Sierra Buttes and Lassen 7/20 to 7/27 (Part 1)

by Steve Gottlieb


In July I had an 8-night observing extravaganza with the first three nights at Lassen Park with the Nelms star party followed by five consecutive nights at the Sierra Buttes at the Sierra Nevada Field Campus with SF State's class on observational astronomy. The last six nights were superb starting with a great evening on Saturday night at the 8200' Bumpass Hell parking lot followed by five clear nights with excellent seeing and transparency at 7200' Packer Saddle adjacent to the Sierra Buttes.

On Sunday morning from Lassen, I packed up and drove back three hours along the Feather River valley to the SF State's field campus (http:// www.sfsu.edu/~sierra/) on highway 49, southwest of Yuba Pass. I've been helping out with this class for 18 years (almost 90 nights at this site!), often with Jim Shields and Ray Cash and I always enjoy returning to the Lakes Basin area between Sierra City and Graeagle. This section of the Sierras does not attract the crowds of the better- known locations but easily holds its own in natural beauty with a several dozen alpine lakes (including nearby Sardine, Deer, Salmon, Gold, Big Bear, Long, Silver) that often have few visitors, all in the shadow of the jagged crown of the Sierra Buttes. From the fire lookout tower on top of the Buttes (3 mile hike) you can look north to Lassen and even glimpse Mt Shasta, 150 miles away. Here's the view from the top http://virtualguidebooks.com/NorthCalif/ TahoeNorthernSierra/SierraButtes/SierraButtesLOL.html

We had a dozen participants this year (including TAC's Bill Cone), though neither Jim nor Ray were able to make the class. Many folks brought a scope along some just learning to use and others more experienced and we had a very enthusiastic group. Of course, that's easy if the weather is warm and the skies spectacular. I'm not really a Jupiter devotee as I try to keep my dark adaption intact before heading off to look for faint fuzzies, but the remarkably steady seeing on a couple of nights made me a convert. These notes fail to capture all the visible detail and some of my feature jargon may be wrong, but here's a sense of the view on two of the nights

Monday 7/24: I was mesmerized by the view of Jupiter which was exhibiting more detail than I remember seeing on Jupiter in any of my scopes. Viewed intently at 160x, 225x and 325x and the image never deteriorated at higher power. Just off the western limb was Ganymede. At an angular diameter of 1.4" Ganymede was beautifully resolved into a tiny, but easily visible, crisp-edged disc (other moons were cleanly resolved). From the northern equatorial belt several distinct festoons were lined up across the disc that swept "up" to the south with a wide base and then thinned and trailed to the east, like a like a series of huge arching fountains or sprays. Between the festoons were a series of creme ovals and the band itself was quite irregular with brighter streaks and fine structure. Between the north and south belts was a distinct razor thin belt at the equator. The south band had a couple of very small, but sharply defined white ovals just inside its northern boundary. Besides the white ovals, the south band resolved into two brighter small bands at the north and south border that had scalloped edges. At the north and south polar caps, there was subtle structure and banding. The overall view evoked a space image in moments when the seeing was perfectly still.

Wednesday 7/26: Again we were treated to an amazing wealth of detail on Jupiter in the early evening. In excellent seeing there were five or more equatorial belts alone with three very thin belts within the equatorial band. A prominent white oval was situated within the northern belt and a couple more within the equatorial belt. Within the south belt itself a series of tiny swirls or loops were often resolved along the northern edge of the belt. The individual swirls occasionally sharpened up perfectly and displayed irregular jagged edges. Embedded within the swirls were a series of tiny white ovals. All four moons (lined up to the east) were resolved into discs of varying sizes with some color.

OK, back to deep sky observing. I decided before this observing odyssey to reobserve a number of summer planetaries and globulars. In addition I took a look at some interesting objects on my observing list. Here are three of these as viewed with my 18-inch Starmaster.

Quasar PG 1718+481
17 19 38.2 +48 04 12
V = 14.6

18" (7/25/06): this quasar has a redshift of 1.083 and a light travel time of ~8 billion light years. It was easily identified using a finder chart at 115x as a mag 14.5 "star" within a small group of stars. Located 12' SW of mag 6.4 HD 157373 (double) and 3' E of a mag 9.7 star. The quasar forms the south vertex of a small triangle with two mag 13 stars ~1' W and 0.8' NE. The mag 6.4 star is a very unequal double with a mag 6.4 primary (not listed in WDS).
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Active galaxy Stephenson-Sanduleak 442 = PGC 90334
19 37 33.0 -06 13 05
Size 0.7x0.5

18" (7/25/06): this compact Seyfert galaxy was surprisingly easy at 225x as a very faint, small halo of roughly 15" surrounding a very faint stellar nucleus. The halo was of uniform surface brightness except for the stellar nucleus that appeared like a faint central star of a planetary. At 325x there appeared to be a tiny, brighter core surrounding the stellar nucleus and the halo seemed slightly elongated, ~20"x17". Located 6' SW of mag 8.3 HD 185125 (at the very edge of the 12' field at 325x). Not listed in any of the major galaxy catalogues though a relatively easy object!
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Reflection Nebula NGC 7023 = Iris Nebula
21 01 36 +68 10
Size 18x18

18" (7/24/06): viewed at 160x, this detailed reflection nebula displayed a great deal of interesting structure! Surrounding the mag 7.4 illuminating star is a bright halo of nebulosity extending mostly north of the star and ending just south of the star in a well defined slightly curving border. A wide dark lane intrudes into the nebulosity from the southwest towards the bright star. To the south of the star is a triangular region of haze (brightest just south of the central star) roughly filling in the region defined by a mag 13.5 star 5.5' SSE and a fainter star a similar distance SW. Seemingly detached at the periphery is a larger section of faint haze on the east side of the nebula that is extended N-S (this is an outer "wing" on photographs) and a more vaguely defined region of low surface brightness haze detached on the western side (also oriented N-S). These two detached wings give a diameter of at least 7'. ************************************************************

more to come...
Steve


Observing Reports Observing Sites GSSP 2010, July 10 - 14
Frosty Acres Ranch
Adin, CA

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