Category Archives: Astronomy

It’s been easy to watch Comet Lovejoy every clear night, although most nights here recently have been hazy to foggy and completely overcast. But tonight was clear and there were special, non-cometary treats at sunset.

The thirty-eight hour old moon was hanging above the western horizon, right next to Venus. Those a few time zones to the east (Europe, US East coast) got to see it even slimmer and tinier, but it was gorgeous here. And if I’m lucky, there might still be a chance to see Mercury, which has been heading back closer to the sun. After a very long, productive, and intense day, it was time to grab the gear and head toward the park to see if I can get a better view than I can from my yard.

Here’s how the hunting went.

Sunset was at 17:08, this first set of pictures were at 17:43. There’s a hill off in the distance with houses and trees so I don’t have a clear horizon, but it’s better than at my house. In the upper left, Venus was clearly visible, as was the sliver of a crescent moon. Mercury is somewhere down below them, not quite at the other point of an equilateral triangle. No sign of it here.

Looking at Venus and the Moon close up, it’s still light enough so most of what you see on the moon is the illuminated part. That will change as it gets darker.

17:49, Mercury should still be above the trees, but it’s getting close. Still no sign of it.

As it gets darker you can see more “earthshine,” the illumination of the dark part of the moon’s surface by sunlight reflected off of the Earth. If the moon is nearly new as seen from the Earth, then the Earth is nearly full as seen from the moon. Since the Earth is also much larger in the moon’s sky than the moon is in the Earth’s sky, there’s a lot more surface to be reflecting. when it all gets added up, there’s a fair amount of light on the moon when it’s dark like this.

Here’s the diagram taken at this time from the Star Walk app. (A bit pricey for an app, but so wonderful and worth it!) You can see the relationship between the moon, Venus, and Mercury.

18:00. Mercury should be somewhere down around the top of that big, full tree under the moon. I’m sure it actually IS there, it’s not like we lost it or anything, it’s just too dim to be seen in what are still twilight skies.

Moving a bit to see if maybe Mercury might have been hiding behind that tree. Unfortunately, still no sign of it.

19:04 and we’re probably past the point where Mercury is above those trees. but the Earthshine on the moon is looking wonderful!

Looking closely at the moon we can clearly see the dark and light areas lit up by the reflected sunlight.

17:08 and the other stars are starting to be visible in the west (they’ve been visible in the east and overhead since I got here). The pair of Venus and the thin crescent moon are beautiful above the trees.

Now that it’s getting dark in the west, look waaaaaaay up there in the upper left corner. Just barely sneaking into the frame is Mars.

19:14, as Venus and the moon start to go behind the trees, shift locations again so that they can straddle a tree and we can more easily see Mars in the upper left.

19:24, as long as it’s clear and the moon’s not lighting up the sky, let’s look one last time for Comet Lovejoy. It’s gone to the west past the Pleiades and is nearly overhead. Still easily visible in binoculars it is starting to fade. With the moon getting brighter every day, making Lovejoy harder to see, this is probably it for naked eye viewing of the comet. By the time the moon has moved past full so it’s rising later in the evening, Lovejoy will be a binocular and telescope object only. (See it, that green fuzzy blob in the left-center, at about the 11:00 position?)

19:25, one last look at the crescent moon as it goes behind the trees. This is often referred to as “the old moon in the new moon’s arms.” Whatever you call it, it’s gorgeous. Look for it tomorrow night again, a bit more illuminated and a bit higher up in the sky at sunset.

I know, today’s supposed to be my nominal Flash Fiction day, but that’s going to have to wait. (I’m working on it.) In the meantime, celestial mechanics grabbed my attention and gave me a treat.

Mercury’s hard to see. It’s never far from the sun, so the only time to see it is right after sunset or right before sunrise, when the sky is still partially illuminated. The times when it’s furthest from the sun from our point of view is called “greatest elongation” and sometimes even that doesn’t help. If the plane that we’re seeing Mercury in is shallow to the horizon (it changes as the Earth moves around the sun because the earth’s axis is tilted) it’s almost impossible to see.

Dim object in a still bright sky is not a good thing.

Mercury’s was at greatest elongation a day or two ago but this time the plane of the ecliptic is up high, and to boot you’ve got Venus really close (called a “conjunction”) which makes it easier to know where to look for Mercury, because Venus is really stinkin’ bright even when it’s close to the sun.

I knew all of this, but I have hills to my west and it’s been cloudy and hazy. I was seeing pictures that others were taking and figured if I got a clear night I would go over to a local spot where there’s a nice hill with a decent western horizon. Tonight might have been a good night, but I had other things to do and wasn’t going to be home until nearly an hour after sunset.

Then, driving home, headed west…

Hanging in the sunset, right next to Venus shining so bright it looks like the landing lights on a 747, was Mercury, more clear to see than I’ve ever imagined. Mercury was as clear as day, even dealing with traffic and street lights and the lights of oncoming cars.

More importantly, as I pulled up at home and looked again, the pair was more than high enough even to be seen over the hills to my west! Run into the house, kiss The Long-Suffering Wife, grab the camera (fortunately still set up  on the tripod for Comet Lovejoy hunting), and sprint back out into the front yard.

I think that I’ve only seen Mercury with the naked eye once before, maybe twice. No, just once. Anyway, it was hard to miss tonight. Spectacular!

180 mm zoom, 1/20 second

Remember to click on the image to see the full-sized versions.

300 mm zoom, 1/4 second

154 mm zoom, 1/3 second

192 mm zoom, 1 second

As it got darker, you can see a few other stars starting to pop out, like the one that’s disappearing underneath the phone wires at the bottom and the one that’s just coming into view at the top of the frame.

If it’s clear out tomorrow, the next goal might be to try to get a wider picture — Mars is off to the upper left but would require a much wider angle picture. Worth trying. Of course, if I really had some good hear set up and could get Mars included in the picture, Neptune is fairly close to Mars… It would be fantastic to get all four of these planets in one picture, but that might be a stretch for me with just a camera on a tripod.

Mercury will be slowly pulling away from Venus and sinking back down toward the sun over the next couple of weeks. If you get a chance in the next couple of days to take a look and you’ve got a clear western horizon at sunset, take a gander at Mercury, the closest planet to the sun!

Now, back to writing Flash Fiction…

Despite my earlier misgivings,

the fog and haze sort of settled in toward the ground, so there was a halo around all of the street lights, but it was reasonably clear up higher.

Fortunately, that’s where Comet Lovejoy is these days, and from there I can actually see it through the trees from the back yard, where it’s much darker than the front. Tonight Lovejoy formed close to an equilateral triangle with one leg being between Taurus and the Pleiades, with Lovejoy below them at the third point.

It was actually the first time that I’ve seen it with the naked eye. Knowing where it was at was a help, not sure I would have identified it without knowing which fuzzy spot and/or dim star it was in advance. But since it was a very easy object to spot in my binoculars, knowing where to look was easy.

All pictures are 3.2 second exposures with the lens at 75mm, ISO 1600, Canon Digital Rebel xT, no additional processing:

To make sure I got some pictures of the comet, I covered that whole section of sky with overlapping wide angle (75mm instead of 300mm) pictures. First aiming low and to the right, Lovejoy can be seen in the upper left corner, a green fuzzy spot.

Aiming higher, it’s now in the middle left, a bit in from the left edge.

Aiming still higher, Lovejoy’s now in the lower left, just above the bottom edge. You can see the Pleiades at the upper right. If the frame were slightly bigger, just up out of the frame’s upper left corner you would see Taurus.

For spotting Lovejoy over the next few nights, keeping Taurus and the Pleiades as reference points, Lovejoy will be in a shallow climb through this view, in a line up and to the right. By January 18th or 19th it will be directly below the Pleiades about where the top of that blurry tree branch is in the lower right.

Coming back down and over to the left a half-frame or so, Lovejoy’s now just to the lower right of center at about 5 o’clock.

Getting down to just over the treetops again, Lovejoy is near the top, just to the right of center.

Finally, even though it doesn’t show Comet Lovejoy, this picture does show something we get to deal with living where we live. The approach to Burbank Runway 8 is pretty much right over our heads. Here’s Taurus in the upper left, the edge of the Pleiades at the center edge right, (Lovejoy is out of the picture, approximately a third of a frame below the lower left corner) and a Southwest 737 going overhead.

When last we left our plucky hero (i.e., me) we had spotted Comet Lovejoy and managed to get a couple of blurry photos of it. There was considerable room for improvement.

Last night I went out and spent some time playing with the manual focus on the Tamron 70-300mm zoom telephoto lens that I’m using on my Canon Rebel xT camera. Eventually I got better (leaving more room for improvement yet) by concentrating on bright constellations, such as the Pleiades and Orion. Eventually I ended up with this (remember, click on any image to get the full-sized version):

This is an eight-second exposure at 70mm. The “belt” of Orion is in the upper left corner (three bright stars in a row) and you can just see the Orion Nebula (the middle star in the “sword”) at the far left edge, right about in the middle. Minimal blurring, which is good. No comet, which is bad. On January 3rd, it would have been visible in the lower right corner — but of course, it’s moving (up and to the right in this view), so it’s now out of the frame.

It wasn’t that hard to find, pretty easily visible in just a few seconds through binoculars. This is another eight-second exposure at 70mm. Unfortunately, despite my practice earlier in the evening, all of my 300mm exposures (and we’re talking a couple hundred here) were all out of focus and trash. (Frustrating!)

Again, if you’re looking yourself (and you should be, assuming you’re not in one of those places with -40°F temperatures tonight), it will just be a hazy, grey or white patch through binoculars, almost like a vague and dim cloud. Sorry, the human eye doesn’t have enough receptors to see it like a camera can and give you that bright green glow that you see in pictures. For example, that picture is from a 12″ telescope in dark skies with almost 18 minutes of exposure on eight frames combined. Compared to that, your eye doesn’t stand a chance!

Tonight we have scattered clouds that are getting thicker as the evening wears on. I managed to get this eight-second image at 81mm…

…and this one (also eight-seconds at 81mm), both of which clearly show the green comet as a small, fuzzy ball. Both of these images are in pretty good focus, but the stars are a tiny bit blurred because of “trailing”. I’m using the camera on a fixed tripod, but the Earth is moving, so in a longer exposure the stars look like little streaks. For example…

…compare this image to the first one above. This is the 30-second exposure taken in the same set as that 8-second exposure, and you can see how all of the stars are little arcs/lines going from the upper left toward the lower right. Proof that Galileo was correct — the Earth DOES move! (The “fix” for this is a telescope mount which is designed to counter-rotate at the same rate as the Earth does, so if it’s aligned correctly, the stars stay motionless relative to the camera. But I didn’t want to go to all of the effort tonight of hauling the big scope out and setting it up in the yard. Maybe after these clouds clear in a couple of days.)

Now, it’s 22:46 PST — let’s save the draft of this and take go back out to take one more shot tonight at getting some 300mm shots that don’t suck.

23:16 PST — The good news is that I got some 300mm images that are in much better focus than before. The bad news is that I wasn’t pointed at the comet.

You can’t actually see the faint, fuzzy comet through the camera viewfinder. You can only the brighter stars that way. Also, with the lens zoomed in like that you’ve got a much smaller field of view. So I sort of get it “close” to where I need to be, then take sets of pictures in a “search pattern” — sort of like playing “Battleship”. But midway through the first set the clouds rolled in with a vengeance. Right now you can’t even see the moon except as a brighter blotchy area in the thickening clouds, so I think that’s it for tonight.

But the next clear night, we’re going to kick that comet’s ass!

In the winter of 1973, I spent many a sub-zero night standing knee-deep in snow, trying to see that decade’s infamous “Christmas comet”, Comet Kohoutek. I had no telescope, just a “Sears grade” pair of binoculars. I had no digital or video camera (of course, it was 1973!) but only an Argus C3 film camera.

In Vermont that winter, at night, it was really, really cold. I remember seeing the comet a few nights, just a fuzzy, white patch in my low-power binoculars.

Tonight, it’s not quite that cold in Los Angeles, but it’s down into the mid 30’s. This time with high-quality, astronomy-grade, Celestron binoculars and a pair of good DSLR cameras and telephoto lenses, I was after Comet Lovejoy.

The full moon wasn’t far away, and Los Angeles isn’t any less light polluted than it’s ever been. While I was not able to see Lovejoy with the naked eye (that should come when the moon’s not so bright in a few days), in the binoculars it was pretty easy to spot.

It’s not going to look like the pictures you might be seeing. (And you really, REALLY should click on that link!) In particular, at least here tonight, none of the distinctive green color of Lovejoy could be seen by eye. Through binoculars tonight, it was a white smudge, a powder puff. Where the stars were all pinpoints, Lovejoy looked like a small, round, pale white cloud.

So what happens when I try to get it with the camera?

First, the technique. This was fast and dirty, the cameras on a tripod, shooting a whole lot of frames from about 1/6 second all the way up to 25 seconds. Using the camera it was impossible to see the comet directly, so I went through series of pictures, moving the camera a bit for each set, changing the zoom and field of view for each set of sets.

It’s sort of like carpet bombing the sky with the camera, hoping to get lucky.

With the 28mm wide angle lens, the first thing that’s obvious is that the full moon is really messing with the pictures.

Here the moon is just out of the picture at the upper left corner.

Annotating that first picture, Orion is obvious, as it Taurus, and the Pleiades.

Tonight Comet Lovejoy is somewhere around where that yellow circle is. The way I found it (tonight — it’s moving so it won’t be quite in the same spot tomorrow) was by first finding Orion. In my binoculars, the field of view just covers the distance between Orion’s belt and Rigel, the really bright star that makes up the bottom of Orion’s right leg. Using that distance/FOV as a unit, I was seeing Lovejoy about two “FOV’s” to the right (east) of Rigel.

But with this picture and that bright moon, I couldn’t see Lovejoy. It might be the dot that’s inside that circle (click on any of the images to enlarge to the full sized image), but it might not be. Any longer exposures aren’t any better because the moon just washes them out even more.

I moved to the telephoto lens at 75mm. In these pictures you can clearly see Lovejoy, and you can clearly see it’s green color. In this picture, Rigel is the bright star at the mid upper left, where Lovejoy is on the right side, about halfway out from the center to the edge of the picture, between the 3:00 and 4:00 positions. This was a 4 second exposure.

Again, I was shooting blind, trying to blanket the area with different overlapping series of pictures. In this 4 second exposure, Rigel’s right at the center of the left side, while Lovejoy is at the 6:00 position, again about halfway from the center of the picture to the bottom edge. The green color is clear, as is the fact that it’s a bigger, fuzzier object compared to the stars, which are more or less pinpoints.

The big problem of the night occurred when I tried to zoom in to 300mm. Again, blanketing the area with hundreds of pictures pointed in slightly different directions with a series of exposures, I got a couple of photos that are recognizable, if not good. Here Lovejoy’s at the far left side, near the top.

Here Lovejoy’s at the far right side, again near the top.

The problem with the 300mm pictures is obvious – they’re out of focus. Focusing through the eyepiece is tricky at best, since the difference between in focus and out is absolutely miniscule. One might think that you could simply set the lens at ∞ and forget about it, but like 99.9999% of all lenses, the Canon lenses actually stop at a focus point just beyond ∞, so you can’t rely on that.

So Lovejoy’s there, I can see it, I can sort of take pictures of it, but I have to figure out something to get the focus right on the high magnification settings for the zoom lens. Something to work on over the weekend and into next week.

Look back at that annotated picture (above) or any of the sky maps showing Lovejoy’s path. Over the next month it will head up past Orion, past Taurus, and past the Pleiades.

You keep looking for it — I’ll keep trying to figure out how to get better pictures.

Clear skies!!