The heart of our portable Hyperstar imaging system is the Celestron C6 Optical Tube Assembly (OTA). We chose the Celestron C6 not just for its size and weight, but because it is the smallest OTA with Fastar capability. Fastar is a system invented by Celestron in the 1990s to quickly and easily convert their Schmidt-Cassegrain telescope (SCT) f/10 OTA into a very short focal length, fast f/2 imager.  The system enables the SCT to gather light 25 times faster than the original optical configuration. Imaging at f/2 allows for very short exposures—30 seconds to 1 minute—for deep sky objects.

The Fastar system consists of two parts. The first is the secondary mirror cell assembly in the OTA. The second is a two-element lens that replaces the secondary. Fastar has an easily removable secondary mirror holder with an alignment pin. Taking out the secondary is very straightforward and we'll have more to say about the entire process in a future article.

Readers should note that Celestron discontinued the Fastar feature in 2005, but all Celestron EdgeHD OTAs are still made with Fastar cells. For those with a non-Fastar OTA, Starizona makes conversion kits to mount the HyperStar (Fastar) cell to older SCTs. If you are uncertain as to whether your OTA is HyperStar compatible, find out how to tell here.

We acquired our Celestron C6 OTA from Steve E. via Astromart.  It  came with the standard 1.25" visual back, the 1.25" diagonal, a red dot finder and a Celestron E-Lux 25mm eyepiece. The OTA was a perfect fit on our CG-5 ASGT mount.

We hope readers have enjoyed this week's FirstLook at the various components (wedge, lens, CCD, scope) of our Portable DeepSky Imaging System (PDIS). Our goal is to assemble the componets in the next few week and do the FirstLight test before the end of Winter.  Come and join us for it! [Permalink] -Celestron C6 OTAFirstLook