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MTSca - PC GOTO software -

for Boxdoerfer PowerFlex MTS-3SDI and MTS-3SLP

MTSca is a Windows program offering remote PC control of the MTS-3SDI controller. The main idea is to provide manual remote control, GOTO, PEC training, autoguiding and solar system tracking, see feature list below.

For more info on the controller itself see the
MTS-3SDI page or the product website.

Before you Download the program, please review the information below.

Recent changes

- Added NGC and IC catalogs
- Introduced separate program thread for GOTO to make user interface 
  more responsive during GOTO. See readme.txt for details.
- Guiding dialog recently redesigned. Now similar guide parameters as 
  K3CCDTools2 have been introduced for both RA and DE axes.
- Easy real-time tuning of guiding parameters
- Added support for download and use of ASTORB (Asteroid Orbital Elements Database)
- Added feature for mount flexure compensation in autoguiding.
- Some bug fixes (for details see readme.txt).


The MTS-3SDI is a high precision dual axis telescope drive that offers the usual up/down/left/right operations by means of the hand controller buttons. With firmware version 2.xx, it has no built-in GOTO capability, and various programming operations such as PEC (Periodic Error Correction) and mount configuration is performed using special button combinations and dipswitch settings. Such procedures can be a bit cumbersome and difficult to remember, but this controller has more to offer!

PC remote control is possible using an optional serial (RS232) communication cable. This way, the operation is simplified and many new possibilities become available, including autoguiding and PEC training. The MTSca program is dedicated to providing easy access to these possibilities, thereby increasing the user value of the controller.

Notice that MTSca will work with MTS3 firmware version 2.x only.

Mount configuration and PC connection

MTSca communicates with the MTS-3SDI over a serial cable. The PC needs a serial port (or a USB to serial port replicator). The serial communication employs baudrate 9600, bytesize 8, no parity and one stop bit, i.e. the default MTS-3SDI setting. You should not normally have to adjust anything.

The program automatically reads the MTS-3SDI EEPROM memory containing mount configuration information, and the dipswitches #9 and #10 which control the directions of the RA and DE motors respectively.

In short, the MTSca program is automatically configured, and therefore very easy to use.

Program versions

MTSca is now available in 2 versions, version 2.9 (free) and MTSca Pro (version 5.0 and higher) which offers a 30 day free trial period (after the trial period you need to register if you want to continue using MTSca Pro).

MTSca Version Comparison
Feature MTSca v2.9 MTSca Pro
Licensing Free 30 days free trial
Full install/uninstall support
Available for immediate download

Manual scope control
FAST and SLOW slewing
Set FAST speed up to 512x
Sidereal rate tracking
Mean Solar rate tracking
Mean Lunar rate tracking

Basic GOTO
3200+ object star catalogue
Separate Messier catalogue
User defined catalogue support
Filter catalogue by magnitudes
GOTO to any RA, DEC coordinate
GOTO speeds from 4x to 512x
Filter by constellation name
Sort by constellation, name, RA, DEC or magnitude *
No need for axis encoders
Optional automatic 'Meridian Flip'

Solar system support
Web download of latest orbital elements for comets and asteroids
Correct for observer location
ALIGN on planets, comets and asteroids
GOTO planets, comets and asteroids
Magnitudes for planets, comets and asteroids
Track planets, comets and asteroids using orbital elements
Use ASTORB (Asteroid Orbital Elements Database)

Periodic Error Correction (PEC) & Autoguiding
Manual PEC training
Automatic PEC training using IRIS autoguiding
Automatic PEC training using K3CCDTools2 autoguiding
Dead zone control in PEC training and autoguiding
Enable/disable PEC
Autoguiding RA
Optional autoguiding DE

DEC drift compensation
Support for mounts with different RA and DEC motor gearing
Improved support for mounts with different
number of teeth on RA and DEC axes
Additional 24x and 48x slewing speeds
MTS3 firmware compatibility 2.14 & 2.15 2.14 & 2.15

*: Sorting is default in MTSca Pro, must be explicitely enabled in V2.9

GOTO with MTSca

MTSca provides a convenient GOTO capability. Finding faint objects in the sky that often cannot be seen directly is made possible, and especially for deep sky, comet or asteroid imaging, GOTO is essential.

When you click the ALIGN or GOTO buttons in the main window, you get access to the catalogue, where objects can be selected:

ALIGN and GOTO for comets (similar to asteroids)

ALIGN and GOTO for constellatons

You can select objects via the constellation filter in the built-in catalogue, or by adding your own user-defined catalogue. You can also enter manual RA,DEC coordinates, or use the solar system options where you can choose between the Sun and Planets, asteroids or Comets.

Some characteristics of the MTSca GOTO feature:

Autoguiding and PEC (Periodic Error Correction)


With MTSca you can now perform autoguiding using for example a webcam as guide camera. This feature requires use of K3CCDTools2 or IRIS for use. The setup is just as for PEC training (described below), but using the "Autoguiding" option instead of "PEC training". Notice that using PEC training first, and then autoguiding, can be a very efficient way of almost completely eliminate periodic error, even for simple mounts.

Periodic Error Correction

PEC is a method of compensating for the periodic error found in any mount. The MTS-3SDI supports permanent PEC (PEC table stored in the controller itself). MTSca simplifies the use of PEC greatly by offering two PEC learning modes, manual and automatic (via K3CCDTools or IRIS), and PEC can later be enabled/disabled with a simple mouse click. An example showing the effectiveness of PEC can be seen

Guiding parameter explanation

Guiding is performed by issuing guide pulses to the controller at each Read Interval when the x.dat and y.dat files are read and a new guide pulse is calculated.

Guide pulse length : T = K * delta + Q
K = guiding amplification factor [ms/arcsec]
delta = measured guiding error [arcsec]
Q = minimum guide pulse [ms]

Dead Zone [arcsec] : If guiding error is less than this value, no guiding is performed.
Rev. : Reverse guiding direction

Using K3CCDTools2 for autoguiding or PEC training

K3CCDTools2 is available from Peter Katreniak's website.

K3CCDTools2 is an excellent program with complete documentation. Please consult the documentation on webcam autoguiding using the Drift Explorer.

In short, to use K3CCDTools for autoguiding or PEC training, use the settings dialog (Guiding tab) and set some options to ensure proper communication between K3CCDTools and MTSca:

  • Select File Interface and RA file name X.DAT
  • Make sure file names are x.dat and y.dat
  • Select Record Only Last Values
  • For high accuracy it is recommended to use Subpixel Guiding
  • Make sure the Log files directory refer to the MTSca installation directory.
  • Make sure the Decimal separator is period, not comma.
To start autoguiding or PEC training, do as follows
  • Press the Guide button in MTSca.
  • Select "Autoguiding" or "PEC training".
  • Start K3CCDTools Drift Explorer, check "Guide".
  • Click the upper left icon button, then the guide star.
  • Press the Start button in MTSca Guide/Pec dialog.
  • Notice guiding feedback on main window buttons!

MTSca will now pick up the guiding instructions and pass them on to the MTS3 controller. When using PEC training, this will continue until a whole worm period (about 600 seconds on a Vixen mount, different time for other mounts) is completed, after which it completes automatically and the controller LED turns red to indicate PEC is active. You can then shut down the K3CCDTools drift explorer dialog, the PEC training is complete. If Autoguiding is used, the guiding continues until the dialog is closed.

PEC autolearning using IRIS autoguiding

The freeware program IRIS is available here. There is also a page describing the IRIS autoguiding feature. To use PEC autolearning, you need to set up IRIS working directory to be the same as where MTSca is started from (see File | Settings.... in IRIS). Then, the procedure is:

Manual guiding / PEC training from PC

Start the PEC recording and make RA+ and RA- adjustments in the main window (or the physical controller buttons) during one full worm period, after which the PEC table will be saved automatically. You can then choose to activate or disable PE corrections without losing or invalidating the PEC table.

The field in the PEC dialog that shows "100", indicates how many milliseconds a button is pushed when doing automatic learning. Sometimes, you may have to increase this value to e.g. 200 if the periodic error is large.

Solar System support

In the Solar System guiding dialog, you can select between 3 main object categories: planets, comets and asteroids. In each category you have many objects to choose from, and their coordinates are always up-to-date as they are recalculated continuosly.

Once you have centered an object, you can use the ALIGN button to synchronize the program with the telescope. Many asteroids and comets have a significant movement against the background stars, so by using the GUIDE button, you can easily track the object for as long as you wish (assuming proper polar alignment). As an example of this feature, see the tracking of asteroid 2004 RX164.

Another useful feature is to ALIGN on a bright star as described for GOTO above, and then use the GOTO button in the solar system guiding dialog to arrive at a faint asteroid, which you may want to track. Similarly, during daytime, you can align on the Sun and GOTO a bright planet like e.g. Venus.

Using the www... button available in the program, you get access to a utility for downloading the very latest comet and asteroid orbital element data directly from the website of Harvard-Smithsonian Center for Astrophysics. This way, you can follow the latest detected objects easily and with extreme accuracy. An internet connection is required to download the orbital element files.

Program Download

Legal notice: All information and software in this page is Copyright (c) Carsten A. Arnholm. You may download and use the software for non-commercial purposes according to the licencing terms specified on this page. Contact the author for permission prior to using the software for other purposes. You may not distribute the software to any third party.

Disclaimer: The author regularly uses the software on several of his computers and firmly believes that the software is without any damaging effect, including the computer and telescope controller. Nevertheless, the author accepts no responsibility for damages resulting from use of the software and makes no warranty or representation, either express or implied, including but not limited to, any implied warranty of merchantability or fitness for a particular purpose. The software is provided "AS IS" and the author does not assume or accept any risk by its use.

Download: By downloading any software, you agree that any use of the program is at your own risk.
Download (V6.3, 02 March 2006, 30 day trial)
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