Built for wide-field imaging, the Gear Series 90mm Triplet APO Refractor optical tube assembly from Starfield features a triplet lens with an Ohara FPL-53 apochromatic element. Internal baffling counters stray light and improves contrast. The ball bearing-supported 2.5" focuser accepts 2" and 1.25" eyepieces and accessories. Threaded for 63mm accessories, the focuser is sturdy enough for heavy cameras and astrophotography equipment. The manual camera angle adjuster provides framing options during your imaging sessions. The OTA is compatible with an optional motorized focuser and requires a separately available tripod or pier and mount for use.
Optical Performance
- 90mm diameter aperture
- 540mm focal length and fast f/6.0 focal ratio allow low exposure times
- Triplet lens with extra-low dispersion FPL-53 apochromatic element for true color rendition without aberrations across the entire field of view
- Standard finderscope mounting shoe
- M63 x 1 female thread
Focuser
- 2.5" rack-and-pinion focuser with 1:10 gearing, Teflon bushing, and ball bearing support can accommodate heavy astrophotography cameras, filter wheels, etc.
- Accepts 1.25" and 2" eyepieces and accessories
- 2" adapter with brass compression ring and three clamping screws
- Compatible with optional focusing motor
Construction
- CNC-machined aluminum rings and handle with slots for accessories
- Retractable dew shield
- Long Vixen-style dovetail bar