SharpCap Forums

What would yield better results all things being equal 5 seconds of 720 subs or 20 seconds of 180 subs, Gain being equal in all cases and total integration being 1 hour..?

What if two 1 hour integrations are stacked together?

I did an exposure regimen of G=100, E=20s, total subs =180, HCG with my Mallincamsky D10c camera and I had very good results. The galaxy (NGC891) had a whole range of subtle colours while the stars did not.

How do I get the graph that is in the manual displayed after I click on the "brain" in the smart histogram?

Dan Kahraman

Hi Dan,

the answer to your question (and the shape of the graph in the brain window) depends on the following

* how bright is your sky background as seen by the camera - this depends on light pollution levels, filters, pixel size and scope f-ratio
* how much read noise does your camera have.

Optimum exposure should be (by rule of thumb) at least 10 * (read noise squared) / (sky brightness in e per pixel per second)

If you have a read noise of 2 and a sky brightness of 1 e/pixel/s, then you need exposures of 40s or more - anything less will suffer, the shorter the worse.
If you have the same read noise, but a sky brightness of 3 e/pixel/s, then 14s exposures will be fine - in which case your 20s option will be fine, but not the 5s option
Add more light pollution for a sky brightness of 10 e/pixel/s and 4s exposures will be fine - you will not see much difference between your two options.

cheers,

Robin

Hi Robin:

I want to know how I get the calculation window displayed which makes recommendations as to what Gain, number of exposures and subs I should make for sequence. I can click on the brain but I want the information that the manual shows.

Dan Kahraman

Robin:

This is what I want displayed on my monitor prior to setting up my sequence analysis.


https://docs.sharpcap.co.uk/3.2/SharpCa ... age178.jpg

Dan Kahraman

Hi Dan,

you have to show the brain window and then do one of the following

* Press the 'measure' button to let SharpCap measure the sky background brightness

of

* Enter a sky background brightness manually - perhaps because you have previously measured a few times and you know that it is always about 1.5 or 2.75 or whatever.

Once you have done one of these then the recommendations will appear.

cheers,

Robin

Robin:

Thank you very much for this

Dan Kahraman