Wednesday, August 17, 2016

2016 Perseids

Clouds here at the ObservaRory spoiled much of the show during the 2016 Perseids. I set up the camera sometime after midnight and had it take 30-second exposures until the battery ran out. Despite the clouds, though, it caught images of several meteors, as well as a few other sky fairies.

The image below is my favorite. It was taken sometime near the end of the run. A thin layer of clouds covers much of the sky. The Pleiades is on the right, and Capella--appearing large and fuzzy due to refraction caused by the clouds--is at center bottom. The tree in the lower-right appears blurred because of the wind.

This little meteor originated below and left of the Double Cluster in Perseus.

One of the streaks in this image is a meteor, but the other is a satellite. Guess which one! (Answer below.)

While both appear to be good candidates for Perseids (they seem to originate from the same radiant), the lower streak is actually a satellite. Bright meteors show up in images as multi-colored streaks. They also only appear in one image because they move across the sky so quickly.

Satellites, on the other hand, are usually white and move slowly, often appearing in two or more images.

The animate GIF below is composed of two frames that were taken during a satellite flare, possibly from an Iridium satellite. The fuzzy object at the top is the Andromeda Galaxy. The frames are aligned on the object. Each frame is 30 seconds long, with a 5-second gap between. The motion of the background stars represents the rotation of Earth during the 65-second period.

A flare, possibly from an Iridium satellite.

Saturday, August 6, 2016

Milky Way on a Country Road

There is a region north of Huntsville, Texas where the sky is considerably darker than most of East Texas. It measures from a low to a high 3 on the Bortle scale, and is roughly located between the Old Spanish Road (OSR) to the south, Palestine to the north, Interstate 45 on the west, and Lufkin on the east. A portion of it is south of the OSR, not far from my house.

My son and I drove through part of this area last February doing a light pollution survey. I was really impressed with how the sky looked there, and decided to revisit it during the summer. So, the other day we drove out to a spot on the side of a road somewhere between Weldon and Lovelady, about 30 minutes from our house. The view was spectacular!

The Milky Way stood out with very high contrast compared to how it appears at the ObservaRory. It's not quite X Bar Ranch dark there, but it is still very good. Below is a composite image of photos that I took with the DSLR and a zoom lens.

Milky Way, Canon EOS Rebel T3, EFS 18-55mm lens @ 18mm (f/3.5), 6x30 @ ISO-3200, stacked in DeepSkyStacker, color-corrected in Photoshop CS6
Below is an enhanced version that brings out the stars and dust lanes:

Same image as above, enhanced using the Detail Extractor in the Color Efex Pro 4 filter collection, which is part of the Google Nik Collection of filters in Photoshop.

Monday, August 1, 2016

Back Yard Astronomy

The right combination of time, energy, and weather conditions still elude me lately. I haven't done much more than peek out the window at the stars now and then. That gave me an idea, however.

Last night I set up the trusty DSLR at one of the back windows and started making a time-lapse of the sky.

But I didn't account for last night's high humidity. The window fogged up shortly after the sequence was started, and I didn't discover the problem until the morning. There weren't enough frames to make a decent time lapse.

Still, there were a few pictures that I thought were pretty.

Below, the constellation Scorpius, containing the bright red star Antares, dominates the center of the image. Mars and Saturn are visible in the upper-right. Ptolemy's Cluster and the Teapot asterism are on the left. There are clouds, mostly above the treeline, to the right. The Milky Way is visible at the top, just to the left of center. The image at the end of the post has labels.

To the ancient Greeks, the star Antares appeared similar in color and brightness to Mars, which they called Ares. The name Antares means, "rival to Ares" or "equal to Ares." Mars is approaching Antares in the sky, and the two will be less than 2 degrees apart, forming a nearly straight line with Saturn, on August 24, 2016.

Single, 30-second exposure at ISO-1600 made with a Canon EOS Rebel T5 with the stock EFS 18-55mm zoom lens @ 18mm. Corrected for lens distortion and color balanced in Photoshop CS6. Noise reduction using Google Nik Collection Dfine 2.0 Photoshop plug-in.

Saturday, May 14, 2016

2016 Mercury Transit

The Mercury transit...

Well, I almost missed it. Most of Texas (and the United States, for that matter) was socked in with clouds. The few places that were clear were too far for me to travel.

But amateur astronomers almost always hold on to at least a little bit of hope, even when the odds are overwhelmingly against us. We patiently scan the sky for "sucker holes" and engage in our preferred ritual superstitions to drive away the clouds. (Yeah, I know, we're supposed to be scientific and all that...but desperate circumstances often lead to desperate actions.)

The sky DID clear up for a few minutes--at least enough for me to focus and get a few shots in. It's nothing spectacular, but here it is:

Click here for the full-size version.

Mercury is the dot to the upper-right of center. The big sunspot group to the left is AR2542. Other smaller sunspot groups are also visible.

This is a stack of four exposures, each 1/2000th of second at ISO-100, taken with a Canon T3 on my Orion ShortTube 80. I used an Orion full-aperture solar filter, and the Baader Contrast Booster (to reduce chromatic aberration). The images were stacked and wavelet sharpened in RegiStax5. I did an "auto color" correction in Photoshop CS6 to brighten the image a bit.

Click here to see my images of the 2012 Venus transit.

Sunday, March 27, 2016

Sword of Orion

Yet another image of the Sword of Orion. I admit that it's one of my favorite targets, however, my primary purpose was to test how the Baader Contrast Booster performed.

The Moon rose around 10:00 PM, so my window was tight. I limited each set of exposures to 8 "good" subs each. The exposure times were 5, 15, 30, 60, and 120 seconds at ISO-3200. Images were stacked in Deep Sky Stacker with darks, flats, and bias frames, and then processed in Photoshop CS6 using the Google Nik Collection.

Sword of Orion; ST80 w/Baader CB on Vixen SP; Canon EOS Rebel T3

Close-up of Messier 42 (right), the Great Orion Nebula, and Messier 43 (lower-left), De Mairan's Nebula.

Close-up of Running Man Nebula
The detail on this version isn't quite as sharp as my previous attempt. I think this may have been due in part to the seeing being poor (a front had come through the day before). More 120-second subs would have definitely helped.

The filter performed as expected. There was very little chromatic aberration, and I did nothing to remove what little there was. Note how the stars are not nearly so bloated as in the older image. Keep in mind that these images are from a relatively inexpensive achromat!

The distortion that is particularly noticeable in the stars on the left is due to coma.

Google recently made their Nik filter collection free to the public. There are tons of features and options, and I haven't explored them all. I used the Detail Extractor from the Color Efex Pro 4 collection and Dfine 2 noise reduction filters for these images. I was particularly impressed with the Detail Extractor as it brought out some very faint parts of the nebula in the lower part of the full-size image.

Sunday, March 20, 2016

2016 Spring Equinox

Here is a portrait of my family about 15 minutes before sunset on the Spring Equinox. Our road runs east/west, so the sun rises and sets at the ends on the equinoxes. I've dubbed the street "Roadhenge."

Rite of Spring at Roadhenge

Thursday, February 11, 2016

Globe at Night, Part 2

My son and I collected some more sky brightness measurements on the night of February 9, 2016 in the vicinity of the small town of Bedias, Texas. Bedias is located in a rural area, surrounded by flat pastureland. There are many areas with views down to the horizon, or nearly so. Regretfully, there are several light domes that spoil what would otherwise be a spectacular view. Still, the skies there are fairly dark, at least at zenith.

The following two images were taken with the same equipment and settings as those in the previous post.

For reference, here is an image of the Orion constellation taken from my house the same night as the Bedias trip:

Orion at the ObservaRory
This image was taken on a county road near the western edge of Walker County, just a few miles east of Bedias.

A few miles east of Bedias, Texas. The red line to the left was from a passing aircraft.
The light dome of Houston, Texas and surrounding cities dominated the sky to the southeast. The light dome of Huntsville was visible to the east, and Madisonville's light dome was barely visible to the north.

While not as dark overall as the sky near Weldon, the view was very nice, with many faint stars visible to the naked eye at zenith, and the Milky Way clearly visible.