telescope mount

Wireless EQDirect - a Bluetooth connection to your Synta mount

2007 was the year that I bought my first dual-axis mount: an Orion Sirius EQ-G. This mount is virtually identical to the Skywatcher HEQ5 with the recent motorization. Apart from it being an affordable mount with decent performance, it also features lots of interest from enthusiast amateur astronomers, either eager to enhance the mount's performance (see the EQ6 Yahoo! Group), or even to give it advanced computerized control for free (see the EQMOD Yahoo! Group).

All facts mentioned above have influenced my final decision to get the non GoTo "SynTrek" variant of the Orion Sirius EQ-G (the GoTo version of the handcontroller is "SynScan"). Nine months later I decided to acquire an EQDIR module from Shoestring Astronomy, along with the EQCBL-01 mating cable. I then installed the free planetarium software Cartes du Ciel, the free and standardized ASCOM Platform (free, Windows platform), and the latest EQMOD ASCOM drivers allowed me to control my mount from my laptop. I was impressed by the relative ease with which all was installed and how the hardware and software collaborated without major issues.

The only real problem I witnessed was a mere usability issue: since I observe mainly on a small balcony or on a remote location, the cable connecting the mount to the PC was often in the way. For a permanent setup this most likely is not a problem, but in my case I was thinking in terms of «this can be done in a more user friendly way». Hence I decided to look at wireless solutions to replace the RS232 serial link with the mount.

Aligning an equatorial mount

The earth rotates about its axis once every day. When observing an object with a telescope, we have to compensate the rotation of the earth. An equatorial mount compensates this motion if the following 2 conditions are met:

  1. its polar axis is parallel with the polar axis of the earth;
  2. the mount rotates about its polar axis at exactly the same rate as the earth rotates about its axis

The first condition is met if the mount is correctly set up. The procedure of setting up an equatorial mount is called polar alignment.

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