Fireball!

1997 July 25/26


The TAC public night at Van Meter school turned out to be a very good night in terms of the diversity and rarity of what we saw, and in the amount of interest the public showed throughout it.

Although there probably under 20 people at the event, it seemed to be a good match for the three scopes that were set up (Rich, Michelle, and I). As a result everyone got to see a lot and ask a lot of questions. And everyone seemed genuinely interested in learning about what they were seeing.

I spent a large part of the night giving a private "beginning astronomy class" to one individual, complete with constellation lore, star-hopping through binos, and a tour of different types of astronomical objects through my 8" LX-200. All the while answering the questions of those "just passing through" for another glimpse each time the scope moved.

My evening started out with spotting Venus (first through binos and then immediately naked-eye) at around 8:15. I did a quick pseudo-alignment there which allowed me to easily find Mercury even though it was still invisible to me through binos at the time. Venus was slightly gibbous, and Mercury was slightly crescent. They made a nice pair. Over the course of the evening, I managed to see all of the planets except for Pluto which was just too washed out through the city lights.

Jupiter was gorgeous, and showed good detail. We got to enjoy a tight grouping of three of its moons, a moon transit/exit, a moon shadow transit, and the GRS transiting with two mysterious white circles appearing to be inside of it.

Luna came up orange and amazingly steady as it peaked over the horizon a little after midnight. The solar angle was just "perfect" for making the surface seem more 3D than usual to me.

The Southern Delta Aquarids were quite active considering we were two days from peak, and were seeing them before midnight. I probably saw over a dozen without even looking for them.

One highlight came after the public had gone. It was the most intense fireball any of us could recall ever seeing. It fell at 12:37 from high in the South to low in the South-East, cutting right between a setting Scorpius and Ophiuchus positioned above/right of it. I saw the flash on the cars and had enough time to turn around and find it in the sky. It fell slowly in the end as it burned with an intense green color (perhaps a little blue as well), and sprayed sparks reminiscent of the old Flash Gordon spaceships. It broke into a few pieces and then crumbled into many more as it went out. I'm fairly sure this was an S.D.Aquarid as well.

I'd do the whole night again tomorrow if I could!

-- Mark Taylor


July 25 and 26, 1997, brought good observing conditions to Fremont Peak State Park, near San Juan Bautista, California. On both nights, thick fog and cloud lay over the coastal plain from Santa Cruz to Monterey, and spilled through the gap to Gilroy and Hollister. The light block was not perfect, but it got pretty dark. Seeing was also good, with frequent intervals when instruments of 12-inch aperture, or more, could run diffraction-limited. Temperatures stayed balmy.

On Friday evening, I had the only telescope in the southwest parking lot. Before end of twilight, I showed some non-astronomers five naked-eye planets at once. Mercury and Venus lay close together in the western sky, Mars was higher up, Jupiter had just risen in the east, and Earth lay beneath our feet. After they left, I had the area to myself, except for the occasional squeaking bat zooming overhead.

My program for the evening was galaxies from the full Herschel list (not just the "400" list) with my Intes 6-inch Maksutov. Most of what I sought lay in the western sky, which is usually brightened by lights of coastal cities, so I was again greatful for the low cloud. The six-inch has low light-collecting ability for such faint fuzzies, but that's what makes it fun. I have tried various magnifications, and am now using 94x -- a 16 mm Erfle eyepiece -- for this work. I logged over 40 new galaxies in the couple of hours before moon rise.

While taking down my equipment, at 0040 PDT on the morning of the 26th, I was treated to what was probably the brightest fireball I have ever seen, moving slowly for a meteor, descending across the western sky, from the head of Serpens to half way between Corona Borealis and Arcturus. The dazzling green apparition cast sparks and shadows. Observers elsewhere reported it brighter than the just-risen last-quarter moon, which was still behind trees for me. Thus the fireball may have reached apparent visual magnitude -10, or brighter. Based on the different positions of the tracks seen by me and by other observers several tens of Km away, any impact would have been in the Pacific Ocean, very roughly 100 Km west of Santa Cruz, California.

I always have a duck-and-cover reaction to bright fireballs, which comes from growing up in the height of the cold war, near several US military sites likely high on the Soviet target list. I was amused to note that my instant reaction to this one was relief, that given its location and direction of motion, it was probably not an ICBM.

Saturday repeated Friday's weather, so I returned to the Peak and continued my program. There were plenty of other telescopes. I set up next to a friend with a Meade 12-inch LX200, and borrowed its use for a time, for my galaxy observations. It found faint fuzzies as fast as I could press keypad buttons -- it took me nearly three hours to log 46 more galaxies with my Intes, but the Meade knocked off a run of 18 in ten minutes. Yet the main advantage of the big LX-200 was not go-to capability, but aperture: With the 6-inch, I usually spend far more time and trickery making sure I can actually see a faint Herschel galaxy than I do identifying the field and centering the location. At 12 inches, all the galaxies were immediately obvious with just averted vision. That sped things up. Of course, the Meade's frequent slewing-motor noises left me hankering for my favorite beverage, but I've learned -- I had a thermos of hot water and a jar of instant espresso handy.

Lots of people were looking at planets. The LX200 owner located Venus with the Sun up, calibrated the telescope's orientation, then found Mercury and Mars. Mercury was particularly satisfying, for the seeing was okay, and the planet was much higher in the sky than on any of my previous views. It was my first look at Mercury without the tiny disc seriously distorted by atmospheric refraction. We saw no markings, but I can believe telescopes this size or larger might find some.

We also looked at Neptune, and may have seen Triton, except there was a difference of opinion whether our ephemeris program was set up to display with left-right reversal or not. We saw an object of about the right brightness and distance from the planet for Triton, on the opposite side of the planet from where the display showed it. When I left the telescope, the vote was about 60/40 that the program was right, and that we had not seen Triton, but the computer's edge at the ballot box was declining, and the polls had not yet closed. Another observer also had trouble with software -- he was hunting Pluto, with several different programs to locate it. Unfortunately, no two agreed on where it was. Tsk, he should have known better than to use more than one...

Jupiter required no hunting: I saw the giant planet in a 12-inch Meade SCT, a 180 mm Astro-Physics EDT, and a 9-inch Takahashi SCT: All gave wonderful views. Near the end of the evening, I found a Meade ETX set on Saturn, and took a look. At only a little over 100x, the instrument was loafing, but the jewel-like image reminded me that my first telescopic view of any celestial object, as a newbie eight-year-old, was of the ringed planet. Saturn was captivating in small aperture then, and it still is.

-- Jay Freeman


As soon as Luna rose above the trees, I noticed a nice shadow show on the floor of the crater Archimedes. (Archimedes is just east (lunar) of Dave North's favorite crater, Timocharis :) As the Sun sank lower, the shadows filled Archimedes except for a bright ray which took about 2 hours to fade. For a while, Archimedes looked just like a letter theta. Then the ray faded into a tiny dash and disappeared. It takes a long time for these events to play out on the Moon, since it rotates so slowly (compared to Earth). At the end, I was using averted vision to hold the last tiny bit of it. Averted vision on the Moon -- who woulda thunk it?

-- Bill Arnett


Mark Taylor / Jay Reynolds Freeman / Bill Arnett; last updated: 1997 July 28