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We will be closed for the Holidays from 16th December to the end of January. All orders received during that time will be sent upon our return. Merry Christmas and a Happy New Year to all!
We will be closed for the Holidays from 16th December to the end of January. All orders received during that time will be sent upon our return. Merry Christmas and a Happy New Year to all!
William Optics Guide Star 61 - ProAstroz

William Optics GuideStar 61 GS61

by ProAstroz
Sold out - more on the way!
$729.00
$729.00 - $729.00
$729.00
$599.00
$599.00 - $599.00
$599.00

Use as a portable high quality imaging scope or an ultra-high quality guidescope.

The new William Optics GuideStar 61 APO features the same high quality FPL53 ED doublet lens as the Zenithstar 61 so delivers sharp, high contrast images virtually free of false-colour.

Other features include a new lightweight optical tube with 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 existing Adjustable Flattener for the ZS61 (FLAT61A) and a new 0.8x Reducer/Flattener FLAT61R.

CNC machined aluminium for a superior fit and finish.

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.

Specifications

Focal Length: 360mm
Diameter: 61mm
Focal Ratio: F5.9
Tube Length: 340mm
Tube Weight: 1.44kg