William Optics Megrez 72 Doublet APO
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William Optics Megrez 72 Doublet APO
William Optics Diagonal
William Optics Red Dot Finder
Lens heating for WO Megrez 72
In November 2008 I bought a new WO Doublet APO Megrez 72. The telescope has an aperture of 72mm and a focal length of 432mm. This telescope is a compact F/6.0 system in good quality.
Technical Data: Aperture: 72mm Focal length: 432mm F-stop: F/6.0 Objective: ED Doublet air spaced, Multi-coated, SMC coating Resolution: 1.58 arc seconds Viewing limit: +11mag Focuser: Crayford 2 Inch with 1:10 dual speed microfocuser and compression ring 1.25-Inch adapter with compression ring 360° rotatable Focus length: 81mm Tube: Outer diameter 87mm, 2 baffles, protection cap Length without/with extended dewcap 300/360mm Bracket: L angle bracket with 2 threaded holes for 1/4 Inch foto screws Weight: 2.2kg
The WO Megrez72 will be used for imaging of wider objects with my cameras.
Camera field of view / Pixel size at 432mm: DSLR Canon 20D 179 x 119 arc minutes / 3.1 x 3.1 arc seconds DSLR Canon 60D 177 x 118 arc minutes / 2.1 x 2.1 arc seconds CCD Atik 314L+ 71 x 53 arc minutes / 3.1 x 3.1 arc seconds Video WAT-120N 51 x 38 arc minutes / 4.0 x 4.0 arc seconds Video WAT-902H2 Ultimate 51 x 38 arc minutes / 4.0 x 4.0 arc seconds Video modul SK-1004XC 41 x 29 arc minutes / 4.7 x 3.0 arc seconds Webcam Philips 740K 29 x 22 arc minutes / 2.7 x 2.7 arc seconds
Because of the compact aperture of 72mm and the short focal length this optic is relative insensitive for seeing effects. Even images in very turbulent air can give useful results with this optic.
An example for this can be seen on this first test images of M42 and NGC1977 on November 24, 2008. This image were made by me inside a room on an open window and a temperature difference of 30 degrees. So the air was very turbulent.
Beside the good optical quality of a doublet APO I was also persuaded by the high quality of the mechanics on this telescope. The Crayford focuser holds DSLR Canon 20D with Off-Axis guider + MPCC and WAT-120N video camera sure in focus even in upright direction of the telescope.
|The WO Megrez72 in a compact and so very practical case for transport|
|The WO Megrez72 with extended dew cap and full extracted focuser|
|The 2 Inch Crayford focuser with 1:10 microdrive and additional 1.25 inch adapter|
|The Crayford focuser with tensioning screw for the adjustment axis in the middle is working very exactly|
|The WO Megrez72 can be disassembled in few minutes if necessary|
|The flattened tube of the Crayford focuser for the adjustment axis and fixing screw|
|The four ball bearings on the upper side are holding the counterpressure of the steel made adjustment axis|
|The WO Megrez72 can be mounted also on the Manfrotto 410 gear tilt head with the L bracket|
|The dovetail fixed on the L bracket for mounting on the parallactic mount EQ6|
|Lumicon Off Axis Guider, WAT-120N, Baader MPCC, Canon 20D with angle finder on WO Megrez 72|
With this setup ASCOM Puls Guiding also works very good on EQ6 mount
|William Optics Diagonal|
Carbon, 2 inches, Lambda 1/10, Reflexion 99%, Dielectric
|WO Megrez72 with WO Diagonal and Pentax XW14|
This combination also shows visual a fantastic image
|The WO Red Dot Finder is a very solid metal device|
The WO Red Dot Finder can insert four different symbols in seven brightness levels
|The WO Red Dot Finder screwed on the Megrez72|
The WO Red Dot Finder is a very accurate help for positioning made in high quality
|Dew Not flexible heating element for the WO Megrez72|
Maximum heating power of 6 Watts at 12 Volts DC and a current of 0.5 Amperes
|Dew Not flexible heating element on the front lens of the WO Megrez72|
A small heating from outside prevents the front lens from dew
April 19, 2011
Questions and suggestions to => Gerhard Dangl