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Starlight Instruments Focuser Boss II Electronic Focus Control - FB-II-KIT1


Starlight Instruments Focuser Boss II Kit
with Hub & Power Supply
Choose Motor & Other Optional Upgrades Above

Control your Starlight Instruments Feather Touch focuser electronically with the Focuser Boss II! The Focuser Boss is compatible with a Mac through Sky X with a daily build 7315 or later, as well as with a PC. This kit includes a digital hub and your choice of a 12VDC AC/DC power supply or a DC cigarette plug (Please Note: With the DC plug, the Focuser Boss requires 2amps). You have two options should you want a motor - the Handy Motor with Temperature Compensation or the more robust Posi-Drive Motor with manual focus override and temperature compensation. There are also several other upgrades you can add to the basic Focuser Boss Kit II, including wireless control, a hand controller, and even an extra control board if you want to control two focusers at the same time.

Below is some basic information on Focuser Boss II options and upgrades, and if you look at the additional pictures to the left, you will see what they look like. To build out your “custom” Starlight Instruments Focuser Boss II Focusing System, choose from the option & upgrade drop-down lists at the top of the page. If you see a price next to the option of your choice, that amount will automatically be added to your total amount due. Your choice of Power Supply is included at no additional charge. After you have finished choosing your options & upgrades, please click the Add to Cart link.

HSM Handy Stepper Motor: The design of the Handy Stepper Motor motor housing allows you to manually turn the focus knob on the focuser by simply turning the override knob on the motor housing. This motor has a built-in temperature thermistor for temperature control through the Focuser Boss II digital system.

If you pick the HMS standard motor for your Focuser Boss, you will be asked to choose the right size for your focuser:


  • The HSM20 motor unit will fit any Feather Touch Micro Focuser, Feather Touch retrofit pinion assembly upgrade, or 2.0" Feather Touch Crayford focuser.


  • The HSM30 option will fit any 2", 2.5", or 3.0" Feather Touch Rack and Pinion focuser.


  • The HSM35 fits any 3.5" Feather Touch focuser.


Alternately, you could choose the Posi-Drive Motor Upgrade if you want extra lifting power for heavy loads...

Posi-Drive Motor System Upgrade: The Posi-Drive Motor System can lift in excess of 56 pounds. This motor system attaches to the pinion shaft and not the reduction assembly which eliminates any slip and offers precise repeatability with heavier payloads. The PDMS has 2.3 microns per step (.00009") which is 11,400 steps per inch. The PDMS motor comes standard with an override to allow for manually focusing with either the course or fine focus knob (depending on your option choice). The PDMS motor has the thermistor built onto the motor circuit board for temperature compensation.

Wifi Upgrade: The WiFi upgrade is a wireless option that allows you to use your Smart Phone or iPad to control the focuser. This feature allows you to control your focuser wirelessly without having any cables attached. A wireless router is not required but is recommended. The hand controller is not needed with this setup unless you want to have an option of controlling the focuser wirelessly or with the wired controller.

Hand Controller Option: This hand controller will allow you to manually control the Focuser Boss electronic focuser via simple push buttons.

Control Board for 2nd Feather Touch Focuser: This upgrade allows you to control two focusers simultaneously; of course, you supply the focusers.