MIlky Way and airglow

 These images of the Milky Way rising over the western ridgeline of Snowshoe Mt were obtained in the late evening of 01 June 22 in Creede.  The camera was riding on a motorized Orion EQ-1 equatorial mount.  There are strong bands of green and red airglow visible in these exposures.  The sky was reasonably dark, with sqml=21.45.

In this image the constellation Scorpius is on the right and the Milky Way Core is left of center.

Sony A7 + Samyang 35mm f/1.8 + Softon filter.  ISO 1600, 30s.

 The Summer Triangle: Vega (top), Deneb (left), Altair (lower right).

Sony A7 + Samyang 35mm f/1.8 + Softon filter.  ISO 1600, 30s.

The next evening the sky was darker (sqml=21.5) and the airglow greatly diminished.  I switched to a wider-angle lens:

Sony A7 + Samyang 24mm f/1.8 + Softon filter.  ISO 1600, 30s.

 All images on this blog are best viewed on a computer monitor.  As usual, click on an image to get into gallery view and then download or open in a new tab to see the full-size version.

The Snow Moon and the Sun

 Tonight's February full moon is traditionally known as the "Snow Moon".  

E-M5iii + Orion 80mmED f/7.5.  ISO 200, 1/1000 s.

The Moon is currently very near apogee, the farthest distance from Earth in its elliptical orbit.  This makes its apparent size smaller than average, the opposite of a "Super Moon".

Here is an image of the Sun today:

E-M5iii + Orion 80mmED + Lunt Solar Wedge + ND-0.6 filter.  ISO 200, 1/1600 s.

And here is a merged image showing the relative sizes:

 The angular diameter of the Moon is currently only 91% of the Sun's diameter.

A large and active sunspot

 There is currently a large and very active sunpot (AR3590) traversing the face of the sun.  It is large enough to be seen with the unaided eye when viewed through safe solar filters.

E-M5iii + Orion 80mmED f/7.5 + Lunt Solar Wedge + ND-0.6 filter.  ISO 250, 1/1600 s.

This photo is a good representation of the unaided view through a black-polymer solar filter:

E-M5 + SIgma 30mmf1.4 @ f/4 + black-polymer filter.  ISO  400, 1/1600 s.

 

That "tiny" speck is visible even with my old eyes.  The sunspot is actually many times larger than the earth.  The black circle in the photo below shows the relative sizes:

Moon Landing!

The IM-1 Odysseus probe constructed by Intuitive Machines and launched by SpaceX landed near the south pole of the moon today, the first US vehicle to land on the moon since 1972.

13.6-d moon. E-M5iii + Orion 80mmED f/7.5 refractor.  ISO 200, 1/800 s.

The landing area near the crater Malapert A is marked with a white rectangle in this enhanced crop from the above image.

The Moon tonight

 The Moon is 11.8 days past new and high and bright in the sky.  Not a good time for wide-field astrophotography.

E-M5iii + Orion 80mmED f/7.5.  ISO 200, 1/1000 s.

Messier 41 (M41) is an open cluster about 4° south of Sirius.  It is about 2300 ly distant and has an apparent size slightly larger than the full moon.  The faintest stars visible in this image are between magnitude 14 and 15.  The scope was riding on a Celestron CG-4 motorized mount, unguided.

M41. E-M5iii + Orion 80mmED f/7.5. ISO 1600, 30 s. 1° FOV.

The Super Flower Blood Moon of 2022

Digging through the archives.  

Yuck, what a title.  The "Super" part is an adjective coined by an astrologer (ahem) for a perigean full moon.  The "Blood Moon" adjective is a term popularized by an evangelical minister (double ahem) as part of his prophesy of the imminent apocalypse in 2015 (And how did that work out?  I thought so).  The "Flower" part is the folklore term for a May full moon (when the spring flowers bloom).  Unfortunately, the popular science media have  seized on all these terms because they produce effective click-bait headlines.  So don't blame me - they started it.

For all rational people there was a total lunar eclipse on the night of 15-16 May 2022 .

The sky was mostly cloudy in Santa Fe for this event, but there was a brief break in the clouds near the time of maximum eclipse.  I was able to snap a few pictures and then the clouds closed in again.  

Equipment:  Orion 80mm f/7.5 refractor and Olympus E-M5iii camera.

10:06 MDT. ISO 800, 1/10 s.

 The star visible just above the moon is HR 5762, a 5.5-magnitude star in Libra.  The "HR" part of the designation refers to the Harvard Revised Photometry Catalog.

Testing a new mount: ZWO AM3

The computerized Go-To astrophotography mount that I have been using since 2018 is the now-discontinued iOptron SmartEQ Pro+.  It has served well and still works fine, but it seemed time to upgrade to something more modern and robust. The new mount is a ZWO AM3 Strain-Wave drive.  This type of mount does not require careful balancing with counterweights, a big advantage over traditional worm-gear driven portable mounts like the SmartEQ.

ZWO AM3 mount carrying an Olympus E-M5iii and Rokinon 135mm f/2 lens.

Yesterday the moon passed by the Pleiades star cluster.  The closest approach happened around noon, so the moon was well past by the time it was dark enough to see the cluster in the early evening sky.

The 1st quarter moon and the Pleiades.  ISO 200, 1/2 s.

7.9-d moon.  ISO 200, 1/640 s.

The Double Cluster in Perseus.  ISO 200, 15 s.

The asteroid (4) Vesta.  ISO 800, 15 s.  2° FOV.

Alignment was easy and the mount pointed where it was supposed to.  The exposures here are short, but the stars all look good.  So far, so good.  A tougher test will have to wait for darker skies.

Mizar and Alcor: a double, double, double star system

 Mizar (Zeta Ursae Majoris) and Alcor (80 Ursae Majoris) form a magnitude 2.2 and 4.0 naked-eye double star in the middle of the handle of the Big Dipper.  

The Big Dipper and Little Dipper.  The Mizar-Alcor pair is marked with a white circle.

Image data: Sony A7iii + Samyang (Bower) 35mm f/1.4 + softon filter.  ISO 1600, 30 s.  

Location: Creede, 03 Sep 2023

This pair is often mentioned as a test for good eyesight, but success in separating the two stars depends strongly on sky conditions as well.  The angular separation of Mizar and Alcor is 0.2° - this corresponds to about 40% the width of the full moon.  The white circle in the image above is the same diameter as the moon.  Alcor is magnitude 4.0, which can be difficult to see under urban skies.  I had trouble making out this pair last night in Santa Fe with a sky brightness of sqml=19.64.  However, I have little trouble in Creede with its much darker sky.

Here is a closer look at the pair:

Alcor on the left, Mizar on the right.  E-M5iii + Rokinon 135mm f/2.  ISO 1600, 30 s.  2° FOV.

 The physical connection between the two stars has been uncertain until very recently.  It is now believed that they are weakly gravitationally bound with a separation of about 1.2 ly.

Mizar and Alcor was the first ever double star to be photographed.   This was accomplished in 1857 by Bond and Whipple using the Harvard 15-inch "Great Refractor".  The 6.9 m focal length would have produced an image separation of 2.4 cm on their photographic plate.

A closer look reveals that Mizar is itself a double:

Alcor (left) and Mizar (right).  The third star that forms a shallow triangle is a background star about four times farther away. E-M5 + Orion 80mmED f/7.5.  ISO 1600, 1/2 s.

Mizar was the first ever double star discovered telescopically.  It was reported by the Italian mathematician Benedetto Castelli in 1617 and documented by Galileo.  This is an easy double star for small telescopes.  A magnification of 25x to 30x is all that is required.  I had a very nice view of this double with a 50mm f/4 refractor and a 5mm FL eyepiece (40x).

TS-Optics 50mm f/4 ED refractor + Celestron Xcel-LX 5mm eyepiece.

The two visual components of Mizar (A and B) are each double stars themselves.  Mizar A was the very first spectroscopic double star discovered, in 1890.  Subsequently, Mizar B was determined to be a spectroscopic double, as well as Alcor.  This system therefore consists of six stars total: a double, double, double.

In summary, the Mizar-Alcor system contains:

• first double star discovered telescopically
• first double star discovered spectroscopically
• first double star to be photographed
• six stars total
  

Melotte 111 - the second nearest star cluster

 The closest star cluster is the Hyades Cluster at a distance of 47 pc (153 ly).  This cluster is well known because of its location between Orion and the Pleiades, and the bright star Aldebaran (which is actually a foreground star and not part of the cluster).

The second closest star cluster is Melotte 111 in the constellation Coma Berenices.  Also known as the "Coma Star Cluster", it is 86 pc (280 ly) distant, almost twice as far away as the Hyades.  This cluster has an apparent width of about 6 deg and is not associated with any notably bright stars.  The brightest member stars have magnitudes between 4.8-6.4 and are not easily visible to the eye except in a dark-sky location.  It is, however, a fine sight in binoculars.  I confirmed this last night with a Nikon 7x50mm binocular which closely matches the field-of-view of the image below.

Melotte 111, the Coma Star Cluster. 

Image details: E-M5iii + Rokinon 135mm f/2 + softon filter.  ISO 800, 30s, binned by 4.  Image width is about 5.5°.  

Sky brightness: sqml=19.64. 

Here is a chart showing the cluster's location last night in the eastern sky:

credit: SkySafariAstronomy.com

A break in the weather, another supernova, and some sunspots

Last night was a welcome break from our run of cloudy weather,  The clear sky enabled a look at another recent supernova: SN2024gy.  The letter suffix translates to g*26 + y = 207, where g=7 and y=25.  This supernova in the galaxy NGC 4216 was discovered on 4 January by Koichi Itagaki.  There are thousands of supernovas discovered every year.  This particular example is notable only because it is bright enough to be within the reach of modest amateur equipment.

The measured sky brightness was sqml = 19.64, not very dark by Creede standards but very typical for Santa Fe.  This level of brightness makes it difficult to capture faint extended objects, such as the host galaxy in which this supernova resides.  The galaxy NGC 4216 is a spiral galaxy in the Virgo Cluster,  seen nearly edge-on from our perspective.  Its distance is variously quoted as being between 40 Mly and 55 Mly.  

The white circle is centered on the the host galaxy, the two lines point to the supernova. E-M5 + Rokinon 135mm f/2, ISO 800, 30 s.  2° FOV.

It looks like the magnitude on this date (11 Feb) is between 13.0-13.5 based on comparison to other stars visible in the field of view.

Here is a finder chart for the surrounding field of view:

 

Credit: SkySafariAstronomy.com

 A clear morning sky enabled me to capture an image of our nearest star and its current array of sunpots on 12 February:

E-M5iii + Orion 80mmED f/7.5.  ISO 800, 1/800 s.

 As usual, click on an image to get into gallery view and get access to the full-size versions.