Mercury Sightings - Details for 2023

Mercury has six elongations in 2023. The initial sighting by Joe Stieber for each of these is tabulated below:

Elongation #6

The first sighting of the sixth elongation for 2023 (the 82nd elongation in a row overall) was on November 14, 2023, from Bishops Gate in Mt Laurel, NJ, under a clear sky, even along the western horizon. Initially, I spotted the young crescent Moon, 36.6 hr old, 2.6% illuminated and 4.1° altitude with 12x50 binoculars at 4:53 pm EST, 7 minutes after sunset at 4:44 pm. Then I set up my 88 mm spotting scope and using 25x, scanned 4.3° to the right and spotted Mercury at 4:58 pm EST. It was dim against the still-bright orange twilight, but I was then able to find it with the 12x50s. Increasing magnification to 60x with the scope, I could see Mercury's small disc, with accompanying atmospheric chromatic aberration (reddish at the top, bluish at the bottom). When first sighted, Mercury was 3.8° altitude, 235° azimuth, magnitude -0.44, 5.0″ apparent diameter and 92% illuminated. Solar elongation was 14.8° and the ecliptic latitude was 1.9°S; the ecliptic had a shallow 34° tilt with respect to the horizon. I lost Mercury in the treetops around 5:05 pm.

The second sighting of the sixth elongation for 2023 was on November 19, 2023, from Bishops Gate in Mt Laurel, NJ, under a clear sky, even along the western horizon. Initially, I spotted  Mercury at 4:59 pm EST with my 88 mm spotting scope at 25x, then one minute later with 15x56 binoculars. Sunset was at 4:41 pm so it was too dim against the brightish orange twilight to see with unaided eyes before it sunk into the treetops around 5:05 pm. When first sighted, Mercury was 4.4° altitude, 233° azimuth, magnitude -0.42, 5.3″ apparent diameter and 88% illuminated. Solar elongation was 17.1° and the ecliptic latitude was 2.2°S; the ecliptic had a shallow 36° tilt with respect to the horizon.

The third sighting of the sixth elongation for 2023 was on November 25, 2023, from Bishops Gate in Mt Laurel, NJ, under a clear sky, with a few wispy clouds along the western horizon that did not interfere. Initially, I spotted  Mercury at 5:01 pm EST with 12x50 binoculars. Sunset was at 4:37 pm. Mercury was not difficult to see against the background twilight and was glimpsed with unaided eyes at 5:17 pm before it sunk into the treetops about 5:19 pm. When first sighted, Mercury was at 5.3° altitude and 230° azimuth in Ophiuchus. It was magnitude -0.42, 5.7″ apparent diameter and 81% illuminated. Solar elongation was 19.5° and the ecliptic latitude was 2.5°S; the ecliptic had a modest 38° tilt with respect to the horizon.

In the eastern sky at the time, the nearly-full Moon was just 8° east of Jupiter, and with the 12x50 binoculars steadied against the car, I could see all four Galilean satellites, Callisto and Io wide spaced to each other east of the Jovian disc, while Europa and Ganymede were more closely spaced to each other on the west. At 7:35 pm, more than an hour after the end of twilight (but still in a Moon-brightened suburban sky), I was able to easily spot Uranus with the 12x50s about 4.2° east of the Moon. Uranus was at the western end of a nearly semicircular arc it formed with the stars (east-to-west) 65-Tau¹-Tau² Ari, Zeta Ari and Delta Ari (Botein). Then at 7:55 pm, I went back out and looked at Saturn with unaided eyes and the 12x50s, and from there, spotted Neptune with the 12x50s (Neptune was relatively dim, near the limit for these binoculars in this sky).

The fourth sighting of the sixth elongation for 2023 was on November 28, 2023, from Baseball Field Complex in Maple Shade, NJ, under a clear sky, with a few small cumulus clouds along the western horizon that did not interfere. It was windy and cold, 34°F. Initially, I spotted  Mercury at 5:07 pm EST with 12x50 binoculars, shortly after arrival. Sunset was at 4:36 pm. Mercury was easy to see against the background twilight and was glimpsed intermittently with unaided eyes through 5:15 pm before I surrendered to the wind at 5:15 pm. When first sighted, Mercury was at 5.2° altitude and 230° azimuth in Sagittarius. It was magnitude -0.43, 5.9″ apparent diameter and 76% illuminated. Solar elongation was 20.4° and the ecliptic latitude was 2.5°S; the ecliptic had a modest 40° tilt with respect to the horizon.

Elongation #5

The first sighting of the fifth elongation for 2023 (the 81st elongation in a row overall) was on September 16, 2023, from Swede Run in Moorestown, NJ, under a largely clear sky, except for a wall of cloudiness along the eastern horizon. Mercury was initially sighted with 15x56 binoculars (on a monopod) at 6:04 am EDT after it reached clearing above the clouds, which were beginning to break up by then. It was found by dropping 8° from Regulus towards the 6:30 o'clock position; it was bright enough to easily see in with the 15x56s the increasing twilight. Sunrise would be at 6:41 am. When first sighted, Mercury was 6.6° altitude, 85° azimuth, magnitude +1.0, 8.6″ apparent diameter and 21% illuminated. Solar elongation was 15.3° and the ecliptic latitude was 0.8°N; the ecliptic had a fairly steep 73° tilt with respect to the horizon. I followed Mercury until 6:12 am when it was obscured by a passing cloud.

The second sighting of the fifth elongation for 2023 was on September 17, 2023, from Swede Run in Moorestown, NJ, under a clear sky, even along the eastern horizon. Mercury was initially sighted with 8x42 binoculars at 5:47 am EDT, then with its location pinpointed, it was easily seen with unaided eyes. Like Sept 16,  Mercury was found by dropping 8° from Regulus towards the 6:30 o'clock position. Sunrise would be at 6:42 am. When first sighted, Mercury was 4.1° altitude, 83° azimuth, magnitude +0.7, 8.3″ apparent diameter and 25% illuminated. Solar elongation was 16.0° and the ecliptic latitude was 0.5°N; the ecliptic had a fairly steep 72° tilt with respect to the horizon. I followed Mercury until 5:57 am when it was still visible to unaided eyes in brightening twilight.

Starting after sunset on Sept 16 at Bishops Gate in Mt Laurel, NJ, where I attempted to spot comet C/2023 P1 (Nishimura), unsuccessfully with my 88 mm spotting scope, I did manage to see Mars about 3° altitude and 1.5° from the 1.9 day old crescent moon (3.2% illuminated) with the 88 mm at 25x (it was only magnitude +1.7). Then on the night of  Sept 16-17 at Batsto in Wharton State Forest, NJ, I observed (from west to east) the planets Saturn, Neptune, Jupiter and Uranus. They were all seen through Suzanne's 12.5-inch Dob (saw four of Saturn's satellites and three Jovian satellites plus Sigma Arietis, and the small discs of Neptune and Uranus, bluish and greenish-blue respectively). Uranus was seen with unaided eyes too. Finally, on Sept 17 before sunrise at Swede Run in Moorestown, NJ, Venus was a brilliant object two days before its Greatest Illuminated Extent, and of course, Mercury was spotted as noted in the previous paragraph. So, all seven planets were seen overnight, five of them with unaided eyes.

The third sighting of the fifth elongation for 2023 was on October 2, 2023, from Wharton Sate Forest, NJ, under a clear sky, even along the eastern horizon. Mercury was initially sighted with 12x50 binoculars at 6:07 am EDT through treetop branches, then a moment later, with unaided eyes. As it rose in brightening twilight, it was easy to see with unaided eyes, the final such view at 6:25 am through the car's windshield. Sunrise would be at 6:56 am. When first sighted, Mercury was 3.6° altitude, 88° azimuth, magnitude -1.1, 5.6″ apparent diameter and 85% illuminated. Solar elongation was 13.6° and the ecliptic latitude was 1.9°N; the ecliptic had a fairly steep 74° tilt with respect to the horizon.

Elongation #4

The first sighting of the fourth elongation for 2023 (the 80th elongation in a row overall) was on July 5, 2023, from Bishops Gate in Mt Laurel, NJ, under a largely cloudy sky. Mercury was initially sighted at 8:35 pm EDT, three minutes after sunset, with an 88 mm apo spotting scope at 25x after it descending out of a cloud bank into a narrow horizontal gap along the western horizon (the picture below shows the scope aimed at Mercury, the azimuth guided by the orange Sun setting earlier). The sky was hazy in that gap and Mercury wasn't easy to see, even though it was bright just 4.8 days after superior conjunction on July 1 at 1:06 am (so Mercury was still near it's "full" phase). When first sighted, Mercury was 3.9° altitude, 298° azimuth, magnitude -1.6, 5.1″ apparent diameter and 97% illuminated. Solar elongation was 6.0° and the ecliptic latitude was 1.7°N; the ecliptic was tilted just 40° with respect to the horizon. I followed Mercury until 8:44 pm when it was lost in the trees at 2.5° altitude.

Subsequently, brilliant Venus was spotted at 8:50 pm in a higher cloud gap; it's now 36.2" apparent diameter and 28.1% illuminated, displaying a lovely crescent in the scope at 60x. About 4° east of Venus, I spotted Mars at 8:53 pm; its ruddy 4.2" disc was apparent at 60x. From there, I slid another 3° east to Regulus (Alpha Leonis); this bluish-white star is a sharp contrast to the ruddy disc of Mars. Finally, I swept about 8° north from Regulus to Algieba (Gamma Leonis); this pretty golden-hued double, magnitude 2.0+3.6, 4.5" separation, was split at 60x.

I was back out to Swede Run on the morning of July 6 to spot the Moon and the rest of the planets, Saturn, Neptune, Jupiter and Uranus (from west to east). The waning gibbous Moon (88.5% illuminated), Saturn and Jupiter were easily seen with unaided eyes on arrival at 3:00 am. Because of the bright Moon, and some fog, Neptune and Uranus were only seen with the 88 mm spotting scope (although all objects were examined with the scope at 60x). I left at 3:38 am (75°F) having spotted all seven planets overnight (eight including Earth, plus the Moon and the Sun).

My 88 mm Kowa apo spotting scope aimed towards Mercury at 8:39 pm on July 5. Mercury first appeared below the bright horizontal edge at the base of the cloud bank. The dark diagonal band above the trees is a shadow from a cloud just behind the trees.

The second sighting of the fourth elongation for 2023 was on July 12, 2023, from Bishops Gate in Mt Laurel, NJ, under a largely clear sky, but with murky horizontal cloud streaks along the western horizon. Mercury was initially sighted at 8:47 pm EDT, 18 minutes after sunset, with 15x56 binoculars. When first sighted, Mercury was 5.7° altitude, 293° azimuth, magnitude -0.88, 5.3″ apparent diameter and 88% illuminated. Solar elongation was 13.3° and the ecliptic latitude was 1.8°N; the ecliptic was tilted about 36° with respect to the horizon. I followed Mercury with an 88 mm spotting scope until 9:04 pm when it was lost in the trees at 2.8° altitude.

The third sighting of the fourth elongation for 2023 was on July 20, 2023, from Bishops Gate in Mt Laurel, NJ, under a largely clear sky, but with murky clouds along the western horizon. Mercury was initially sighted at 8:42 pm EDT, 18 minutes after sunset, with an 88 mm spotting scope at 25x, then subsequently with 8x42 binoculars at 8:48 pm. When first sighted, Mercury was 8.2° altitude, 285° azimuth, magnitude -0.34, 5.7″ apparent diameter and 77% illuminated. Solar elongation was 19.9° and the ecliptic latitude was 1.3°N; the ecliptic was tilted about 33.4° with respect to the horizon. The crescent Moon, crescent Venus and Mars were also observed during the session.

The fourth sighting of the fourth elongation for 2023 was on July 23, 2023, from the Barnegat Rd Observing Site in Woodland Twp, NJ, under a clear sky. Mercury was initially sighted at 8:44 pm EDT with 10x42 binoculars, 24 minutes after sunset at 8:20 pm (after receiving direction assistance from Suzanne Leap). When first sighted, Mercury was 7.9° altitude, 283° azimuth, magnitude -0.19, 5.9″ apparent diameter and 73% illuminated. Solar elongation was 21.9° and the ecliptic latitude was 1.0°N; the ecliptic was tilted about 32.0° with respect to the horizon. The crescent Moon, crescent Venus and Mars were also observed during the session.

The fifth sighting of the fourth elongation for 2023 was on July 24, 2023, from Bishops Gate in Mt Laurel, NJ, under a clear sky, with just a few modest clouds along the western horizon. Mercury was initially sighted with 15x56 binoculars at 8:36 pm EDT, 15 minutes after sunset at 8:21 pm. When first sighted, Mercury was 9.6° altitude, 281° azimuth, magnitude -0.15, 6.0″ apparent diameter and 71% illuminated. Solar elongation was 22.4° and the ecliptic latitude was 0.9°N; the ecliptic was tilted about 32.6° with respect to the horizon. The crescent Moon, crescent Venus and Mars were also observed during the session. The following morning, July 25, at Swede Run in Moorestown, NJ, the planets Saturn, Neptune Jupiter and Uranus (from west to east) were spotted in a one minute sweep with 15x56 binoculars about 2:30 am. So, all seven major solar system planets (eight with earth) were seen overnight.

The sixth sighting of the fourth elongation for 2023 was on July 30, 2023, from Bishops Gate in Mt Laurel, NJ. Mercury was initially sighted at 8:27 pm EDT with an 88 mm spotting scope at 25x. The crescent Moon, crescent Venus and Mars were also observed during the session. On the morning of July 30, in Wharton State Forest, NJ, the planets Saturn, Neptune Jupiter and Uranus were seen with 15x56 binoculars and a 115 mm spotting scope, Saturn and Jupiter with unaided eyes too. So, all seven major solar system planets (eight with earth) were seen on the same calendar day.

The seventh sighting of the fourth elongation for 2023 was on July 31, 2023, from Bishops Gate in Mt Laurel, NJ. Spotted at 8:32 pm EDT with an 88 mm spotting scope at 25x.

The eighth sighting of the fourth elongation for 2023 was on August 1, 2023, from Bishops Gate in Mt Laurel, NJ. Spotted at 8:47 pm EDT with an 88 mm spotting scope at 25x.

The ninth sighting of the fourth elongation for 2023 was on August 2, 2023, from Bishops Gate in Mt Laurel, NJ. Spotted at 8:32 pm EDT with an 88 mm spotting scope at 25x.

Elongation #3

The first sighting of the third elongation for 2023 (the 79th elongation in a row overall) was on May 26, 2023, from Swede Run in Moorestown, NJ, under a clear sky with only slight cloud streaks along the eastern horizon. Initially, I spotted Saturn and Jupiter with unaided eyes and verified them with 15x56 binoculars (I've already seen those two in the morning after solar conjunction). I also spotted dim Neptune with the 15x56s between Saturn and Jupiter (that's the first time for Neptune since solar conjunction). Mercury was spotted with 15x56 binoculars at 4:51 am EDT, 12 minutes after rising, when it was 2.0° altitude, 76° azimuth, magnitude +0.8, 8.7″ apparent diameter and 33% illuminated. Solar elongation was 24.7°, but the ecliptic latitude was 3.6°S and the ecliptic was tilted just 32° with respect to the horizon, so much of the elongation was sideways rather than perpendicular to the horizon.

The second sighting of the third elongation for 2023 was on June 1, 2023, from Swede Run in Moorestown, NJ, under a clear sky with murkiness along the eastern horizon. Initially, I spotted Saturn and Jupiter with unaided eyes and verified them with 15x56 binoculars and ultimately looked at them with my 88 mm apo spotting scope. At 60x in the 88 mm, Jupiter's equatorial belts were visible and all four Galilean satellites were west of the Jovian disc. From the disc, there was Io, then Europa and Callisto in a vertical pair, then Ganymede. Saturn's Rings were noticeably more closed compared to last year, and its satellite Titan was visible west of the planet. I also spotted dim Neptune with the 88 mm scope, but not convincingly with the 15x56s. Mercury was initially spotted with the 88 mm scope at 4:44 am EDT, then faintly in the 15x56 binoculars two minutes later. Sunrise would be at 5:33 am. When first sighted, Mercury was at 2.2° altitude, 73.9° azimuth, magnitude +0.35, 7.7″ apparent diameter and 44% illuminated. Solar elongation was 24.6°, but the ecliptic latitude was 3.4°S and the ecliptic was tilted just 34° with respect to the horizon, so much of the elongation was sideways rather than perpendicular to the horizon.

The third sighting of the third elongation for 2023 was on June 2, 2023, from Swede Run in Moorestown, NJ, under a clear sky with murkiness along the eastern horizon. Initially, I spotted Saturn and Jupiter with unaided eyes on arrival at 4:35 am EDT (sunrise would be at 5:33 am). Dim Neptune could not be seen with 15x56 binoculars. Mercury was spotted with the 15x56s at 4:47 am. When first sighted, Mercury was at 2.9° altitude, 74° azimuth, magnitude +0.28, 7.5″ apparent diameter and 46% illuminated. Solar elongation was 24.4°, but the ecliptic latitude was 3.3°S and the ecliptic was tilted just 34° with respect to the horizon, so much of the elongation was sideways rather than perpendicular to the horizon.

The fourth sighting of the third elongation for 2023 was on June 14, 2023, from the railroad tracks in Maple Shade, NJ, under a clear sky with just a couple of wispy clouds along the eastern horizon.  Mercury was initially spotted with  8x42 binoculars at 5:03 am EDT when it was at 5.3° altitude, 69° azimuth, magnitude -0.6, 6.0″ apparent diameter and 72% illuminated. Solar elongation was 18.2°, while the ecliptic latitude was 1.6°S and the ecliptic was tilted 39.4° with respect to the horizon, a little steeper than for the earlier sightings this elongation. About 27° west of Mercury, the crescent Moon and Jupiter were paired about 2½° apart.

Elongation #2

The first sighting of the second elongation for 2023 (the 78th elongation in a row overall) was on March 26, 2023, from Bishops Gate in Mt Laurel, NJ, under a clear sky with only vague cloud streaks along the western horizon. Shortly after arrival, Venus was visible with unaided eyes, then dropping down from there with 15x56 binoculars, I spotted Jupiter and Mercury in the same 4.5° field of view at 7:41 pm EDT. Mercury was 2.5° below-right of Jupiter. A couple of minutes later, with a little effort, I could see Jupiter with unaided eyes, but not Mercury. At first sighting, Mercury was 4.3° altitude, 275° azimuth, magnitude -1.4, 5.4″ apparent diameter and 92% illuminated. Solar elongation was 9.6°, ecliptic latitude was 0.0° (so it was actually on the ecliptic).

The second sighting of the second elongation for 2023 was on March 28, 2023, from the baseball field complex in Maple Shade, NJ, under a partly cloudy sky with a few cloud streaks along the slightly murky western horizon. Shortly after arrival, I spotted Jupiter at 7:35 pm EDT by scanning along the western horizon with 8x42 binoculars (9.1° field of view). A minute later, I spotted Venus with unaided eyes when it emerged briefly from broken clouds. Mercury was spotted at 7:36 pm in the binoculars near Jupiter (Mercury may have been hidden behind a utility wire when I first spotted Jupiter). In contrast to March 26, Mercury was now 1.9°above-right of Jupiter. In the 8x42s, Mercury looked stellar while Jupiter was a somewhat ghostly disc. With some difficulty, Mercury was spotted with unaided eyes at 7:51 pm, and with even more difficulty, Jupiter was seen with unaided eyes at 7:53 pm, even though Jupiter at magnitude -2.1 was brighter than Mercury (I suspect that it's larger disc, about 33″ apparent diameter, may have a lower surface brightness; in any case, it's lower altitude close to the horizon would have a more than negligible increase in atmospheric absorption. At first sighting, Mercury was 7.5° altitude, 274° azimuth, magnitude -1.3, 5.5″ apparent diameter and 88% illuminated. Solar elongation was 11.6°, ecliptic latitude was +0.3°.

Just before I left the field at 8 pm, the clouds overhead cleared further, so Mars was prominent 5.5° below the bright first-quarter Moon. I also looked for Uranus, about 2.5° above-left of Venus, but twilight was still too bright see this magnitude 5.8 object. While running some errands, I stopped at Bishops Gatre in Mt Laurel, NJ, and then saw Uranus with 15x56 binoculars at 8:40 pm.

The third sighting of the second elongation for 2023 was on March 30, 2023, from Bishops Gate in Mt Laurel, NJ, under a very clear sky. Shortly after arrival, I spotted Venus with unaided eyes at 7:35 pm EDT, then Jupiter at 7:40 pm with 15x56 binoculars and then Mercury with 8x42 binoculars at 7:41 pm. Two minutes later, I saw Mercury with unaided eyes (Jupiter was never seen with unaided eyes). At 8:02 pm, Uranus was spotted 1.2° from Venus with 15x56 binoculars. When first sighted, Mercury was 8.8° altitude, 276° azimuth, magnitude -1.2, 5.7″ apparent diameter and 83% illuminated. Solar elongation was 13.4°, ecliptic latitude was +0.8°.

The fourth sighting of the second elongation for 2023 was on April 2, 2023, from Bishops Gate in Mt Laurel, NJ, under an initially cloud-streaked sky in the west, but it cleared as twilight progressed. Shortly after arrival, I spotted Venus with 8x42 binoculars at 7:33 pm EDT, then immediately afterwards, with unaided eyes. Mercury was spotted with 15x56 binoculars at 7:46 pm, then unaided eyes at 7:48 pm. Mars was spotted with unaided eyes at 7:57 pm, then checked with binoculars to make sure it wasn't a reddish star (e.g., Betelgeuse). At 8:10 pm, Uranus was located 3.8° below Venus with the 15x56s. When first sighted, Mercury was 10.9° altitude, 277° azimuth, magnitude -1.0, 6.1″ apparent diameter and 73% illuminated. Solar elongation was 15.9°, ecliptic latitude was +1.3°.

Perhaps the main target the evening was Jupiter, which was only 6.7° solar elongation. I could not find its ghostly disc with the 15x56s in the still-brightish twilight glow by time it reached the treetops about 2° altitude. As I suspected, March 30 would be my last sighting for this apparition.

The fifth sighting of the second elongation for 2023 was on April 4, 2023, from the baseball field complex in Maple Shade, NJ, under a cloud-free, but very hazy sky. Upon arrival, I spotted Venus with unaided eyes at 8:30 pm EDT, and then with 10x42 binoculars, I slid down from Venus and spotted Mercury, and immediately afterwards, saw Mercury with unaided eyes (due to the haze, it was somewhat dim). When first sighted, Mercury was 4.5° altitude, 285° azimuth, magnitude -0.8, 6.4″ apparent diameter and 66% illuminated. Solar elongation was 17.3°, ecliptic latitude was +1.7°.

The sixth sighting of the second elongation for 2023 was on April 9, 2023, from the Wharton State Forest, NJ, under a very clear sky. On the way, I spotted Venus with unaided eyes through the car's moon roof at 7:52 pm EDT. On arrival at 8:15 pm, I immediately spotted Mercury with unaided eyes. At 8:30 pm, I located dim Uranus with 15x56 binoculars and I remembered to spot Mars with unaided eyes at 8:33 pm. At 8:52 pm, I spotted the asteroid (1) Ceres with the 15x56s. At Swede Run in Moorestown, NJ, on the morning of April 9, I spotted Saturn with the 15x56s at 5:36 am, then immediately afterwards, saw it with unaided eyes (just after it emerged from a horizontal cloud along the horizon). When first sighted, Mercury was 10.3° altitude, 284° azimuth, magnitude -0.2, 7.3″ apparent diameter and 47% illuminated. Solar elongation was 19.3°, ecliptic latitude was +2.5°.

The seventh sighting of the second elongation for 2023 was on April 10, 2023, under a very clear sky. Initially, I spotted Venus with unaided eyes at 7:45 pm EDT from my Maple Shade, NJ, driveway. At 7:57 pm, I spotted Mercury from the local Acme parking lot with 8x42 binoculars then with unaided eyes. When first sighted, Mercury was 14.0° altitude, 281° azimuth, magnitude -0.03, 7.5″ apparent diameter and 43% illuminated. Solar elongation was 19.5°, ecliptic latitude was +2.6°.

The eighth sighting of the second elongation for 2023 was on April 12, 2023, under a very clear sky from Smithville Park in Easthampton, NJ. Mercury was initially spotted at 8:00 pm EDT with 8x42 binoculars then with unaided eyes. When first sighted, Mercury was 13.5° altitude, 283° azimuth, magnitude +0.3, 7.9″ apparent diameter and 36% illuminated. Solar elongation was 19.43°, ecliptic latitude was +2.8°.

The ninth sighting of the second elongation for 2023 was on April 13, 2023, under a very clear sky from Atsion in Wharton State Forest, NJ. Mercury was initially spotted at 8:18 pm EDT with 15x56 binoculars then with unaided eyes. When first sighted, Mercury was 10.2° altitude, 286° azimuth, magnitude +0.5, 8.2″ apparent diameter and 33% illuminated. Solar elongation was 19.27°, ecliptic latitude was +2.9°. Greatest Eastern Elongation was on April 11, but will become stationary (with respect to the celestial sphere) on April 21.

The tenth sighting of the second elongation for 2023 was on April 18, 2023, under a very clear sky from Atsion in Wharton State Forest, NJ. Mercury was initially spotted at 8:12 pm EDT with 15x56 binoculars after being first sighted with Jim F's go-to scope. It was seen with unaided eyes at 8:18 pm. When first sighted, Mercury was 10.0° altitude, 287° azimuth, magnitude +1.5, 9.4″ apparent diameter and 18% illuminated (due to poor seeing, the crescent wasn't visible in Jim's scope). Solar elongation was 16.9°, ecliptic latitude was +3.0°.

The eleventh sighting of the second elongation for 2023 was on April 19, 2023, under a mostly clear sky (a little haze streaking along the horizon to the west) from Bishops Gate in Mt Laurel, NJ. Mercury was initially spotted at 8:03 pm EDT with an 88 mm apo spotting scope at 40x. It was seen with 8x42 binoculars at 8:14 pm, but not with unaided eyes through 8:38 pm when it sank into the distant trees. With the 88 mm scope at 96x, I was able to discern the crescent shape (15% illuminated) during brief periods of steadier seeing. The cusps were nominally at about 8:30 and 2:30 o'clock (as seen in the correct view of the spotter). Because of the low altitude, Mercury displayed significant atmospheric chromatic aberration at 96x. With difficulty, I was able to spot then pair of stars, Rho 2 & 3 Arietis, that were roughly midway between Mercury and Uranus, but alas, I just couldn't locate Uranus in the residual twilight. When first sighted, Mercury was 11.4° altitude, 286° azimuth, magnitude +1.7, 9.7″ apparent apparent diameter and 15% illuminated. Solar elongation was 16.1°, ecliptic latitude was +2.9°.

The twelth sighting of the second elongation for 2023 was on April 20, 2023, at Bishops Gate in Mt Laurel, NJ, under a mostly clear sky, but there were broken, slow-moving clouds above the western horizon. Venus was spotted with unaided eyes at 7:40 pm, four minutes before sunset. Mercury was spotted at 8:04 pm EDT with an 88 mm apo spotting scope at 25x. It was subsequently seen with 10x42 and 15x56 binoculars, but not with unaided eyes. With the 88 mm scope at 60x, I had glimpses of the 13% crescent during brief periods of steadier seeing. Uranus, about 4° left of Mercury, was not seen (but I didn't look too hard). The prime target for the evening was a nominal 20 hour old crescent Moon, 0.7% illuminated. Alas, it was seen, after searching with the binoculars and the spotting scope (it would have been a challenge even without the clouds). When first sighted, Mercury was 10.5° altitude, 286° azimuth, magnitude +2.0, 9.9″ apparent diameter and 13% illuminated. Solar elongation was 15.2°, ecliptic latitude was +2.9°.

Elongation #1

The first sighting of the first elongation for 2023 (the 77th elongation in a row overall) was on January 16, 2023, from Marter Ave in Mt Laurel, NJ, under a clear sky with a one-third illuminated Moon, along with a sighting of comet C/2022 E3 (ZTF). Using Ophiuchus a an azimuth guide, Mercury was spotted at 6:07 am EST with 15x56 binoculars and then glimpsed with unaided eyes at 6:12 am. The comet, in Boötes, was spotted at 6:10 am with the 15x56s, 26 minutes after the start of astronomical twilight. At first sighting, Mercury was at 1° 03′ altitude, 117° azimuth, magnitude +0.90, 9.0″ diameter and 24% illuminated. Solar elongation was 17.9°. I didn't try to see the crescent as the seeing was horrible at the low altitude.

Later that day, not too long after sunset at 5:00 pm EST, brilliant Venus, bright Jupiter and bright Mars were easily seen with unaided eyes. A little later, Saturn was picked up with 15x56 binoculars, then seen with unaided eyes. As twilight deepened, dim Uranus and Neptune were spotted with the 15x56s. Combined with Mercury seen before sunrise, all seven planets, plus the Moon and a comet, were seen on the calendar date of January 16, 2023.

The second sighting of the first elongation for 2023 was on January 24, 2023, from Swede Run in Moorestown, NJ, under a mostly cloudy sky (there was a gap in the clouds along the southeastern horizon). Mercury was spotted at 6:08 am EST with unaided eyes. Astronomical twilight started at 5:41 am and the sunrise would be at 7:15 am. When sighted, Mercury was at 4°09″ altitude, 122° azimuth, magnitude +0.04, 7.5″ diameter and 50% illuminated. Solar elongation was 24.0°.

The third sighting of the first elongation for 2023 was on February 14, 2023, from East Point, NJ, on the north shore of the Delaware Bay after a successful excursion to spot Omega Centauri. Under a clear sky down to the horizon, Mercury was spotted at 6:00:30 am EST with 15x56 binoculars; it was not seen with unaided eyes. Astronomical twilight started at 5:23 am and the sunrise would be at 6:53 am. When first sighted, Mercury was at 0°30′ altitude, 116.5° azimuth, magnitude -0.2, 5.5″ diameter and 82% illuminated.

_{________________}

The current streak is now 82 elongations in a row, completing thirteen calendar years of seeing Mercury at every elongation (beginning in January 2011). There are six or seven elongations per year. The years 2011, 2015, 2018 and 2022 each had seven (7) elongations, while 2012, 2013, 2014, 2016, 2017, 2019, 2020, 2021 and 2023 each had six (6). That's 82 elongations in 13 years, or an average of 6.3 elongations per year. 2024 will have seven (7) elongations. Click here for sightings in 2022. The purpose of this ongoing effort is not to set some record, especially since I have no idea what sort of record might exist. My note to Gary Seronik that was published in S&T magazine (see on the 2022 Mercury page) yielded no responses. Regardless, it demonstrates that locating and seeing Mercury is not nearly as difficult as many suppose. It just takes a little planning and effort, although circumstances make some elongations easy and some difficult.

Return to the SJAstro home page.

Last Update: Saturday, December 30, 2023 at 07:58 AM Eastern Time