3.5" Diameter: Precisely matches the mounting pattern of Starlight Instruments 3.5" focuser bases. 4.0" Height Extension: Adds 4.0 inches of height to solve focus reach issues on custom telescope builds. System Component: Integrates seamlessly between a 3.5" Feather Touch focuser and its corresponding base. Rigid Construction: Machined to eliminate flex and maintain the stability of your imaging train. Description FAQ Specifications In the Box Warranty Starlight Instruments 3.5" Diameter Riser The Starlight Instruments 3.5" Diameter Riser provides a critical 4.0" of height extension, enabling you to achieve focus in optical configurations where the focal plane sits significantly outside the stock focuser's travel range. 4.0" Height Extension for 3.5" Feather Touch Focuser Bases Designed for Newtonian telescopes and custom builds, this riser addresses the common problem of insufficient outward focus travel. By installing this 4.0" riser between your 3.5" Feather Touch focuser and its mounting base, you physically elevate the entire focusing assembly, effectively extending its reach to meet a distant focal plane without compromising stability. Starlight Instruments Build and System Integration As a genuine Starlight Instruments component, this riser is not a generic spacer. It is machined in-house from high-grade aluminum to the same exacting tolerances as the Feather Touch focusers themselves. This ensures a perfect, rigid fit that prevents tilt or flex, preserving the mechanical integrity of your high-precision focusing system even with heavy cameras or accessory loads. How do I know if I need the Starlight Instruments 4.0" Riser? You need a riser if your focuser runs out of outward travel before your eyepieces or camera can reach a sharp focus. This is common in Newtonian telescopes where the mirror's focal plane is positioned far from the tube wall. Measure the distance from your focuser's fully racked-out position to where focus is achieved to determine the required riser height. Is the 3.5" Diameter Riser compatible with other focuser brands? No. This riser is specifically designed for the 3.5" diameter bolt pattern and mechanical interface of Starlight Instruments Feather Touch focuser bases. It will not fit focusers or bases from other manufacturers. Will adding the 4.0" riser introduce flex into my imaging setup? The Starlight Instruments 4.0" Riser is machined from solid material to be extremely rigid. When properly installed, it is designed to provide a solid, stable extension that does not introduce flex into the focusing system, maintaining the precision necessary for critical imaging. Can I stack multiple Starlight Instruments risers to get more height? While mechanically possible, stacking risers is not recommended. Each additional component connection is a potential source of flex or tilt. It is always best to use a single riser of the correct height for maximum stability. Will this riser work with my 2" or 2.5" Feather Touch focuser? No. This model has a 3.5" diameter intended for Starlight's largest focusers, such as the FTF35xx series, and their corresponding 3.5" bases. You must use a riser that matches the diameter of your specific focuser's base. What hardware is needed to install the 3.5" Diameter Riser? Installation typically uses the same mounting hardware (screws and hex wrenches) that secures your focuser base to the telescope tube. The riser is placed between the focuser body and the base plate. Longer screws may be required depending on your specific setup. Diameter 3.5" Riser Height 4.0" Compatibility Starlight Instruments 3.5" Focuser Bases 3.5" Diameter Riser (4.0" Height) × 1 Starlight Instruments 2-Year Warranty
