Instruction manual

do the initial training, and then follow the instructions. Note that FocusMax allows you to choose your star

and to control many other properties that are “hidden” in other software.

Temperature Training Using Autofocus.

Using autofocusing, it is easy to collect temperature data needed to train the temperature compensation

function in RoboFocus. Simply focus with your autofocusing program, then switch over to RFCP, take a

temperature/data reading and record it (with focus position that will automatically be there) in the database.

As the temperature changes during the session (or in later sessions), you can repeat the process to get more

temperature compensation data for RoboFocus. You can also combine temperature data from multiple

sessions (see the Chapter on temperature compensation for details).

Changing Setups.

What is the best way to handle a new optical setup? For example, you might install a Barlow or a Reducer

that you know will greatly change the focus. If you have already used the setup, you would probably have

recorded the RoboFocus position for each setup either using your logbook or using the FocusSetup menu

item. Thus, if at position 5643 for setup 1, when you go to setup2 you might simply command a move to

12523 (outward 6880 steps) to get very close to the correct focus. This move might take several minutes.

You would then tweak the focus using your CCD imager.

On the other hand, if you are changing to a new setup that you have not used before, how do you find focus

without doing dozens of slow tests? One way is to put in an eyepiece that you know has about the same

focus point as the camera. You would then use the manual buttons to move to approximate focus, and then

refine with the camera.

You can also do it easily without visual work. You would direct the scope to a reasonably bright star, and

set the CCD to take quick pictures (e.g., 0.1 sec, bin X3). You will see a huge out-of –focus star image, or

maybe only a piece of one (or maybe even just the “hole” in an out of focus S-C star image!). You could

repeatedly move the RoboFocus a hundred steps and reshoot, but that will be slow. A better way is to

direct the RoboFocus to begin a large move (say from present 5624 to 25,000). You then take repeated

images (continuously) while the focuser is moving. As you approach focus, the image will improve as you

watch, and you can stop the RoboFocus as you pass through focus. You would then refine the focus in the

usual way. Once you have the focus position for the new setup, you would record it for future use.

In any case, once you are close to focus, you can usually achieve "perfect" focus in only a few minutes by

taking several images and comparing peak or FWHM readings. No matter how you use RoboFocus, once

you have a good focus position, you should record it in your log. In fact, most users will have several

optical setups (e.g., with and without a Barlow), so you may have several different values recorded.

When using RoboFocus, you may want to redefine the current position (in the Configuration screen) to a

more convenient value (such as 1000). Of course, unless you keep a record, you will lose the absolute

position determined from training; however, the ease of referring to round numbers often outweighs this

factor.

Multiple Setups. You can use Configuration/Setups to record the information about a setup. This might

include which lenses are in use (e.g., reducer), filters, or other things that might affect the focus position. If

you use the same controller that you attach to different motors, each setup (including configuration items)

can be described in this mini-log.

Some users will have several RoboFocus controllers (each with its own motor) that they want to control

from a single computer. You might have each controller attached to its own port. In that case, you could

run one copy of RFCP and switch the COM port as desired to run each motor in succession. The minilog

would then include the relevant comport number of that controller. On the other hand, you might want to

run several copies of the RFCP at the same time, each set to its own comport. Again, the minilog would

help you keep straight which program is controlling which motor.