Collecting  Photons

NGC 2392 "the Eskimo Nebula" (Gemini)

The inner ring surrounding the central star is about 19"x15". The outer shell is about 40". Canon 300d, C8 f 10, 28x20" , iso 1600.

NGC 2438 (Puppis)

A small ring (1.3') inside the open cluster M46. Canon 300d, C8 f 6.3, 34x4', iso 400 .

NGC 3587 - M97 "Owl nebula" (Ursa Mayor)

The star right under the left edge of the disk seems to has a tiny wisp of nebulosity: this is a background galaxy. On the large image there are 12 tiny galaxies identified by careful comparison with the Sloane Digital Survey. The limiting magnitude for the dimmest stars and galaxies on the picture is about 19.5. The central star in the nebula shines at mag 14. Size 150". Modified Canon 350d, C8 f 6.3, 13x8', hyperbolic sine stretch.

M 57 - NGC 6720  (Lyra)

Arguably the most famous planetary nebula of all. Size 3'x2.4'. Notice the barred galaxy IC 1296. Modified Canon 350d, C8 f 6.3, 24x4' + 18x8' exposures, iso 800. Very complicated processing. The brightest part of the nebula comes from the 12 best frames, stacked and passed through 5 iterations of RL deconvolution. This layer has been blended with a layer obtained by entire data set and passed through curves operations to extract the dimmer outer area of the ring and IC1296. A third layer was obtained by enhancing star colours with a hyperbolic Asin operator. The chroma information of this layer was blended in the image.

NGC 6826 "the blinking Nebula" (Cygnus)

Image displayed at twice the original resolution. Canon 300D and C8 at the f 6.3 focus.  Size 25", in average the star size (FWHM) was about 2". Stacking of 60x30" frames, iso 1600. Notice the two bright patches at the equator of the nebula. These are FLIER, regions of hot hydrogen expelled by the central star. They would look red if the 300D would not have a very low sensibility to Ha. The image is the 50% average of two different processing. One line has been digitally developed to bring out the entire extent of the nebula without too much bloating of the central star. Then it has been aggressively processed with a Richardson Lucy deconvolution algorithm (Iris, RL 30 1). The second processing has been optimized to bring out the nebulosity of the edges that has been further enhanced by application of the wavelet filtering of Registax. Final curves adjustment  and moderate unsharp masking in Photoshop.

M 27 - NGC 6853 "Dumbbell nebula" (Vulpecula)

At 8'x5' this is one of the largest planetary of all. The central star (mag 13.5) is a hot blue dwarf and one of the hottest star of all: over 85000 °K. Like most other planetary it shines in red (hydrogen) and blue (doubly ionized oxygen). Canon 300D at the f 6.3 focus of the C8. 22x8' exposures, iso 400.

M 27 - NGC 6853 "Dumbbell nebula" (Vulpecula)

A new picture one year later with the modified 350D. During the processing I decided to stetch less and to maintain a better appearance of the star field. The red channel has been low passed and overlayed with the original channel to enhance the red nebulosity without affecting the color balance of the stars. See here for details on this technique. 26x8' exposures, iso 800.

NGC 7009 "The Saturn Nebula" (Acquarius)

Canon 300D and C8 at the f 6.3 focus. Central star is about mag 12, the central oval is about 25"x17", the largest dimension is about 44".  60x30 s. Wavelet filters applied in Registax. Final curves adjustment in Photoshop.

NGC 7009 "The Helix Nebula" (Acquarius)

Modified 350D at the f 6.3 focus of the C8; This object is pretty low on my southern horizon which is heavily light-polluted: an IBAS filter was essential to keep the background in control. The largest planetary nebula.  44x8'. Pre-processing in Iris. Asinh stretch (asinh 0.003) followed by level and curves regulation in Photoshop. The red layer was passed through a moderate unsharp mask. Neat image.