"The Sprinter", aka star cluster NGC 2516. This pretty group of stars can be easily seen by the naked eye as a misty/sparkly patch near the southern tip of the False Cross (made from the stars of Vela and Carina). While it appears to span almost two moon diameters in size, this cluster lies 1,300 light-years away in space.
This image was taken on the morning of the 4th of January at 2am, with a nearly full-moon still in the sky. It is made from a stack of 60 15-second exposures at ISO800 with a Nikon D5100 and IDAS filter on a 6" F/5 Newtonian telescope. This stack images was combined in Deep-Sky Stacker with flat and bias corrective images and then post-processed in Adobe Photoshop.
Very pretty, as Kevin said, but unless my old eyes deceive me, your
tracking seems to be a bit off, which is unusual for such short subs.
raymo
Are you sure it's not coma that you're seeing Raymo? The star elongate away from the centre of the image. That's what you get for using a parabolic mirror with no corrector.
The radial coma pattern far out from the centre of the image is quite obvious, but if you mag your screen to 175% or so, you will see that all the stars at, near, or even fairly near, the centre of the image, are elongated top to bottom of the screen, with very little sign of leaning left or right which coma would do. I must have another look to make sure I'm not
talking bulldust, my old eyes struggle a bit these days. Had another look, and even the stars at the centre of the image are
elongated; from memory, my f/5 gives round stars about a 1/4 to 1/3 of the way out from the centre.
raymo
Last edited by raymo; 06-01-2015 at 01:50 PM.
Reason: more text
You can see the elongation without magnifying the image, so not
enlarging it wouldn't help Kevin. I've had a look at a single frame
of mine of The Sprinter that I took with my 8" f/5, and the stars around the centre are still round at 175%. I'm not engaging in gratuitous criticism; I always welcome comments on my output, good or bad.
I did think that it could have been caused by wind, but the outer stars
are not elongated in the appropriate direction. It's actually getting a bit odd, because the outer stars are only elongated in the direction dictated by coma. So, if the outer stars show no sign of tracking error, why are the central stars not round?
raymo
