The River and the Whale

 The neighboring constellations Eridanus (The River) and Cetus (The Whale) cross the southern meridian during late night in mid-October.  Between the two of them they contain four of the nearest star systems and two of the nearest naked-eye stars: magnitude-3.7 Epsilon Eridani (Ran) and magnitude-3.5 Tau Ceti.  These two stars are circled in the image below, Epsilon Eridani on the left, Tau Ceti on the right.

E-M1iii + Leica 15mm f/1.7 + softon filter.

Epsilon Eridani, aka "Ran",  is 10.5 ly distant, the third closest naked-eye star (after Alpha Centauri and Sirius), and the 9th closest star system overall.  Tau Ceti is 11.9 ly distant and is the 9th closest naked-eye star and the 19th closest star system.  

Epsilon Eridani has one known planet and two asteroid belts. Tau Ceti has two confirmed planets and possibly an additional six that are suspected.  Both of these stars are slightly smaller than our sun at about 80% of the sun's mass.

The finder chart below shows both naked-eye stars and two nearby red-dwarf stars: UV Ceti and YZ Ceti, which are the 6th and 21st closest star systems, respectively. These two stars are too faint to show up in the image above, but were discussed in a previous post here.

credit: SkySafariAstronomy.com

 

Open Clusters in Auriga

 The constellation Auriga contains three open clusters cataloged by Charles Messier: M36, M37, and M38.  

Auriga and star clusters

M36.  E-P5 + Rokinon 135mm f/2. ISO 1600, 60 s.

M37.  E-P5 + Rokinon 135mm f/2. ISO 1600, 60 s.

M38 + NGC 1907 (below).  E-P5 + Rokinon 135mm f/2.  ISO 1600, 60 s.

All of these clusters are 4000+ light years distant.  The region including M36 and M38 is shown here in a 4° view:

Orion Ascending, and more bumps in the night

 

E-M1iii + Sigma 30mm f/1.4 + softon filter, ISO 1600, 60 s.

The yellowish (in this image) star to the bottom left is Betelgeuse, a red supergiant star and future supernova that is the 9th brightest star.  At the right edge is Rigel, the brightest star in the constellation Orion, and the 7th brightest star.  At the top is Aldebaran, the 13th brightest star.

 

Constellation Auriga.  E-M1iii + Sigma 30mm f/1.4 + softon filter.

This shot of the constellation Auriga is much different than my previous attempt, when the sky was red with auroral glow.  In the upper left quadrant is Capella, the 6th brightest star.

When I stepped outside to set up for these shots I heard some noises off to my left.  The high-intensity setting on my headlamp revealed a constellation of glowing eyes.  There was a herd of deer hanging out behind the shed just 30 ft away.  They were just as confused and surprised as I was and couldn't decide which way to flee, or if that was even necessary.

I was outside an hour later for some follow-up shots, but the sky had clouded over and the deer had moved on.

Auroral Glow and Nearby Galaxies

 I was out in the early evening to take a few quick constellation photos.  The sky brightness was once again rather poor (sqml=21.15) for this area.  The previous night I had measured sqml=21.25 and could see the familiar green tint of airglow in the out-of-camera images.  Here is one of the first images I shot last night, after processing:

Olympus E-M1iii + Sigma 30mm f/1.4 + softon filter.

There are two galaxies in this image marked by white circles: the famous Andromeda Galaxy (M31), at the top, and the Triangulum Galaxy (M33), near the middle.  Triangulum is the constellation name associated with the three stars that form a narrow triangle in the lower middle of the image

The red glow in the bottom left of the image bothered me.  I thought perhaps I had left my headlamp on during the exposure, or there was glow from the cabin lights behind me.  I went out to reshoot the image a half hour later with this region higher in the sky.  I also added a shot of the constellation Auriga rising over the northern ridgeline.  That shot was a big surprise:

E-M1iii + Sigma 30mm f/1.4 + softon filter.  ISO 1600, 60 s.

The earth was recently hit by a CME (Coronal Mass Ejection) from the sun causing auroral displays in the north.  Although it was not obvious to the naked eye, that pink auroral glow has extended down into southern Colorado and shows up intensely in photographs. 

 My original purpose for being out last night was to get a wide-angle shot showing the relative locations of the Andromeda Galaxy (M31) and the Triangulum Galaxy (M33). The Triangulum Galaxy is the third largest galaxy in our Local Group (after M31 and our galaxy).  It is 2.8 million ly distant and is just visible to the naked eye in a sufficiently dark sky (not the case last night) if you have good eyes (not me).  If you do manage to see it you will be gazing at the most distant object possible to see without optical aid.  The Andromeda Galaxy is a bit closer at 2.5 million ly distant and is much brighter and easier to locate in a dark sky.

Triangulum Galaxy.  E-P5 + Rokinon 135mm f/2.  ISO 1600, 60 s.

 

Some Early-Morning Showpieces

 While hunting nearby stars in the pre-dawn hours on Oct 25, it was hard to resist pointing the camera at some well-known showpiece objects.

Horse-head nebula

Messier 35 + NGC 2158

Messier 41

Messier 42+43 (and satellite tracks)

Messier 46 (left) + Messier 47 (right)

All images are with an Olympus E-P5 + Rokinon 135mm f/2 lens, ISO 1600, 60 s exposure.  Cropped to 2° field of view.  There was some strong green airglow on this morning (sqml=21.25), so the stars take on a more reddish hue than normal after compensating for the green background.

Messier-catalog objects are usually abbreviated as M41, M42, ..., etc.  The Horse-Head Nebula (Barnard 33) is a dark nebula silhouetted against the glow of the emission nebula IC434.  It sits just below the bright star Alnitak at the end of Orion's belt.  The Horse Head, along with the Orion Nebula (M41), the Andromeda Galaxy (M31) and the Pleiades (M45), is one of the most photographed objects in the sky.  And, why not?  These are all iconic celestial sights and everyone wants their own personal memento.

Messier 35 is an open cluster in the constellation Gemini, about 3000 ly distant.  The fuzzy blob to the right and below M35 is another open cluster, NGC 2158.  This cluster is much farther away, about 16,500 ly.

Messier 41 is an open cluster in the constellation Canis Major, about 4° below Sirius. In a dark sky it is visible to the naked eye and was possibly recorded by Aristotle in 325 BC.  It is about 2300 ly distant.

Messier 42, otherwise known as the Orion Nebula, is the bright naked-eye nebula in the Orion's Sword asterism.  It is one of the nearest star-forming regions to our solar system at a distance of about 1400 ly.  M43 is the smaller comma-shaped blob detached just above the main nebula.

Messier 46 and Messier 47 are open clusters in the constellation Puppis.  M46 is about 4900 ly distant and M47 is much closer at 1600 ly.  There is a planetary nebula (NGC 2438) in the same line of sight as M46, visible as a small bluish blob in the image above.  This nebula is a foreground object and not part of the cluster.

Two nearby stars and two star clusters

 In an hour before dawn on Oct 26 I was able to image two more nearby stars and two star clusters.  These are all winter objects, but viewing them now in the early morning has the advantage of fall temperatures (balmy 26° F on that morning) rather than the bitter cold of winter.  The two stars are Lalande 21185 and Ross 128, and the two star clusters are M44 and M67.

Here is a finder chart:

credit: SkySafariAstronomy.com

Lalande 21185

Lalande 21185 is a magnitude-7.5 red dwarf star in the constellation Ursa Major.  It is the brightest red dwarf in the northern hemisphere but still requires a small telescope or binoculars to be seen.  It is 8.3 ly distant, making it the fourth closest star system, after Wolf 359. It was first cataloged by French astronomer J. Lalande in 1801, but its high proper motion and close distance were not discovered until 1857-58.  At that time it was thought to be the second closest star system, after Alpha Centauri.  It is a fairly large red dwarf at 0.39 solar masses.  It has two and possibly three planets.

Lalande 21185. E-P5 + Rokinon 135mm f/2. ISO 1600, 60s.

Ross 128

Ross 128 is a magnitude-11.1 red dwarf star in the constellation Virgo.   It is 11.0 ly distant and the 11th closest star system.  It has a mass of 0.18 solar masses and has one known planet with an orbital period of 9.9 d. 

 

Getting an image of this star at this time of year was a race between the brightening pre-dawn sky and waiting for the star to rise over the eastern mountain ridgeline. 

 

Ross 128.  E-P5 + Rokinon 135mm f/2.  ISO 1600, 60s.

 

While waiting for Ross 128 to rise I turned the camera to a couple star clusters in the constellation Cancer.  M44, the "Beehive Cluster", is visible to the naked eye and is mentioned in ancient literature.  It is 610 ly distant.  It is an excellent target for binocular viewing.

M44.  E-P5 + Rokinon 135mm f/2.  ISO 1600, 60 s.

Nearby is the open cluster M67.  This cluster is about 2600 ly distant and is also a good target for binocular viewing.

M67.  E-P5 + Rokinon 135mm f/2.  ISO 1600, 60 s.

 All four images have a field of view of 2°.  Click to get the gallery view and access to the full-size versions.

A Harvest of Nearby Stars

 Early-morning observing sessions on Oct 23 and 25 yielded images of nine of the nearest stars. They are:

• (3) Wolf 359
• (5) Sirius
  
• (9) Epsilon Eridani (Ran)
• (13) Procyon
• (17) DX Cancri
• (20) Luyten 372-58 (GJ 1061)
• (22) Luyten's Star
• (24) Kapteyn's Star
  
• (29) Ross 614

 The number in parentheses is each star's rank in closeness to our solar system.  Three stars in the list are visible with the naked-eye (Sirius, Ran, Procyon), the rest are red dwarf stars that require a telescope.  Sirius is the brightest star in the sky and Procyon is number 8.

Below is a finder chart showing the relative positions in the sky.  Two stars that I discussed in previous posts (Teegarden's Star and van Maanen's Star) also show up on this chart.

credit: SkySafariAstronomy.com

Here is a real-life image of Orion rising over the not-so-distant hills:

Sony A7iii + Laowa 15mm f/2 + softon filter.  ISO 1600, 30s.

I have already discussed Wolf 359 in a previous post, so I will take the remaining eight stars in order.

Sirius

Sirius (Alpha Canis Majoris) is the brightest star in the sky at magnitude -1.4 and is 8.7 ly distant, the fifth closest star system to ours. It is about twice the mass and 25 times the luminosity of our sun.  It is a double star with a white dwarf companion that is an observational challenge for amateur astronomers.  The companion is actually quite bright at magnitude 8.4, but in a telescopic view it is overwhelmed by the brightness of the main star.  This companion star was once more massive and more luminous than Sirius itself and was a red giant star in the Cretaceous Period 120 million years ago.

 

Sirius.  E-P5 + Rokinon 135mm f/2. ISO 1600, 30 s.

 Ran (Epsilon Eridani)

Ran is very similar to our sun, with about 80% of the mass and one third the luminosity.  It is 10.5 ly away.  At magnitude 3.7, it is the third closest star visible to the naked eye (after Alpha Centauri and Sirius).  It is the 9th closest star system. 

 

Many of the brighter stars have names with roots in antiquity, but Epsilon Eridani did not have an official name until 2015 when Ran (Norse god of the sea) was chosen in a contest sponsored by the International Astronomical Union.

Epsilon Eridani (Ran).  E-P5 + Rokinon 135mm f/2. ISO1600, 60s.

Procyon

Procyon (Alpha Canis Minoris) is one corner of the "Winter Triangle", along with Sirius and Betelgeuse.  It is 11.4 ly away, the 13th closest star system, and is the 8th brightest star at magnitude 0.3.  Like Sirius, Procyon has a white dwarf companion. 

Procyon.  E-P5 + Rokinon 135mm f/2, ISO1600, 60s.

DX Cancri

DX Cancri is a magnitude-14.8 red dwarf star in the constellation Cancer.  At 11.7 ly it is the 17th closest star system.  With a mass of about 9% of our sun, it has an estimated hydrogen-burning lifetime of around 8 trillion years.

 

The image below is a 1-deg field, upscaled by x2 from the original.  DX Cancri is a faint dot at the center of the circle with a brighter star just up and to the left.

DX Cancri.  E-P5 + Rokinon 135mm f/2.  ISO1600, 60s.

 GJ 1061 (Luyten 372-58)

German astronomer Wilhelm Gliese published the Gliese Catalogue of Nearby Stars in 1957.  An extension to the second edition of this catalog was published in 1979 in collaboration with his successor Hartmut Jahreiß.  Stars referenced in this later edition are prefixed with the letters "GJ".  Willem Jacob Luyten was a Dutch-American astronomer who cataloged thousands of high-proper-motion stars.  Since nearby stars also exhibit high proper motion they will appear in several catalogs with overlapping characteristics.

 

GJ 1061 is a magnitude-13.1 red dwarf star 12 ly distant, the 20th closest star system.  It has 1/8 the mass of the sun and does not exhibit flares, unlike most red dwarf stars.  It has two known planets.

 

 

GJ 1061. E-P5 + Rokinon 135mm f/2.  ISO1600, 60s. 2° field of view.

Luyten's Star

Luyten's Star is a magnitude-9.9 magnitude red dwarf 12.3 ly distant and the 22nd closest system to ours.  Its position in the sky is just under 3° from Procyon.  In space, it is only 1.2 ly from Procyon.  If we were that close to Procyon it would shine at magnitude -4.5, sixteen times brighter than Sirius.  Luyten's Star is a fairly large red dwarf with a mass of about 29% of our sun.  It has two known planets and two more suspected.

Luyten's Star.  E-P5 + Rokinon 135mm f/2. ISO1600, 60s.

Kapteyn's Star

Kapteyn's Star has a proper motion of 8.7"/y,  which was the highest known at the time of its discovery by Dutch astronomer Jacobus Kapteyn in 1898.  In 1916 Barnard's Star was discovered to have a proper motion of 10.35"/yr, moving Kapteyn's Star to second place.  Kapteyn's Star is a magnitude-8.8 red dwarf at a distance of 12.8 ly, 24th closest to the solar system.  It has a mass of about 28% of our sun.

Capturing an image of Kapteyn's Star was a challenge because at this latitude its maximum distance above the horizon is only 7.3°.  Wildfire smoke and local hills interfered with the first two attempts.  Significant green airglow at this elevation also forced a shorter exposure time.

Kapteyn's Star.  E-P5 + Rokinon 135mm f/2. ISO1600, 40s.

Ross 614

Astronomer Frank Ross was the successor of E.E. Barnard at Yerkes Observatory, home of the 40" Alvan Clark refractor, the world's largest.  Ross repeated many of the photographic surveys inherited from Barnard and discovered more than 1000 high-proper motion stars by comparing the newer to the older images.  Four of the nearest 32 star systems are known by their Ross catalog numbers (Ross 154, Ross 248, Ross 128, Ross 614).

Ross 614 lies near the center of the "Winter Triangle".  It is a red-dwarf double star with two components of magnitude 11.1 and 14.2.  At 13.4 ly it is the 29th closest star system. The two stars have masses of about 22% and 11% of our sun.

Ross 614. E-P5 + Rokinon 135mm f/2. ISO 1600, 60 s.