[Shiraz (Ray)]

the QHY5L2 and ZWO 120 both use the same high performance Aptina MT9M034 CMOS sensor. The ASI130 uses the older MT9M001, which is also used in the Orion SSAG and the venerable QHY5 - it has lower QE than the 034 (55% vs 75%) and seems to be significantly noisier. I have a QHY5, a QHY5L2 and a DMK21-618 and could do a quick comparison of performance in the next few days if that would help anyone - and to make sure that the spec advantages of the MT9M034 carry over to reality.

Dust is a problem for all cameras at f20, where any crud will form very well defined dark shadows and even the tiniest spec of dust will easily cover a few 3.75 micron pixels (eg a human hair will cast a shadow about 50 pixels across). Expect to spend a lot of time meticulously cleaning the chip (or the window) - I use dry cotton buds after breathing on the surface to slightly mist it. ZWO now have a window in front of the ASI120 chip, presumably to help keep everything cleaner.