Instruction manual

RFCP will be faster! When you are near best focus, adjust the exposure and star choice to get about 10,000

counts. Write down the focuser position for this best focus.

Now manually step outward using the @Focus large steps and take images as you go. Move outward until

the max value is about 20% of the starting value. It should take 5-7 steps or so to go from focus to the 20%

point. If it takes more or fewer, change the “large” step size in @Focus setup to a value that gives the right

step size to make 5-7 steps. Write down this focuser out-of-focus “start” position for future use in

@Focus.

Now choose either sharpness or maximum value as your focus quality parameter, click on @Focus, select

move “inward”, and allow @Focus to work. @Focus should generate the focus curve and ultimately move

to focus. In later focus operations, you simply move to the out-of-focus start position, find a star that

produces an out of focus image brightness of 1000 or more, then start @Focus.

@Focus (at least in the earlier versions) can cause a communication problem. Due to a deficiency in the

earlier versions of CCDSoft, you can make the initial connection to the RoboFocus controller without a

problem. However, if you terminate the connection, CCDSoft does not properly release the com port,

which makes it impossible to connect RFCP until CCDSoft has been closed (and reopened). This is a bug

that will presumably be fixed in later versions.

Using MaxIm DL

In Maxim autofocus, you will be asked for a variety of settings. The most unusual one is Focuser Step Size

(in microinches or microns). Note, this is NOT the same as the RF StepSize number, but must be

determined for YOUR particular scope/focuser/optical setup. Because the RoboFocus stepping motor can

be used on a variety of scopes, filling in this box requires YOU to do a little measurement.

If you are using an R&P or Crayford style focuser, use RoboFocus to move the focuser say 1000 steps, and

a ruler to measure how far the focuser moved. Then divide the numbers to get the inches per step. For

example, if your focuser moves 0.17 inches in 1000 steps, that is 170,000 microinches in 1000 steps, or 170

microinches in one step. You would enter 170 in the Maxim Focuser Step Size box.

If you have a S-C scope, RoboFocus will be moving the focus knob, which moves the focused image in and

out. The easiest way to measure this is to insert an eyepiece and focus on an object (does not need to be a

star). Again, use RoboFocus to move the focuser by about 1000 steps. Now refocus, then measure with a

ruler how far in/out you moved the eyepiece. Again, divide the numbers to get the inches per step. As an

example, an 8inch LX200 gives about 680 microinches per step (if the RoboFocus StepSize=4).

Because the measured value depends on the RFSS setting in the RFCP, if you change the RFSS, or if you

change the scope configuration (e.g., add a reducer or a Barlow), you should redetermine the Maxim value

to use. You can store numbers for different setups in the RFCP Config/Setup screen if you like.

Other Maxim settings that may help get you started (don’t be afraid to experiment, but keep track of what

you are doing so that you can converge to values suitable for your setup)

• Use about 0.5 sec for the exposure and choose a star field with one star that will not saturate at x1 BIN

• Use 3x3 bin for rough focus

• Use about 120x120 for the sub frame

• Use 7-9 pixels for HFD minimum setting

• Be sure the Maxim RoboFocus Setup tab Max Position is set large enough to allow for needed

movement of the focuser (this setting is to prevent a runaway focuser movement by Maxim).

Using FocusMax

FocusMax runs a detailed sampling of focus vs. position in an initial training operation. It then uses this

data in future autofocus sessions to speed up the focusing process. Because the training automatically

calibrates the movement per step, no separate measurement needs to be made. Use the built-in Wizard to