CELESTRON - C9.25-A XLT CG-5 9.25" Optical Tube Assembly • 91025-XLT
Like most Schmidt-Cassegrain telescopes, the Celestron C9.25-A XLT has a focal ratio of f/10, lending itself quite suitable for either Visual or Imaging use. XLT StarBright Multi Coatings leave the C9.25 XLT versatile for looking at many different celestial objects without the annoying optical disturbances caused by chromatic aberration The StarBright XLT coatings bring excellent light transmission from the corrector to the eyepiece ensuring as little light wasted as possible to produce the brightest images. Schmidt-Cassegrain designs use both corrective plates and primary mirrors (aspects of both refractors and reflectors), resulting in the rather slow ƒ/10 focal ratio but also will accommodate many accessories that can change it, making it even more suitable for faster CCD imaging or viewing. For instance, the focal reducer by Celestron (NOT INCLUDED, PURCHASED SEPARATELY) brings the focal ratio to f/6.3, making lower surface brightness objects look more impressive. This also assists in astrophotography because faster focal ratios are more efficient when taking exposures with larger pixel sizes since slower focal ratios tend to take too long often result in undesirable results (such as possible pixel blooming). For visual astronomy, a 6x30 finderscope, 25mm eyepiece eyepiece, 1.25" star diagonal, and 1.25" visual back are all included with the Optical Tube Assembly (OTA). This OTA is the very same quality as the tube assemblies that come with Celestron telescope packages, but without the mount. This is a great way to upgrade, without the need to buy the whole telescope system.
- 9.25" Schmidt-Cassegrain, 2350mm focal length (f/11) Aluminum Optical Tube.
- Starbright XLT Multi-Coatings.
- 6x30 finderscope.
- 25mm eyepiece (94x).
- 1-1/4", star diagonal.
- 1-1/4" visual back.
- Dovetail slide bar for Celestron's CG-5 Mount.
|Name||Celestron - C9.25-A XLT (CG-5) 9.25" Optical Tube Assembly|
|Custom Stock Status||Ships in 3-5 Days|
|Aperture||234.95 mm (9.25 in)|
|Dovetail Compatibility||CG-5 Mount|
|Eyepiece 1||25 mm (0.98 in)|
|Eyepiece 1 Magnification||94 x|
|Focal Length||2350 mm (93 in)|
|Highest Useful Magnification||555 x|
|Light Gathering Power||1127 x|
|Limiting Stellar Magnitude||14.4|
|Lowest Useful Magnification||34 x|
|Optical Coatings||StarBright / XLT|
|Optical Tube Length||22 in (559 mm)|
|Resolution (Dawes)||0.49 arc seconds|
|Resolution (Rayleigh)||0.59 arc seconds|
|Secondary Mirror Obstruction||3.35 in (85 mm)|
|Secondary Mirror Obstruction by Area||13 %|
|Secondary Mirror Obstruction by Diameter||36 %|