Hiked April 12, 2025. Moved this one up in the publication queue because of its timeliness.
A recently discovered comet had me itching at the chance to get out somewhere dark to have a try at it. Its name is C/2025F2 SWAN. It's called "SWAN" because it was discovered by the "Solar Wind ANisotropies" instrument, about the European Space Agency's Solar and Heliospheric Observatory (SOHO). Most comets nowadays are being discovered by these automated imaging observatories, once someone gets around to reviewing the data. NEOWISE and Tsuchinshan-Atlas were two other recent examples of that.
On March 29, this comet was observed on data collected by SWAN. On April 8, it got the current official name. Unfortunately, it may have been undergoing an outburst right about when the first photographs were taken following the announcement. It apparently got dimmer after that, so, unlike some previous comets, it has really been pretty quiet on my facebook feed and news stories for this guy. Most are still using the first photos following the report, which showed a long and thin tail. The more recent photos look more like what I got on April 13, which was a small and undefined fuzziness.
As I write this, Comet C/2025F2 SWAN is in the morning sky, rising a little before sunrise. It gets less than five degrees up (ten apparent moon diameters) before dawn starts brightening the sky.
On the morning I viewed, it was in the east-northeast. It's moving further north each night, but also getting lower in the sky. It'll be hard to catch as we get towards later April, unless it gets a lot brighter.
I had two ideas for where I might view: Ryan Mountain trailhead, or Arch Rock Trailhead. I've done viewing from both locations in the past, and visited both sites the afternoon of the 12th. Ryan Mountain works better for things to the west, but, to the east, the land climbs in altitude, and there are rocks and hills, so for a low in the east-northeast comet, it didn't look like it would work well.
Meanwhile, although there is a slight hill to the east and northeast of Arch Rock trailhead, it's far enough away that it doesn't take too long for objects in the east to rise above them. I confirmed this while parked in the lot, and picked my spot within the lot for the next morning. Then, with about 90 minutes before the end of civil twilight, I went hiking.
No particular destination. I've seen the major attractions here many times (Arch Rock and Heart Rock), and also wandered, in the past. Did the same, this evening.
Late afternoon and early evening is a great time to go hiking in the desert. The sun is low, and the soft, warm light makes the desert look rather magical. Everywhere I turned, I saw somethng photogenic.
Began my return trek as the sun went down. Atop several different outcroppings, my fellow hikers sat, watching the sun set over the Joshua trees.
Not sure of my hiking distance, because I forgot to shut my Alltrails recording when I got back to the car. The actual Arch Rock trail is given as 1.2 miles roundtrip. However, I wandered a lot before looping back to Arch Rock. I also made the spur to Heart Rock. So I would estimate somewhere near three miles for the afternoon.
The next morning, I got to the parking area around 3:45am, and assembled my 8" dob, and two photographic setups. But I forgot the setting to let me take longer exposures with my Nikon D3500 (you need to change a video setting if you're using Liveview to take exposures longer than 1/60th of a second, even in photo mode), so I only took photos with my refractor system, and visually searched with my Dob.
It was somewhat cloudy to the northeast, and a practically full moon was off in the west, so the sky was pretty bright, even before dawn. That limited the exposures to only 8-13 seconds. Good for limiting star trailing, I guess. But not good for picking up comets.
I did get images of the comet, but no tail was visible. Just a greenish smudge.
I'm going to try again on April 20. As noted above, the comet may be brighter, but it will also be lower in the sky. Also, while the moon is smaller (waning, last quarter), it will also be closer in the sky to the comet.
Unfortunately, the latest news is not encouraging. Sounds like the comet may have disintegrated, which would explain the brief outburst early last week, then the dramatic dimming after that.
Well, I was up late doing astronomy outreach on Saturday night, and wasn't motivated enough to get up with three hours of sleep to try, again. But the information from Friday and my not seeing encouraging photos all week convinced me that even a "successful" hunt on the 20th would have been a pretty poor showing.
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