Target planning and imaging time

starfield

Hi Adam,

Just noticed your SH2-216 PNe image won an IOTD on Astrobin - congrats.  It was a beauty so no surprise there.     What caught my attention was the 68 hours of integration.    I'm curious.   When you select a target to image, how do you determine how long you'll need to go?   Are you targeting a specific SNR?   I'm just interested in your planning process for non-comets.   

Thanks, Steve

PS: Had a chance to visit Tuscon and drive up Mt Lemmon a couple of weeks back.  What a beautiful spot (and snowy).

BlockHead

There isn't  particular time and there isn't a penalty for going "too long"...though there is a point at which there are not much gains in taking more exposures. I do not know exactly there this is... but I I know that at least 20 hours per filter is about right at a minimum. This nebulosity cannot even be seen in the calibrated images... you have to stretch the image quite a bit. So I am trying to minimize the noise floor enough that after stretching the starless image...there isn't something reasonable (and useable) there. 

-the Blockhead