NGC206- Astronomy and astrophotography CCD camera images

20th Nov 2005
Object name: NGC206
Object type: Extragalactic Open Cluster
Size: 4.2 0
Classification: GxyP
Apparent RA: 00 40 32.3 Apparent Dec: +40 44 18
Constellation: Andromeda

Another visit to one of my favourite DSOs. NGC 206 is a vast starcloud in the M31 galaxy. This is the first time I have produced an RGB colour image of this region. I am pleased with this result - slightly better i think than my previous effort (scroll down), but hard to tell. I autoguided this image with a 400mm refractor using a BW SC1 toucam and k3ccdtools as a test of guiding at short focal lengths. I have been quite gentle with the colour. I noticed that if I pushed the saturation to far, the left hand galactic clouds became tinged with red colour and the right hand clouds went green. Not sure whats happening there. Also not sure whats going on with the blue around the bright stars in the bottom right... I think it might have been dew or mist on the blue filter.

Whichever colour balance I tried, the stars of the cluster came out quite blue, which makes sense if they are young hot stars.

I have also made an animated GIF showing the zoomed region of the cluster. This clearly shows the improvement from the previous image... this is probably due to better seeing tonight. The improvement may also be due to better collimation... but I do not remember how good the collimation was on the previous image. If it is due to collimation, then this sends a strong message on the importance of collimation on DSO targets.

Such an animation can also be used to spot variable stars in the cluster... however, it is hard to say if any are indeed variable because of the difference in sharpness.

I also note that the globular cluster, G52, which is identified on this page and in this image shows up as yellow-orange, as you would expect for a globular cluster - these objects usually contain old yellow stars.

The noise in the colour layer does show through in the final image. It is difficult to create a convincing RGB image with an SC3 which does not have the capacity for binning.

Captured in k3ccdtools with BW SC3 toucam webcam. Guided with k3ccdtools. Each of the 4 avis stacked in registax and exported FIT32. Coregistered and colour scaled in IRIS. Colour layer exported from iris as psd. L layer fits and colour layer combined in photoshop. Curves on L and colour layers. 50% with darken faded minimum filter on highlights of L layer. Multiple LLRGB layering to produce final image.

Exposure Details :

60x45s on 200mm @ F5 with SC3.5
Blue 7x60s on 200mm @ F5 with SC3.5
Green 7x60s on 200mm @ F5 with SC3.5
Red 7x60s on 200mm @ F5 with SC3.5

Curdridge Observatory, Southampton,UK