What is possible in 3 seconds?

Exposing for 3 seconds is very short if we’re talking astrophotography. We are used to exposures of at least a couple of minutes, so what could we possible image with 3 seconds exposures? Well, actually quite a lot!

Why use 3 second exposures?
Shooting at 200mm with my Nikkor 80-200mm F2.8 lens, the longest exposure you can use when using a static tripod is 3 seconds before the stars will turn to elongated and start to become trails. So this is something everyone can do that owns a DSLR for daytime usage with standard gear.
I decided to do some experimentation and see what we can capture when using 3 second exposures, but a lot of them. Processing was a lot of work, since I couldn’t get PixInsight to recognize and register the frames so I couldn’t stack ‘automatically’. Instead I used Nebulosity to register the images by hand by picking the same 2 stars in every frame. And I used over 150 frames per image, so that was quite some clicking to do……
I must say I was quite happily surprised by the results!

All images are taken with the unmodified Nikon D7000 and the Nikkor 80-200mm F2.8 at 200mm F2.8, ISO1600
3 seconds of Andromeda
Andromeda, 153 x 3sec. ISO1600

M33 3seconds
M33, 198 x 3sec. This one is a crop from the original image

Pleiades 3 seconds
The Pleiades, 153 x 3sec.

Double cluster
Double Cluster, 87 x 3sec.

M42 3 seconds
M42 Orion Nebula, 33 x 3sec.

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