M103, NGC581  an open clusterHome

M103 in Cassiopeia, is the last entry put into his catalogue by Messier himself.  He did so on a report by Pièrre Méchin in 1781.  It is estimated to be 25 million years old and about 8,000 light-years away.  It contains at least 127 stars but the brightest star, Struve 131 a double star of magnitude 10 (at the top of the cluster in my image), is not part of the group.  It contains a giant red star of magnitude 10.8 which can be identified in my colour image below.  It subtends 6 arc-minutes in the sky which corresponds to a diameter of 15 light-years.  It is approaching us at 37 Km/sec.

This wide-angle view was obtained with my ETX125 fitted with a 0.33 focal reducer and my Starlight Xpress MX716 camera.

Date and Time: 18th January 2011 21:17 UT
Camera: MX716
Telescope: ETX125 with 0.33 focal reducer and Astronomik CLS filter
Capture: Star_mx7_usb. 25 frames, 20" exposure
Pre-processing: Star_mx7_usb, dark-frame and background subtraction, non-linear stretch (factor 25).
Processing: RegiStax. 25 frames stacked, wavelets 1-2 = 5.
Post-processing: PhotoImpact. Reduction to 85%.
This picture was taken using the same optics as above but with my DFK colour camera which has a smaller CCD chip so that the scale appears larger.  The red-giant star is clearly shown as red.  I have increased the colour-saturation of the image to 100% to make this more obvious, but you can see the original image, if you wish, by moving your cursor over the image.

Date and Time: 18th January 2011 21:46 UT
Camera: DFK 21AF04.AS
Telescope: ETX125 with 0.33 focal reducer
Capture: ICCapture. 25 frames, 8" exposure
Processing: RegiStax. 25 frames stacked, wavelets 1-2 = 5, gamma 0.6.
Post-processing: PhotoImpact. Colour saturation 100%.
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