guide rate:
1: 1.0X 2: 0.8X
3: 0.6X 4: 0.4X
Parks ‘scope then displays
Please turn the
controller power off.
Returns 'scope to
Park Position if not
already there.
By number in catalog
By number in catalog
Named stars
Double stars
GCVS variable stars
SAO catalog
User objects
Enter R.A. DEC.
Named deepsky object
Messier Catalog
NGC IC Catalog
UGC Catalog
MCG Catalog
Caldwell Catalog
Abell Catalog
Herschel Catalog
Electric focus
Speed: 16X
Display briefly clears,
then returns to menu
Enter local date &
time + daylight savings
Select city
Set up lat. & Long.
North hemisphere
South hemisphere
Adjust LCD contrast
Adjust on-screen slider
R.A. & DEC anti-backlash in 1.5 arcsec steps
German equatorials only
Displays splash screen
and enters upgrade mode
LCD Backlight sliders
KeyPads Backlight
Key Beep ON
Key Beep OFF
Reset all settings
Start in Park Position, press “ENTER”, then follow instructions
Start in Park Position, press “ENTER”, then follow instructions
Start in Park Position, press “ENTER”, then follow instructions
Displays error of polar axis position in altitude and azimuth
Allows you to adjust backlash settings in R.A. and DEC
PEC data will be
replaced. Continue?
PEC play back ON
PEC play back OFF
Erase PEC data?
Enter R.A. and DEC in Epoch J2000 coordinates
Select user catalog number and modify accordingly
Select user catalog entry by number to delete
Erase all records?
How do I navigate my way around
the Gotostar menus?
After the power on message appears, press the button
labelled MENU under the screen to access the menu
structure depicted above. Use the up (∆ ) and down
(V) arrows to move vertically through the list. Selecting
an item and pressing ENTER moves you to the right of
the diagram; BACK moves you to the left.
For example, turn on your Gotostar and press MENU
followed by the down arrow three times: this brings you
to the ‘Setup GOTOSTAR’ menu. Pressing ENTER at this point takes you to the ‘Setup
Local Time’ option; pressing ENTER here enables you to edit the date and time entries.