Infinity hard and software

[305mm_f/5]

Hello,

I use the Infinity on a 305mm f5 newton with a DIY horseshoe mount.

The camera makes great pictures - but some questions came up:

1) will there be more information in the fits header in the future? ( like total exp. time, number of stacked images, CCD temperature?).

2) I use the Infinity mono. The color version must have a little lower sensivity. How much would I lose if both (mono and color) run in mono mode with 2* binning.?

3) when comparing the camera sensivity with a ICX285 camera (meade DSI 3) I can see only very little difference.
Could it be due to the BK7 cover glas on the Infinity or the high read out speed, or the hot pixel rejection process?

is there a CDS preamp in the Infinity camera?

4) How many stacks make sense? for example 30 * 2sec stacks would be equal to a x sec. single exposure. What is the right math for that?

best regards: Bert

[Howie]

Bert, I just got the book called "Astrophotography on the Go" for Christmas. The author has some formulae and guides for what happens with astrophotos depending on everything from exposure time right through light pollution, noise, photon noise, effect of filters and even different types of street lights!
He reckons signal strength (the actual data/photons getting captured) increases linearly with time, so 2x30s has twice the amount of data than 1x30s, while 3x30s has three times and so on.
But noise, apparently, only increases with the square root of time. So not only does 2x30s pull twice the amount of signal/photons/data but only has 1.4 times the noise of the single 30s shot. So an improvement in S/N ratio of 40%. 3x30s has only 1.7 times the noise of the single exposure but 3 times the data of the single shot. So it shows an improvement in S/N ratio of 70% over the single shot.
So the actual signal to noise ratio is better and better with the more shots you can stack. So in stacking ... the more the merrier. So apparently 1x360s is the equivalent of 2x180s, 3x120s, 4x90s, and so on.
Except ... he also says you cannot go too short in exposure with some objects if their 'photon flux' is not high enough to 'register' on the sensor/ISO amplification. And so far I haven't been able to totally understand that part of the book which explains how to figure out your target's brightness/photon flux and your cameras ability to 'see' it.
But, hope the above stuff on S/N helps.
Howie