Observing 9/19/1998: Farewell to Summer, Greetings to Autumn (long)
By Bruce Jensen

September 19 - 20, 1998, Fremont Peak:

It has always seemed to this observer that the late summer-early autumn is the best time of year to get out and watch the skies. We still have time to say a long loving "Goodbye" to the summer Milky Way and the home-galaxy treasures it contains, and then have the opportunity to greet the deepest-sky denizens of the fall. Pegasus, Andromeda, Cetus, Pisces and Fornax all yield views of their distant galactic jewels now, and if we persevere through the night we even have a chance to savor a few brilliant winter objects before the sun brightens the dawn. All this and the crisp autumn atmosphere, with the aroma of dried herbs wafting past, make autumn a favorite season for being outdoors at night.

After a late afternoon arrival at Fremont Peak and setting up with perhaps 30 other scopes and their hopeful owners, the sky began to darken and the summer stars began to show. Early on, the Pacific coast fog that sometimes mercifully covers the city lights seemed as if it would just tease us, and for the first few hours it didn't settle significantly; but as the night progressed, the moisture haze deepened and condensed, and after midnight the sky became quite dark and useful for deep-sky searches. After a quick visit to the 30" Challenger scope at the observatory, it was time to begin sweeping the wonderfully transparent sky.

I used an 18" Starmaster F/4.5, with widefield eyepieces for magnifications of 92x and 145x, as well as a 2.5x barlow on these and an 11mm plossl for higher magnification (184x). First, some bright and easy objects were sought (M15, M33 among others) as well as some fainter but nonetheless valued friends (Stephan's Quintet, aka Hickson 92, and Jones 1 in Pegasus). M15 was beautiful at 145x and 220x, with many tiny sparkling stars and a dense but seemingly resolved core. M33, the big spiral in Triangulum, was best at 92x with a Deep-Sky filter - early on, the galaxy would barely show it's spiral arms in the still-considerable sky glow, along with its H-II nebular regions, but after midnight and the onset of valley fog, it would gain greatly in contrast and detail. Hickson 92 revealed all five galactic components with some effort at 145x (the mediocre seeing apparently made the nearly merged pair a sometimes-thing), but Jones 1 at 92x with an O-III filter was just lovely, giving the normal impression of a c-shaped almost-ring-type planetary nebula. At SAV a month ago, the sky was very steady and Jones 1 seemed to reveal some degree of structure, like multiple thin shells; but tonight, the stability permitted only the basic ring-shaped view. It was also faintly visible using an O-III filter through the 10" F/4.5 dobs of some friends who were present, and I suspect that an 8" under dark skies would also reveal Jones 1.

After that, onto some new items. The first was another Pegasus planetary, NGC 7094. It could not be called bright, requiring as with Jones 1 an O-III filter for a really good view, nor was it very large (184x showed it's 1.5 arcminute disc best), but it did reveal detail such as a soft ring shape (it's brightness dropped off toward the center) and it's 13.5 magnitude central star, as well another star of similar brightness superimposed. It's just a short hop from M15 and fairly easy to find by starhopping in the finder.

A search for Hickson 10 was fruitful, revealing a fleet of galaxies with NGC 536 as the flagship. The A, B and C components were sufficiently bright to view, although the fourth of the quartet eluded me this night. Hickson 1 was not so easy, and in fact did not show it's face after several minutes of searching the field.

Hickson 2 in Pisces contains four galaxies all brighter than mag 16, including UGC 312, it's brightest component at mag 13.4. This galaxy was visible, it being the only one in the field and with no other bright galaxies shown on SkyAtlas 2000 in the vicinity. The remainder were not seen, and I shall have to try again under slightly better conditions.

On to some faint galaxies. NGC 95 in Pisces was small but fairly bright at it's core, at mag 12.6. NGC 128 (mag 11.8) is the brightest of a lovely group of galaxies in Pisces that also includes NGCs 125, 126, 130 and it's faintest member, NGC 127 at mag 15.3. The first four were easy to spot without additional direction, but it took the high-detail chart from a neighbor's computer to point out the faintest member, and then it was visible only with averted vision; still, a great find. NGC 237 (mag 13) was faint but with a small bright nucleus, and NGC 245 at mag 12.2 was similar but brighter.

Midnight rolled around, and with it the dome of the sky. Taurus now ascended with the Pleiades bright, and the fog began to really darken the skies. A quick point toward the Crab Nebula, the first object on Charles Messier's list of annoying comet-like objects, revealed an irregular oval disc with lots of ragged edge detail; the wide and narrowband filters improved the views, showing the distinctive gentle S-curve of the object and more ragged detail on the edges. A wonderful view, the best this observer has seen.

The three Auriga M-clusters (M36, M37 and M38) were blazingly bright in the 18" scope, and the 92x eyepiece seemed just right for all three, with many stars occupying between 50 and 75% of the diameters of the respective fields. The Orion Nebula M-42, still quite low on the horizon and whose image was still caught in the grip of the unstable lower atmosphere, was just the same bright and detailed, with six shimmery stars visible in the Trapezium and quite a lot of detail revealed with the Ultrablock and O-III filters, including a razor-sharp knife edge on the interior of one edge of the great complex. On closer inspection, this feature gives the impression that the Orion Nebula is a true "cradle" of starbirth, because it appears to wrap around the hollow and bright star-forming region from behind; a genuinely breathtaking effect in a widefield eyepiece. I am eager to try a binoviewer on this object at some point.

At no time did the planets present a really fine view in the 18" this night, probably due to a number of factors including local atmospheric stability and the proximity of the mirror to warmer pavement; nonetheless, a few moments of good seeing yielded acceptable views of Jupiter and Saturn (a friend's super-high-quality 180mm Astrophysics refractor a few scopes down revealed beautful gem-like views of each one at magnification up to about 200x or so).

Next, nebula IC 443 in Gemini near the Taurus border is apparently the remnant of an ancient supernova, and consists of two faint portions that are apparently detached. The larger and brighter portion, which forms a semicircular arc, showed but a portion of its large faint extent using the O-III filter, and none of it without filtration, unlike the Veil Nebula which can be seen fairly well using most any scope 6" and bigger under a dark sky (and in fact was seen quite well in a friend's Meade 8" LX-200 without a filter). The fainter portion of IC 443 was invisible to this observer's eye, and might be considered a fine challenge object for those who enjoy incredibly difficult objects.

The next object is a real beauty. NGC 2174, a very large nebulous patch near IC 443, was bright and easy using the O-III filter. It is large to the eye, about 25 x 30 minutes, and contains or lies behind a few bright stars. It is appealingly irregular, with much shape and substance and darker regions fraying around the edge, and it seemed like nothing so much as a haphazardly-prepared pie crust, with the dough tattered and broken around the edges. It's brightness indicates that a much smaller scope would have no trouble with this object when a filter is used. Removal of the filter made the bulk of the nebula extremely faint, except for one small portion near one edge about 12 arcminutes from the center that stayed relatively bright. When the filter was replaced in the eyepiece again, the brighter nebulous portion did not stand out from the rest of the object, which invites the question as to whether it is actually part of the nebula. Higher magnification did not reveal any resolution in this bright portion, so it does not seem like a star cluster. Perhaps it is a background galaxy? Sky Atlas 2000 does not give a clue. This mystery will need to wait for another night.

Finally, the Ultrablock filter was placed in the 92x eyepiece and the scope was swung toward Zeta Orionis and the Horsehead Nebula, Barnard 33, against the gently glowing backdrop of emission nebula IC 434. Across Zeta from the much brighter and lovely Flame or Tank Tracks Nebula, and faint but definite, the dark bent-finger-shaped ghost of Barnard 33 blacked out a bit of the sharp-edged emission nebula that lay behind. Removal of the filter left it invisible in my scope. Several other folks were able to see this apparition using their scopes as well, such was the quality of the sky at 3 AM.

One more look at M33, now high overhead, revealed a glorious tangled swirl of ragged spiral arms, knots, H-II regions, and brilliant core. With that, the behemoth was shut down and I lay down on a cot for a few hours rest before the ride home. With warm blankets around my chin, the glow of the Cassiopeia Milky Way high overhead and the bright winter stars rising to the east, I drifted off into one of the deepest, most blissful sleeps I have had in years.

Bruce Jensen