Category: Astronomy

Orion in January

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One of my goals this month was to capture the constellation Orion using a wide angle lens. Several months ago I purchased the Tamron 35mm f/1.4 Di USD lens. This is a very good wide-angle lens for astrophotography because the stars remain sharp in the corners. I have written about this lens in a previous post.

Orion and neighboring gas clouds and nebula.
Orion and neighboring gas clouds and nebula.
Orion and neighboring gas clouds and nebula with labels.
Orion and neighboring gas clouds and nebula with labels.

A good reason to photograph Orion with a wide angle lens is the abundance of interesting objects that are near and surround Orion. These include the Orion Molecular Cloud Complex, the Witch Head Nebula, Rosetta Nebula, Flame Nebula, and Barnards Loop, among others.

A screen shot from the Stellarium application showing Orion and the field of view with a 35° lens.
A screen shot from the Stellarium application showing Orion and the field of view with a 35° lens.

I shot 40 two-minute images (80 minutes total exposure) at f/2.8 and ISO 400 and then stacked them using Siril. I also ran a star reduction algorithm to remove some of the stars so that the gas clouds would be more visible. Here are the results of that astrophotography session.

Next I would like to use a large telephoto lens to zoom in on some of these objects. Now I just need to wait for the Moon to shift into the early morning hours.

Objects in the Night Sky–December 2025

It has been a busy week shooting two very different night sky subjects. The first was to capture the Pleiades star cluster with the planet Uranus in the same field of view. I did a test shot of this a few months ago and finally dedicated an evening to capture this pairing. This was shot using a Nikon D850 and a Nikkor 180mm ƒ/2.8 Ai-S lens. This lens has become one of my favorites for short-telephoto shots of the sky. It’s pretty good wide open at ƒ/2.8 but becomes excellent at ƒ/4.0. This is a composite of 27x120second images. Image stacking was done using Siril.

Pleiades star cluster and the planet Uranus.
Pleiades star cluster and the planet Uranus.

A few days later it was time to catch the peak of the Geminid meteor shower. The moon did not rise until well after midnight so I had plenty of time to capture meteors in the late evening. The image is a composite taken between 2100 and 2159 MST while using a star tracker — and then blended with a foreground image taken earlier. Jupiter is the bright object in the center with Pollux and Castor to its upper left. The red star on the right is Betelgeuse. The meteor at top center left a long-lasting smoke trail.

Geminids meteor show. Jupiter is in the center with Pollux and Castor to its upper left. The red star on the right edge is Betelgeuse.
Geminids meteor show. Jupiter is in the center with Pollux and Castor to its upper left. The red star on the right edge is Betelgeuse.

Here are cropped versions of the bright meteor and the smoke trail.

A bright Geminid meteor...
A bright Geminid meteor…
...and the smoke trail it left.
…and the smoke trail it left.

Fortunately, it has been a warm December so far and standing around at night shooting photos is not as cold as it could/should be.  It won’t last.

Aurora Borealis: 10–11 December 2025

Solar Max continues to produce auroras that are visible at low latitudes. The most recent occurred on the night of 10–11 December. Once again, I chose to shoot from Ashurst Lake because it has very good visibility to the north. This time, though, we did not venture out to the edge of the lake. Heavy rains in November (almost 5″) has resulted in wet soils that have not dried in the colder temperatures and low sun angles of December. No desire to sink in the mud!

Shooting from the parking lot was a good alternative but did not give the expansive reflections from the lake that I have enjoyed before.

The aurora substorm starts up to the northeast with numerous pillars visible.
The aurora substorm starts up to the northeast with numerous pillars visible.
The pillars move westward over the next few minutes. The North Star, Polaris, is highlighted here to give a sense of the low heights of these pillars.
The pillars move westward over the next few minutes. The North Star, Polaris, is highlighted here to give a sense of the low heights of these pillars.
The substorm subsided leaving just a faint glow to the north. A meteor (probably a Geminid) streaks across the sky with the aurora as a backdrop.
The substorm subsided leaving just a faint glow to the north. A meteor (probably a Geminid) streaks across the sky with the aurora as a backdrop.

This aurora was lower intensity and much more difficult to see than the event in November. In fact, we were unable to see it with the unaided eye. Reviewing the photo images after the event clearly showed there was a sub storm that lasted about 20 minutes. The peak heights of the pillars was much lower than we have seen before.

I have been learning how to use satellite data to forecast when these substorms might appear. Here is a plot of the data leading up to the substorm which occurred around 1918—1940 MST (0218—0240 UTC 11 December 2025). The vertical line shows when the substorm pillars first appeared in my photographs.

Solar wind data used to forecast the aurora substorm.
Solar wind data used to forecast the aurora substorm.

Images: Nikon D850, 17mm, f/2.8, ISO 3200, 15 seconds.

Milky Way with the Tamron Lens

Earlier this year I rented a Tamron SP 35mm ƒ/1.4 Di USD lens to use for shooting the Perseids meteor shower. Yes, I know, the Moon was an issue in 2025 but I wanted to test this lens. The reason I was interested in a 35mm ƒ/1.4 can be seen in this article at Clarkvision.com in which he describes the best combinations of aperture vs. focal length to maximize the number of meteors per exposure. And the choice of this particular lens was informed by this review article.

Milky Way with the Tamron 35mm f/1.4 lens. The star Vega is visible at the center bottom and the North America Nebula is located in the upper right.
Milky Way with the Tamron 35mm f/1.4 lens. The star Vega is visible at the center bottom and the North America Nebula is located in the upper right.

While I did not capture many meteors (the Moon, remember?) I was impressed with the optical quality of this lens. In fact, I ended up purchasing the rental lens since I had already done my testing with that particular sample.

I have used this lens on a couple occasions to photograph Comet C/2025 A6 (Lemmon) in which I used tracking to get a 2-minute exposure of the comet followed by untracked to get a similar exposure of the foreground. The results were further proof that this was a very good lens with sharp stars all the way into the corners.

Earlier this month I put it to another test when I did exposures of the Milky Way and aligned the camera so that the Milky Way passed diagonally across the lens and into the corners. I then stacked ten 2-minute images using Siril.

These images were shot with the aperture wide open at ƒ/1.4, ISO 200, and 120 seconds.

Interestingly, the result was too many stars! Indeed, the wide-open ƒ/1.4 aperture captured so much light that there were too many stars so I used some star reduction techniques available in Siril. The reduction technique resulted in a very pleasing final image presented here.

This will be a useful addition to my collection of astrophotography lenses for capturing wide views (54.3° x 37.7° field) of the night sky.

Edit: 11/20/2025 Fixed typo.

Comet C/2025 A6 (Lemmon)–November 2025

There haven’t been too many opportunities to photograph the comet in the first half of November owing to a bright Moon and cloudy skies. But I did get very dark skies on the evening of November 6 and shot a sequence spanning about 15 minutes near the end of twilight and when the comet dropped below the trees. The images were stacked and aligned using Siril and then finished in Lightroom/Photoshop.

Comet C/2025 A6 (Lemmon) on 06 November 2025 with a 180 mm lens.
Comet C/2025 A6 (Lemmon) on 06 November 2025 with a 180 mm lens.
Black-and-white negative version of Comet C/2025 A6 (Lemmon) on 06 November 2025 using a 180 mm lens.
Black-and-white negative version of Comet C/2025 A6 (Lemmon) on 06 November 2025 using a 180 mm lens.

The final image was then converted to a black-and-white negative as this format can show more of the detail in the comet’s tail. It also shows more of the satellite tracks that criss-cross the sky.

It has been fun shooting this comet and now I look forward to the next photogenic comet to grace our skies.

Nikon D850, Nikon 180 mm AI-s, f/4, ISO 200, 7×120 seconds.