The Explore Scientific Photo Newtonian 208mm f/3.9 with Carbon Fiber Tube; 812mm focal length; 97% EMD Coatings; No Tool Secondary Collimation; ES Finder Scope Base ONLY installed on scope and Soft Carrying Case. Cradle Rings with Handle and Vixen-Style Dovetail. Weighs 18.3 lbs. (Finder Scope and HR Coma Corrector NOT Included).
The Crescent Nebula below⬇︎⬇︎(also known as NGC 6888, Caldwell 27, Sharpless 105) was photographed by Chris Sullivan with an Explore Scientific N208CF with the optional ES Coma Corrector. It is an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It was discovered by Friedrich Wilhelm Herschel in 1792. It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000 to 400,000 years ago. The result of the collision is a shell and two shock waves, one moving outward and one moving inward. The inward moving shock wave heats the stellar wind to X-ray-emitting temperatures.
It is a rather faint object located about 2 degrees SW of Sadr. For most telescopes it requires a UHC or OIII filter to see. Under favorable circumstances a telescope as small as 3.2" (with filter) can see its nebulosity. Larger telescopes, like an 8" or larger, reveal the crescent or a Euro sign shape which makes some to call it the "Euro sign nebula”.
The Explore Scientific Carbon Fiber Photo Newtonian allows this larger primary mirror, with faster aperture ratio compared to the usual 8" f/4 for deeper shots with the same exposure time. The completely redesigned secondary mirror mechanism ensures easy and optimal collimation. The large 80mm secondary mirror offers optimal field illumination. This amazing scope includes a high quality 2" focuser with 10:1 reduction; cradle rings with vixen style dovetail rail and carrying handle with option for mounting a camera or other accessory. The Newtonian Carbon Fiber scope also stands out with a lighter weight compared to the aluminum Bresser version and a virtually nonexistent focus drift during long exposures.
||208mm Newtonian f/3.9 with Carbon Fiber Tube
|Primary Mirror Diameter
|Secondary Mirror Diameter (M.A.)
||.6 arc seconds
|Optical Tube Assembly Weight
|Material Primary mirror
||Special low expansion H-PZ33
|Material Secondary mirror
||Borosilicate-glass with low thermal expansion, individually matched to main mirror