I am doing something dreadfully wrong.

Here is my image of a double star in Pisces. Taken by clicking "set" at .5" in the Main Control panel. Gain set to 0. No other changes from default.

Why only 2 shades of gray?

Thank you.

What if you change gain?

I didn't know until now, but fv the fits file viewer is helpful.

The image I posted was .5" exposure of STF 12 in Pisces with magnitudes 6.1 and 7.5. The FITS data are all positive integers < 2^2.

Now I have an image of the "double double" in Lyra, magnitudes 5.2 and 6.1, only this time with .05" exposure and gain set to 200. In this case FITS data are all positive integers < 2^3, or 3 bit data. Please see the text attachment. Strange how there are 22 "7"s in a row. That is, if the data is 3 bit only because of the low light, strange that there would be so many maxed pixels in a row.


I have other images whose preview clearly showed stars but which upon saving consist of an array of 0's only.

So I'm wondering, what determines the bit depth of the data that is actually saved to file?

Thanks for reading.

I'm pretty sure my ZWO has always given me at least 8 bit data. This is odd.

I have another exposure, this one pointed at (or near! (no go-to)) a cluster (M15), exposed for 5" with gain set to 540. Here the maximum recorded pixel value is 109.

So this camera with Ekos *can* produce higher pixel values.

But this still really bothers me.

There are 14,663 pixels with value 109. And there are only 6232 pixels with value 100-108. Visually, even the smallest stars contain pixels with value 109.

Why would so many values be recorded at the maximum? I was expecting a smooth tail like a bell curve (or binomial distribution).

I'd be glad to post additional data in some form if anyone would like.

Thanks.