M16 - Eagle Nebula - Serpens

Object Data: M16 (NGC 6611), the Eagle Nebula is both an open star cluster and a large bright area of emission nebulosity. It is located in the south east corner of Serpens Cauda, close to the Scutum boundary. Within M16 are several complex star forming regions, the most noteworthy of which is variously referred to as the "Star Queen and her Throne" or the "Towering Pillars" (made famous by the HST image). Towards the centre in this photograph, it is a giant structure more than 6 light years from end to end. Another giant star forming region is the "elephant trunk" structure to the north east. M16 is about 7,000 light years distant and was probably first observed by the Swiss astronomer P.L. de Cheseaux in 1746. It was catalogued by Charles Messier in June 1764, who was also the first person to note the nebulosity surrounding the star cluster.

Date: 15/06/02
Location: Southern France
Conditions: calm, transparency=8, seeing=9 (zero Jetstream)
Optics: RCOS Ritchey-Chretien 12.5" f/9 working at f/6.7 with AP x.75 focal reducer
Mount: AP 900 GTO on Portable Pier
Camera: SBIG ST-8E / CFW-8
Guiding: Integral ST-8E autoguider
Exposure: High resolution R/RGB (no binning): 40/40:40:60 minutes

Processing: Image acquisition, calibration, combining, and DDP were applied using Maxim DL. Deconvolution was applied using AIP. Registration of Luminance and RGB images done using Registar, with and final image adjustments applied in Photoshop.

Notes: You may also see my later wide field image of M16 here.
This was an R/RGB more through necessity than choice (causing the image to appear a more monochromatic red than it should be). Explanation: I already had a full high resolution RGB set of M16 from the night of the 13th June, however the seeing was rather poor. Subsequently the night of the 15th June had excellent seeing and my preference would have been to re-image the entire RGB sequence, however there was time for only one such image, so I chose to re-image the Red frame and use it for the luminance. Although a compromise, this resulted in a far better image overall than using the RGB set from the night of the 13th. Note that broadband (unfiltered) luminance images could not be used owing to the problem of Spectral Dispersion at Low Elevation.





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