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by Randy Muller
The conditions of the sky looked grim as Gary Manning and I drove up to Blue Canyon Saturday afternoon, September 11, 1999, for the monthly Sacramento Valley Astronomical Society star party.
The skies of Northern California had been filled with smoke since late August, severely reducing transparency. Depending on how the wind has been blowing, conditions have ranged from "kind of hazy" to "how can you breathe this junk?"
On Sunday, September 5, the winds had been favorable, and those of us who were at Blue Canyon that night were above 80% of the smoke at Blue Canyon. This night, we would not be so lucky.
We never did emerge from the smoky haze as we finally reached altitude. We were above some of it, but plenty of it was above us, reducing visibility.
I planned to check out Pluto and look for moons of Uranus tonight, as well as track down more galaxies.
At around 8:30pm, while it was still relatively light, I took a look at Mars. The seeing seemed fairly good, and I was able to see the brilliant white dot which was the North Polar Cap with some regularity. It was coming and going with the coming and going of the seeing, but it was definitely there.
Hellas was also apparent as a light patch in the upper left. There was also a dark area in the center of the disk.
I did not see any canals.
This Mars was a sad little relic of its former glory in April, when it was at opposition.
Finally it was dark enough to hunt down Pluto.
There is something about Pluto that is both very mysterious and very adventurous. I am sure that much of this has to do with the rich, adventurous and kooky Percival Lowell (of Martian canal fame), who searched for "Planet X" himself, and who funded the search for "Planet X" that actually located Pluto. It is clear that Pluto bears utterly no resemblance to the "Planet X" that Lowell was searching for.
"Planet X" was supposed to be a large, massive gas giant (probably) that was perturbing the motions of the Neptune and particularly Uranus. Pluto is not nearly massive enough to produce these perturbations, and even the necessity of such perturbations was eliminated later when some of the historical positional data of Uranus and Neptune were found to be in error.
Still, the "Search for Planet X" has romantic images of astronomers with hoary white beards peering in the dead of night through 60 foot long telescopes in observatory domes associated with it. Well, possessing three out of five 'romantic' images isn't bad -- I have no dome, and my scope is only 60 inches long.
I had first searched for and found Pluto the week before (September 5, 1999) at this same location. I wanted to see it again, to see how much it moved, and possibly show it to others. (I had seen Pluto for the first time 'live' on June 12, 1999 at the SVAS Star-B-Que at Blue Canyon in Jay's scope, "Harvey".)
I dug out my chart, specially generated by SkyMap for this occasion. I was careful not to repeat the mistake I made last week of not including enough stars -- I included stars down to magnitude 14.5.
I quickly found the field, and shortly after that I found Pluto itself. I was surprised at how much it had moved in only 6 nights. Pluto moves rather slowly, being so far from the sun: It has not even completed one orbit since it's relatively recent discovery.
It was no longer the tail star of a row of four stars -- it was now the head of a small comet asterism several arcminutes to the east.
I could see the forlorn group of 3 stars that Pluto had recently departed from.
I had the clearest views at 142x with a 10mm plossl.
Like all good Plutocrats, I next attempted to show it to several people. I explained where it was in the field: A bright star was at the bottom of the field, and a comet-shaped crescent of stars, concave down, with the tail starting at the middle right-edge of the field, and the head of the comet (Pluto) in the center of the field.
These stars and Pluto all seemed about the same brightness, and all were at or near my personal limit of visibility.
I don't think anyone else saw it in my scope. One person stated that he could not see it, and another, a novice attending Vic Maris' astronomy class, stated that she thought she saw it, but I was doubtful because Pluto was nowhere near the field when I stepped back up to the scope after she left.
This person went back to the class and was excitedly telling the others about her 'find', and presently Vic asked me to find it in his 12" scope. I gulped, gathered my Pluto charts and walked over. Now I had an audience.
Using an alien scope I searched for the field -- and couldn't find it. Everything was so bright. I was using Vic's 20mm Nagler, giving about 68x and the magnification was a bit too low considering what I was using in my 10". I was also befuddled by the apparent field of view -- 80 degrees. I am much more comfortable with my 50 degree plossls. At length I found the field, and then asked him to step it up to about 140x. He put in a 9mm, giving 152x.
Now I was completely lost, and could not find the field. The field was rotated by a large angle compared to the field in my scope, because the position angle of Vic's focuser (as viewed from the front of his scope facing the primary, and using straight up for 'north') is 270 degrees (horizontal on the left side of his scope) vs. 45 degrees (half way between vertical and horizontal on the RIGHT side of my scope).
I spent about 20 minutes searching, then gave up. Frustrated, I went back to my scope and recovered it immediately, of course.
A couple hours later, Gregg Blandin, the guy I originally bought my 10" dob-newt from, asked me to find Pluto in his equatorial platform-mounted 16" dob-newt. I thought it had set, but when I looked over, I could see it was still up, but was very low, enmeshed in the grip of smoky haze and Sacramento light pollution. I told him it was still up, to my surprise, and that I thought it was doubtful, but I'd give it a try. Still stinging a little bit from my failure earlier, I grabbed my charts and hustled over to his scope.
Within a few minutes I found the field and ordered a higher power eyepiece. A few minutes later I had the familiar comet-shaped asterism centered. It looked remarkably similar to the view in my 10". It was only slightly brighter. I was expecting it to be much brighter, but I suppose the low altitude was robbing photons.
I described it, and Gregg had a look and saw it. Because of the tracking, there was no need to move the scope, and I verified that it was still in the field. Two students were still left from Vic's class, and one of them saw it. The other, a gentlemen in his 60's, could not see it. I warned people that they might not see anything.
I did not give anyone the secret Plutocrat handshake, not having learned it myself.
Uranus is the butt of a lot of jokes, including this one. It all stems from the fact that most of us American-English-speaking amateur astronomers pronounce it as "your anus". Or want to. Some attempt to maintain a small amount of decorum by pronouncing it "urine us", and while this is also funny, it's not nearly as funny as "your anus".
I sometimes think the emotional age of most amateur astronomers is somewhere between 6 and 8. We like shiny toys and we like pretty things in the sky. Sometimes it's all I can do to just gawk naked-eye with child-like wonder at the brilliant starry sky with the Milky Way. And many of us like Uranus jokes.
A common Uranus joke goes like this:
Have you found Uranus yet?No.
Oh, well here's a mirror!
Such jokes are not universally well-received. On Saturday night at the Alan Nelms star party at Lassen, I had the scope pointed at Uranus and made a couple off-handed Uranus jokes to the people looking through the scope. There was utterly no reaction, so I stopped doing it.
But Gary Manning laughs, and even encourages this sort of behavior.
I turned my 10" scope on Uranus, to see if I could see any of its moons. It was easy to find just 19 arcminutes from the relatively bright Theta Capricorni. Never having seen a sea goat, I don't see Capricornus as one. Instead, I see it as a gigantic smiling open mouth. Theta C. is just east of the center of the upper lip, and is easily visible naked-eye. Uranus itself should also have been visible naked-eye, but I didn't think to look.
In the scope, Uranus was its usual very pale greenish self. I had made a chart of its moons, and looking in the eyepiece, I saw Uranus and some nearby stars or moons, and I suddenly realized a fatal mistake I made. I didn't include any background stars in the chart I generated.
I had made this same basic error last week when I generated a chart for Pluto. This time, I made the scale of the chart too big, and there were no stars nearby to calibrate the scale with what I could see in the eyepiece.
I told my buddy Gary (who was also looking at Uranus) that I thought those nearby stars were moons, but after examining the field and the chart, and noting the scale of the disk, I concluded that the several stars I saw were indeed stars and not moons, because they were too far away from the planet.
I could see nothing closer to the planet, so I decided I had to mooch some photons from some Big Iron. And there was plenty of Big Iron nearby.
Shneor Sherman, owner of an 18" Sky Designs dob, was four or five scopes south of me. Shneor (a Yiddish name pronounced 'shneer') was one of the observers at Blue Canyon the fine night the week before. His scope has been heavily modified, and in fact, someone at one point hacksawed the mirror-box in half and put a hinge on it to make it more portable.
When I showed up at his scope, looking properly hungry, down-and-out and willing to work for some photons, he was looking at M13, the great globular cluster in Hercules, with a binoviewer. This device supplies half the light of whatever you're looking at to both eyes, instead of the full light to one eye.
I quickly took advantage of this visual feast. It's amazing how much more one can see with two eyes than with one. I guess it's because we are using more than twice as much of our brain when we use both eyes. It's also amazing how much more is visible in 18" than in the 10".
The resolved stars appeared to stand out like sparkling diamond dust in front of the unresolved stars making up the silvery background. It took on a completely false, yet completely compelling 3D look.
He gave me control of his scope, and I quickly pointed it at Uranus. I asked for higher power, and he put in a Speers-Waler 5-8mm zoom eyepiece at 8mm, giving about 257x.
After studying the field, I was excited to find the two moons Titania and Oberon. They were faint, but relatively easy to see. Titania seemed slightly brighter. Shneor took a look and confirmed the two moons.
I could not see any other moons.
I happily walked back to my scope and told Gary, "I saw moons around Uranus, Gary! <snicker>"
After this planet fest, I decided to hunt down some faint fuzzies, but I was frustrated by the lack of transparency. I found a galaxy in Delphinus, NGC 6956. At magnitude 12.3, I was having difficulty seeing it, which surprised me -- usually I have no trouble seeing galaxies this faint from this location. I guessed that the smoke was causing between .75 and 1.0 magnitude extinction.
Next, I took a look at the wonderful Helix Nebula in Aquarius, NGC 7293. What an enormous planetary nebula! I could easily see it in my finder.
By now, a powerful wind had kicked up, and was making it hard for me to stabilize my scope. I thought it would go away soon, but the wind kept getting stronger with more powerful gusts.
At one point, while I was away from it, the wind sent the front end of my scope crashing down. I came back to my scope to find it resting on the pavement. I wasn't worried about damage -- but I was worried about the collimation.
I checked it, and the secondary mirror looked OK, but the primary mirror was way off. This was somewhat of a relief, because it's difficult to adjust the secondary in the dark. It's much easier to adjust the primary. I did so, and was off and running again, but because of the wind, I felt like I always had to have a hand on my scope from then on.
I found a nice group of three galaxies in Aquarius, NGC 7184, 7180 and 7185. The wind was buffeting the scope so much that I gave up looking for 7188 nearby. I might have been able to see it without the wind, but I was having a lot of difficulty just keeping the scope still. On the other hand, the lack of transparency might have prevented me from seeing it anyway.
I decided to give up, but I wanted to grab quick looks at Jupiter and Saturn, now that they were nice and high. They both showed lots of detail, though not quite as much as the week before.
Upon leaving Blue Canyon on Sunday morning at 7:45, we had a nice view of one of the sources of the smoke, if not the primary source: Due north, at a great distance, an enormous plume of dark brown smoke to a great height -- far higher than 5000 ft. This was undoubtedly the Butte/Plumas county fires near Lassen. When we saw it, the plume was blowing off to the north and east.
Although I thought the conditions of the sky were crummy, they were still far better than my backyard, and the company was great.
| Date | September 11/12, 1999 8:30pm-2:00am (0330-0900 Sep 12 UT) |
|---|---|
| Location | Blue Canyon (near Sacramento), CA 120W 50', 39N 11' |
| Altitude | 5000 ft. |
| Instrument | Orion DSE 10" f/5.6 dob-newt |
| Oculars | 7.5, 10, 17, 26mm Sirius Plössls |
| Seeing | 8/10 Very good |
| Transparency | 6/10 lots of smoke |