After a summer reprieve from El Nino, gloppy weather returned to the California Coast on the weekend of October 23-24, 1998, as the onset of a front dropped half an inch of rain in my back yard, and put an end to hopes of Friday observing. A clearing trend and satellite images of a dry air mass suckered a few people out on Saturday, but I found Fremont Peak practicing for Hallowe'en, with fog dense enough that I could neither see the incandescent lights in the observatory building at less than a hundred meters, nor verify for sure that the brush rustling near the side of the path was merely wild pigs.
I have been a life member of the Fremont Peak Observatory Association almost since its inception, but have never checked out on its Challenger telescope, a 30-inch Newtonian on a cross-axis equatorial mounting. There are other benefits of membership, however, for the room adjacent the roll-off roof area where the telescope sits is lighted and somewhat warmer than the soggy outside. Several of us sat there for a few hours, eagerly awaiting clearing skies.
We had no luck with the weather, but as I wistfully wished for stars, my eye was drawn to some of John Gleason's magnificent astronomical photographs, framed and mounted on the walls. The prints in question were of negatives obtained with a Celestron Schmidt camera, whose enormous photographic speed made possible the use of fine-grained but very slow 2415 film. The images were obtained about a decade ago: John had used the red-sensitive emulsion in connection with a deep red filter to produce wonderfully detailed photographs of nebulous areas that emit in the red hydrogen line at 656.3 nanometers. One of them included the location of an object of noteworthy interest.
The photo showed the region of Orion's belt, south almost to the Orion Nebula. In this wonderfully well-exposed print, IC 434, the emission nebula against which the Horsehead Nebula appears in silhouette, is burned in white. Details in the Horsehead show up well, though the object is small. All of the nebulae on the relevant page of the _Millennium_Star_Atlas_ are easily identified, except for one, though a few are faint, perhaps because they are reflection nebulae without especially bright red emission. There is lots more, too -- for example, the entire periphery of the great oval HII region about sigma Orionis is outlined in white, and there is visible nebulosity across most of its interior.
What's missing is NGC 1990, the sprawling amoeba frequently charted as roughly centered on epsilon Orionis. The photographic process has widened the image of epsilon considerably, but not nearly as wide as the nebula is usually depicted -- for example, in _Millennium_ itself. I cannot be sure that there is no nebulosity in the area -- and indeed, there are a few tiny wisps and curls here and there near epsilon, mostly south and west of the star -- but there is nothing like the conventional fat blob, at least, not in red, down to well below the brightness levels of even the faintest parts of IC 434. Brian Skiff has mentioned wanting a photograph to point at to show the non-existence of this object, and at least in red light, this one of John's is the closest thing I have seen.
What better way to spend a fogged-out night than with an indoor observation of a non-existent object, I thought on the drive home, trying to sooth my craving for starlight. Yet as luck would have it, though clouds capped ridges south of San Jose, the sky was clear and not too moisture-laden above my home in Palo Alto. So I hauled out my new 70 mm f/8 Vixen fluorite for a little Messier hunting.
It's not that I am partial to Messier work in bright sky, nor do I need to make a point about the capability of small telescopes in suburbia -- I have already completed a Messier survey from Palo Alto with Refractor Red, which has the even smaller aperture of 55 mm. Yet quick-look observing, right outside my home, is one of the most common things I do with telescopes. Equipment as small as the 70 mm is very handy, and the Messier objects are likely targets simply because I can find most of them without charts.
The 70 mm is very pretty in its white tube with pastel green and black trim, but it appears rather mundane compared to its day-glow colored smaller sibling. Perhaps I will have to give it a pedestrian name. How about Refractor Fred? Naw...
Anyhow, the difference between 55 and 70 mm is the difference between detectability and detail for many Messier objects. I used my Vixen 8-24 mm zoom eyepiece, which gave magnifications between 23x and 70x, the better to pick what was exactly right to show the features in question.
M34 was too close to the zenith for my altazimuth mount, but M33 showed a moderately concentrated nuclear region, with the brightest non-nuclear part of the galaxy elongated and hinting of a stretched-out "S" shape. M77, further south, had a much more sharply compact nucleus, and was somewhat comma-shaped. M81 was round and moderately concentrated at the nucleus, and M82 showed hits of mottling across its broad streak.
Open clusters M35, M36, M37, and M38, were well resolved. M1 was a not quite symmetric blob, but I could not see precisely what the shape was. M78 warranted a similar description, but as I tweaked the magnification, at least one star occasionally popped out within it. Globular cluster M79 showed no hint of stars, but its round shape and smoothly concentrated central brightening revealed its nature. M42 and M43 showed much texture and detail, but no color that I could discern. I could see only four stars in the Trapezium, but the seeing was still rather ratty in the unsettled air that followed the front. I would like to try the 70 on it again in better conditions, to look for the fifth and sixth stars.
Fog notwithstanding, it was a pretty good night, after all.