Astro-Blog

This version of my amateur astronomy weblog is now using WordPress to manage the content. The older version, which was a static html page, is left as an archive.

April 23, 2009

Venus and the Crescent Moon

Filed under: Naked eye observing,Observing — nick @ 2:13 am

22 April 2009: Moon and Venus Conjunction

An occultation of Venus by the waning crescent moon early in the morning was visible in much of the western part of North America this morning. I didn’t get up early enough to see it; in fact, it was so cloudy last night that I didn’t even try to find out if and when it might visible from my location.

However, when I went outside this morning about 6:30 am, I did see a beautiful pairing of Venus and the crescent moon in the dawn twilight (click on the smaller image to see a larger version):

A little later, I thought I would try to use the moon as a guide to see Venus in the daytime. About 7:25 am (about 25 minutes after sunrise) I scanned the sky for the area where I thought the pair should be. The moon was thin enough that even it was hard to in in the bright morning sky, but after a few minutes, I was able to focus on it and with the aid of the moon as a guide, could now easily see Venus clearly in sky during the day, as I had done previously.

December 31, 2008

New Years Eve Conjunction

Filed under: Naked eye observing,Observing — nick @ 3:28 am

31 December 2008: Double Conjunction

Tonight just after sunset a double conjunction was visible: the crescent moon with Venus nearby, and, close to the horizon, Jupiter and Mercury. Around 6:00  pm I could all four objects from my backyard in the twilight of the setting sun. Venus and the Moon were shining bright in the southwest, and Jupiter, with nearby Mercury barely visible in the residual sunlight just over the roof of neighbor’s house. I called the family for a look, which they took, with varying levels of enthusiasm.

I got a more unobstructed look from across the street in front of the house as the sky darkened. I also knocked on the door of a neighbor whom I thought would  be interested in this sort of thing, and indeed, they were appreciative.

I also took a quick photo using a older Canon Digital Elph camera, and surprisingly, it turned out to be not too bad (see the thumbnails above, which link to larger images).

December 28, 2008

Various Deep Space Nebulae

Filed under: Observing — nick @ 4:16 am

28 December 2008: Various nebulae

It was a clear night, and not too cold, at least, by comparison to the rest of the month. I haven’t done much observing lately (other than a quick look at Jupiter with my my small Dob a few weeks ago, that I didn’t blog about),  so I decided to get the 10 in. Dob out. I set it up in the driveway around 9:00 pm.

The finder scope was severely out of alignment, and it took a surprisingly long time to get it set right. Eventually I got it aligned with the main tube by sighting on M42, the great nebula in Orion, because it has an unmistakable appearance in both the finder and the main scope.

I found that the batteries in the electronic object finder in the Intelliscope were  out of power, so, rather than taking the time to replace them, I decided it would be a night for star-hopping. In any case, I had not done any manual star-hopping in quite some time, so I needed the practice. My son was interested in looking at some objects (he could stay up late since the school was still on break),  so at first I showed him the aforementioned Orion Nebula. While he was using the scope, I grabbed a pair of binoculars to take a quick look around. I looked at the Pleiades and the Beehive cluster, which are always pretty objects in binoculars, and too large to be good objects with my larger scope anyway. I was also able to locate M31, the Andromeda galaxy.

I asked my son if he was interested in seeing that, and he was, so I trained the scope that way. M31 was nearly straight overhead, which is normally no problem for looking at using a Newtonian reflector scope—once the object is located that is. However, using the finder when the scope is pointed up is neck-straining work, especially for me since I had disc surgery on my neck in August. Instead of star-hopping with the finder scope, I located Mirach (?-Andromedae), and laid my green laser pointer along the tube of the scope to point at it. Then, without taking the laser off the scope, I used the visible beam to point the scope in the area in which M31 ought to be, or at least close to it. I found M31 soon this way, but in the poor seeing in these relatively bright skies only the core was clearly visible.

I wanted to show my son something a little better looking, so I used a similar strategy to find M35, an open cluster in Gemini, which is also nearly straight overhead. In my opinion, open clusters are always good objects to see in poor skies, and indeed he enjoyed the view. By this time, it was getting late, and he was getting cold and tired, so I packed it in for the night.

February 21, 2008

Lunar Eclipse 2008

Filed under: Naked eye observing,Observing — nick @ 4:53 am

20 February 2008: Lunar Eclipse

A total lunar eclipse was forecast for tonight. Earlier this day, I had poor hopes for good visibility; it was snowing when I woke up (the kids; school district called for a two hour delay, which just messes up everyone’s schedule) and the sky was completely overcast all morning.

Around 9:00 pm I had just finished a soccer game (I play on a “40 [years old] and over” indoor soccer league—yes, we won, thanks for asking) and as I exited the building the moon clearly visible with a noticeable “bite” out of it. By the time I got home I could see the sky was clear and the moon was in Leo, nestled between Regulus and Saturn. The air was crisp but cold—around 15°F (about -10°C), so I put on some extra layers of clothing.

The eclipse was approaching totality, so I asked the girls if they wanted to come out for a look, and they did. We decided it was too cold to get out a telescope but we did grab a pair of binoculars. We watched the bright limb disappear from one side of the moon and looked at the copper-shadowed moon with the binoculars for awhile. It’s funny how dark the eclipsed portion appears when part is still sunlit, but when totality occurs it seems brighter.

Since it was cold, the girls went in shortly after 10:00 (it was past their bedtime, anyway) and I went inside as well, popping out every ten minutes or so to take a look until the sunlit portion began to emerge from the Earth’s shadow.

Eclipse trivia: Aristotle used the roundness of the Earth’s shadow on the moon during a lunar eclipse as an argument in favor of a spherical Earth.

December 26, 2007

Christmas Day 2007

Filed under: Observing — nick @ 4:23 am

25 December 2007

Around 10:00 pm I had few quiet moments. I had spent much of the day cooking (roast beef, pastitsio, roasted potatoes, and stewed green beans) and cleaning up. After dinner I watched It’s a Wonderful Life with my daughters—one of them hadn’t seen it before, and the other one had only seen part of it. They thought it started slow, but in the end they said it was “all right.”

I went outside to take in some fresh air and look around. They sky was pretty clear, but brightly lit by the gibbous moon that outshone even the Christmas decorations that were all around. I could see Mars shining brightly like a orange beacon high overhead. I briefly considered getting out one of the ‘scopes, but then decided I was too tired and it was a too cold. Moreover, if Comet Holmes was still visible, it wouldn’t be able to fit it within the field of view of any combination of eyepiece and tube I had. Instead, I brought out the binoculars for a quick look. I scanned the area around Perseus to determine if I could see any sign of Comet Holmes, but didn’t have any luck, so I decided to wait a few minutes to let my eyes adapt to the dark. I took a look at the Pleiades (also naked-eye visible despite the bright moon), and M42 (a wispy gray ghost in Orion with a few stars embedded in it). After about ten minutes, I searched somewhat more diligently for Holmes, but without any luck. For comparison, I found M31; it was dim in the glare of moonlight, but still (barely) visible. Since I had previously determined that Holmes had a lower surface brightness than M31, it didn’t seem that I would have any luck with Holmes tonight.

November 30, 2007

Venus in the daytime

Filed under: Naked eye observing,Observing — nick @ 10:05 pm

30 November 2007: Early morning naked-eye observations

Around 6:30 am I was outside to let the dog out. The sky was still dark, and it was crisp and clear. I looked around and saw the moon (about half-full), Mars, Saturn, and Venus (shining like a bright jewel in the eastern sky) strung out in a line, demarcating the plane of ecliptic. Orion was also astride the sky in the southwest with another dog or two nearby to keep him company, and to the north the great bear was upside-down.

Around 8:00, after the kids were off to school, I took my dog for a walk before going to work. It was bright and clear, so I decided to see if I could do a naked-eye sighting of Venus after sunrise. I had spotted Venus in the daytime a couple of times in the past, but only with a visual cue such as nearby moon to help out. I scanned the sky in the area I thought Venus should be. I had an early success! A point of light flitted into view for a brief few seconds before I lost sight of it.

Maddeningly, I then spent a few minutes trying to repeat the observation. Fortunately my dog was very patient because she found some kind interesting smell to keep her occupied. It can be very frustrating experience attempting to find a rather small point of light at infinite focus without nearby visual cues to help. Other thing interfered as well; I became acutely aware at the number of floaters and other junk that had accumulated within my eye over the last 47 years. Also, I began to experience the blue field entoptic phenomenon. This is when you can actually see the movement of blood within the capillaries of your retina; it appears as tiny points of light that follow defined tracks within your field of view.

Well, fascinating as this was from a physiological point of view, it was no help at all in finding Venus. At last, however, I caught site of the elusive planet and held it in my gaze for about half a minute. I checked the time on my cell phone: it was 8:14 am (EST), fully half hour after the local time of sunrise, according to the paper. This was the deepest into daytime that I had seen Venus with my naked eye, and also the only time observing it in the daytime without a visual guide such as the moon nearby or the with aid of binoculars to use as a finder.

Comet Holmes

Filed under: Comet Holmes,Observing — nick @ 3:51 am

28 November 2007: Comet Holmes, Mars

Over the last few weeks either circumstances or weather conspired to keep me from tracking Holmes, but tonight I had a chance and the sky was clear with only a few high clouds scattered about. Around 7:30 I scanned the area around Perseus with my binoculars. The comet was no longer visible to the naked eye (at least not around here) and even with binoculars it was hard to find—it had grown much larger but also much dimmer than it was before. It appeared as a large (greater than a full moon’s-width) but dim, gray, fuzzy smudge just to the east of Mirfak.

With the comet  as dim as it was, I decided to use the 10 in. Dob. I let the tube cool outside for a few minutes while I bundled up (the temperature was just below freezing). After setting it up on the sidewalk in front of my house I scanned the sky around Perseus for the comet. It took a few minutes to find it; oddly enough, it seemed easier to see through the binocs than through the scope. I suppose the extra magnification spread it around enough so that it appeared very indistinct even using the 35 mm eyepiece. It had a very low surface brightness and it appeared as a wispy gray ghost that occupied nearly the entire field of view.

For comparison, I also located M31; it was nearly straight up so I had to crane my neck to use the spotter. I could now see that Comet Holmes had a lower surface brightness than M31.

Before calling it a night, I noticed that Mars was rising; it had been growing noticeably brighter lately so I took a quick look. I could make out a distinct orange disk, but not much surface detail was visible. I’ll have to give it another look sometime when it is higher in the sky.

November 5, 2007

Tweaking the theme

Filed under: Uncategorized,meta — nick @ 2:38 am

4 November 2007

After a lot of messing around with the CSS for this blog, I think I finally got it to look something close to the way I wanted it, with only some minor glitches.

November 3, 2007

Comet Holmes

Filed under: Comet Holmes,Observing — nick @ 4:02 am

2 November 2007: Comet Holmes

This was my third night that I observed comet 17P/ Holmes (The first two observations were on Oct 28 and Oct 29). Around 10:30 pm I went outside to look at the sky. It was pretty clear; some scattered clouds were about, and the seeing was medium quality as the air seemed a bit hazy. Comet Holmes was still easily visible, not noticeably dimmer than before. I could definitely see it as a “fuzzy” object tonight.

I decided to get out the 4.5 in Dob tonight instead of the big one, since I planned on just a quick look. I quickly set the scope on on a small table in the driveway and found the comet quickly. It was definitely dimmer looking than before, but then this scope has only about a fifth if the light gathering ability of the 10 in. Nevertheless, it seemed a litter bigger than before; I estimate it was about a sixth of the angular field of view using my 25 mm eyepiece (calculated total field of view should be about 1.39°). The nucleus was not apparent at all; I thought I might have seen it using averted vision (or perhaps it was just “averted imagination”).

Before I went back inside I took look at Albireo (shining like a pair of blue and gold gems—always a fun object) and the Pleiades (nice but too big to be a good telescope object, at least with my equipment).

As to comparing the the two telescopes over the last few days, there are a couple of points. First, aperture wins, as the saying goes. Bigger glass makes for better views. However, the small Dob is very light and easy to set up and get to viewing; it’s a really fun scope for that reason. It’s pity I don’t use it more often, and if I had better skies, I might.

October 30, 2007

Comet Holmes

Filed under: Comet Holmes,Observing — nick @ 2:23 am

29 October 2007: Comet Holmes

Around 9:30 tonight I took the 10 in. Dob out for another quick look at comet Holmes. It looked much the same as it did yesterday, with the exception that there was only one bright point of light (perhaps the nucleus) just off-center. So yesterday’s observation that there were two “nuclei” was the result of having a background star in the field of view.

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