Mercury Update - Details for 2018

Mercury has seven elongations in 2018. The initial sighting for each of these is tabulated below:

Sequence

Initial Sighting Date (2017/18)

Observing Location

Greatest Elongation (2018)

#1

December 24, 6:10 am EST Swede Run, Moorestown, NJ

January 1, western (morning)

#2

February 26, 5:56 pm EST Baseball Fields, Maple Shade, NJ

March 15, eastern (evening)

#3

April 22, 5:26 am EDT Old Mart Site, Pennsauken, NJ

April 29, western (morning)

#4

June 14, 8:41 pm EDT Swede Run, Moorestown, NJ

July 12, eastern (evening)

#5

August 24, 5:10 am EDT Swede Run, Moorestown, NJ

August 26, western (morning)

#6

October 13, 6:41 pm EDT Swede Run, Moorestown, NJ

November 6, eastern (evening)

#7

    December 15, western (morning)

 

Elongation #6

The first sighting of the sixth elongation for 2018 was at 6:41 pm EDT on October 13, 2018, from Swede Run in Moorestown, NJ, shortly after sunset at 6:23 pm EDT, with 16x70 binoculars. This is also the initial sighting of the 50th elongation in a row spanning almost eight years (starting in January 2011). At the time, Mercury was 23 days past superior conjunction on September 30 and 15.5 east of the sun, but only at 2.7 apparent altitude because of the shallow angle of the ecliptic after sunset. It was magnitude -0.36 and 91% illuminated, but visible only with difficulty because of twilight and atmospheric absorption at the low altitude, even though the sky was clear. It was not visible with unaided eyes.

The second sighting of the sixth elongation for 2018 was at 6:40 pm EDT on October 18, 2018, from Swede Run in Moorestown, NJ, not long after sunset at 6:16 pm EDT, with 15x56 binoculars. At the time, Mercury was 18.0 east of the sun, but only at 2.5 apparent altitude because of the shallow angle of the ecliptic after sunset, but also because it was at -1.5 ecliptic latitude (vs. -0.9 on the 13th). Mercury was now magnitude -0.27 and 88% illuminated, but visible only with difficulty in twilight, despite a clear sky along the horizon. It was not visible with unaided eyes.

 

Elongation #5

The first sighting of the fifth elongation for 2018 was on August 24, 2018, at Swede Run in Moorestown, NJ, where astronomical twilight started at 4:42 am EDT. Mercury was at magnitude +0.35 and 33% illuminated, sixteen days after inferior conjunction on August 8th. It rose at 4:53 am and was initially seen with 15x56 binoculars at 5:10 am, when it was at 2.8 altitude and 71.5 azimuth. It was directly below Castor and Pollux at the time, so the azimuth was easy to establish. I was able to glimpse it with unaided eyes at 5:15 am, when it reached 3.7 altitude. In the binoculars, I could just barely see M44, 6 above Mercury, while Asellus Borealis and Asellus Australis just fit in the field with M44 centered. I was able to spot comet 21P/Giacobini-Zinner high overhead near Kemble's Cascade with the 15x56s between the initial binocular and unaided-eye sightings.

The second sighting of the fifth elongation for 2018 was on September 4, 2018, at Swede Run. Astronomical twilight began at 4:56 am EDT and Mercury would rise at 5:14 am. There was fairly heavy fog along the ground out to and beyond the distant trees along the eastern horizon. With 15x56 binoculars, a dim, reddish Mercury appeared just above the tree tops at 5:27 am, about 2.1 altitude. It was first spotted with unaided eyes at 5:33 am as it ascended into thinner fog, about 3.2 altitude. By 5:45 am in brightening twilight, magnitude -1.0 Mercury was an easy object to unaided eyes at 5.3 altitude above the fog. A couple of minutes later, I spotted Regulus with the 15x56s below Mercury through some dissipating fog at 2.6 altitude.

 

Elongation #4

The first sighting of the fourth elongation for 2018 was on June 14, 2018, at Swede Run in Moorestown, NJ. Mercury was at magnitude -1.2, nine days after superior conjunction on June 5th. It was initially seen with 15x56 binoculars at 8:41 pm EDT, when it was at 6.3 altitude and 298 azimuth. I followed it with the 15x56s until 9:05 pm when it reached the distant tree tops. I thought I might have glimpsed it with unaided eyes in the last minute before the trees, but that was quite uncertain. Interestingly, I used Mercury to find the sublimely thin, 2.2% illuminated young Crescent Moon at 8:43 pm when it was 29.0 hr old (New Moon was June 13 at 3:43 pm EDT). The thin crescent, about 7 to the left of Mercury and two-thirds of a degree higher, was subsequently seen with unaided eyes. It was not obvious, but not too difficult either, becoming easier as it neared the tree tops in darkening twilight, shortly after Mercury reached the trees.

While looking for the Crescent Moon and Mercury, bright Venus and Jupiter were obvious to unaided eyes in early twilight before 9 pm (sunset was at 8:30 pm EDT on June 14). In the 15x56s, on a braced monopod, I saw all four Galilean moons at 9:10 pm. Notably, I could clearly see Io and Ganymede, about 19" apart, when they were about half an arc minute from the Jovian disc (they would be occulted between 11 pm and midnight). I suppose that twilight tempered Jupiter's brightness, facilitating the view of Io and Ganymede. From my front porch in Maple Shade, NJ, I saw Saturn with unaided eyes around 12:30 am on June 15, then used it as a guide to find (4) Vesta in the binoculars. I then stepped off the porch (to avoid a tree and a house blocking the view) and saw bright Mars. A look in the 15x56s showed Mars' disc. Finally, I went back to Swede Run, and at 3:35 am, a minute after the start of astronomical twilight, I picked up Neptune (magnitude 7.9, 28 altitude in Aquarius) and Uranus (magnitude 5.9, 10 altitude in Aries) with the 15x56s. I was working off hand-drawn finder charts, so a few minutes later, I checked them again against a magnified view with SkySafari on my iPad. Saturn and Mars were still visible too, and Mars had a definite butterscotch color to unaided eyes. So, I saw all eight major planets (including Earth), the Moon and an asteroid (minor planet)  overnight on June 14-15, 2018.

The second sighting of the fourth elongation of 2018 was on June 19, 2018, at Swede Run in Moorestown, NJ. Shortly after arrival, Mercury was seen with 15x56 binoculars at 9:04 pm EDT, then at 9:05 pm with unaided eyes, when it was in a break between clouds along the northwest horizon. Before I could set up the camera to take a picture, it disappeared into the clouds for good. Besides the northwest horizon, most of the sky was clear, so bright Venus and Jupiter (as well as the nearly-first-quarter Moon) were obvious to unaided eyes in twilight at 9:15 pm. In the 15x56s on a monopod, I saw all four Galilean moons at 9:15 pm. They were in a classic straight line that followed Jupiter's equator. Europa was to the east, while Io, Ganymede and Callisto were to the west (in that order). The four moons, and Jupiter too, were almost evenly spaced with a 12.5 arc minute span between Io and Callisto at either end. Saturn was seen with unaided eyes over the tree tops in the southeast at 9:40 pm (confirmed by its oval shape in the binoculars). I left at 9:15 pm, and by then, some thin clouds were covering the northern half of the sky. Later, back at home, I stepped out to my front porch in Maple Shade, NJ, to look for (4) Vesta. Sweeping up from Saturn, I quickly found it with the 15x56s in a distinctive asterism 1.5 southwest of M23. Luckily, passing thin clouds did not interfere. Finally, at 3:15 am, I stepped out front again and immediately saw bright Mars. A look in the 15x56s showed Mars' disc. There were patchy thin clouds in the east, but I was able to find Neptune by moving up and to the left from Fomalhaut near the rooftop of a neighbor's house across the street. I didn't descend from the Water Jar asterism of Aquarius as I've been doing for the last few years because at this time, it was covered by clouds. The last planet to find, Uranus, was the most difficult as I had to wait for the clouds to move to reveal the field stars that would identify it (as shown in SkySafari on my iPhone). I first saw it at 3:30 am, but it wasn't confirmed against the field until 3:34 am. I saw all eight major planets again (including Earth), the Moon and an asteroid (minor planet) overnight on June 19-20, 2018.

The third sighting of the fourth elongation of 2018 was on June 30, 2018, near the intersection of New Albany Rd and Church St in Moorestown, NJ. There were some "trashy" clouds along the western horizon, but I finally picked up Mercury at 9:20 pm EDT with 15x56 binoculars, then immediately saw it with unaided eyes, after it descended from a horizontal band of clouds. At the time, Mercury was at magnitude 0.0, 7.2 altitude. Using Mercury as a guide, I was able to find Pollux at 9:25 pm, then Castor with the 15x56s a couple of minutes later (as they too descended from clouds). They were about 11 and 15 to the right of Mercury respectively. These nominal first-magnitude stars were not seen with unaided eyes. I wanted to be certain there was no confusion between them and Mercury.

The fourth sighting of the fourth elongation of 2018 was on July 1, 2018, at Swede Run in Moorestown, NJ. Again, there were some clouds above the western horizon, but I picked up Mercury at 9:10 pm EDT with 10x50 binoculars, then saw it with unaided eyes at 9:13 pm, after it descended out of clouds. At 9:10 pm, Mercury was at magnitude +0.1, 9.0 altitude. Using Mercury as a guide, I found Pollux and Castor in the binoculars at 9:25 pm. They were about 12 and 16 to the right of Mercury respectively. They were not visible with unaided eyes.

The fifth sighting of the fourth elongation of 2018 was on July 2, 2018, at Kirkwood Park in Voorhees, NJ. There were no specific clouds, but the sky was murky above the western horizon. I did not intend to look for Mercury, I was there to take advantage of excellent seeing predicted by Meteoblue to observe Jupiter, the Great Red Spot and  Ganymede transit with a friend and his 12.5-inch dob. The seeing  was excellent and we had a fine view of Jupiter, and Saturn too, plus i had a quick look at gibbous Venus. The seeing was so good that Antares was split easily. I decided that since I had my 10x50 binoculars, i would walk across the parking lot to get a tree-free view towards the horizon where mercury would be. I spotted it with the 10x50s at 9:10 pm EDT at the end of a hot July day. I picked up Mercury at 9:10 pm EDT with 10x50 binoculars, then saw it with unaided eyes at 9:13 pm, then after maneuvering to avoid a streetlight in Mercury's direction, I spotted it with unaided eyes a few minutes later. I didn't look for Castor and Pollux, and trees blocked Mercury from where the scope was set up.

The sixth sighting of the fourth elongation of 2018 was on July 7, 2018, at Atsion Field in Wharton State Forest, NJ. The sky was quite clear and Mercury (magnitude +0.3) was spotted with 15x56 binoculars at 8:50 pm EDT by sweeping 16 towards the 4:30 o'clock position from Venus. I then set up my 130 mm apo refractor for a look and saw the 49% illuminated disc (technically a waning crescent), but it was wriggling in poor seeing (seeing in general wasn't that good on this unusually cool July evening, and even worse at Mercury's low altitude after 9:10 pm). Around 9:20 pm, as Mercury approached the tree tops across Rt 206 (roughly 7 altitude), it was finally seen with unaided eyes. I also observed the waning gibbous Venus (67% illuminated) in the scope.

The seventh sighting of the fourth elongation of 2018 was on July 8, 2018, at Swede Run in Moorestown, NJ. It was again an uncharacteristically cool and clear early-July evening. I initially spotted Mercury (magnitude +0.4) with 15x56 binoculars at 8:58 pm EDT, shortly after arrival. I was able to glimpse it with unaided eyes at 9:02 pm, but it was 9:15 pm before it became regularly visible with unaided eyes (but I won't say an object that would have necessarily been seen by a casual observer). Venus, Jupiter and Saturn were also seen with unaided eyes in twilight shortly after arrival, and at 9:14 pm, I picked up the asteroid (4) Vesta in the 15x56s. Around 1:30 am on July 9, I was observing Mars in my 130 mm refractor from my backyard in Maple Shade, NJ. Finally, I went back to Swede Run and saw Neptune and Uranus in the 15x56s at 3:04 and 3:06 am respectively. There was also a nice Crescent Moon low in the east. I then looked for comet C/2017 S3 (PANSTARRS) with the 15x56s and my 85 mm spotting scope. This comet has recently been in outburst to the magnitude 9 to 10 range, but even though I had a good match on the star field, no cometary haze was seen. In any case, I saw all eight major planets again (including Earth), plus the Moon and an asteroid (minor planet) overnight on July 8-9, 2018. I tried to see a comet, C/2017 S3 (PANSTARRS), but at magnitude 9.x, it was too dim for 15x56 binoculars or an 85 mm spotting scope at suburban Swede Run.

The eighth sighting of the fourth elongation of 2018 was on July 14, 2018, from the side of Rt 693 (Columbia Rd) in Hammonton, NJ, about 2 miles east of the Hammonton Airport. The 46-hour old, 6% illuminated Crescent Moon was spotted with unaided eyes at 8:40 pm EDT, 15 minutes after sunset when it was about 12.5 altitude. Magnitude +0.7 Mercury was spotted at 8:42 pm with 15x56 binoculars at 11 altitude, just below the Moon. Both were seen again 15 minutes later on arrival at Batsto for a WAS Public Star Watch. Venus, Jupiter and Saturn were also seen with unaided eyes in twilight shortly after arrival. The asteroid (4) Vesta was spotted a number times with the 15x56s during the evening. Around 10 pm, after it cleared the tree tops,  bright Mars was seen with unaided eyes and through several of the scopes set up (no detail due to the dust storm on Mars). About 12:30 am on July 15, Neptune was spotted at Batsto with the 15x56s. Uranus had not yet risen, so I waited until I returned home, but it was cloudy when I arrived at 2 am, 5 minutes after the start of astronomical twilight. I went out front of my Maple Shade, NJ, home, and after half an hour of searching between broken clouds, I spotted and confirmed Uranus in the 15x56s at 3:52 am. So, I saw all eight major planets again (including Earth), plus the Moon and an asteroid (minor planet) overnight on July 14-15, 2018.

The ninth sighting of the fourth elongation of 2018 was on July 15, 2018, from the baseball field complex in Maple Shade, NJ. It was actually incidental as I was there to capture images of the Crescent Moon near Venus. During a lull in picture taking, I grabbed my 10x50 binoculars from the back of the car and spotted Mercury at 9:06 pm EDT, not far above the tree tops and shortly before it disappeared into a cloud. At the time, Mercury was at magnitude +0.7 and 6.2 altitude. I grabbed a snapshot of it since I already had the camera set up for the Moon and Venus (see below, mouseover for label). Taken at 9:07 pm with a Canon 6D digital SLR camera and a Canon 400 mm f/5.6 lens on a fixed tripod. Exposed 1/10 second at f/5.6, ISO 1600, daylight white balance.

 

An image of Mercury from July 15, 2018.

 

The tenth sighting of the fourth elongation of 2018 was on July 19, 2018, from the baseball field complex in Maple Shade, NJ. I hadn't planned on looking for Mercury anymore this elongation, but the weather was so nice, I decided to see if the 29% illuminated crescent was visible. I went to the local baseball field complex in Maple Shade, NJ, and since it was a last-minute decision, I just grabbed my 85 mm spotting scope, which has a zoom eyepiece capable of 27 to 60x magnification (with a 2.23 to 1.32 true field of view respectively).

I had magnitude +1.0 Mercury in the spotter at 8:57 pm EDT when it was about 5 altitude. Because of the low altitude, it just looked like a wriggling, compressed oval at 60x. I then swung the scope east for a look at Venus, the 61% illuminated gibbous disc was nice, then the first-quarter Moon, which showed nice detail on the terminator, but no "Lunar X," and then Jupiter at 9:05 pm. The Galilean satellites were all on the west side of the disc in an interesting zig-zag pattern. The two equatorial belts were obvious at 60x, but I was surprised by a dark dot at the Southern Equatorial Belt, just past the Central Meridian. No real color was evident, but could it be the Great Red Spot? I had not checked on Jupiter beforehand, so I had no idea if the GRS would be visible, and if so, where it would be. Therefore, I got out my smartphone and opened SkySafari, which confirmed the GRS had just passed the CM. This spotting scope is nice, but but it's not an astronomical telescope and it only gets up to 60x, so I wouldn't have expected to see the GRS with it, but since I did, the seeing must have been pretty good (and the recent intensification of the GRS doesn't hurt). I then looked at Saturn and it was beautiful. I even think I saw the Cassini Division at 60x. Indeed, the seeing must be good.

Since I had already seen four planets and the Moon in the spotting scope, I decided I might as well see the rest of them, as well as an asteroid (or minor planet), (4) Vesta, and a comet, C/2017 S3 (PANSTARRS). The latter had recently experienced an outburst and was around magnitude 8, a quite-accessible brightness. For an added twist, I also decided that all of the objects needed to be seen in the spotting scope (which has no finder), not just a quick view with unaided eyes or binoculars. I had to wait a bit for it to get darker, but I spotted (4) Vesta at 9:20 pm. I've been following Vesta since early June, so I knew where to look (about 3 northeast of Theta Oph), and was familiar with the star patterns in that area.

I had to wait for the rest of the objects to rise, so I went home. About 2 am, I was back out at Swede Run in Moorestown, NJ. It's a little darker there and the horizons are low, but some haze and ground fog were developing, so transparency was reduced somewhat. Bright Mars was obvious with unaided eyes. Through the spotting scope at 60x, a definite disc was seen, but no white areas at the poles (as I saw in my 130 mm refractor a couple of weeks ago). I also saw a vague darkish patch below center, Mare Cimmerium? The global Martian dust storm has severely reduced visibility of surface features. Next was Neptune, 4.5 east of Lambda Aqr, then Uranus, 4.5 east of Omicron Psc. I've also been following them for more than a month, so I'm familiar with the adjoining star fields. Finally, I spotted C/2017 S3 (PANSTARRS) near 5 and 7 Camelopardalis at 2:26 am. Since I had seen it the two previous mornings, I was again familiar with the adjoining patch of sky.

So, I saw all eight major planets again (including Earth), plus the Moon and an asteroid (minor planet), plus a comet overnight on July 19-20, 2018. Out of the ten (10) different evenings that I spotted Mercury this elongation, I saw all of the other planets on five (5) of those nights (plus two or three other solar system objects).

 

Elongation #3

The first sighting of the third elongation for 2018 was on April 22, 2018, at the old mart site in Pennsauken, NJ. Mercury, at magnitude +0.9, was initially seen with 15x56 binoculars at 5:26 am EDT, 5 minutes after it rose when it was at 1.0 altitude and 89 azimuth (and 53 minutes after the start of astronomical twilight, 46 minutes before sunrise). Its diagonal rising path was followed until 5:40 am when it reached 3.5 altitude. It was also seen with an 85 mm spotting scope at 27x, but it was not seen with unaided eyes. The sky was quite clear this morning, even along the eastern horizon (unlike the streaky horizon clouds present on the three previous failed attempts in the past week at Swede Run). The bright planets Mars, Saturn and Jupiter were obvious to unaided eyes upon arrival at 5:23 am.

 

Elongation #2

The first sighting of the second elongation for 2018 was on February 26, 2018, at the baseball field complex in Maple Shade, NJ. Mercury, at magnitude -1.4,  was initially seen with 15x56 binoculars at 5:56 pm EST, when it was at 5.4 altitude and 3.6 below Venus (at the 5 o'clock position). Mercury was followed until 6:10 pm when it descended into the tree tops at 2.2 altitude. It was never seen with unaided eyes. Venus, magnitude -3.9, was initially seen with the 15x56s at 5:52 pm, then immediately afterwards with unaided eyes. It was the first sighting of Venus with unaided eyes since its superior conjunction on January 9, and the first sighting since it was seen with binoculars on January 25.

The second sighting of the second elongation for 2018 was on February 28, at Swede Run in Moorestown, NJ. It was briefly seen in 15x56 binoculars at 5:54 pm EST, when it was 2.4 from Venus at the 5 o'clock position, in the same 4.5 binocular field. Shortly after, it disappeared into a thickening cloud bank above the western horizon.

The third sighting of the second elongation for 2018 was on March 3, at the baseball field complex in Maple Shade, NJ. It was briefly seen in 15x56 binoculars at 6:34 pm EST, when it was 1.1 to the right Venus, through a gap in the clouds just above the distant tree tops. At the time, it was mostly overcast, except for some fast-moving clear streaks in the clouds along the western horizon (it was also somewhat windy from the remains of yesterday's nor'easter). The image below was captured at 6:36 pm with a Canon 6D digital SLR camera (on a fixed tripod) and a Sigma 70 to 300 mm, f/4-5.6 zoom lens set to 300 mm focal length, then cropped to about 60% of the original size (and a 16:9 ratio), which yielded a field about 4.6 wide x 2.6 high. Venus (magnitude -3.9) is on the left, dimmed somewhat by the foreground cloud and Mercury (magnitude -1.2) is on the right. They were approximately 3 altitude in the picture. Venus was seen with unaided eyes several times as the clouds passed, but Mercury was not unambiguously seen with unaided eyes.

 

 

An image from March 3, 2018.

 

The fourth sighting of the second elongation for 2018 was on March 4, at Swede Run in Moorestown, NJ. Mercury and Venus were initially seen with 10x50 binoculars on arrival at 6:03 pm, then Venus was seen immediately with unaided eyes, but not Mercury with any certainty (1.2 separation). Upon completing camera and tripod setup at 6:15 pm, Mercury was definitely visible with unaided eyes. By 6:25 pm, they were both easily visible with unaided eyes. They were still visible as they disappeared into the distant trees around 6:40-6:45 pm. The sky was quite clear.

The fifth sighting of the second elongation for 2018 was on March 5, at the railroad tracks near Steinhauer School in Maple Shade, NJ. Mercury and Venus were initially seen with 10x50 binoculars on arrival at 5:52 pm, 4 minutes before sunset. Venus was then seen immediately with unaided eyes, but not Mercury with any certainty (1.5 separation). I then went to the baseball field complex, and after setting up the camera, Mercury was definitely visible at 6:15 pm with unaided eyes. By 6:30 pm, they were both easily visible with unaided eyes. They were still visible as they approached the distant trees around 6:40-6:45 pm.

The sixth sighting of the second elongation for 2018 was on March 9, at home in Maple Shade and at Swede Run in Moorestown, NJ. It was a very clear evening and I saw both Venus and Mercury out the rear window of my kitchen, through tree branches in the back of the yard, with unaided eyes at 6:30 pm EST. I then left for Swede Run, and as I drove along the railroad tracks in Maple Shade, I could see the pair quite brightly through my windshield as I made a short detour west, then in my exterior rear-view mirror after I turned back towards Swede Run. At Swede Run, they were prominent above the horizon when I arrived at 7:50 pm. I last saw Mercury at 7:15 pm when it was around 1 altitude. Venus was still at magnitude -3.9 while Mercury had dropped to magnitude -0.9. The reason I went to Swede Run was to spot the "Humanity Star" satellite, which I did. It was unusual in that it was mostly a dim, binocular object (appx. magnitude 6), except for irregular bright blinks (appx. magnitude 2), most unlike an Iridium flare or a tumbling satellite.

The seventh sighting of the second elongation for 2018 was on March 18, at Swede Run in Moorestown, NJ. It was a very clear evening and I saw both Venus and Mercury again after sunset (7:10 pm EDT), but they were also joined by the 1.5-day-old Crescent Moon. The picture below shows them at 8:01 pm EDT. The Moon, of course, is at the lower left, Venus is at the center and Mercury is at the upper right (Canon 6D + 200 mm f/2.8L, not cropped).

 

An image from March 18, 2018.

 

All three objects were easily visible above the tree tops to the west. The Moon was at 4.3 altitude and 2.5% illuminated. Venus, 3.9 from the moon, was at 5.3 altitude and magnitude -3.9. Mercury, 3.8 from Venus, was at 7.2 altitude and magnitude +0.4. After taking pictures, I looked at Mercury with an 85 mm spotting scope at 27 to 60x, hoping to see its crescent shape (at the time, Mercury was 30% illuminated). It was difficult to discern due to the small diameter (8.5") and poor seeing, but Mercury looked oval rather than round.

The eighth sighting of the second elongation for 2018 was on March 24, at Atsion Field in Wharton State Forest, NJ. There were some murky thin clouds along the western horizon and Mercury was now 7 below-right of brilliant Venus. She was first sighted at 6:45 pm EDT, 30 minutes before sunset, with 15x56 binoculars, then shortly after, with unaided eyes. Mercury was finally spotted at 7:36 pm with an 80 mm refractor at 53x (1.9 field), not far above the tree tops. Knowing the position, it was then seen with the 15x56s. It was popping in-and-out of the clouds and was never seen with unaided eyes. At the time, Mercury was 9.8" apparent diameter, 11% illuminated, magnitude +2.2 and 8.2 altitude. In the scope at 102x, Mercury looked non-circular, perhaps like a horizontal oval, although with poor seeing at that altitude, it wasn't clear-cut. It certainly didn't look like the thin crescent it was. The crescent would have appeared horizontal since Mercury was 12.8 directly above the sun at the time (the ecliptic was tilted a steep 74 to the horizon and Mercury had an ecliptic latitude of +3.4). A dramatic change from six days ago on March 18 and probably the last sighting for this fine elongation.

 

Elongation #1

The first sighting of the 2018 elongation cycle was on December 24, 2017, at Swede Run in Moorestown, NJ. It was initially seen with unaided eyes just above the tree tops at 6:00 am when it was magnitude +0.2 and 3 altitude. However, because the sky was generally cloudy with clearing mainly between streaky clouds along the eastern horizon, there were no visible reference stars to confirm the position. In particular, Antares was 8 from Mercury at the 4 o'clock position, and until I saw both objects, I couldn't be sure which was which. With 15x56 binoculars, I spotted Antares in the trees at 6:10 am, and over the next five minutes, it showed movement up and to the right, so it wasn't a distant antenna warning light (there are many antennae around Lockheed-Martin in that direction). Antares was also confirmed by spotting Aliyat (Sigma Scorpii) 2 from Antares at the 1 o'clock position.

The second sighting of the first elongation of 2018 was on December 28, 2017, at Swede Run, when the temperature hovered around 14F. It was initially seen with an unintentional glance of unaided eyes just above the tree tops at 5:55 am, when it was magnitude -0.2 and 3 altitude. A few minutes later, Antares was spotted 8.6 to the right of Mercury (at the 3:30 o'clock position), confirming the sighting. The image below, looking southeast down Westfield Rd towards the intersection of Borton Landing Rd, was captured at 6:04 am EST with a Canon 6D digital SLR camera and a Canon 100 mm f/2.8L macro lens on a fixed tripod. It was exposed 1 second at f/4, ISO 4000. It was cropped to about 75% of the original size for a field 15 wide x 10 high. Mouseover for labels. Mercury was still visible with unaided eyes when I left at 6:30 am.

 

An image from December 28, 2017.

 

The third sighting of the first elongation of 2018 was on January 1, 2018. First, I wanted to make sure I saw this 2018 elongation in 2018, not just 2017, and second, I wanted to catch Mercury on the day of its greatest western elongation, which is January 1 at 2:58 pm EST. We're still in a cold spell and the temperature hovered around 8F. Initially, I went to Swede Run in Moorestown, NJ. After picking up (4) Vesta (in Libra) with 15x56 binoculars at 5:45 am EST, I spotted Mercury in the treetops at 5:52 am with the 15x56s, then saw it with unaided eyes at 5:53 am; it was magnitude -0.3 and 2.3 altitude. After leaving Swede Run, I decided to check out the old Mart site in Pennsauken, NJ, which had been my workhorse morning twilight site until construction started there in August 2017. As soon as I pulled up, I could easily see Mercury through the windshield at 5.2 altitude. Based on what I could see in the semi-darkness of twilight (the sun wouldn't rise until 7:22 am), they were still preparing the ground at the Mart site as no visible structures had risen yet. When I arrived home at 6:25 am, Mercury was still easily visible at 7.4 altitude in brightening skies. Mercury's position viewed from home this morning was reminiscent of the first sighting in this series of observations back in January 2011.

The fourth sighting of the first elongation of 2018 was on January 14, 2018, from Swede Run during morning twilight with the temperature at 14F. I arrived at 6:15 am EST, and although the sky was generally clear, there was a band of clouds starting a few degrees above the tree line and ending below Jupiter and Mars, which were around 30 altitude. The Crescent Moon was in the band of clouds and popped in and out of view until it emerged from the cloud bank at 6:45 am. Regardless, glimpses of the moon through the clouds guided me to Mercury, which I picked up at 6:16 am with 15x56 binoculars. Saturn, a couple of degrees west of Mercury, also peeked in and out of the clouds and during the next ten minutes, I momentarily had Mercury and Saturn in the same binocular field several times. Finally, I was able to see Mercury with unaided eyes at 6:25 am, but I never caught Saturn with unaided eyes.

________________

 

The current sighting streak is now 50 elongations in a row, starting in January 2011, which includes seven complete calendar years of six or seven elongations each. The years 2011 and 2015 had seven (7) elongations, while 2012, 2013, 2014, 2016 and 2017 had six (6). Click here for previous sightings. The purpose of this ongoing effort is not to set some sort of record, especially since I have no idea what sort of record might exist, but to demonstrate that locating and seeing Mercury is not nearly as difficult as many suppose. It just takes some planning and a little effort, although circumstances make some elongations easy and some difficult.

 

Return to the SJAstro home page.

 

Last Update: Friday, October 19, 2018 at 10:07 AM Eastern Time