Testing the Pulsar controller

30 Dec 2007, dvk

A few years ago I bought a custom-built mount from Jaques Suurmond in Zeeland. The mount was old-fashioned, with a wormgear in R.A. allowing tracking and guiding via a CCD camera. However, in Declination the mount allowed only about +/- 1 deg excursion, for more one had to manually loosen a screw and move the scope by hand. Herman ten Haaf has recently upgraded the mount to a real Goto-mount, by adding a worm wheel also in Declination. He added strong 24 V stepper motors. I checked out two different guiding systems for the mount: The FS2 from Mr. Koch in Germany, and the Hungarian Pulsar control. I decided for the Pulsar - mainly because it is being distributed by a colleague of Herman here in the Netherlands, Peter Pulles (see http://www.ecliptica.org) and because from reading the manual I got the impression that the FS2 would not store the pointing positions of the telescope when switched off. The Pulsar, on the other hand, does have a so-called "parking position" which after power cycling lets me go back observing immediately. As I am dreaming of a remote-controlled observatory, this functionality is vital.

Anyway, a few weeks ago I reinstalled the mount in my observatory (see http://www.koschny.de/The_Koschny_Observatory.html and navigate to 'Modifications 2007'. Herman still has my large telescope (a 16" Cassegrain) for some mechanical modifications, thus I have mounted my small 102 mm William Optics refractor on the mount.

Here is the log of me trying to start using the Pulsar controller.

Some time in November

I have put the mount on the pier. I plug in the cable between controller box and R.A. and Dec motors. The power cable goes into a power supply from Conrad Electronics set to 24 V, the hand controller is connected. I switch everything on and - the mount moves as expected. Great! Not first light, but first sound... The sound is interesting, by the way, it steps up in octaves it seems. I unplug everything again.

22 Dec 2007

I put the cables properly in place, with the power supply located in my little isolated room next to the telescope, as the power supply is not rated for outdoors. Another check with the hand controller and it seems to work.

Then I also connect a PC via and RS 232 cable. I download the control software (release 2.59) from the internet at http://www.astronomy.hu/pulsar.htm. I press 'connect' and it connects. Again, great! A little window pops up with arrow buttons for N/S/E/W. I press them and the telescope visibly moves. Then I go to the other window which shows all sorts of features, e.g. the setup, a simulation of the handbox with all the shortkeys, and more. The 'catalog' menu is empty. So I download catalogues and press 'Upload catalogue'. However, even after it says that the upload was done, I can't select anything in the catalog menues. Hm. Also, I realize that when I press 'south' the mount moves 'north' and vice versa. The 'east' and 'west' buttons seem to not work at all. After some pressing buttons nothing works any more. I give up for today, as it has -4 deg C. Will have to play more later...

29 Dec 2007

It is clear - at least for a few hours. I take advantage of that and polar-align my mount. Also, I did some reading and found the buttons for swapping N/S and E/W directions.

30 Dec 2007

More time to play... I decide to go through the menu in the hand controller and check all the items. I realize that there is no good instruction book or user manual where this is documented in a systematic way. So I produce my own table, which is available here. I find the buttons to change the slew speed, again, I didn't really understand the description in the instructions so it took me a while. But now I can switch between a fast 'slew speed' and a slow 'adjustment rate'. It seems to me that this does not work properly in the PC software which I downloaded from the internet - there are buttons which are marked 'guiding', 'center', 'find', 'slew', but once pressed I only get the small speed, I cannot go back to the fast one.

Concerning the catalog - now all the data is there, which I uploaded the last time. So apparently it needs a power cycle to get the catalog into the system.

Preliminary conclusions

Already my conclusions are clear - I expect the controller to be quite good, I still have to learn how to use all the features and need a clear night to do some 'goto' tests. I haven't even started to get into the Periodic Error Correction, or tested the 'parking position', which is why I bought this controller to begin with (that means that I can go to the parking position, switch everything off, and come back a week later and after switchon the mount knows where it is and GoTo's should work...).

The culprit is that the useage is - at least to me - not really intuitive and a good user manual would have been comforting. An example: There is a menu item 'Autostop global' and one 'Autostop loc.'. The second one comes with the option 'RA limit ON/OFF' and one can anwer 'YES' or 'NO'. While I assume that 'YES' means 'ON' this to me is not really unambigious. I would have preferred a toogle between ON and OFF rather than YES and NO.

There are instructions both in German and English, but they are written by users and I had the feeling they already know a lot about the useage and thus did not write it down in a way that the beginner can understand it. So, here there is room for improvement!

Having said that, I admit that Peter Pulles, who sold the controller to me, even offered to come by and help me installing everything. I had to try it myself, of course. But I think this is a great offer which I will probably take up very soon. And, to be even more constructive, I have put the document with the menu list and some instructions on line for others to use too, see here (created from a Word document). The table is not yet completely filled in, I'll continue to do so as I go on.