Tuesday, April 25, 2000

More Backyard Astro-Card Fun

As noted in last night's observing report, I had constructed a "duck blind" in order to squelch the experiment in fission taking place in my neighbor's kitchen window. By afternoon I had half the surface covered with black garbage bag material (on PVC), and decided the other half could wait, that the neighbors hadn't had their backyard light on recently (where the other half of the blind would be effective), only the kitchen. At 9:30 p.m., amidst the insanity of their dog going berserk at the noise I was making, up it went. I looked, and perfect! There was no light in my backyard from their kitchen. Success! The sky was clouding over, so I went in to pass some time. No sooner did I check back than, to my amazement, the neighbor's kitchen light was off, and (here comes Murphy) the backyard light was on! Oh well, still cloudy.

By 11 p.m. the sky had cleared, and to my amazement all the neighbor's lights were off. Out I went, looking to spend perhaps an hour. Despite the lack of neighbor's lights, the sky seemed bright. There were some puffs of clouds to the west, but they were evaporating. It was warm enough to be outside in a t-shirt.

I took out several Astro Cards, from sets 2 and 4, and began hunting first in Canes Venatici, which was up quite high and a bit north of zenith. I was having trouble picking out Chara (Beta Canum Venaticorum), it was just in-and-out at mag 4.25, so this was not the darkest of nights, although once past zenith to the north, the sky at my home brightens dramatically due to San Jose's light dome. I assume about mag 5 - 5.3 to the south this night.

My equipment for the night, same as last night... 10" f/5.6 Dob with Telrad, 11x70 finder, 19mm Tele Vue Panoptic and Astro Cards.

I began in Canes Venatici, searching out NGC 4490. Sitting about 1/4 the distance from Chara to Cor Caroli is mag 6.35 9 Canum Venaticorum, a nice yellow-white star a couple hundred light years distant. In my finder I could easily see Chara and 9-Camum. About the same distance away from Chara as is 9-Camun sits NGC 4490. This object was easy to find and see, appeared elongated about 2x1 in an E/W orientation. It seemed to have a thick core. A small triangle of mag 11 stars lay about 13' to the north. I was unable to see NGC 4485, which should have been in the same field. In a dark sky, this is a wonderful pair of interacting galaxies to observe. NGC 4490, also known as the Cacoon Galaxy is 6.3' x 3.1' with a magnitude of 9.8 and surface brightness (sb) of 12.9, well within backyard range. On the other hand, NGC 4485 (Arp 269) is much smaller at 2.3' x 1.6' and dimmer at mag 11.9 with an sb of 13.2. I'll try to pull in 4485 again tonight... I think it should be possible.

I next moved on to NGC 4449. Again using my finderscope, I could see Chara and a pair of stars out past NGC 4490, which were perpendicular to a semicircle of dimmer stars with one star alone, centered in the half-circle. This pointed me right at NGC 4449, an equal distance beyond the semicircle from the pair. This is a large galaxy, taking up 1/8 my field of view. It appears elongated N/S and seemed to be shaped somewhat like M104, with a 2x1 ratio along its major axis. I thought it might be an edge-on, but looking at photos today, it is obviously a highly disrupted galaxy, still, in the skies I'm working in, it is easy to mistake it for edge-on due to some of the irregular extensions. The closest dim star sits about 7' E.

I came back to Chara next, and moved to the 9-Canum, then toward and past a mag 8.3 star about 8' away. Took me almost directly out to NGC 4618. It is interesting to look at this galaxy's DSS image the day after. My notes say "small with bright core, round or face-on, diffuse halo, dim star 1/4 FOV to west, briter star 1/3 FOV north, no sign of NGC 4625, dim close double 2/3 FOV to SE, core stellar, possible extended NE/SW." The DSS image shows why it looked round, there is an obvious arm curving north of the bright core This one would be fun in a dark sky. The galaxy, also known as Arp 23, is 4.2' x 3.5' in angular size, mag 10.8 with a sb of 13.5, so, not bad for my backyard!

One of the objects that eluded me the night prior was NGC 4699 in Virgo. I just could not see the guide stars to pin the location down. This night was different. I could just see mag 4.8 Psi-Virginis and mag 4.6 Chi-Virginis. NGC 4699 lay almost exactly between the two stars. Using the finderscope, I put Chi in the center. Three mag 7 stars formed 3/4 of a diamond shape around Chi, and provided orientation. I spotted a dim chain of 5 mag 7 and mag 8 stars to the SSE of Chi, and NGC 4699 lie just off them to the north. 4699 was small, with a bright core and small disk. A star lay 1/4 the FOV east, a dim double oriented N/S was 2/3 the FOV to the west. This was a nice The DSS image confirmed my notes, there is a very bright core, and a face-on disk appearing very dusty. Nice image! The galaxy is larger than the eyepiece view reveal, at 3.8' x 2.6', but at mag 9.5 and sb 11.9, this one is a good in-town object.

My final object for the night was NGC 4697, about 2 degrees away from NGC 4699 to the north. Again using the finder, I was able to see field stars that easily identified the correct field. My notes call the galaxy large, elongated E/W (I had a question mark by that remark) about 3x1, possibly disrupted (another question mark). A nice "L" chain of stars ran from the galaxy's south in and E to W direction, then bending S to N. A mag 9 star sat near the edge of the FOV to the NNE. My last note calls the core of the galaxy stellar. Looking at the DSS image, the only thing wrong in my description was the comment about disrupted. The galaxy is 7.2' x 4.7', bright at mag 9.2 and sb 13.1. The significantly dimmer sb in this one indicates just how bright the core is and how large the dimmer nearly halo must be.

The one object I didn't see that in retrospect I would love to is NGC 4731, very nearby NGC 4699. The DSS image shows this galaxy as a highly disrupted barred spiral. I'll be trying for it tonight, but expect is will be a challenge... although it is mag 11.5, the sb is 14.6 (yikes!).

Monday, April 24, 2000

Backyard Astro-Card Fun...

Last night I decided to quit work at 9 p.m. and haul out my 10" f/5.6 Dob "Pliskin" for a bit of galaxy hunting. I had put off taking it out over several nights, and finally overcame my feeling of "hassle" at carrying the scope 40 feet to the backyard. The evening had been beautifully clear and the temperature pleasant, so by 9:15 I was set up, using my 19 Panoptic (which had been relegated to the eyepiece case in favor of the 20 Nagler for months), a Telrad, Celestron 10x70 finder and sets 2 and 4 of Astro-Cards.

Across the yard, in direct line of sight, was my neighbor's kitchen window, fully illuminated and pouring enough light onto me to make dark shadows. Bummer. Behind me, the TV made the window blinds light up like a lightning storm was destroying the interior of my home. But, I decided trying was better than quitting. I am now in process of building a large "astronomy blind" that will sit atop the pool filter enclosure, between the neighbor and my observing site. I am sure the neighbor thinks I'm nuts. She may be right.

I began by looking for NGC 4361 in Corvus. This planetary nebula sits in an easy to locate position within the "sail" shape of the Crow. It seems far too elusive, until I noticed some clouds had worked their way over to cover only the part of the sky I was looking at. Drat!

I moved to Leo, hunting for NGC 3521. In the bright skies of suburbia, this portion of Leo, down south of the beast's haunches and belly, is plenty difficult to find. Fortunately, the galaxy sits close to 62-Leonis, a 6th magnitude star accompanies closely by a magnitude 7.8 star, pointing toward the galaxy. These stars were visible in my finder. The galaxy itself was quite large and bright. I estimate it at about 10'x5', with a bright core and seemingly gradual diffusion to its edges. Maybe dusty. The Astro-Card lists it as mag 8.9v, but the surface brightness of 13.2 seems deceivingly dim. Anyway, this one was a whopper, and worth coming back to visit.

I looked back at Corvus, and the clouds were moving east off of my target. I walked around the yard looking for more clouds, but none were there... only the neighbors and the city's light pollution to cope with. I began thinking of hauling the 18' out back after seeing that galaxy... all I need is more gumption!

Back to Corvus, I sighted the Telrad and landed on NGC 4361. Don't you just love it when it happens that way? In the 19mm eyepiece, the planetary had a brightish middle and seemed not quite round. It was big too... compared to many of the little planetaries I've been looking at lately. I think I recall seeing the central star, but am not 100 percent on that. I should take better notes. This object too was transfixing. I eyeballed it for a good amount of time, enjoying the 19 Panoptic. I find with the 19 that I can get my eye completely surrounded by the eyecup, and suddenly, all that exists are light years of emptiness and a distant wonder.

I popped up into the tail of Leo next. Using the finder, I kept going over the area just east of Delta-Leonis. Try as I might, NGC 3646 would not appear. Strange, since it is much smaller than NGC 3521, and although dimmer by magnitude, it is its equal in surface brightness. I spent a good amount of time failing on this one. Yet, just down below the "ain't there" sits a cluster of galaxies, containing the bright pair NGC 3626 and NGC 3607. Both shown easily in the eyepiece, and were a snap to locate. I could almost see others in the field, but ended up logging just the two bright ones and some Lumpy Darkness.

About this time, I convinced my wife, who was asleep on the couch with the TV going, to go to bed. Off went the TV, and as is by some strange coincidence, so did the neighbor's kitchen light. Everyone was asleep, and it was a lot darker out back.

I looked up at Coma Berenices. Mel 111, the open cluster we all see as the hazy triangular area of stars, was blinking in and out. My targets were the familiar NGC 4565, and a few less spectacular (but brighter) galaxies, NGC 4494 and NGC 4559. I accidentally ran into NGC 4494 first while looking for the big edge-on. 4494 was obvious. It is rather small, but that is in comparison to the bigger objects I'd been observing thus far. In fact, were it on my current observing list, I would call it large and bright. It magnitude makes it a good in-city target, listed at 9.8, and its surface brightness made it one of the brighter objects of the night. It was certainly brighter than NGC 4565, which I star-hopped to in my finder scope using the Astro-Card. 4565 was not as "big" as I'm accustomed to in the 18" Dob, but what could I expect considering the observing conditions. It was noticeably dimmer than NGC 4494. Still, it was pleasant to see this streak of light, and hints of its dust lane. Next, I worked and worked to star hop to NGC 4459. I had to use a bright chain of stars beginning just off NGC 4494 to get to a good jumping-off point. The stars, 17, 16, 14 and 15 Comae Berenices were obvious, and 15 turned me right toward the galaxy. This one was not so bright, seemed smaller than either of the other two, and was not remarkable. I know NGC 4559 is better than what I saw last night, for it is large, has a bright core, and is nicely elongated. The conditions coupled with a surface brightness of 14 made this mag 10 galaxy rather disappointing.

Finally, I thought I'd like something a bit different. I pulled out an Astro-Card for NGC 5534 in eastern Virgo. This is an area I am unfamiliar with, since when I think of Virgo, I think of the galaxy fields north of Spica, between Vindemiatrix and Denebola. This object, a small globular cluster, resides on the line between Mu-Virginis and Iota-Virginis. It is easily seen in 10" aperture, although it is grainy but unresolved. Size is 5' and its magnitude of 9.6v coupled with the smallish size makes it a good in-town target. I tried "walking" the Astro-Card over to NGC 5534, but no luck. There is an easily distinguishable asterism of stars, a parallelogram with an extra star along one major axis, and two bright pairs of one end of the figure which should have bracketted the galaxy, but mag 13.5 was just too dim for the skies, even though the object was small in size and possibly visible.

By now, the sounds of late night were evident. Even the nearby freeway failed to make much of a stir. I was tired but content. The backyard is a good place to spend a few hours unwinding. The Astro-Cards are a fun challenge. Other objects eluded me during the night. I have left them out of this report.

The scope is still sitting out back, just in case the sky cooperates tonight.

Saturday, April 8, 2000

How was the FP last night?

I was able to do some comparisons between Fremont Peak on Saturday night and Henry Coe Friday night. I came home between observing session (had some sleep, shower and good meal).

I did not leave for the Peak until after 8 p.m. Saturday night. All my gear was still in the truck from Friday. The entire drive down was under cloud cover, and I wondered if I would arrive at the top and find it clouded out and deserted.

When I arrived at San Juan Canyon Road and began the last 11 miles of the drive, I saw some strange objects through the windshield of the truck. Slowing so I could look, I was astonished to see the odd vision was of stars, a sky full of them.

Pulling into the SW lot, I found newcomer Todd Rogers, Jamie Dillon, Nilesh Shah and David Cooper. Jamie and David's sons were along too.

No sooner had I stepped out of my truck than Jamie commented that his Telrad had dewed up in the last minute or two. I decided to leave my 18" Dob in the truck.

The moon was quite bright, but still there was some deep sky observing going on. The cities were buried under low cloud and fog. We walked over to the observatory and found Robert Hoyle there with a few park campers on their way back to the campsites.

Arriving back at the SW lot, the moon eventually set. I was looking through Jamie's 11" Dob, Nilesh's 6" and David's 5" AP. Nice views. Jamie and I would think up objects to hunt. The ones I liked best were NGC5053 just off M53... nice contrast in globulars, NGC 4565 (Jamie's first time finding it), Nilesh's view of NGC4490 and its interacting partner up in Canes Venatici, The Antennae in Virgo. Nilesh "found" a large mag 10 galaxy in Coma Berenices, but could not see it... at 13'x10' it must have a very low surface brightness (Nilesh, if you have the NGC number, I'll check how dim it really is). Nilesh also found a nice edge on galaxy in Coma that I think is nicknamed "the Slug"... it has two other edge-on's in the same field (one of the two others were visible in the 6"). Dave had been fighting dew, but we did get a beautiful and contrasty view of M5 through his scope.

All of a sudden, I looked east and saw the fog rising up from the valley. Within 5 minutes we were in the soup. We stood around talking for a while and the fog settled down. After a bit more observing I noticed the stars to the west disappearing. I could tell the fog had come up very high suddenly and looked like a dark approaching tidal wave. The wave broke over us, the sky disappeared completely. Everyone tore down and by 2:15 a.m. we were driving down the hill.

It was nice night observing although I did not set up any equipment.

While there, after the moon dropped, I had a chance to look for dim stars naked eye around Ursa Minor. I was able to see SAO 3020 (aka Lambda Ursae Minoris), mag 6.4, blinking in and out. Not too bad. I commented that our faces lacked detail, and this was how I remember the Peak from ten years ago.

That Saturday morning, at Coe, before driving home, Rich Neuschaefer and I were talking about how dark it had been. At Coe on Friday night, the fog lay in through all the valleys and took out San Jose too. Rich's comment was that Coe is certainly as dark as the Peak. I have to agree. When there is no fog, the Peak has to contend with a very bright skyglow from Salinas to the SW and SJ to the N. Coe contends with SJ to the NW, and the south county cities to the S. Neither place seems to have an advantage over the other for skyglow these days. What is better is that Coe has the large parking lot with excellent horizons, and is further removed from the ocean, meaning the "tidal wave" of fog we experienced at the Peak on Saturday night would have had to push in significantly further inland to take out the observing site at Coe. The downside at Coe is the dirt lot, but that might be changing in the next year or two.

I was beat when I arrived home at 3:30 a.m. Sunday morning. Two nights out takes its toll. I don't know how we do 4 or 5 nights at Lassen each summer. Still it was fun, even without setting up a scope.

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