Astronomy Specialist



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The Sharpstar SCA260 is an Aspherical Cassegrain astrograph with a fast focal ratio of f/5 and a focal length of 1300mm.   This telescope features a 260mm aspherical primary mirror made of PZ33 borosilicate glass with a similar low expansion coefficient of the Pyrex. The enhanced aluminium mirror coating ensures a reflectivity of over 95%. The secondary mirror has a new lever adjustment function that can be moved in a horizontal position.    The optical path includes a triplet air-spaced 3" field flattener optimized for full-frame photography with minimal vignetting. The heavy duty rack & pinion 3.2" focuser ensures smooth operation without slipping and the high capacity for accessories. The focuser is compatible with the ZWO EAF electronic focuser bracket.
The two M54×0.75 threads and M48×0.75 threads at the rear of the focuser can meet different needs, are convenient to connect to most commercially available imaging-terminal and achieve perfect focus.
  The optical tube is made of carbon fiber with CNC-machined aluminium parts for enhanced structural rigidity and durability, and features three cooling fans at the rear.    -    -    CCDInspector plot showing the curvature of the SCA260.


Optical design

Aspherical Cassegrain reflector

Primary mirror diameter

260 mm

Focal length

1300 mm

Focal ratio


Secondary mirror 

Spherical, 120 mm (minor axis)

Corrector rear group

Triplet air-spaced

Image circle

80 mm


Rack & pinion, dual speed (10:1) 3.2" diameter

Resolving power

0.46 arc second

Stellar limiting magnitude



Rack & pinion, dual speed (10:1) 3.2" diameter

Camera connection

M54 x 0.75 male, M48 x 0.75 male

Corrector distance

75 mm from base of M48 thread

Tube weight

15 kg

Tube length

712 mm

Tube diameter

280.5 mm

Tube material

Carbon fiber





Eastern Veil Nebula - Sharpstar SCA260 Super Aspherical Cassegrain Astrograph
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