The software falls into three categories: the camera control, the mount control and the scripting programs. In addition to the control software is a program that enhances the pointing accuracy of the mount even further. See Figure 12.1 for a block diagram of how the software programs work together.
The main control program for the mount is TheSky level 5. This uses the GSC catalog and can send coordinates to the mount for slewing to any chosen galaxy in the catalog. The instruction can be given manually by clicking on a galaxy shown on the screen, by inputting one of its names and clicking on the slew button or by entering its coordinates directly (see Fig. 12.2).
This would be a rather slow process if a large number of galaxies were to be patrolled and all but impossible if more than one telescope is to be controlled. For this reason, a scripting program is available that will input the galaxy names or coordinates. Called Orchestrate, this is also part of the Software Bisque suite. Orchestrate is capable of reading a galaxy's name or coordinates from a script and sending the slew instruction to the telescope. After allowing time for it to settle (which is also programmable), it can control the camera's exposure via yet another program in the suite called CCDSoft. See Figure 12.3, which shows the Orchestrate program screen opened with a sample script.
CCDSoft automatically triggers the camera shutter, takes a dark frame if so instructed and stores the image taken with a title in a directory whose name is preselected by the user. For the purposes of supernova patrolling, a dark frame is necessary to eliminate hot pixels, which can obscure candidates. I do not bother with flat fields unless accurate photometry is required. This saves time and speeds the process. Figure 12.4 shows the screen of CCDSoft and the progress bar showing the time into the current integration.
The final but still important program is TPoint. This is a clever program that improves the pointing accuracy of the telescope significantly. The user has to train TPoint in advance by slewing the telescope to known locations, usually stars. The star is then centered on the screen. The difference between where the telescope was pointing and where it should have pointed is a measured error. The program remembers this for locations covering the sky and reproduces a correction whenever the telescope slews in future. The software uses correction terms that interpolate the errors allowing any location in the sky to be corrected. The more points the user trains, the more accurate the slewing becomes, up to a point of minimal returns. This is usually around 100 points. More can be used for training if long-exposure, unguided photography is required. The Paramount ME uses a feature called Protrack, which continually corrects guiding using the TPoint corrections during long exposures. Effects due to mount flexure and atmospheric refraction are therefore reduced. Figure 12.5 shows TPoint opened and a scatter diagram, which displays the corrections that it has calculated for different areas
of the sky. This can be used to tune the operation and balance the mount. It is also a very good tool for accurate polar alignment (see Fig. 12.6). All the data shown here are simulated.
This might sound a little complicated. I can assure you that it isn't. Once the software is loaded, much of its use is intuitive and familiarity will come very quickly. The result will be a system capable of slewing and pointing with an accuracy of better than one arc-minute. It will do this completely unsupervised if you are brave enough to leave it. I prefer to keep sight of what each of the systems is doing using a local area network and a program like pcAnywhere from Symantec. Windows XP Professional has a similar feature included as part of the operating system. I must admit I have left it for up to three hours, completely unsupervised, while visiting my local pub. It is only seven minutes walking distance from the observatory so it didn't require too much courage, and I could easily sprint back quickly if the weather changed.
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