Rosliston Astronomy Group


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DSOs and displays

Roger Samworth



Finally got a (relatively) clear moonless night to do some DSO imaging, although it involved a degree of cloud-dodging.

1st image is NGC 7023 / C4 in Cepheus. This is a reflection nebula. You can see a fair amount of detail in the centre, and if you look hard you can see (some of) the outer halo.

No. 2 is NGC 404 and Mirach in Andromeda. This is known a "Mirach's ghost" as it is so close to the star. It is supposed to be quite difficult to see because of the glare from the star, but it seemed clear enough to me.

I then went hunting galaxy groups in Pegasus

No 3 is the NGC 7769/7770/7771 group. I was quite surprised to see this as the magnitudes of the brightest two are 12.9 and 14.4.

Encouraged by this I went searching for Stephan's quintet and :

No.4 is the quintet. Not entirely a successful image due to haze, and probably not as good as last year's. However, Stephan's quintet is one of those things that is gratifying just to see!

No 5 is NGC 7814 / C43. Nice edge-on galaxy with a nice dust lane.

No. 6 is NGC 7479 / C44. Interesting barred spiral.


I have noticed a peculiar effect that seems particularly prevalent with DSO images on an essentially black background. The quality of the image seems to strongly depend on what display you look at the image on. I usually process my images using a stand-alone desk-top 17" flat screen display, for which they are optimised. Displaying the images on a tablet or lap-top totally alters the quality of the image. The images I posted yesterday for example, look awful on the lap-top, but fine on the desk-top.

Anyway, you will notice that there are two versions of each of the above images, with difference processing including processing for (my) lap-top display.

See what you think.

The effect isn't anything like as marked for non-DSO images such as the Sun.


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