Deminishing returns.....

Started 3 months ago | Discussions thread
Alen K Senior Member • Posts: 1,123
Re: Deminishing returns.....

Kemo-sabe wrote:

I am using Clarke's methodology of in camera dark frame extraction for the subs. Using Clarke's Methodology the subs actually take 10 minutes to shoot per sub. I use Sequator and/or DSS for stacking.

Wow, 32+ hours taking exposures? I give you high marks for effort but IMO you needlessly wasted at least half of that time. I would not recommend in-camera dark-frame subtraction (AKA Long-Exposure Noise Reduction or LENR) for anything but single exposures (think nightscape) or very short stacks. There are more efficient methods. And where on Roger Clark's website does he advocate using LENR? I must have missed that.

Now, maybe you have no choice but to shoot in Bortle 9 but personally I would shoot from darker skies. Heck, I live in Bortle 7 but get Bortle 4 by driving less than an hour. It's a no brainer. Use of a dual-band filter is obviously going to help in badly light-polluted skies but it's not a panacea. For one thing, it's only going to be good for emission nebulae.

As an example, here is 12 minutes at f/5.6 from Bortle 4.
https://www.cloudynights.com/gallery/image/83577-an-early-season-m42/
No dark frames. In fact, no calibration frames at all. And no filter. Yeah, it's noisy as heck but it IS only 12 minutes. Imagine what an hour would have given me.

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