Tag: Deep-Sky Objects

Two views of Orion

Orion is one of the most conspicuous and recognizable constellations in the night sky. It was named after Orion, a hunter in Greek mythology. Its brightest stars are Rigel (Beta Orionis) and Betelgeuse (Alpha Orionis), a blue-white and a red supergiant, respectively.

Hanging from Orion’s belt is his sword which contains the Orion Nebula, also known as M42. This is a spectacular object that can be clearly identified with the naked eye as something other than a star. It is one of the most easily photographed Deep Sky Objects and can be captured by most modern digital cameras.

The first image of Orion was taken last winter on an evening with a very thin layer of high clouds. This cloudiness was enough to cause a beautiful glow around the brighter stars in the constellation. Some nebulosity is visible in both the belt and sword of Orion. (Nikon D700, ISO 1600, f/5.6, 120 seconds, 80mm).

Constellation Orion (February 2015)
Constellation Orion (February 2015)

The second image was taken this spring (Nikon D700, ISO 1600, f/4, 10x120s, 200mm) and is zoomed/cropped on the Orion Nebula (M42).

Orion Nebula--M42 (April 2016)
Orion Nebula–M42 (April 2016)

I recently heard someone say that a reasonable goal of astrophotography is not so much to produce the best image, but to produce a better image than your previous best. In this case, I can claim some success.

And, for comparisons sake, here is a richly detailed image of the Orion Nebula captured by the Hubble Telescope and posted on the Astronomy Photo of the Day (APOD) site.

Comet Catalina and its closest approach to Earth

Over the past few years I’ve been interested in capturing images of comets as they move through the inner solar system. Some have been easier than others primarily because of their brightness but also because of where they lie in the sky.

Comet Catalina (C/2013 US10), however, has been a challenge. When it first became visible in the northern hemisphere it was difficult to see in the early morning twilight. Later, it moved so that it was well up in the sky before twilight but then I was fighting both bright moonlight and cloudy weather.

Finally, clear skies have allowed me another chance to take images of the comet this week. It is quickly moving through the northern skies towards the constellation Ursa Major and made its closest approach to Earth (at a very safe distance of 110 million km) last night (17 January 2016).

The comet isn’t bright enough to be visible to the unaided eye but binoculars are sufficient to reveal it as a fuzzy spot in the sky. With a DSLR and long exposure it’s possible to get reasonable images.

C/2013 US10 (Catalina) showing its double tail structure (12 January 2016).
C/2013 US10 (Catalina) showing its double tail structure (12 January 2016).
C/2013 US10 (Catalina) long exposure showing motion in the comet (12 January 2016).
C/2013 US10 (Catalina) long exposure showing motion in the comet (12 January 2016).
C/2013 US10 (Catalina) moving past stars in the Big Dipper handle and a couple of galaxies (12 January 2016).
C/2013 US10 (Catalina) moving past stars in the Big Dipper handle and a couple of galaxies (12 January 2016).

The first set of images are from 12 January 2016. The comet is approaching the handle of the Big Dipper. One long-exposure image shows points of light for stars but a short streak for the comet as it moves through the sky.

C/2013 US10 (Catalina) as it continues on its journey (18 January 2016).
C/2013 US10 (Catalina) as it continues on its journey (18 January 2016).

The second set of images are from 18 January 2016. Occasional clouds and a quarter moon made it more challenging to get a great image but there will be more opportunities later this month.

Perseid meteor shower

The Perseid meteor shower of 2015 was better than average because it occurred one day before the new moon. The absence of moonlight meant that many fainter meteors were visible.

Although the shower peaked on the night of 12–13 August, meteors could be seen for several nights before and after. I went out for several hours photographing the shower on two different evenings and was happy to report that clear and dark skies produced a great event.

On the night of 12–13 August, I set up the camera on my equatorial mount so that I could track the radiant across the sky for several hours. I then combined the images with meteors into a single image that clearly shows the radiant. The result was pretty good although I’m certain I saw more meteors than the camera was able to capture.

Perseid meteor shower.
Perseid meteor shower. Andromeda Galaxy (M31) is also visible in the upper right.

In addition to the meteors, there was a prominent set of waves in the airglow visible low on the horizon. From wikipedia:

Airglow is caused by various processes in the upper atmosphere, such as the recombination of atoms, which were photoionized by the sun during the day, luminescence caused by cosmic rays striking the upper atmosphere and chemiluminescence caused mainly by oxygen and nitrogen reacting with hydroxyl ions at heights of a few hundred kilometres.

Here is a short time-lapse video of the multitude of waves present in the airglow that evening. (A higher quality version of the video can be found here.)

The following night also had meteors but at probably half the hourly rate as the previous evening. Once again I mounted the camera on the equatorial mount but this time I pointed the camera towards the southwest and aligned it with the Milky Way. I managed to capture two very bright meteors as they streaked from overhead down towards the horizon.

Perseid meteor shower.
Perseid meteor shower.

The last time the Perseids peaked at about the same time as the new moon was in 2007. In August 2018, the moon will be only 4% illuminated providing another dark sky opportunity.

 

Milky Way Rises over Cathedral Rock in Sedona

With a very clear night and the moon rise not expected for several hours, I set up the iOptron SkyTracker to capture images of the Milky Way and Cathedral Rock in Sedona. The star image was 4 minutes in length and shot at ISO 1600. The SkyTracker works well enough that the stars still appear as points with this long-exposure image. A second image was then taken using the same exposure settings but with the tracker turned off in order to get a sharp foreground.

The Milky Way rises above Cathedral Rock in Sedona.
The Milky Way rises above Cathedral Rock in Sedona.

Taking the images was easy. So was the post processing. It turned out that combining and blending the two images was harder than I thought. But the result was worth it.

Dark skies and the Milky Way

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With the moon well past full combined with very clear and dark skies it was time again to do some night sky astrophotography. On an earlier outing, I had taken a few “exploratory” images of potential targets. It was now time to take some longer exposures.

My first target was Rho Ophiuchi cloud complex, a dark nebula of gas and dust that is close to the star ρ Ophiuchi of the constellation Ophiuchus (and located adjacent to the better known constellation Scorpius).

Rho Ophiuchi cloud complex. The planet Saturn is in Scorpio and is located in the upper right of the image.
Rho Ophiuchi cloud complex. The planet Saturn is in Scorpio and is located in the upper right of the image.

My tools for the night were a Nikon D700 DSLR (fairly old camera technology by today’s standards), a Nikon 85mm f/1.8 lens (a short telephoto lens that works well for astrophotography), a tripod, and an iOptron SkyTracker equatorial mount for tracking the stars on long exposures.

I took 10 exposures each of 4-minutes duration and then stacked them using the (free) Deep Sky Stacker application. The resulting image was post processed in Photoshop CS6 using Astronomy Tools v1.6.

The result isn’t bad considering I’m still pretty much an amateur at this astrophotography thing. For comparison, check out this amazing version of the Rho Ophiuchi cloud complex at the APOD site.

The next night was almost as clear so I returned again to my viewing location near Mormon Lake. This time, I used an ultra-wide angle lens (16mm). Here you can see the Milky Way rising in the east with Saturn in Scorpio and visible in the center right part of the image. The Rho Ophiuchi cloud complex is also visible to the right of the Milky Way. The glow in the lower right is from the city of Phoenix—locateded over 150 kilometers to the south.

Milky Way rising.
Milky Way rising.

While capturing these images I was treated to the yipping of coyotes, hooting of owls, and could hear a small herd of elk grazing in a nearby meadow.