- Introduction
- Features and photos
- Temperature Compensation
- Prices
- How to order
- FAQ
- More photos
- Automated focusing software
- Robo-Focus on the LX200 -- focus knob vs. JMI focuser
- Focus to less than 0.001 inch
- Automatic backlash correction
- Remote control via computer
- Digital readout on PC Screen
- Full manual operation
- Fits either Rack & Pinion, Crayford, or Schmidt-Cassegrain focussers
- Optional four-outlet 120 VAC power box, which can be controlled remotely
- Rack & Pinion. ROBO-FOCUS may be used on any rack and pinion, Crayford, zero shift focuser, or similar eyepiece holder that has an accessible shaft (1/4 inch diameter is standard). In a typical application, ROBO-FOCUS provides approximately 0.0005-inch steps using a 0.1-degree stepping motor. The available torque is about 90 in-oz, which is more than enough for moving and holding a color filter wheel and CCD camera. The ROBO-FOCUS stepping motor drives the R&P shaft via a special clutch coupling (supplied). The stepping motor is mounted to the scope using the hardware supplied. Because of the variety in focuser geometry, we supply flat brackets that the user bends (by hand) to provide the motor mounting surface.
- Schmidt-Cassegrain. ROBO-FOCUS may also be used on the LX200 or similar S-C scopes. These scopes have a large focussing knob in the base plate that has approximately 40 turns. The stepping motor provided for this application normally has 0.1 degree per step which is sufficient to drive even the 16" LX200 when vertical. The ROBO-FOCUS stepping motor drives the focus knob using a cog (toothed) belt. The motor mounts on a bracket (supplied) that attaches to the rear of the scope using double back tape. All parts are removable when desired.
- JMI Focuser. The motor driven zero shift focuser by JMI is a widely used fine focuser. However, its DC motor drive is not a stepping motor, and so does not provide digital focus position control. We can provide a ROBO-FOCUS compatible replacement stepping motor that you can fit onto JMI's mounting (this takes about ten minutes). By using this new motor plus the ROBO-FOCUS controller and software, you can control the JMI Focuser in a remote observing setup.
- Mandel Digital Focuser for wide field CCD imaging. This is a Robo-Focus adaptation developed by Steve Mandel for use with a CCD camera and wide field camera lens. See Steve's web page description for more photos and additional hardware suggestions for this special installation.
- VanSlyke Engineering Monster Focuser. You can now purchase a VSE focuser with a stepper motor which you will control using our control software, cables, etc. You will purchase the motor from VSE and the other RoboFocus components from us. For photos and more detail, see the VSE web page.
- ROBO-FOCUS Controller (with buttons for manual use and internal temperature sensor)
- Stepping Motor (to fit specified application)
- Bracket(s) to fit application
- Power Supply (120VAC to 12VDC 1A)
- Stepper Power Cable (9 conductor, 8 feet long)
- RS232 connecting cable (12 feet) and DB9 adapter
- ROBO-FOCUS Control Program (on CD)
- Instruction Manual
- 4-outlet Remote Power Module unit with five foot power cord (120VAC)
- Connecting cable (12 ft)
- what kind of motor/bracket to send (specify R & P, S-C, JMI retrofit, Mandel, VSE)
- the focuser shaft diameter if your setup is R&P or if your SCT is not an LX200. Please measure with a micrometer. If you do not have a micrometer, call for directions on how to get a very precise measurement using a strip of paper. Check with us - we know most sizes
- if you want the optional Remote Power Module or other optional equipment
- if you want us to provide an adapter for the RS232 pass-through to your scope
- @Focus (a part of CCDSoft image processing software from Software Bisque)
- HFR Focus (now called FocusMax; uses MaximDL software for image processing)
- MaximDL (latest release contains an automated focusing routine; from Diffraction Limited)
Introducing
ROBO-FOCUS
ROBO-FOCUS is a remote
focus driver to be installed on your existing telescope focus mechanism.
It provides digital control and feedback of the focus position using a stepping
motor controlled by a microprocessor.
To use the ROBO-FOCUS from a remote location, you send commands from your computer to change the focus position, and receive back digital position information. You'll check the results by taking a CCD image to judge if the focus is now where you want it. If you are in the observatory, you can also change the focus by using buttons on the ROBO-FOCUS control unit while looking through the eyepiece.
What does this mean for you?
With ROBO-FOCUS, you can make tiny changes to the focus setting so that you can finally take full advantage of the resolution of your optical system for either visual or imaging applications. You can repeat a focus setting at will, and you can always get back to a setting that you found was optimal. And you can make focus changes from your control room or in the observatory.
When you change your optical setup (say, by adding a Barlow), with a simple data point entry you can set the focus to almost exactly the correct position, subject only to the refinement of actual observing. ROBO-FOCUS makes CCD focusing particularly easy. Many users find that they can focus perfectly in only 3-5 minutes after taking only a half dozen fast star images.
ROBO-FOCUS
Features and Photos
Your ability to adjust
focus in steps of less than .001 inch means ultra-fine images in the eyepiece
of your telescope. Whether your scope is small (6" for example) or
triple that size, our stepping motor will smoothly, quietly and precisely
move the focus knob for you. Even the steadiest of hands cannot achieve
such fine focus.
Another major advantage of ROBO-FOCUS is its automatic backlash correction. Backlash in focusing is the result of slack in the mechanical system, and shows itself as difficulty in making fine adjustments - a slight move "in" requires a larger move back "out" to repeat the same position. ROBO-FOCUS automatically finishes all moves in the same direction (all user adjustable, of course). This automatically removes almost all the effects of slack in the mechanical system. The result is that even an S-C focuser can produce focusing approaching the precision of the finest zero-backlash (Crayford, etc.) focussers.
A third benefit of ROBO-FOCUS is on-screen command of your focus setting, so you do not have to touch the scope to adjust the focus. With the ROBO-FOCUS Control Program installed on your computer, you have a variety of on-screen data and commands such as the ability to move a chosen number of steps in either direction, or to move to a particular location. We've even kept the size of the control screen very small so that it takes the least space possible.
You can recalibrate your ROBO-FOCUS at any time. You can control Backlash Compensation, adjust communication settings, and change the labels on the four outlets of the Remote Power Module on the Configuration Screen.
Of course, ROBO-FOCUS remembers its position (and all other settings) even if the power is turned off/on. The Control Program operates under Windows 95/98/NT®. Because it is open source, you can write your own control software if you wish.
We
will ship your ROBO-FOCUS with stepping motors and mounting brackets to
match the focuser you plan to use. Or, you can get two motors to operate
different focusers. Here are the options we currently offer, followed
by some sample photos:
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|
| ROBO-FOCUS installed on an LX200 8" scope. Cogged belt turns the focus knob on the scope. | JMI focuser modified with a ROBO-FOCUS stepping motor that is connected to Control Box. | |
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| Robo-Focus used to control the focus of a wide field lens on CCD camera, as adapted by Steve Mandel | Van Slyke Engineering Monster Focuser adapted for auto-focusing using a Robo-Focus |
Although ROBO-FOCUS is designed primarily for operation from a computer, it can also be used in a manual mode using the two push buttons on the control unit. These buttons not only move the stepper, they also provide access to most of the other functions of ROBO-FOCUS. For example, these buttons provide controls for training ROBO-FOCUS to fit your particular setup.
For observers who desire a more convenient hand control, we offer an optional hand paddle containing the two control buttons and LED pilot light (to access all the digital commands and data the computer is required).
ROBO-FOCUS even includes an RS232 pass through that will allow you to use a single COM port to control both your telescope and the ROBO-FOCUS. NOTE: This pass-through feature will require an adapter for your telescope. Please consult with us about what you will need.
The ROBO-FOCUS control box operates from a 12VDC 1A power supply, which is included.
ROBO-FOCUS also has the ability to control four remote 120VAC power outlets using the optional Remote Power Module. The Remote Power Module contains four individual outlets, each with its own pilot light. The user can turn on/off each outlet either from the control unit or remotely via the ROBO-FOCUS. Thus, you can remotely power on the telescope, CCD camera, surveillance camera and light, dew zappers or other devices.
Click here for photos of ROBO-FOCUS components. User reactions are quoted on our customer comments page.
Many
scopes, especially S-C types, experience a focus shift as a result of temperature
changes such that 5-7 degrees F can unfocus a scope. The RF3 RoboFocus can
automatically compensate for this shift. It features a built-in sensor that
measures the temperature. The control software determines the proper focus
and commands the focuser to move. The software provides for the storage
of the scopes temperature characteristics, and provides the ability to account
for its temperature performance.
Prices
ROBO-FOCUS $425.
Items included:
Options
Van Slyke Engineering --
RoboFocus without a motor will cost $325. Purchase motor separately
from VSE.
Remote Power Module $125.
Items included:
Optional additional stepping motor/bracket for a second scope $115
Pass-through serial adapter and cable for LX200 scope $20
Pass-through serial adapter and cable for AP GOTO mount or other mounts - call for details; you must provide information about the wiring and connector on your mount.
Shipping and handling extra.
How
to Order
Contact
us to provide your name, address, phone, email and shipping address.
You can pay by check, wire transfer or Credit Card (VISA, Master Card or
Discover).
We need to know
Software for automating the Robo-Focus has become available from two sources in the last few months:
We did extensive testing
of @Focus and HFR Focus during the 2001, both with actual and artificial
stars, then wrote up the results in a paper which you can download
and print (pdf file, 41K).
The bottom line is that either program will deliver good focus under good conditions, though HFR is superior under poor focus and image conditions or frequent setup changes. On the other hand, @Focus is simpler in the initial setup. The choice between them for most people, will turn on which CCD software the user already has or prefers (CCDSoft of Maxim DL).
Using Robo-Focus on the LX200 - Focus knob versus JMI focuser
We also evaluated the quality of focusing an LX200 using Robo-Focus (with HFR Focus) on the scope's focus knob and on a separate JMI NGF-S Crayford style focuser. The results showed that Robo-Focus on the focus knob performed as well as on the NGF-S. We put the results in paper that also discusses backlash measurements on the LX200. Click here to download and print this paper (pdf file, 32K).
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