Please Read This Important Note Regarding the HyperStar C9.25
The HyperStar C9.25 lens will ONLY work with factory-equipped Fastar-compatible telescopes. This means older 9.25" telescopes are NOT compatible. The older telescopes cannot be retro-fit with a conversion kit like the other size SCTs. This is because the opening in the 9.25" corrector plate is smaller than the diameter of the secondary mirror, meaning the mirror cannot be removed from the telescope.
To determine if your telescope is compatible, check out the secondary mirror assembly on the front of the scope. If it looks like the picture below, you are all set. If not, the HyperStar lens will not work.
Introducing the new HyperStar C9.25 Lens. Now 9.25" SCT owners can join the HyperStar revolution. Ultra-fast, wide-field CCD imaging has never been easier. HyperStar quickly converts your SCT into a fast imaging system. The HyperStar lens easily replaces the secondary mirror in the telescope, allowing a camera to be placed in front of the telescope. Switching between HyperStar and standard configurations is quick and simple--no tools required. See this video for a demonstration.
The HyperStar C9.25 lens converts a standard Celestron 9.25" SCT from f/10 to f/2.3, making the system 18 times faster. That means 18-times shorter exposures! Now you can capture deep-sky images without guiding and without an equatorial wedge (in alt-az configuration). The HyperStar lens shortens the focal length of the telescope, giving a much wider field of view, and giving a greater tolerance of tracking errors, allowing for unguided, alt-az imaging.
The HyperStar C9.25 is compatible with a variety of cameras, including both CCDs and DSLRs. Like the other 8" and larger HyperStar models, the HyperStar C9.25 covers up to a 27mm (APS-size) sensor. Separate adapters are required for different cameras. One adapter is included with the HyperStar lens.
Optical performance is excellent, with a coma-free, flat field of view almost 3 degrees wide.
What telescopes are compatible?
Only new, factory-equipped Fastar-compatible 9.25" SCT telescopes have a removable secondary mirror assembly, allowing the use of the HyperStar C9.25 lens. Older 9.25" SCTs are NOT compatible, nor can they be converted.
Why are the other HyperStar lenses faster?
The 9.25" SCT uses a slightly different optical configuration, in order to produce a flatter field of view and have a smaller central obstruction. This means it uses a slower primary mirror (f/2.3 versus the f/2 mirror in other SCTs). This means the HyperStar has to be slightly slower to retain its excellent optical performance. The difference between f/2.3 and f/2 is negligible.
Focal Ratio: f/2.3
Focal Length: 540mm
Maximum Usable Sensor Size: 27mm Diagonal (APS Format)
Field of View (with 27mm sensor): 2.8 degrees
Camera Adapter Threaded for 2" (48mm) Filters*
Backfocus (from mounting thread to focal plane): 59.7mm (2.35")
Length (without camera adapter): 4.2"
Weight: 1.8 lbs.
* On the C925 HyperStar, there is not enough room for a filter in the Nikon adapter due to the longer flange focal distance of Nikon cameras.