Hoshitomo (星友)

The Pinwheel Galaxy (M101) is a galaxy in the constellation Ursa Major. Thanks to its size, brightness, and relative proximity to Earth, it can be observed with simple binoculars from locations with little light pollution. Its diameter is 252,000 light-years, about three times that of the Milky Way, and it is "only" 21 million light-years from Earth. It is located about 6 degrees east of one of the most famous binary stars in the northern sky, the Mizar-Alcor pair (ζ [zeta] UMa). It was discovered by Pierre Méchain in 1781 and subsequently observed by William Herschel in 1784. It was only in 1851 that Lord Rosse, with his 180-cm (72-inch) Newtonian reflector, described and sketched its spiral structure .

(credit: http://www.messier.seds.org/more/m101_rosse.html)

The stars contained within it are estimated to be on the order of a trillion. M101 also contains numerous regions of ionized hydrogen; a 1990 study identified as many as 1,264, some so large that they were discovered by Herschel in the 18th century and subsequently catalogued in the New General Catalogue (NGC) as NGC5447, NGC5461, and NGC5462.

The spiral's asymmetry is due to tidal forces interacting with nearby galaxies belonging to the same group (M101 Group), such as NGC5474 and NGC5477.

After the Eta Carinae Nebula, another image taken with the small Seestar during a March trip to Ishigaki Island, at 24 degrees north latitude under a fantastic Bortle 2 sky (the Bortle index indicates the degree of light pollution; lower values ​​indicate less light pollution) during the New Moon.

Scope: Seestar S30 in equatorial mode Aperture: 30 mm, focal length: 150 mm, f/5 Camera: ZWO ASI662 (embedded in Seestar S30) Exposure: 667 frames @ 30s (ZWO UV/IR cut filter, calibration frames performed automatically) Total integration time: 5h33m30s Software: N.I.N.A., PHD2, GraXpertAI, SetiAstro Cosmic Clarity, Siril

The Summer Beehive Cluster (IC 4665) is an open star cluster with fewer than 50 stars in the constellation Ophiuchus, imaged once again with the Seestar. In unpolluted skies, this cluster is faintly visible to the naked eye and can be easily observed with binoculars about one degree northeast of the star Cebalrai (β Oph). Discovered by the Swiss Philippe Loys de Chéseaux in 1746, it is estimated to be only 35 million years old and is approximately 1,200 light-years away. Scope: Seestar S30 in equatorial mode Aperture: 30 mm, focal length: 150 mm, f/5 Camera: ZWO ASI662 (embedded in Seestar S30) Exposure: 521 frames @ 30s (ZWO UV/IR cut filter, calibration frames performed automatically) Total integration time: 4h20m30s Software: N.I.N.A., PHD2, GraXpertAI, SetiAstro Cosmic Clarity, Siril

On the few clear evenings at the end of this unfortunate last winter, I photographed this strange pair with my little Seestar: the Surfboard Galaxy (M 108) and the Owl Planetary Nebula, in the constellation Ursa Major.

The two objects are located about two degrees east of the star Merak (β UMa), are completely different objects, and are only perspectively close:

The Surfboard Galaxy (M 108) is a galaxy located about 46 million light-years away and is part of the Ursa Major group of galaxies, a different group from the Milky Way's Local Group. It was discovered in 1781 by Pierre Méchain.

The Owl Planetary Nebula (M 97) is a much closer object, located within the Milky Way at a distance of "only" 2,030 light-years. It consists of gas expelled during the final stages of a giant star's life, and this star is currently evolving into a white dwarf with a mass approximately half that of our Sun, at magnitude +14, visible in the center when zoomed in. It was also discovered by Pierre Méchain in the same year.

With rather unreliable weather, clouds accumulating within minutes, and the risk of rain, using larger telescopes, with all the associated setup (the mount alone weighs more than 20 kilos), is impractical. Assembly and setup alone takes over an hour, and in case of rain, it's quite difficult to dismantle everything in a few minutes due to the complexity of the entire system: mount, telescope, guide scope, cables, computer, plus all the electrical connections—the real danger in case of rain. The Seestar is the ideal alternative in these cases, a small object weighing just 1.6 kg mounted on a photographic tripod. It literally takes 3 minutes to dismantle everything.

The Knife Edge Galaxy (NGC 5906) is a galaxy in the constellation Draco, about 47 million light-years away. This is the first image I've taken with my Celestron after over three months of absolutely horrible weather, during which I only managed to use Seestar for a few hours on a couple of occasions. By pure chance (because I was completely unaware of it), I photographed my second supernova in another galaxy, supernova SN2026kid, clearly visible in the lower part of the galaxy.

Scope: Celestron Nexstar 6SE on Celestron AVX mount Lens: Celestron 0.63 focal reducer Aperture: 150 mm, focal length: 1069 mm, f/7.1 Camera: ZWO ASI294MC Pro Guidescope: SVBony SV106, aperture 60mm, focal length: 240mm, f/4 Guide camera: ZWO ASI120mm mini Exposure: 240 frames @ 60s @ 0°C, gain 121 offset 5 + calibration frames (ZWO UV/IR cut filter) Total integration time: 4h Software: N.I.N.A., PHD2, GraXpertAI, SetiAstro Cosmic Clarity, Siril, Veralux suite

The Eta Carinae Nebula (NGC 3372) is an emission nebula in the southern hemisphere, in the constellation of Carina, west of the Centaurus and Southern Cross constellations. It was recently imaged from a location at 24° north latitude with the Seestar S30. The image was quite challenging, as at that latitude it reaches a maximum altitude of only 5 degrees above the horizon, so it was necessary to carefully choose a south-facing, unobstructed hill overlooking the sea. A panoramic viewpoint (which was also very crowded) served the purpose. The nebula, however, is extremely bright, 16 times brighter than the Great Orion Nebula, and therefore can be photographed even in these unfavorable conditions.

Although in ancient times the nebula, like the Southern Cross, was visible at mid-northern latitudes, due to the precession of the equinoxes, it gradually receded, becoming almost exclusively an object in the southern hemisphere. The nebula was first cataloged by Nicolas Louis de Lacaille during his stay in Cape Town in 1751. It is located 7,500 light-years from Earth and is one of the largest objects in the Milky Way, reaching 260 light-years in diameter. It hosts several star clusters, other substructures such as the Little Man Nebula and the Keyhole Nebula, and the star Eta Carinae, a binary star, one of whose components is a blue hypergiant 5 million times brighter than the Sun. Discovered in 1595, this blue hypergiant, due to its variable nature, is currently only visible with instruments, although it has experienced periods of much brighter brightness in recent times. In the photo it is located in the central part, slightly above.

Scope: Seestar S30 in equatorial mode Aperture: 30 mm, focal length: 150 mm, f/5 Camera: ZWO ASI662 (embedded in Seestar S30) Exposure: 183 frames @ 30s (ZWO LP filter, calibration frames performed automatically) Total integration time: 1h30m30s Software: N.I.N.A., PHD2, GraXpertAI, SetiAstro Cosmic Clarity, Siril (Veralux Hypermetric Stretch, Veralux Vectra, Syqon Starless Zenith plugins), Gimp

The Medusa Nebula (IC 443) is a supernova remnant in the constellation Gemini. It lies between the stars Tejat (μ Gem, to the left/east) and Propus (η Gem, to the right/west), visually very close to the latter but physically much further away. It originated from a star that exploded between 3,000 and 30,000 years ago, which later became the neutron star CXOU J061705.3+222127. Its distance is approximately 5,000 light-years from Earth and its visual dimensions are about 50 arc minutes in diameter, therefore it completely encloses the lunar disk. Given its visual dimensions and distance, a true diameter of approximately 70 light-years can be calculated. Scope: Svbony SV503 80 ED on Celestron AVX mount Camera: ZWO ASI294MC Pro Lens: Svbony 0.8 Focal Reducer / Field Flattener Aperture: 80 mm, focal length: 448 mm, f/5.6 Guidescope: Svbony SV106 Guidescope camera: ZWO ASI120MM 105 frames @ 300s @ -20°C, gain 121 offset 5 + calibration frames (Sightron Quad BP filter - III) 106 frames @ 180s @ -20°C, gain 121 offset 5 + calibration frames (Sightron Quad BP filter - III) Total integration time: 14h3m Software: N.I.N.A., PHD2, GraXpertAI, SetiAstro Cosmic Clarity, Siril (Veralux Hyperbolic Stretch, Vectra, Revela plug-ins), Starnet, Siril IC, Gimp

The Crab Nebula (M 1) is another of the most famous objects in the night sky, located in the constellation Taurus, about one degree northwest of the star Tianguan (ζ Tau). It is the remnant of a supernova observed and recorded by Arab, Chinese, Mayan, and Japanese astronomers in the year 1054. There are also accounts by Native Americans who likely witnessed the event and depicted it in a cave painting found in Penasco Blanco. Despite its distance of approximately 6,500 light-years, contemporary chronicles described the supernova as an exceptionally bright event, with a magnitude between -7 and -4.5, which exceeded the maximum brightness of Venus. Discovered in 1731 by John Bevis, the nebula was the first object cataloged by Charles Messier and included in his astronomical catalog, but it was not until 1939 that astronomer Nicholas Mayall demonstrated that the nebula was the result of the supernova of 1054. The gas cloud, with a magnitude of 8.3, currently has a diameter of 11 light-years and is still expanding at a speed of 1,500 km/s, and the expansion is visible when comparing images taken over several years. At its center, it houses the remains of the exploded star, a pulsar approximately 30 km in diameter, NP 0532, discovered in 1968 by the Arecibo Observatory. It rotates 30.2 times per second and is a source of gamma rays, X-rays, and radio waves.

Scope: Celestron Nexstar 6SE on Celestron AVX mount Lens: Celestron 0.63 focal reducer Aperture: 150 mm, focal length: 1069 mm, f/7.1 Camera: ZWO ASI294MC Pro Focuser: Gemini focuser Guidescope: SVBony SV106, aperture 60mm, focal length: 240mm, f/4 Guide camera: ZWO ASI120mm mini Exposure: 90 frames @ 180s @ -20°C, gain 121 offset 5 + calibration frames (Sightron Quad BP filter - III) 117 frames @ 120s @ -20°C, gain 121 offset 5 + calibration frames (Sightron Quad BP filter - III) 220 frames @ 60s @ -20°C, gain 121 offset 5 + calibration frames (Sightron Quad BP filter - III) Total integration time: 12h4m Software: N.I.N.A., PHD2, GraXpertAI, SetiAstro Cosmic Clarity, Siril (Veralux Hypermetric Stretch, Aberration Remover plugins), Starnet, Siril IC, Gimp

Bortle 7/8

The Witch's Head Nebula (NGC 1909, IC 2118) is a reflection nebula in the constellation Eridanus. It is located at the eastern edge of the constellation, about 3 degrees west of Rigel (β Ori) and one degree south of Cursa (β Eri). It extends for about 3 degrees (6 lunar diameters), but only the northern portion is depicted here due to various obstructions that prevented me from capturing the remainder properly. It is a reflection nebula, whose dust and gas reflect the radiation of the aforementioned Rigel. It is a rather faint object (M=8.0) with little contrast with the background due to its height above the horizon and light pollution. It is located at a distance of about 900 light-years, and therefore, given the angular extension, it can be deduced that its length is about 50 light-years.

Scope: Svbony SV503 80 ED on Celestron AVX mount Camera: ZWO ASI294MC Pro Lens: Svbony 0.8 Focal Reducer / Field Flattener Aperture: 80 mm, focal length (FL): 448 mm, f/5.6 Guidescope: Svbony SV106 Guidescope camera: ZWO ASI120MM 291 frames @ 180s @ -20°C, gain 121 offset 5 + calibration frames (ZWO UV/IR cut filter) 98 frames @ 180s @ -15°C, gain 121 offset 5 + calibration frames (ZWO UV/IR cut filter) 214 frames @ 120s @ -20°C, gain 121 offset 5 + calibration frames (ZWO UV/IR cut filter) Total integration time: 26h35m Software: N.I.N.A., PHD2, GraXpertAI, SetiAstro Cosmic Clarity, Siril (Hypermetric Stretch, StarComposer plugins), Starnet, Siril IC, Gimp

Bortle 7/8

Happy New Year! The first photo of 2026 is the Soul Nebula (IC 1848), an emission nebula in the constellation Cassiopeia about 7600 light-years away from Earth.

Scope: Svbony SV503 80 ED on Celestron AVX mount Camera: ZWO ASI294MC Pro Lens: Svbony 0.8 Focal Reducer / Field Flattener Aperture: 80 mm, focal length (FL): 448 mm, f/5.6 Guidescope: Svbony SV106 Guidescope camera: ZWO ASI120MM 213 frames @ 180s @ -10°C, gain 121 offset 5 + calibration frames (Sightron Quad BP filter - III) 148 frames @ 180s @ -20°C, gain 121 offset 5 + calibration frames (Sightron Quad BP filter - III) Total integration time: 18h3m Software: N.I.N.A., PHD2, GraXpertAI, SetiAstro Cosmic Clarity, Siril (Veralux Alchemy, Hypermetric Stretch, StarComposer plugins), Starnet, Siril IC, Gimp

Bortle 7/8

"Oh my God, it's full of stars" (Commander David Bowman in Arthur C. Clarke's novel "2001: A Space Odyssey"). This is a wide-field photo of the Orion Molecular Cloud Complex that I've been trying hard to capture over the past two years, specifically Barnard's Ring (Sh 2-276) and the Lambda Orionis region (Sh 2-264) in the Orion constellation (see the photo noted in the first comment). In the lower right, you can see the famous rectangular shape of the Orion constellation and, within it, Orion's Belt. Dozens of other objects are also visible, including the Great Orion Nebula (M42), the Horsehead Nebula (B33-IC434), the Flame Nebula (NGC2024), the Rosette Nebula (NGC2237) on the left, part of the Cone Nebula/Christmas Tree Cluster (NGC2264), the Lower Nebula (Sh 2-261), the Monkey Head Nebula (NGC2175), and countless others. For this shot, I used a 42-year-old Olympus wide-angle lens, when I was just starting out in photography. Lens: Olympus Zuiko on Celestron AVX Mount Aperture: 10 mm, focal length: 28 mm, f/2.8 Camera: ZWO ASI294MC Pro Exposure: 130 frames @ 180s @ -20°C, gain 121 offset 5 + calibration frames (Sightron Quad BP filter - III) Total integration time: 6h30m Software: N.I.N.A., GraXpertAI, SetiAstro Cosmic Clarity, Siril (Veralux Hypermetric Stretch & HDR multiscale scripts), Starnet, Siril IC, ASTAP

One October evening, during a brief break in the cloud cover, I imaged the Flame Nebula and the Horsehead Nebula with the small Seestar. I finally managed to process the image I'm showing you.

The Horsehead Nebula (Barnard 33) is a dark nebula that overlaps with the emission nebula IC 434, creating the curious effect of a horse's head against a red background. The Flame Nebula NGC 2024, with its unmistakable appearance, is another emission nebula located to the left of the star Alnitak, the leftmost star in Orion's Belt, visible from Earth with the naked eye. Three reflection nebulae are also visible in the image: NGC 2023 to the left of the horsehead and IC 431 and IC 432 at the top of the image. All these objects are located at a distance of about 1,500 light-years.

Scope: Seestar S30 in equatorial mode Aperture: 30 mm, focal length: 150 mm, f/5 Camera: ZWO ASI662 (embedded in Seestar S30) Exposure: 233 frames @ 60s (ZWO LP filter, calibration frames performed automatically) Total integration time: 3h53m Software: GraXpertAI, SetiAstro Cosmic Clarity, Siril, Starnet, Gimp, Rawtherapee

On two evenings in July, taking advantage of some clear skies, I photographed the Dumbbell Nebula in the constellation Vulpecula for a total of about four hours. The photo quality is not exceptional due to the not particularly clear sky.

The Dumbbell Nebula (M 27) is the first "planetary nebula" object ever discovered. It was first observed by Charles Messier in 1764. The term "planetary nebula", although retained for historical reasons, is misleading. The person who coined the name, William Herschel, thought they were clouds of gas around a star in the process of condensing to form new planets. Today we know that his assumption was incorrect. In reality, the object we see is the future of our Sun: a small dwarf star at its center and the expanding gas expelled by the star at the end of its life. The Dumbbell Nebula is located approximately 1,360 light-years from Earth and its greatest diameter is about one light-year: having also calculated its expansion rate, which is approximately 2.3 arc minutes per year, the age of the object was calculated, approximately 10,000 years.

Scope: Celestron Nexstar 6SE on Celestron AVX mount Lens: Celestron 0.63 focal reducer Aperture: 150 mm, focal length: 1069 mm, f/7.1 Camera: ZWO ASI294MC Pro Guidescope: SVBony SV106, aperture 60mm, focal length: 240mm, f/4 Guide camera: ZWO ASI120mm mini Exposure: 91 frames @ 120s @ 0°C, gain 121 offset 5 + calibration frames (ZWO UV/IR cut filter) 60 frames @ 60s @ 0°C, gain 121 offset 5 + calibration frames (ZWO UV/IR cut filter) Total integration time: 4h2m Software: N.I.N.A., PHD2, GraXpertAI, SetiAstro Cosmic Clarity, Siril, Starnet, Siril IC, Gimp

Bortle 7/8

The night of September 23rd was one of the best summer nights I've ever seen here. Even late at night, many stars and constellations were visible, despite the light pollution. I had already started photographing this object, but this night and the next one, which was good, though not at the same level, made a significant contribution to the sharpness.

The object you see is the Elephant's Trunk Nebula (IC 1396 A), in the constellation Cepheus, and is part of a larger structure, IC 1396, an emission nebula. Discovered by astronomer Max Wolf in 1893, it is 2,400 light-years from Earth, and the portion shown in the photo alone extends about 10 light-years long and 1.5 light-years wide. The dark zones are due to a dark nebula (vdB 142), consisting of dense interstellar dust and gas that obstruct the view of what lies on the opposite sides. The entire area hosts numerous very young stars, a few million years old or even less than 100,000 years old (our Sun is 4.7 billion years old).

Scope: Celestron Nexstar 6SE on Celestron AVX mount Lens: Celestron 0.63 focal reducer Aperture: 150 mm, focal length: 1069 mm, f/7.1 Camera: ZWO ASI294MC Pro Guidescope: SVBony SV106, aperture 60mm, focal length: 240mm, f/4 Guide camera: ZWO ASI120mm mini EAF Gemini Exposure: 107 frames @ 120s @ 0°C, gain 121 offset 5 + calibration frames (Sightron Quad BP filter - III) 185 frames @ 120s @ -10°C, gain 121 offset 5 + calibration frames (Sightron Quad BP filter - III)

Total integration time: 9h44m Software: N.I.N.A., PHD2, GraXpertAI, SetiAstro Cosmic Clarity, Siril, Starnet, Siril IC, Gimp

Sometimes the weather turns unexpectedly clear one evening, despite the weather forecast. It takes over an hour to get the telescope out, assemble everything, and set it up for shooting, so what do you do? You use the little Seestar S30, which is ready to shoot in a quarter of an hour at most.

The Bubble Nebula (NGC7635, C11) is an emission nebula in the constellation Cassiopeia, 11,000 light-years away, discovered by William Herschel in 1787. The star at its center is a powerful blue giant, SAO 20575, which expels a stellar wind at a staggering 6.5 million km/h. This powerful stellar wind sweeps up the interstellar gas in its path and, like a giant snowplow, pushes it to form the bubble we see, about ten light-years across.

Scope: Seestar S30 in equatorial mode Aperture: 30 mm, focal length: 150 mm, f/5 Camera: ZWO ASI662 (embedded in Seestar S30) Exposure: 152 frames @ 60s (ZWO LP filter, calibration frames performed automatically) Total integration time: 2h32m Software: N.I.N.A., PHD2, GraXpertAI, SetiAstro Cosmic Clarity, Siril, Starnet, Siril IC, Gimp

A month ago, I posted a close-up image of the Cocoon Nebula (IC 5146) in the constellation Cygnus. This time, I'm showing the same object, but in a wider field of view to show the uniqueness of its surroundings. No, there's no tear in space! It's the Barnard Nebula 168, a dark nebula, an object similar in nature to the "Horsehead" Nebula in Orion. It absorbs the light passing through it, obscuring the stars behind it, leaving this strange, hollow image in the rich star field.

Scope: Svbony SV503 80 ED on Celestron AVX mount Camera: ZWO ASI294MC Pro Lens: Svbony 0.8 Focal Reducer / Field Flattener Aperture: 80 mm, focal length (FL): 448 mm, f/5.6 Guidescope: Svbony SV106 Guidescope camera: ZWO ASI120MM 100 frames @ 180s @ 0°C, gain 121 offset 5 + calibration frames (ZWO UV/IR cut filter) 93 frames @ 180s @ 0°C, gain 121 offset 5 + calibration frames (Sightron Quad BP filter - III) Total integration time: 9h39m Software: N.I.N.A., PHD2, GraXpertAI, SetiAstro Cosmic Clarity, Siril, Starnet, Siril IC, Rawtherapee

My little Seestar S30 is an extremely portable smart telescope. It's the size of half a sheet of A4 paper and 8cm deep, weighs only 1.65kg, and yet it's capable of producing remarkable images. This is the Sun yesterday, September 2nd, at 12:19 JST (03:19 UT). Sunspots and intense surface activity are clearly visible. This image was taken with a special filter. NEVER point any optical equipment, telescope, binoculars, camera, etc., at the Sun without adequate, certified protection, and NEVER, under any circumstances, look into the eyepieces, viewfinders, etc. with your own eyes. This risks immediate permanent blindness.

On two very clear evenings, I managed to photograph the Cocoon Nebula (IC 5146, C 19), an emission and reflection nebula in the constellation Cygnus. It is a star-forming region about 15 light-years across, located about 4,000 light-years away. To the right of the Cocoon Nebula, the small reflection nebula vdB 147 can also be seen.

Scope: Celestron Nexstar 6SE on Celestron AVX mount Lens: Celestron 0.63 focal reducer Aperture: 150 mm, focal length: 1069 mm, f/7.1 Camera: ZWO ASI294MC Pro Guidescope: SVBony SV106, aperture 60mm, focal length: 240mm, f/4 Guide camera: ZWO ASI120mm mini EAF: Gemini Exposure: 255 frames @ 120s @ 0°C, gain 121 offset 5 + calibration frames (Sightron Quad BP filter - III) Total integration time: 10h8m Software: N.I.N.A., PHD2, GraXpertAI, SetiAstro Cosmic Clarity, Siril, Starnet, Siril IC, Gimp

Bortle 7/8