Sunday, August 3, 2008

Mt. Lassen - Going Dark at 7.5

I had not initially planned on going to Mount Lassen this year.

With GSSP starting its first year in Adin, it looked as if a string of at least fifteen consecutive years of personal astronomy at the park was coming to an end. I had no problem leaving it behind, given the promise of the new star party. My observing buddy Richard was unable to attend, and, last minute, asked my thoughts on going to Lassen in late July when he could go. My daughter had been the most disappointed about not going to Lassen, and work prevented her from attending GSSP as well. She has grown from a young child into young adulthood, spending time every summer at the park. When Richard made the suggestion I jumped on it, calling my daughter who immediately said yes. So, we reserved campsites and announced on our local astronomy mailing list our intention to return again to Lassen at the end of July.

In the ensuing days and weeks fires broke out all over the state, threatening both GSSP and the planned trip to Lassen. I had mentioned our plans to a number of people who kept checking conditions both for GSSP as well as Lassen, and fortunately, both somehow worked out, even though the fires kept things (literally) up in the air until the last minute....

Not everyone who planned to attend made it. But we ended up with Richard Navarrete, Steve Gottlieb, Greg LaFlamme, Bob Jardine, Scott Baker and Greg Claytor, along with me, my daughter Mimi and her boyfriend Brian. Good group. Actually, two individual groups unknowingly making simultaneous identical plans.

Driving up from the bay area the skies were hazing up near Vacaville, and the closer we got to Redding, the worse things looked. The smoke thickened continually until we were climbing highway 44 toward the park, when blue began replacing the ochers and grays. Soon blue was everywhere. Lassen was in the clear.

In the park there was road work between Dersch Meadows and Bumpass Hell, which included our campsite at Summit Lake South, so we had delays and were required to wait for a pilot car to caravan us through. Delays were the rule in the park this trip, with a few exceptions.

My days were spent relaxing in camp, sipping Coronas, reading, cleaning gear, visiting with friends and laughing. It was great to again be there with other observers, and of course my daughter (and her boyfriend too). The string remains unbroken. The Nelms Star Party continues.

After dinner the first night (chili cheese dogs - woof!), Richard, Mimi, Brian and I headed to the Bumpass Hell parking lot. Richard and I had ridden up from the bay area together, with two 18" Obsessions, a 10" f/5 Dob and a TV 101 (as well as all our camping gear) packed into my Suburban. When we arrived at the lot, smoke was to our west, and soon blew in overhead blotting out the sky. We set up anyway, and just after dark the smoke dropped and we had very clear, very dark steady and transparent skies.

About the sky.... I usually brew up some Mexican Coffee to drink while observing. This consists of 3 parts strong coffee, 1 part Cuervo Gold tequila, two Equal sweeteners, and melt some whipped cream into it. After the first jolt, it somewhat takes on the flavor of cocoa. But it is a lot more relaxing. I've done many star counts and observing sessions after enjoying part of a thermos of this brew. I've gotten as deep as mag 7.2 or 7.3 the best nights at Bumpass over the years. This trip though, I decided to forgo the concoction.

I was pleasantly surprised to find my visual acuity improved significantly. In Finnish Triangle 6, the eastern portion of Pegasus, my first count was 57 stars. I was astonished. It didn't look that dark. So, I recounted. After reaching 50 and realizing I had a lot of area remaining, I stopped. Mag 7.5. I just shook my head. There I was at Lassen, "going dark" at 7.5.

I would repeat the count the next night, and reached a much higher total. 49 stars is mag 7.5, that's as dim as the triangle calibrates. Observers with SQM meters were getting readings up to 21.80.

M13 was bright, naked eye. Lots of Messiers were there, unaided.

No more Mexican Coffee, while observing....

The best night of the three was Wednesday - darkest, clearest, extremely steady seeing, and warm. Great conditions at over 8200 feet elevation - the best easy to get to location in California for outstanding transparency. And, a magical place - especially twilight, when looking out to the south, over the gaping remains of Mt. Tehama's gigantic ancient caldera. What a view to have as our daytime views fade, and and countless stars begin to cover the sky....

A few asides about this year at Lassen. The park was very quiet. At Manzanita Lake, the parking lots midday Thursday were essentially empty. There were no lines at the showers, and we spent an hour in the shade in front of the store eating great ice cream and talking with a park volunteer. Maybe 8 people came by. At the observing site, we saw maybe a dozen people after we arrived over our three days there. A young couple from Portland returned after dark to look through our telescopes. The woman looked at M51 through Richard's scope, and immediately noted the spiral arms. I then asked her if she understood what she was seeing overhead, in our own galaxy, as she looked at the Milky Way streaming overhead. After a bit of explanation relating it to M51's spirals, she blurted out "Mark.... you're blowing my mind!"

Yes, it is a mind-blowing experience...

If the Messier and Herschel catalogs are the mainstream of observing for the mass of deep sky observers, the "holy river" per se, the estuary beyond holds the more unknown, unexplored sights. This trip, I concentrated on those objects, sailing under and past the Howrah Bridge, downstream to dip my toes in, where the river meets the sea. It wasn't my initial intent, but somehow, that's how things turned out. Mind blowing....

Here are my observing notes. All observations are with an 18" f/4.5 Dob. I spent a lot of time per object, as many were very challenging. Negative observations, of which there were a few, are not listed. I also took time to relax, chat with other observers, exchange stories, peek through other scopes (in particular Steve's), and enjoy the ride. Thanks to everyone who was there and made it such a fun experience.

Abell 71 Cyg PN 2.6' 15.2P 20 32 23 47 20 55
7/31/08 103X OIII, PK 85+4.1, Sh2-116. Very easy star hop from Deneb along the line to naked eye double star Omega Cygni. Large, very faint, even brightness, star at N edge and one inside give feeling of brighter side.

N6888 Cyg BN 18.0'x8.0' 20 12 01 38 23 00
8/1/08 174X NPB, Sh2-105, Crescent Nebula. Located almost a third the distance along a line from Gamma to Eta Cygni. The views of this object each year at Lassen replace the past ones as "the best" and this year was no exception. The fine wisps of nebulousity interior to the egg shaped shell, especially inside the thick bottom band, was amazing. Detail could be picked out all the way across from one side, through the Wolf-Rayet progenitor star, to the other side of the shell. This is a great object at Lassen, where it is in the same class as the Veil Nebula for visual beauty.

N6894 Cyg PN 60.0" 14.4P 20 16 24 30 33 51
8/1/08 174X NPB, PK 69-2.1. I use the stars 39 and 41 Cygni to form a right angle for hopping to this nice planetary. It is a ring with a very dark annular center, slightly elongated WSW/ENE. With the filter, the ring is almost a neon in bright intensity. 294X shows stars embedded in the inner edge of ring, a brighter one on w edge, dimmer on s edge.

NGC 6905 Del PN 72"x37" 11.9P 20 22 23 20 06 16
7/31/08 174X NPB, PK 61-9.1. Use Sagitta as an arrow to point to the mag 5.7 star SAO 88664 in order to get into the right neighborhood for this planetary. Bright round, and with a mottled interior on main shell, surrounded by N/S elongated dimmer shell, bracketed by two stars with N being brighter. Interior appears chaotic.

Abell 59 Sag PN 86" 17.2P 19 18 40 19 34 26
7/30/08 174X NPB, PK 53+3.1. A bit trickier location, I imagine a line from Albireo to Zeta Aquilae, to locate two pair of barely naked eye stars (including 1 Vulpeculae) which are a jumping off point for this very dim planetary. Barely visible with NPB, I was only able to glimpse the western edge and very occasionally eastern edge. Relatively large.

Abell 52 Aql PN 37" 16.5P 19 04 32 17 57 08
7/30/08 294X NPB, PK 50+5.1. From mag 3.3 Delta Aquilae to mag 3.0 Zeta, extend beyond to a pair of mid-mag 5 stars in identical orientation. If your skies are dark enough you can see a wider pair of mag 6 stars just to the east, which bracket the planetary. With the filter, I could "possibly" pick out a very large annular ring, with a very dark center.

Abell 72 Del PN 2.0'x1.8' 14.6P 20 50 02 13 33 29
7/31/08 174X OIII, PK 59-18.1. Easy location if you can identify the two mag 5 stars 16 and 17 Delphini, just over a degree apart and orientated N/S. The planetary is about 1.25 degrees due west of of star 17. The object is large, dim, round, and has stars involved. While faint, the edges seem slightly brighter than center.

NGC 6781 Aql PN 1.8' 11.8P 19 18 28 06 32 15
8/1/08 294X NPB, PK 42-2.1. Located about one third the distance from Delta to Zeta Aquilae, this is a round, bright, fairly large planetary with hints of annularity. Easy to locate and surprising!

Abell 53 Aql PN 31" 16.9P 19 06 46 06 23 50
7/30/08 174X NPB, PK 40-0.1. Another easy location! Start at Delta Aquilae, hop to mag 5.6 22 Aquilae then the same distance again to 5.2 19 Aquilae. Just off that star you'll find this very dim planetary. It appears mostly round, but slightly elongated E/W, with a brighter NW edge. There is no annularity, having even brightness except for NW edge.

Abell 67 Cap PN 67.0" 16.0P 19 58 27 03 03 00
7/31/08 174X OIII, PK 43-13.1. A bit trickier to hop to, I go from Delta to Eta Aquilae, make a slightly obtuse angle north, just over a third the distance between those two stars. The planetary is a dim large faint ring with dark center. Its southern edge is the most pronounced, and contains a bright star in eastern edge.

Abell 56 Aql PN 3.3'x2.7' 15.5P 19 13 06 02 52 49
7/30/08 174X NPB, PK 37-3.2. No problem hopping to this one, as it is just over 30 arcminutes slightly north of due west from mag 5.1 21 Aquilae. Now, this one is truly very dim - nothing more than slight difference in contrast, elongated N/W 3x2. There are some stars embedded, and it has an even surface brightness.

Abell 55 Aql PN 50" 15.4P 19 10 25 -02 20 25
7/30/08 174X, PK 33-5.1. I start at mag 3.4 Lambda Aquilae then hop to the naked-eye mag 5.4 identical pair 14 and 15 Aquilae, which I use as a "measure". I measure about three times that distance "above" 15 to find the location. Fortunately this is a bright Abell planetary. It is slightly elongated SW/NE, has a brighter center, undefined edges, large.

HCG 88 Aqr GX4 2.0'x0.7' 14.1B 20 52 35 -05 42 38
7/31/08 294X. Easy star hop! Start with Delta Aquilae, to Eta, Theta, the continue in the same line to mag 4.4 3 Aquarii and then to the cool double 4/5 Aquarii at mags 5.5/5.99. This double will be in the same wide field view as the Hickson. This group of four galaxies is comprised of NGCs 6978, 6977, 6976 and 6975. What stands out is a nice linear trio, the first three, two at mag 14.1 and one at 14.8. These three were easy, direct vision targets, equally spaced and apparently similar shape. The 4th member was off to the WSW, and dimmest at mag 15.8, showing convincingly with averted vision.

Abell 49 Sct PN 35" 16.7P 18 53 28 -06 28 35
8/1/08 174X OIII, PK 27-3.1. You'll have no trouble getting to this one. Start a M11, The Wild Duck cluster, and you're a wide-field view away. The trouble starts though trying to pull this one in. It was very faint with views only about 50% of the time. Usually I saw only the NE quarter of the planetary, but occasionally entire disk would show. Steve looked and noted that in same field is PK 27-3.2 which is a stellar planetary that blinks with OIII - we did it, what an interesting pair - blink, or you'll miss it!

Abell 70 Aql PN 42.0" 14.3P 20 31 33 -07 05 18
7/31/08 294X, PK 38-25.1. Very easy without a filter, this target is round, annular, and marked by the mag 16.0 galaxy MAC 2031-0705 shining through edge of planetary creating appearance of bright hard edge.

Abell 45 Sct PN 4.8' 18 30 16 -11 36 56
8/1/08 174X OIII, PK 20-0.1. Again located between two naked-eye stars, SAO 161632 at mag 5.1 and SAO 161415 at mag 5.7. This is a rich Milky Way star field, and all I could get was a suspected arc elongated E/W section. The field is to identify due to bright mag 8.8 star just north of the target.

HCG 87 Cap GX4 1.5'x0.3' 15.3B 20 48 14 -19 50 57
7/31/08 294X, MCG -3-53-5. From Beta 2 Capricorni hop to 15-Upsilon Capricorni, then not quite half again that distance beyond, to get to the target area. Once there, I easily saw the A&B components, elongated and nearly round. The challenge was component C, which I strongly suspected once with almost sure sighting, then several had marginal suspected. Jiggling scope helped. Dim stars away from obvious double can be mistaken for C, but are too far away.

Abell 66 Sag PN 4.5' 14.9P 19 57 31 -21 36 37
7/31/08 103X OIII, PK 19-23.1. From the handle of the Teapot, mag 3.3 Tau Sagittarii, hop ENE to the naked-eye double 51 and 52 Sagittarii, then the same line to where mag 6.0 SAO 188829 would intersect it at a right angle. This planetary is at that location, large and dim, and with averted vision only. The surface brightness is even across object, and somewhat hard at the edges. It sits south of pair of E/W stars, but more off easternmost. Several dim stars glimmer in and out occasionally, but one bright one is just inside NNE edge. Nice object with patience.

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