The Bubble Nebula, designated NGC 7635, is a stunning celestial wonder located in the constellation Cassiopeia. This breathtaking emission nebula is a region of active star formation, where massive stars at the center emit intense ultraviolet radiation, causing the surrounding gas to glow brilliantly. What makes the Bubble Nebula particularly captivating is its spherical, bubble-like structure, created by the powerful stellar winds and radiation from a central massive star known as BD+60°2522. This stellar wind compresses the surrounding interstellar material, sculpting the gas and dust into a shell-like form. The Bubble Nebula is a visual testament to the dynamic interplay between massive stars and the cosmos, offering astronomers a glimpse into the ongoing birth and evolution of stars in our Milky Way galaxy.

Within the cosmic embrace of M81 and M82, an intergalactic medium of dust particles permeates the space, creating an intriguing interplay of scientific phenomena and aesthetic allure. Delicate tendrils of dust meander throughout the vast expanse, influenced by gravitational forces and stellar activity. These cosmic particles, comprised of micron-sized grains, play a pivotal role in the evolution of galaxies. They act as catalysts for star formation, providing the necessary material for the birth of new stellar systems. As they navigate the intergalactic void, these interstellar dust clouds contribute to the complex dynamics of M81 and M82, shaping their morphologies and influencing their ongoing stellar processes.

Image Description and Details :

The fantastic Coma Cluster (Abell 56) located 330 millions light-years away in Coma Berenice contains over 1000 identified galaxies. Along with the Leo Cluster (Abell 1367), it is one of the two major clusters comprising the Coma Supercluster.The central region is dominated by two supergiant elliptical galaxies : NGC4874 and NGC4889, and as is usual for clusters of this richness, the galaxies are overwhelmingly elliptical, with only a few spirals of younger age near the outskirts of the cluster.I wanted to capture this object for a long time and I'm glad I could do it from my downtown Bortle 6-7 sky.Newton 250mm f/4 on IOPTRON CEM70 mountCamera ZWO ASI2600mm + Antlia LRGB filters23h50 exposures in February and March 2022 from my backyard.L : 232 x 300sRGB : each 18x300sProcessed with Pixinsight and Photoshop

Copyright: Mathieu Guinot

Image Description and Details : 3 astrophotographers' collaboration on M27 :

Halpha and Oiii long exposures with Newton 10" and ASI2600mm : 224 x 300s by Mathieu Guinot
Halpha and Oiii long exposures with RC16" and ASI2600mm : 200x300s by Sebastien Kuenlin
RVB long exposures with Newton 10" and ASI2600mm : 90x120s by Mathieu Guinot
Halpha lucky imaging with Newton 12"and Playerone Neptune color II : 5000x2.5s by Stephane Gonzalez
IR - RVB lucky imaging with Newton 12"and Playerone Neptune color II : 40000x500ms by Stephane Gonzalez

The processing of the M27 nebula always presents a certain difficulty and forces choices because of the great difference in luminosity between the core and the extensions on the one hand, and the strong presence of Halpha and Oiii signals on identical zones on the other hand.
These artistic choices have been made with maximum respect for the scientific coherence of the object, although this is not 100% possible: indeed, one obtains a saturated core if one wants to take advantage of the signal on the most distant extensions, or one does not distinguish these if one wants to maintain an unsaturated core. It is therefore necessary to use HDR processing as sparingly as possible, which inevitably alters the object's dynamic range but allows a compromise to highlight the different signals making up the nebula.

In the end we are very happy to present the fruit of this work with the objectives fulfilled:

- to enjoy the details of the short exposures
- to take advantage of the extensions of the long exposures
- to ensure coherence between the levels of detail thanks to the intermediate image taken in long exposure at long focal length
- keep the dynamics of the object as "real" as possible
- not to perceive any artefact or transition linked to the mixing of the three images


Sébastien, Stéphane and Mathieu, November 2021

Copyright: Stephane Gonzalez, Sébastien Kuenlin and Mathieu Guinot

Image Description and Details :

NGC 7129 open cluster, at about 3000 light-years in Cepheus, associated with LBN 497 reflection nebula.Integration : 26 hours in Amiens City (France) RC8 Altair Astro scopeAvalon Linear MountQHY163mm + Astrodon filtersL : 110x300s + 155x120sRVB : 15x300s eachHalpha 5nm : 94x300sFocal length : 1600mmScale : 0.49"/pixelBortle 62.2<FWHM<2.8Acquisitions Prism V10Processing Pixinsight, Photoshop

Copyright Information: Mathieu Guinot

Image Description and Details :

The Cat Eye Nebula, NGC 6543, is a mythical object from the deep sky of the Northern Hemisphere.

It is a Planetary Nebula (expanding gas shell ejected from an end-of-life star) in the constellation of the Dragon, whose age is estimated at only 1,000 years and the distance at "only" 5,200 light years . (our galaxy has a span of 100,000 light years).

The star in the white dwarf stage is clearly visible in the center of the nebula, the central part of which has a diameter of only 20 arc seconds, which is tiny, one of the reasons why it is relatively little imagined.

The sampling used here made it possible to resolve this core of the nebula by spreading it over approximately 40 pixels of the image and thus to distinguish some details there, which was made possible by the use of one of the telescope Ritchey Chretien 500mm f / 8 from the Astroqueyras observatory in the Hautes Alpes with a focal length of 4000mm.

The outer halo of the nebula, ejected by the star when it was in the red giant stage, extends for its part over nearly 6 minutes of arc, but is much more tenuous than the central part.
It was therefore necessary to mix short exposures on the heart and long exposures on the external halo and the rest of the image and then perform HDR processing.

The galaxy of the "barred spiral" type NGC 6552 visible to the right of the cat's eye also shows us some pretty details despite its dizzying distance of around 360 million light years!

For acquisition data:

- 10 exposures of 1mn in Luminance bin 1 on the heart
- 28 exposures of 2mn in Luminance bin2 on the rest
- 15 poses of 1mn in R, G and B bin1 on the heart
- 12 poses of 2mn in R, G and B bin2 on the rest

A total of only 3 hours of exposure to acquire all of this data at the Pic de Chateau Renard observatory, Alps, France with an RC 500 f / 8 telescope on an AP1600 mount + Apogee 16000 camera

Scale 0.5"
Seeing 1.5"
Bortle 1
1.5<FWHM<1.7

Pixinsight and Photoshop 2020 processing (never managed before to obtain a version which satisfies me).

Copyright Information: Mathieu Guinot

The Flame Nebula, designated as NGC 2024 and Sh2-277, is an emission nebula in the constellation Orion. It is about 900 to 1,500 light-years away.

Much of the glow results when the electrons and ionized hydrogen recombine. Additional dark gas and dust lies in front of the bright part of the nebula and this is what causes the dark network that appears in the center of the glowing gas.
Taken with the Astroqueyras RC500 and Apogee Alta U16000