About this product
Part Number: M-GS61-GD
William Optics GuideStar 61
Use the GuideStar 61 as a portable high-quality imaging scope or an ultra-high-quality guidescope.
The GuideStar 61 APO features the same high-quality FPL53 ED doublet lens as the Zenithstar 61, so it delivers sharp, high-contrast images virtually free of false colour.
Other features include a new lightweight optical tube with a draw-tube (push-pull) focuser for coarse focusing and a rotating lens assembly for fine focus.
Two flatteners are available for the GuideStar 61: the Adjustable Flattener for ZS61 and a new 0.8x Reducer/Flattener.
CNC machined aluminium for a superior fit and finish.
It is supplied with a Vixen/Synta style finder dovetail rail (for a finder-scope) and a soft carry case.
Ohara FPL-53 vs FPL-51 ED Glass
The dispersion properties of ED and SD glass elements are important in determining the overall colour correction. The abbe index is used to quantify the 'partial dispersion' of a particular glass. Pure Fluorite offers the highest partial dispersion at around 94.99 V. Ohara FPL-53 glass is very close to Fluorite at 94.93 V and is often referred to as Synthetic Fluorite. FPL-53 is also noticeably better than Ohara's lower spec' FPL-51 glass, which offers an abbe index of 81.54 V.
Focal Length: 360mm
Objective Diameter: 61mm
Focal Ratio: F5.9
Tube Length: 340mm
Tube Weight: 1.44kg
The price includes a soft carry case.
Telescope Field of View Simulator
|Average Rating (1 Review):
11 April 2022 | Robert
Bought this primarily as a top end guidescope and also will use as piggyback wide angle scope. The build is impressive, solid, smooth with an immaculate finish. Put the camera that I will initially be using to guide using PHD2 (ZWOI 174MM), (will buy dedicated one later) and focussed on a barn about 3 miles away. The image was crisp and very sharp all the way to the corners of the sensor, even when "zooming in" til pixels showed, overkill of course, but there was no breakdown in the clarity and detail up until that extreme point. My cuurent guide scope of same aperture gives a much softer image from the beginning. So shows great potential for finding and getting sharp guide stars. (It looks very good too! )
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