Recommendations on my next imaging Camera after years with modded DSLRs?

[Shiraz (Ray)]

Originally Posted by Slawomir

Just a question out of curiosity - how many bits are dominated by read noise in ASI1600 at unity gain or when adjusting the gain for longer subs?

Would this be a correct way to determining how many bits are really available for signal in my case?

Gain = 0.16 meaning 1 electron results in 1/0.16 = 6.25 ADU
Read noise = 4e thus 4 x 6.25 = 25 ADU equalling about 5 bits (2^5) taken by read noise leaving me with 11 bits per sub for data?

Ta
Suavi

that's the way I would do it Suavi. gosh that read noise is low .
I think that the dynamic range data on the 1600 can be read off from the graphs on the ZWO website

[Camelopardalis (Dunk)]

From measurements with my ASI1600 and plugging the numbers in as Suavi did, I get...

Gain = 75 => 16.4 ADU
Gain = 139 => 25.6 ADU

Methinks at a dark site I'll be using gain=75 and suck up the longer exposures

[Slawomir (Suavi)]

Originally Posted by Camelopardalis

From measurements with my ASI1600 and plugging the numbers in as Suavi did, I get...

Gain = 75 => 16.4 ADU
Gain = 139 => 25.6 ADU

Methinks at a dark site I'll be using gain=75 and suck up the longer exposures

Does it mean that at unity gain one is left with 12-5= 7 bits (or thereabouts) available for real information?

[glend (Glen)]

The original poster, and others, may find the QHY163M Beta Testing thread, on Cloudy Nights, worth following. The initial testers seem to be encountering some of the same things that that ASI1600 testers did. One bonus on the QHY163M is a heated sensor window (Not that I have had any problems with ASI1600 fogging or internal condensation), but it would be a nice feature to have imho.

Thread is here:

http://www.cloudynights.com/topic/55...3m-beta-is-in/

[Camelopardalis (Dunk)]

Nah I was using 16-bit numbers so it's just over 11 bits of dynamic range at unity gain (=139) and 12 at gain=75

[Slawomir (Suavi)]

I thought 16bit files from ASI have first 4 bits = zero

[Shiraz (Ray)]

Originally Posted by Slawomir

I thought 16bit files from ASI have first 4 bits = zero

the bottom 4 bits are padded with zeros after the ADC conversion (ie the noise is multiplied by 16 as well as the signal). At unity gain, the maximum signal is either 4000 electrons or 64000 ADU and the noise is either ~1.6 electrons or ~25.6 ADU - take your pick on how to represent things, but it is an extra complication when trying to understand this camera.

[Slawomir (Suavi)]

Thanks Ray, I think I have enough info for now