Joe Stieber's Home Page

Comet C/2025 F2 (SWAN)
April - May 2025

Recently discovered comet, initially called SWAN25F informally, but now officially designated C/2025 F2 (SWAN), made a surprising appearance in the morning sky of the Northern Hemisphere after it's discovery from images from the SWAN instrument on the SOHO spacecraft. It's currently (as of April 11) leaving the Great Square of Pegasus and heading into Andromeda. Current brightness reports at COBS are largely in the magnitude 8 to 9 range, which is within reach of a modest scope. I was able to see the dim coma, and perhaps a short vague tail, with a 35x115 spotting scope, but nothing with 15x56 binoculars, from Carranza Field in Wharton State Forest, NJ, on the morning of April 9, 2025 (at the end of a rare clear night). My non-expert magnitude estimate, based on comparison to the defocused star SAO 91459, was 8.6.
Update, April 17, 2025: The coma was not detected on April 17, around 5:00 to 5:15 am EDT, with a 35x115 scope at Carranza. A nearby magnitude 9.6 star was seen, even though there was an 84% illuminated Moon behind me at 20° altitude in a clear sky during the early part of astronomical twilight (which began at 4:40 am EDT). Discussion on the Comet Mailing List speculates the comet is disintegrating.
Update, April 25, 2025: A new chart for the early evening sky has been generated for the end of April into early May 2025. Here's a SkyTools ephemeris for April 25 to May 10, 2025, at 9 pm EDT. However, it may be academic as the evidence of F2's disintegration is mounting. As of April 29, it's just a relic cloud of dust.

Venus and the Crescent Moon
March 27, 2025

The planet Venus was joined by the Crescent Moon, on March 27, 2025, as seen from Marter Ave in Mt Laurel, NJ. Venus entered the morning sky after inferior conjunction with the Sun on March 22, 2025 at 9:07 pm EDT. It was spotted from this location just before sunrise on March 23 and will continue its westward movement, reaching greatest elongation from the Sun on May 31, 2025. In contrast, the Moon is moving eastward towards the Sun, reaching New Moon on March 29, when there will be a partial eclipse of the Sun, visible from our area briefly after sunrise. Venus was visible with unaided eyes this morning, but it's not yet the brilliant beacon it will soon become.
This snapshot of them is from a single raw frame taken at 6:22 am EDT with a Canon EOS RP DSLM camera and a Sigma 50 mm f/1.4 Art lens on a fixed tripod. It was exposed 1/60 sec at f/4.0, ISO 1600, daylight white balance and then mildly adjusted. It was cropped to 87% of the width x 43% of the height of the original dimensions, a 3:1 ratio, for a field 34.5° wide x 11.9° high. At the time of the picture, Venus was at 4.2° altitude, 10.6° solar elongation and 1.7% illuminated. The Moon was at 4.0° altitude, 27.8° solar elongation and 5.8% illuminated. The two objects were 23.1° apart, with Venus 8.0° above (north of) the ecliptic and the Moon 2.6° below (south of) the ecliptic. This, and the shallow 27° tilt of the ecliptic resulted in the wide spacing despite being very nearly the same altitude above the horizon. Mouseover for labels.
Update, March 29, 2025: Here's an account of my Venus & eclipse observations on March 29. I didn't take any pictures, but here's one of my snapshots of the partial solar eclipse just after sunrise on June 10, 2021. It's reminiscent of the view I had on March 29, although the degree of obscuration may be a little more, and the recent Sun had thin clouds running horizontally across the disc, giving it a Jupiter-like appearance. I also saw a number of birds flying in front of the Sun with the 88 mm scope, one of which was clearly identifiable as a Turkey Vulture. An aircraft also passed in front of the Sun. I suspect the number of objects so seen was because of the low solar altitude.

Daytime Venus Spotting
March 18, 2025

Here's my 88 mm Kowa apo spotting scope on March 18, 2025, set up in a parking at the baseball field complex in Maple Shade, NJ. With this simple alt-azimuth gimbal mount on a sturdy photo tripod, I was able find the crescent Venus in less than two minutes (here's a close-up of the scope from the other side). First, make the shadow of the scope (on the gravel to the right) as small as possible, then look at the eyepiece lens from the side and move the scope slightly as needed for a bright disc to glow on the eyepiece lens (the Sun, so I don't look directly into the eyepiece). I then aimed the scope upwards 11° using the scale on the altitude axis (which is somewhat coarse with 7.5° increments). Then I looked into the eyepiece and adjusted the position slightly and there was the thin crescent Venus at 1:52 pm EDT. I picked a nominal time of 2 pm EDT because that's when Venus would be directly above the Sun. The relatively wide spacing resulted in only a few airborne seeds, highlighted by forward scattering, from whizzing across the field of view. They can be highly distracting when looking closer to the Sun in the daytime.
Venus will reach inferior conjunction on March 22, about 8.4°N ecliptic latitude, at 9:07 pm. That relatively large span allows for easy spotting with favorable weather as it has been on March 17, 18 & 19. As a result, I spotted Venus at sunset on March 17 & 18, then before sunrise on March 18 & 19. So for two nights in a row, I saw Venus at "both ends" of the night, and Venus was still the "evening star" at the morning sightings (prior to inferior conjunction). So far, Venus was visible with unaided eyes in the evening, but optical aid (binoculars) are needed in the morning. The daytime crescent, around 2 pm on March 18 & 19, was exquisitely thin, 1.8% and 1.5% illuminated respectively, with the cusps approaching 180° separation and the disc itself seemingly present (probably an illusion). It was a sublime sight at 60x in the spotting scope.
Here's a sighting log for the dates around the current inferior conjunction, sunrise, midday and sunset. Venus was observed on March 22, 2025, as a result, it has been observed on four of the last five conjunction days. The only exception during that span was the superior conjunction of June 4, 2024, when Venus was occulted by the Sun for two days, so it was impossible to see.

Venus and Mercury
March 9, 2025

The brilliant planet Venus was joined by the other inner planet, Mercury, on March 9, 2025, as seen in this view from Bishops Gate in Mt Laurel, NJ. This snapshot of them is a single raw frame taken at 7:59 pm EDT with a Canon EOS RP DSLM camera and a Canon 100 mm f/2.8L macro lens on a fixed tripod. It was exposed 0.6 sec at f/4.0, ISO 1600, daylight white balance and mildly adjusted. It was cropped to 80% of the width x 90% of the height of the original dimensions, a 4:3 ratio, for a field 16.4° wide x 12.3° high. At the time of the picture, Venus was magnitude -4.4 and 13.3° altitude; Mercury was magnitude 0.0 and 6.1° altitude. The two were 6.1° apart.
Venus was obvious with unaided eyes when I arrived at 7:05 pm, but I did not see Mercury until 7:20 pm with 8x42 binoculars, then unaided eyes at 7:32 pm (sunset was at 7:01 pm, astronomical twilight ended at 8:31 pm). Venus had reached 55.0 arc seconds diameter and was 6.8% illuminated, a lovely thin crescent in my 88 mm spotting scope at 60x. However, I could discern the crescent with my 8x42s. Mercury, 7.7 arc seconds diameter, was a thick crescent, 38% illuminated, but at 60x88, it was at best an oval blob due to less-than ideal seeing, orientated with an approximate 8 o'clock to 2 o'clock tilt. The star right of, and slightly above Venus, is Algenib, which marks the southeast corner of the Great Square of Pegasus. Mouseover for labels.

Venus and the Crescent Moon
March 1, 2025

On March 1, 2025, the two-day old, 5% illuminated Crescent Moon joined the brilliant planet Venus, itself a 14% illuminated crescent, although not visible here because of Venus' small size plus being significantly overexposed. This snapshot of them is a single raw frame taken at 6:51 pm EST with a Canon EOS RP DSLM camera and a Canon 100 mm f/2.8L macro lens on a fixed tripod. It was exposed 1/15 sec at f/2.8, ISO 6400, daylight white balance. It was cropped to 64% of the width x 72% of the height of the original dimensions, a 4:3 ratio, for a field 13.1° wide x 9.9° high. At the time of the picture, the Moon's altitude was 13.3° and Venus' was 18.0°. The two were 6.9° apart (center-to-center). The glow of earthshine on the Moon's surface not illuminated by the Sun is prominent, as it was visually.
I was surprised on my way to the baseball field that I inadvertently spotted Mercury with unaided eyes through the car's windshield at 6:38 pm. It was relatively bright in the very clear sky, about 10° below the Moon, and I had to watch for a bit to be certain it wasn't an aircraft. It remained visible for most of the time I was taking pictures of Venus and the Moon, but being lower, it went into the trees before the last shot was taken at 6:51 pm. Overhead at the field, Jupiter and Mars were easy with unaided eyes. I did not get out binoculars for Uranus overhead, and I didn't attempt to see Saturn or Neptune, too low for my belated start this evening (and now maybe lost in twilight anyway).

22.5 hr old Crescent Moon
February 28, 2025

On February 28, 2025, the thin Crescent Moon was spotted at Bishops Gate in Mt Laurel, NJ, at 6:14 pm EST using 12x50 binoculars. At the time, it was 22 hr 29 min old after New Moon, which was at 7:45 pm on Feb 27, and 1.1% illuminated (here's a WinJUPOS synthetic image). Sunset was at 5:51 pm and the crescent was subsequently seen with unaided eyes. It was a fine view with an 88 mm spotting scope at 60x. This snapshot is from a single raw frame taken at 6:34 pm with a Canon EOS RP DSLM camera and a Canon 400 mm f/5.6L telephoto lens on a fixed tripod. It was exposed 1/40 sec at f/5.6, ISO 12,800. White balance was set to automatic ambience, but little processing otherwise. It was cropped to 67% of the original dimensions for a field 3.5° wide x 2.3° high. At the time of the picture, the Moon's altitude was 2.7° vs. 6.2° when first sighted. I'm not sure if it's just an illusion, but the rest of the lunar disc outside the thin crescent seems to be illuminated by a faint glow of earthshine.

Crescent Venus
February 25, 2025

On February 25, 2025, the thinning crescent of Venus was 17.4% illuminated and 36.7° altitude at 7:24 pm EST when this snapshot was captured in a dark sky 7 minutes after the end of astronomical twilight. This is from a single raw frame taken with a Canon EOS 7D Mk II DSLR camera (APS-C sensor) and a Tamron 150 to 600 mm zoom lens, on a fixed tripod, set to 600 mm focal length. It was exposed 1/1600 sec at f/16, ISO 800. The only processing was converting the daylight color balance as captured to monochrome. It was cropped to 11% of the original dimensions for a field 0.23° wide x 0.16° high. Venus was 46.6 arc sec apparent diameter at the time, yielding a 136 μm diameter image on the sensor, about 33 pixels.

Crescent Venus
February 17, 2025

On February 17, 2025, as Venus was approaching inferior conjunction (see below), it presented a thinning crescent, 24.7% illuminated at 6:04 pm EST when this snapshot was captured in a still-blue sky 25 minutes after sunset. This is from a single raw frame, unprocessed, taken with a Canon EOS RP DSLM camera and a Tamron 150 to 600 mm zoom lens, on a fixed tripod, set to 600 mm focal length. It was exposed 1/2000 sec at f/16, ISO 1600. The brief exposure was needed to offset (somewhat) the effects of poor seeing and jiggle from a stiff breeze that was blowing. The result was a black background even though set to daylight white balance (also a testament to Venus' brilliance). It was cropped to 7% of the original dimensions for a field 0.25° wide x 0.17° high. Venus was 41.1 arc sec apparent diameter at the time, yielding a 120 μm diameter image on the sensor, about 21 pixels. Mouseover to clear labels.

Venus at Inferior Conjunction, March 22, 2025

Click here for a table of Venus' recent solar conjunctions that have been observed. Mouseover to de-label this illustration. Interestingly, can you figure out how Venus can be 8.4° from the Sun at conjunction, although it's ecliptic inclination is just 3.4°? Also, see Bob King's February 2025 crescent Venus article at S&T online.
I missed Venus' inferior conjunction on June 3, 2020, due to clouds, but I did see the delicate crescent (0.1% illuminated) on June 1 with my 88 mm apo spotting scope at 60x when Venus was just 3.1° from the Sun. It was perhaps the most sublime sight I ever saw in the sky. The best pictures of this conjunction I've seen were taken by Nicolas Lefaudfeux, but to me, they pale compared to the visual view I had.
In addition, Venus' considerable northerly ecliptic latitude near inferior conjunction will allow sighing of Venus in the morning before sunrise for a few days or so before inferior conjunction, when it's still technically the "Evening Star" Hesperus. Starting on the morning of March 23 for our location, it becomes Phosphorus, the "Morning Star". Here's a table of morning rise times for the Sun and Venus for a few days before inferior conjunction.

Click here for the previous page.

Click here for an index to all previous SJAstro pages.