47 Tuc

lazjen (Chris) · #1 08-09-2013, 11:30 AM

47 Tuc peaked over my house in the early hours of this morning, so I grabbed a few shots before packing up for the night.

I'm still a bit unsure how to really image globular clusters well. This image was a stack of 10 sec exposures (800 and 1600), but I have the feeling I should have gone for 15 sec (or more?) instead. I find it easy for the cluster to be wiped by light pollution or become a bright mess.

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cometcatcher (Kevin) · #2 08-09-2013, 11:54 AM

Bright globulars are tricky because as you realise the core can burn out to white if exposed for too long.

Wind your ISO back to 400 and expose just long enough before core burnout. Take as many subs as possible. When processing, only stretch the midtone levels, not the highlights.

lazjen (Chris) · #3 08-09-2013, 11:58 AM

Thanks, that will help. I'll try ISO 400 next time and experiment with the times to find a sweet spot. I'm guessing it will be around 20 to 30 sec.