Mt. Lassen, 7/11-7/14

by Bill Cone

Driving up I-5 on Wed. afternoon towards a solid bank of clouds to the NE looked a bit ominous. However I had looked at the satellite photo animation that morning, and noticed that the whole system was drifting to the N at a rapid clip. That gave me hope. I was very pleased on Wed. night when the curtain of clouds rolled back all afternoon and evening to reveal a very dark and clear sky for sampling the treasures of the summer milky way. It was like a curtain opening for a play that began after sunset. The Bumpass Hell parking lot is at 8000' and sits on a small promontory off the road, with a wide view to the South. The East and West horizons are progressively blocked by arms of the mountain as one turns towards the N., though I never felt constrained by the local horizons. There was some murk in the S., presumably from the Antelope fire, and a low light dome in that direction, that varied in size and intensity depending on the amount of smoke or condensation that lay in that region on any given night. Late Saturday night, someone in the dark commented that they had determined from compass headings that the persistent light dome was probably all the way from Sacramento. If anyone can confirm that I'd be interested in knowing.

At the end of the lot there is a huge erratic boulder left by a glacier that juts up into the sky in a dramatic fashion. Looking past it, the eye travels miles across the forested hills to the Southern horizon, and the multi-colored, diffuse shadowband of the earth rising into the sky. This was a striking location to observe from.

And the company wasn't bad either. I admit I am often pretty self-absorbed while I am observing, and may seem anti-social as a result, However I find that when I do talk with others at these events I often learn all sorts of interesting things. Here's one example.

In heading to the bathroom at Bumpass on Friday evening, I ran into Charlie Wicks who, along with Paul Alsing and John Hoey, had setup on consecutive nights at the south end of the lot. He was talking about an interesting optical effect at dusk, when the value of the sky is at a threshold where the red giants of a globular cluster shine brightly while the rest of the cluster remains close in value to the sky. John Hoey's 25" was pointed low down at M-22, and I took a look. It was just as he had described it: A swarm of orange fireflies popped out, looking like a carbon star convention. What an interesting way to selectively see only a certain population of stars in a remote cluster... by using our own sky as a filter of sorts. One could see the other stars, but their contrast to the background was very low, while the orange stars shown brightly. A beautiful, transient phenomena.

I had spent time putting together a list based on a variety of sources, Hartung's Astronomical Objects for Southern Skies, Burnham, NSOG, my favorite eye candy, Messier logging obligations, some Abell planetaries, Steve Gottlieb's general and challenge lists, etc. While I never finished it, as I just plain ran out of time, I had over 45 objects on it by then. i also made my own charts for a variety of objects that I hoped would speed up the process of tracking down the dim stuff, inspired by Paul Alsing's incredibly vast library of charts he'd assembled that I'd seen last year at Shingletown. Did I get through it all? Nope. Did I learn something? Yep.

I noted that dusk at Lassen was about as dark as my backyard skies ever get. Venus was blazing away over the rim of the mountain, Jupiter was ready and waiting above Antares. Polaris finally emerged from the deepening blue, floating just West of the peak. Finders aligned, I was ready to go.

Jupiter

Jupiter showed interesting detail on each night, and on Saturday night we were treated to a shadow transit across the northern region of the disc. David Cooper had a beautiful view of it in his AP Starfire. The moons showed as discs. The shadow was the most crisp black hole in the warm colored region. The NEB had a reddish hue with a fairly smooth edge to the North and a ragged one to the South. The SEB was a dark, cool grey. In comparing views on Thurs. evening with my neighbor, Coyote Lou, we spotted 3 white ovals (festoons?) 2 stacked on each other near the center of the disc, and one to the W., both tangent to the NEB. The bright central region had several dark bands running into it, but on Thursday the ones to the south seemed to be extinguished about halfway across the disc coming from the West limb. Each night showed subtle differences. On Thurs., the NEB was considerably thicker than the portion we could see on Wed. I realize this is a jumbled description spread over 4 days, but the gist of it is that each night, I started with Jupiter, and was rewarded by a wealth of detail. I probably had the best views of it on Wed. and Sat. night in terms of seeing and level of detail. I did resort to using my left eye to look at it after awhile, so I wouldn't destroy the dark adaptation of my right. You got your planetary eye and your deep sky eye. I noticed that even my red flashlight was knocking down my pupil, so I started using my left eye for reading charts and taking notes. I began functioning in the dark as a two eyed cyclops.

Comet VZ13: In tracking this comet on Starry night, I saw that it was going to pass near some galaxies in Draco, and we were not disappointed. On Wed. night the comet could be viewed in the same 1° field as the great Draco trio of galaxies, 5981, 5982, 5985. The comet itself resembles a bright Messier galaxy, but I admit I didn't study it for structural clues, I was more interested in the groupings with other objects.

VZ13 & NGC 5907: 1:08 am on Friday morning- A 1° field nicely frames this pair of unlikely companions. The comet shows a bright bluish glow, and is among a tight wedge of stars on the W. side of the field. NGC 5907 is in the E., a fairly bright edge on galaxy oriented ~E-W. Very attractive.

A saturated color driving an adjacent neutral color towards it's complement is a well known color perception that folks like Josef Albers have made wonderful examples of. Hartung's descriptions of colorful doubles often refer to this perceptual phenomenon in describing the perceived color of stars vs. the "truth" of spectral analysis. Our eye and brain have no trouble "adding" color to objects in this way. It is part of what helps make paintings appear luminous when they have no radiant light source.

In observing VZ13 comet, both Steve Gottlieb and I, in our mid-morning post mortem discussions, agreed that it looked blue to our eyes, partially because 5907 was such a neutral grey. It was a muted effect of complementary contrast... a seemingly monochromatic object (5907) made the subtle hue of another object in the field more apparent by comparison. I suppose its possible that if the galaxy was as bright as the comet, and they were overlapping each other a bit, then the galaxy might feel 'warm' in hue, but in this case it was much dimmer, and clear across the field, so one's retina doesn't take the bait, so to speak.

Over the four nights, I observed some very interesting planetaries that I found entertaining and provocative to look at, and are worth studying as a group for their differing behavior at the eyepiece:

NGC 6572, PN, Ophiucus- 145x, no filter, 311x VHT. Higher mag keeps enlarging the planetary while the stars in the field remain the same size. Bright blue green disc. I could not sense the lime green color some have mentioned. With or without filter it grows larger w/averted vision, shrinks w/direct. In discussing this one with Steve, he suggested that I look at it again for a change in color between averted and direct vision, so the next night I tried that. Yowza! With averted vision I got a bright bluish green spot, and as I looked directly at it, the spot would shrink, darken, and morph into a deep neon green dot. I had my observing neighbor Bill Porte take a look at it, without telling him what it did, and he got the same response. Objects like this are perhaps telling us more about our own perceptive mechanisms than they may be about themselves.

NGC 6309, PN, Ophiucus- The Box Nebula is it's stated nickname on some lists, but calling it the "Exclamation Point Nebula" wouldn't be inappropriate. A rectangular glow oriented N/S, bright star off North end. At low power almost disappears with direct vision. Higher mag (311x) stays steadier, but interior wiggles and squirms around, giving off different clues and signals to it's structure. The North end appears brighter, center shows darkening.

NGC 6905, PN Delphinus- The Blue Flash Nebula. Bluish form, elongated N-S, tightly bracketed by a star at either end. This one is similar in behavior to the Box, yet direct vision doesn't eradicate it. Instead it shrinks down to a small E-W horizontal blob in the center. At higher power I got a sense of overlapping forms that made the center brighter. A central star also twinkled in and out of view. In this case, the objects averted/direct behavior seemed to be giving a clue about it's own structure. But perhaps my "helpful" rational mind was getting in the way...

NGC 40, PN, Cepheus- What is unique about this object is the coloration, as it is overall warm and reddish in character. Many planetaries have the hue of a swimming pool illuminated at night. Not this one. Ruddy colored outer shell, warm central star. At 311x, structural impression of concentric, or slightly offset, rings. W. and E. rim of outer shell brighten, with the West side being the brighter of the 2. Faint warm field star on Southern rim.

Campbell's Hydrogen Star, PN, Cygnus. Also known by it's nickname PK64+5.1. This one is also orange red in character, though very small. An H-beta filter does a good job of obliterating the rest of the field, so you can guarantee you're on it. However, it is readily seen with no filter, and at 311x, one percieves a small orange ring around the star, like the symbol for a variable star on a chart. This one reminds me of the IC planetary in Lepus that also has a red ring around it.

Barnard 72, The Snake Nebula, Ophiucus- I tried for this last year at Shingletown in my 10" and didn't really have a good sense of what to look for. Even this year I made an amusing blunder before I finally got it. On Thur. night I started poking around that region, as NGC 6369, "The little ghost nebula" a small annular planetary, sits on the E. side of the same asterism that the Snake is a part of. This is in the belly of Barnard's Horse that Bob Jardine pointed out to me and my wife- a large, naked eye conglomeration of dark clouds that includes the Pipe nebula, which now is assigned the unfortunate role of the hindquarters and legs of a vertically positioned horse. Readily visible, and a good symbolic read, but I digress. If one is familiar with this region, Pg, 146 Uranometria, or Pg, 22 SA2k, the bright stars make a sort of square root symbol, with 42 Theta Ophiuci being the brightest and southernmost of the group. When I started my search on Thursday, I mistakenly panned up diagonally from Theta, when I should have been panning up diagonally from 44 Ophiuci. That's not the funny part. As a result I eventually noticed in my finder a large, prominent, curving dark form that resembled the top swishing curve of an 'S'. The Snake! It was either that or the peghead of Eddie Van Halen's signature Hamer guitar. I was looking for the snake, and here was a partial, but quite obvious 'S' form in the finder. Must be it!

Wrong.

I know I'm not the only periodic fountain of misinformation around here, so I don't feel too bad confessing this. After proudly showing it off, and even sketching it, I moved on to other things. However the next morning, I began to question my discovery. I had found an image of the Snake in NSOG, and it didn't seem to hook up with what I saw. For one thing, the scale was wrong. In addition there was an image of Barnard 63, a big swooping Eddie Van Halen peghead dark cloud thing that was staring me in the face on another page. After studying the charts it was clear what my crime was.

I had to go back.

Fri night, back at the square root symbol, I patiently slid up the correct diagonal alignment of stars, and looked in the eyepiece. First nothing, then the small discrete blob of Barnard 68 became quite apparent on the upper left of my field, and suddenly the Snake just snapped into view. It's a fairly large object at 91x, nicely fitting into the 42' fov of a 24mm Panoptic. The contrast is pretty low with the surrounding field, though once you have it in view, it is quite obvious.... much easier than the Horsehead, for example. The tip of the 'S', and the belly of the lower curve are the darkest portions of this object, as it winds out of the field to the NE. Below the Snake are a string of Barnard named clumps of darkness of which B 68 is the most easily seen. In fact it is more obvious than the Snake. However as this string moves SE, the background becomes progressively extinguished by a massive dark cloud, so one can only see darker "pools" where these objects are residing, no discreet edges being visible. Dark on darker is about as difficult as dark, and less dark. Language really struggles to describe the kind of nuanced perceptions one encounters in the realm of photon minimalism.

I showed it to Bob Jardine, and he had a similar response of "Where is it? Oh! There it is." That's the kind of object to expect.

Abell 39, PN, Hercules. I had made charts for a bunch of these but only did one. This object is about the "dark and less dark" perceptions. When large extended objects are so dim that don't seem to emit light, they just differentiate themselves from the surrounding field by being "less dark". That's what I mean, and that's what Abell 39 is: a large, round, extremely faint circle of less darkness in a field of greater darkness sprinkled with stars. If you didn't know it was there, you would pass it right by. When I mentioned this to Steve, he just grinned and said, "Welcome to the Abell Planetaries!" What looking for this object taught me was that it was important to ID the correct field, even if I couldn't see any trace of the object. That meant, no filter, find the right stars, confirm with the chart, drop in the filter and patiently look.... That's either one more circle of observing hell, or an enticing journey into the zen of greater minimalism, I haven't made up my mind on that issue yet.

IC 5146, EN, Cygnus. The Cocoon Nebula. I spent about 40 minutes trying to starhop to this object from M-39, and failed miserably. There were dark lanes snaking all about the field, and the profusion of stars made it hard for me to ID the useful ones. Finally, I just stopped looking through the eyepiece and went back to scanning the region with my eyes, picking out bright stars NE of Deneb and locating them in the Pocket Sky Atlas. In this way I triangulated naked eye within a degree of the nebula, and , at the finderscope, was able to see the tapering river of darkness (Barnard 168) that led directly to the Cocoon. Can't star hop in a crowded field at the finder? Try it naked eye. It works! I'd read that the cocoon was one of the objects that responds to an H beta filter, so I popped that in. I can say that 'yes', the H beta filter does not make the nebula go away, but it sure extinguishes everything else in the field! I'm not sure that's so effective for an object that is plainly visible with no filter. In addition the few bright stars that are in, or superimposed on the nebula, as well as the dark lane that leads to it, are part of the interesting landscape around this object.

Speaking of landscapes, I looked at NGC 6480, designated as a star cloud a few degrees above M-7. Paul Alsing had a page on this in his collection of interesting objects labelled, Another Horsehead- In Scorpius. Brent Archinal's book 'Star Clusters' also talks about this object, as it appeared to be a lost, or non-existent object, though Herschel had sketched the region correctly. What it is to my eyes, is a rich starfield that is being obscured on 2 sides by foreground dark clouds, with the E. side having a very discreet edge, like a ragged coastline. In addition there is a very strange OC, 6451, nearby that I'd love for someone else to look at and comment on. It has a sort of anvil-like shape, one side being almost completely flat, and the whole thing is outlined by a tight string of stars. At first I just thought it was an absurd asterism, but the interior of this shape is brighter than the surrounding field. Cabinet of wonders down in that region.

Sometimes I just wandered around the sky, kind of punch drunk. Jamie was telling jokes to Robert Shelton, The Tappet bros. kept up their steady dialogue further down the row of telescopes across from me. I peeked at M-31 before I quit every night... extraordinary contrast and detail. M-31 globulars, I'm gonna hunt you down one day. Early one evening, Greg excitedly showed me his sketch of M-81 and had me look through his scope. The spiral arms were quite visible, extending off the long ends of the disc, and looping wide. Jamie had a Holmberg, some big, dim, looming ship in the night galaxy that he didn't expect to see. I looked at M-27 through Robert Shelton's scope and could see color in it for the first time. Bill Cherrington had mentioned it last year at Shingletown, and I couldn't percieve it. Yet, there it was. The inner "hourglass" shape was a grey green, and the outer curving forms were a bit ruddy. Steve Gottlieb was most generous and thoughtful with his comments and advice throughout this event. and thanks to Coyote Lou for a peek at her comet chart, and sharing her cookies and hot tea.

I'm wrapping this up. It was a great party... People and venue. See y'all next year.

-B.

P.S. Viewed with an 18", f4.2, Plettstone reflector w/ Paracorr.