Opticstar AR90S Gold DS 90mm f/5.5 Apochromat Refractor Optical Tube Assembly
- Lens diameter: 90mm
- Focal ratio: f5.5
- Achromatic refractor
- Fully multi-coated doublet
- Retractable dew shield
- High quality all-metal construction
- Dual Speed Crayford 2" & 1.25" focuser
- Knife-edge baffles
- Mounting rings and dovetail included
- Includes rings (1/4" photographic thread)
- Quality nylon, padded travel-case
The Opticstar AR90S Gold Dual Speed short-tube refractor is ideal as a portable scope and can be used for observing, imaging or as a guide scope. It uses a 90mm achromatic doublet that is fully broad-band multicoated to increase light transmission.
The optical tube greatly benefits from metal knife-edge baffles (not the plastic less effective step type) that prevent stray light outside the field of view from reaching the focal plane. Knife-edge baffles markedly increase image contrast.
The Crayford focuser, main tube and lens assembly are screwed into each other for maximum rigidity, no peripheral screws are used as they can compromise the rigidity of the telescope.
The AR90S Gold refractor features a smooth dual speed Crayford focuser with a 2" drawtube (with 1.25” adapter), retractable metal dew shield, CNC rings with 1/4" photo tripod threads, broadband fully multi-coated optics and comes complete with a quality padded travel-case.
With a focal length of 500mm (f/5.5) the AR90S Gold Dual Speed is very well suited for wide field astrophotography, guiding as well as nature photography.
With a minimum total length of only 40cm and a large 90mm aperture the AR90S Gold Dual Speed is the perfect travel scope. All you need to start using the AR90S Gold Dual Speed is a photographic tripod, diagonal and eyepieces.
- Opticstar 90mm f5.5 optical tube assembly (OTA).
- Dual Speed Crayford 2" & 1.25" focuser.
- Mounting rings & Dovetail Bar.
- Free: Nylon padded case
- One year warranty.
|Construction||All metal construction|
|Dew shield||Retractable dew shield|
|Dovetail Compatibility||Mounting rings and dovetail included|
|Focal Tube Travel||70mm (marked in 1mm intervals)|
|Focuser||1:10 Precision dual speed Crayford|
|Focuser Adapter||Accepts 2" and 1.25" eyepieces and diagonals|
|Frontal Dew Shield Diameter||110mm (screw-type aluminium cap)|
|Maximum Tube Length||465mm with extended dew-shield|
|Minimum Tube Length||385mm with retracted dew-shield|
|Optical Coatings||Broadband FMC (fully multi-coated)|
|Optical Design||Achromatic refractor|
|Optical Tube||High quality all-metal construction|
|Optical Tube Weight||2.3kg including dual speed focuser|
|Tube Design||Short, suitable for use with bino-viewers|
|Tube Ring||Single wide tube ring with photographic 1/4" thread|