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Gallery XIV

I got a SAC 8 for Christmas. It arrived last week. This has a SONY HAD chip like a Stellacam but its chip has smaller pixels and a smaller FOV. Unlike the the Stellacam it performs on chip integration like a CCD camera (though with only an 8 bit A/D). It can take images that are several seconds long. It can also put out video. However it cannot add video frames like the Stellacam can so its real time video output is only 1/128 as bright as that of the Stellacam at maximum "sense up" (add 128 video frames). So it can only video very bright objects and display them in real time. This makes it harder to locate DSO objects in video mode - as you can't see them! This is a disadvantage relative to the Stellacam. But the SAC 8 has a Peltier cooler and through a combination of on chip and off chip addition (integration) of frames it should generate images of DSO's similar to those produced by the Stellacam - if you can find the object!

I discovered that I could image for 5 seconds of on chip integration with out too much star trailing (this would equal a Stellacam "sense up" of 320 frames). So I shot some images with dark frame subtraction. For the Star cluster images I shot single images of 3-5 seconds. For the other objects, I set the camera to shoot a 5 second image every 5 seconds for a total of 30 - 40 images and add these "on the fly" to produce an image that was effectively 150-200 seconds long. Taking the advice of Tim Tasto, I had the gain cranked all the way down, the contrast set nearly all the way up, and the brightness at about 75-80% of maximum. These were shot through the 10" f5.6 dob with a f6 Steve Mogg focal reducer.

Star Clusters