Using Brain to get correct narrowband exposure

[m32guy]

I was out the other night trying to figure out the optimal settings when shooting narrowband out of my suburban backyard with my 294mm using 3nm HA and 3nn OIII filters. To date, I've been shooting at a gain of 300, but was curious what the "Brain's" analysis would yield. The problem I'm hitting with the HA filter is that at the Unity Gain setting I can't get a solution under 600 which is about as long as I care to go with my rig and weather. If I want to see what solutions I get at a higher gain level, what's the best way to do this?

Thanks, Steve.

[Menno555]

Hi Steve

You can see the settings for different gains when you hover your mouse pointer over the result graph.
Also, more in-depth info can be found here: https://docs.sharpcap.co.uk/4.0/#Smart%20Histogram

Menno

Hover mouse pointer over graph

image199.jpg (25.75 KiB) Viewed 515 times

[oopfan]

Hi Steve,

My scope isn't the fastest in this world: 71mm refractor at f/5.9. I expose for 600 seconds with a 7nm Ha filter. It would need to be longer with a 3nm filter. I don't use the Brain for exposure determination. I simply run some test shots to find the exposure that puts dark space a couple hundred ADU above the bias level. For example, my bias is 216 ADU. A 600-second exposure brings dark space up to about 400 ADU. I get very good results this way.

Brian

[admin]

Hi,

try changing the 'Aim For' option from 'unity gain' to 'max dynamic range' - that will make SharpCap stop worrying about getting close to unity gain and consider all the gain values available on your camera.

cheers,

Robin

[m32guy]

Perfect. Thanks