Saturday, August 27, 2016

Jupiter Venus Conjunction

Today was the occurrence of a very tight conjunction of Jupiter and Venus, the two brightest planets in the sky. Phil Plait has an article on the conjunction on his Bad Astronomy blog. The position of Venus is predicted to be visually closer to Jupiter than the outermost moon Callisto. This tight of a conjunction is a rare event and I did not want to miss it. Unfortunately, the day was very cloudy and I feared I would see nothing. Just before sunset, I headed out with the camera to a spot near home where I could observe the western horizon. The sky was indeed hazy with broken clouds but there looked to be a chance of seeing something so I set up for the show.

I watched the sun pass behind a bank of clouds and set. A very nice view.

After the sun set, I began to anxiously scan the sky for the planets, both below and above the cloud bank. I finally spotted a dot under the cloud bank and took many pictures of it. Humm, I expected Venus to be much brighter but maybe it was the haze ... also, there should have been two dots very close. I started convincing myself that I had not done the field-of-view calculations correctly and that the planets were so close that I could not resolve them. I saw nothing else around so I packed up and drove towards the grocery store.

As I did so, I looked back over my shoulder and saw a clear conjunction higher in the sky peeking out of the clouds ... how embarrassing. I found another place to observe and took more pictures. These next two images, taken at a 190mm and 250mm focal length and about 15 apart, show Venus upper most and Jupiter just below and to the right. This was indeed a spectacularly close conjunction. I had hoped that the third dot was Mercury as this was its expected relative angle to the other two planets. Mercury, however, is much further down near the horizon and behind the clouds. This third dot is actually the star Zavijah (β-Virgo).

Zooming in to a 560mm focal length and cropping, we can see the moons of Jupiter. The three in a row are Io, Ganymede, and Europa. Further out, dimmer, and just below Venus is Callisto. Two hours earlier, Venus would have passed just to the upper right of Jupiter, closer than Callisto. No chance of seeing that closest approach from Texas as the sun was still bright in the sky.

I am glad I saw the real conjunction after all. I am still not sure what star I was staring at initially.

Thursday, August 25, 2016

Ruby Throats are Back

For the last week, we have been seeing Ruby-throated Hummingbirds at the feeders at home. Perhaps up to a half dozen at a time. There was a few days overlap with the Black-chinned that have been here over the summer. Perhaps the rubies passing through have displaced them. I got some pictures of one male perched in the tree as it guarded the feeders and later as it hovered over one of the feeders.

Sunday, August 14, 2016

Green Chile Batch 2016

How does a New Mexican spend August? preparing green chile, of course. From Whole Foods, we purchased three cases, one mild and two hot, of the wondrous pods for a total of 75 pounds. We had them roasted and then spent a few hours each night removing the charred peels under running water and chopping off the heads. When done, we vacuum sealed the pods into one-pound bags and put them in the freezer. All told, we ended up with 32 pounds of finished product which will hopefully last us the year. Gloves are necessary to avoid uncomfortable chemical burns to the skin. A respirator would have been a good idea too.

Thursday, August 11, 2016

2016 Perseids Meteor Shower

I did not have the opportunity to go to a dark site for the Perseids this year. However, I did setup a camera on a tracking mount and took pictures all night. I used the Canon 7D set at ISO-800 and a Canon 18-55mm lens set at 18mm, f/4.0. I took 60sec exposures every 65sec from late evening through dawn. The center of the frame was aligned with where I expected the radiant to be in the constellation of Perseus. I was surprised how few meteors I actually imaged ... only 11. Other AAS members who went to the dark site at Canyon of Eagles reported 50-100 per hour.

The image below is a composite of the eleven frames with meteors spanning from 12:30 to 4:30. In each frame, I flattened out and neutralized the skyglow gradient and lifted the black point to normalize the background level. I then chose a reference frame and merged in the meteor trails from the other frames. Finally, I reintroduced a slight color gradient. The image needs to be seen at full resolution to pick out any but the few brightest trails. See if you can find all eleven!