Tag: Siril

Orion in February

In a recent post I talked about a photo session in which I captured images of Orion using a wide-angle lens. My next goal was to use a telephoto lens to zoom in on specific areas. My first effort did not go well. It was cold and windy. My attempts to get the star tracker aligned were mostly unsuccessful — because of the cold and wind. And the lens I used (Nikon 200-500mm f/5.6) was too big and heavy for the tracking mount.

Flame Nebula and Horsehead Nebula in the constellation Orion with Star Removal.
Flame Nebula and Horsehead Nebula in the constellation Orion with Star Removal.
Flame Nebula and Horsehead Nebula in the constellation Orion.
Flame Nebula and Horsehead Nebula in the constellation Orion.

I tried again the next night and there was less wind–but it was still cold. This time I used the Nikon 180mm ƒ/2.8 ED AI-S manual focus lens. It is much lighter and easier to focus and it produces a very sharp image by the time it is stopped down to ƒ/4.0. My goal was to capture the Flame Nebula (NGC 2024) and the Horsehead Nebula (Barnard 33) plus one or more stars from Orion’s belt.

Both the Horsehead Nebula and the Flame Nebula are in the constellation of Orion and are part of the much larger Orion molecular cloud complex. (Note: an amusing reference to the “Horace Head Nebula” appears in Isaac Asimov’s “The Stars, Like Dust“. Check it out!) The Flame Nebula is an emission nebula while the Horsehead Nebula is a small dark nebula.

I shot 73 one-minute exposures plus the usual assortment of darks, flats, and bias images. The images were stacked using Siril 1.4 with Star Reduction, histogram stretching using rnc-color-stretch, and finally post processed in Lightroom and Photoshop.

The first image is the result with Star Reduction turned on; the second image is without Star Reduction. I like them both.

Nikon D850, Nikon 180mm ƒ/2.8 ED AI-S @ ƒ/4.0, ISO 400, 73 x 60 seconds.

Milky Way at Wukoki Pueblo

Many years ago I shot an image of the Milky Way rising behind Wukoki Pueblo in Wupatki National Monument in northern Arizona. Afterwards, I promised myself that I would do that shot again using newer lenses and cameras along with, hopefully, better technique.

Composite image of the Milky Way with Wukoki Pueblo, Wupatki National Monument, Arizona.
Composite image of the Milky Way with Wukoki Pueblo, Wupatki National Monument, Arizona.

I finally committed to getting the photograph earlier this week. The date/time required that the Milky Way be low in the eastern sky so it was not too far above the pueblo. It also required the waxing crescent Moon be high enough in the western sky to illuminate the foreground—but also low enough to set before the Milky Way got too high in the eastern sky.

I took a shot of the foreground and pueblo with an exposure time of 300 seconds using long exposure noise reduction; LENR doubled the total time required for image acquisition to 600 seconds. I wasn’t in a hurry…

And then I waited about 30 minutes for the Moon to set. Fortunately, I had brought a camp chair to sit on.

After the Moon had set I took several 300-second shots of the Milky Way in a very dark sky—again with LENR on.

Once back home, I took the Milky Way shots and did image stacking to remove both image noise and, more importantly, aircraft/satellite tracks. The stack became the background photo to combine with the foreground photo.

The result was pretty good but I wanted to try something more. I imported the Milky Way image stack into Siril, an astrophotograhy software package, and ran the “reduce stars” script. This has the effect of removing and/or dimming most stars while leaving the glow of the Milky Way alone.

The result is shown above.

I think I will try this again with some changes. Looking forward to this.

Milky Way–June 2025

In late June we had an extended string of days/nights without clouds. So this was a good time to update my Milky Way photographs using an ultra-wide fisheye lens. I did a similar photo shoot in May of last year. As before, I shot from a pullout on the Mormon Lake Village road which gives me a clear view over the top of the lake.

Image of Milky Way over Mormon Lake.
Image of Milky Way over Mormon Lake.
Image of Milky Way with star reduction.
Image of Milky Way with star reduction.

The big difference between last year and this year is a new camera. I upgraded from my Nikon D750 to a Nikon D850. The latter has 45 megapixels; the former has 24 megapixels. Big difference and it should result in better resolution of the stars.

I shot two sets of photographs. One set was on an iOptron SkyTracker to follow the motion of the stars; the second set was without tracking to photograph the foreground. Exposure time for both was 300 seconds and were shot with a Rokinon 12mm F2.8 full frame fisheye lens. As a consequence of the fisheye lens the Milky Way appears curved.

The two sets of images (foreground, stars) were then blended together using Photoshop. The result was imported into Siril, an astrophotography software package, to reduce the stars using the Starnet package. Both the normal star image and the reduced star image are shown here.

It should be noted that there was a lot of airglow that evening and the reduced star image helps to see the structure and waves present in the airglow.

It was a successful and fun evening of astrophotography shooting.

Night Sky and Orion

These two images were taken a few months ago when the constellation Orion was in the eastern/southeastern sky. Both imaging sessions were tests of my recently acquired Nikon D850 and of the Siril software package.

Wide view of Orion and the surrounding Orion Molecular Dust Cloud.
Wide view of Orion and the surrounding Orion Molecular Dust Cloud.
The Witch Head Nebula (IC 2118) near the constellation Orion.
The Witch Head Nebula (IC 2118) near the constellation Orion.

The first was taken with a 50mm lens to show all of Orion as well as the neighboring features. The image is a stack of 32 frames @ 60 seconds, f4, ISO 1600, and shot on a Nikon D850. The images were processed in Siril–a tool I’m still learning to use–and the final result nicely shows the Orion molecular cloud complex (or, simply, the Orion complex). From the Wikipedia article:

The Orion complex includes a large group of bright nebulae and dark clouds in the Orion constellation. Several nebulae can be observed through binoculars and small telescopes, and some parts (such as the Orion Nebula) are visible to the naked eye.

The second image was taken a few nights later with a 180mm telephoto lens and is looking at the Witchhead Nebula (IC 2118), located very near Orion–and is also faintly visible in the previous image.  This image is a stack of 38 frames @ 60 seconds, f4, ISO 1600, and shot on a Nikon D850. As before, the stack of images was processed in Siril. From Wikipedia:

IC 2118 is an extremely faint reflection nebula believed to be an ancient supernova remnant or gas cloud illuminated by nearby supergiant star Rigel in the constellation of Orion.

I have been happy with the results on the Nikon D850 for capturing astro images and equally pleased with how easy it is to use Siril in post processing.

Edit: Fixed blockquote formatting