How low can you go? With the advent of easy to mass-produce, high-quality, CMOS-based, highly sensitive, low-noise imagers, prices are dropping daily on very capable imagers. I've been very impressed with what I've read recently about IMX224-based imagers--especially the low read noise of the camera and its ability to handle high gain settings--so I recently acquired a Mallincam SR AG1.2C, an imager that costs less than $300. This tiny imager could probably be carried around on your key ring! But, as a serious imaging too, does it cut the mustard?
As expected, the clouds rolled in the day the imager arrived, so I spent some time building a darks library at different gain and integration settings. These darks tell an interesting story. The AG1.2C is really low noise! Here are a couple of those images:
This is a moderate gain image (gain 20) and a 40-second integration. The image shows very little noise and amp glow--remarkable performance for an uncooled imager!
Performance on darks is one thing, performance in an imaging setting is something else. The night before last offered an opportunity to try the SR AG1.2C, using a 6 inch RC scope and a .5x focal reducer. This combination produced a nice image scale, as you can see from the image of M33 above (it was cropped very slightly at the edges to chop off some stacking artifacts).
This image is a stack of 10 x 30s integrations at gain 20. Capture was in MallincamSky, with stacking in nebulosity. It is by no means perfect, but I'm quite pleased with the result from such a small and inexpensive imager (image is a jpeg processed to meet size limitations of attachments).
As a reference image-scale, here's a pic of the Bubble Nebula taken with the same setup. This is a stack of 50-second exposures at gain 20 (20 images stacked).