Tag: Starry Sky Stacker

Comet C/2022 E3 (ZTF) Continues to Dazzle in the Night Sky

Comet C/2022 E3 (ZTF) showing both the dust trail and ion trail on 28 January 2023.

Comet C/2022 E3 (ZTF) continues to be a interesting object in the night sky for photography, telescopes, and binoculars. Unfortunately, it never got bright enough to be an easy object for the unaided eye. One could sometimes see it when viewing it from very dark locations without the Moon present–but usually only with averted vision. At its brightest it was reported to have reached magnitude +5. The comet should fade rather rapidly in February and may be as faint as magnitude +8 by the end of the month.

The comet made its closest approach to the sun on 12 January 2023 (1.11 AU; 166 million km) and its closest approach to Earth on 01 February 2023 (0.28 AU; 42 million km). See the included Solar System map that shows the location of the comet relative to Earth or visit TheSkyLive.com for an interactive version.

Schematic diagram showing position of Comet C/2022 E3 (ZTF) relative to other bodies in the Solar System.
Schematic diagram showing position of Comet C/2022 E3 (ZTF) relative to other bodies in the Solar System.

Here are a few of the better images I have been able to capture of the comet over the past few weeks. These have used a variety of lenses but always the same camera, tripod, and star tracker.

These photos were taken on 22 January 2023 using a manual focus Nikon NIKKOR 80-200mm f/4 AI-S zoom lens. This lens has the advantage of having a hard stop at ∞ making it very easy to focus. Image stacking was done using Deep Sky Stacker.

Both of these images of the comet show the tail (pointing up) and the antitail (pointing down). From Wikipedia:

An antitail is an apparent spike projecting from a comet’s coma which seems to go towards the Sun, and thus geometrically opposite to the other tails: the ion tail and the dust tail. However, this phenomenon is an optical illusion that is seen from the Earth…

Comet C/2022 E3 (ZTF) with tail and antitail. Images were stacked using Deep Sky Stacker with both stars and comet fixed.
Comet C/2022 E3 (ZTF) with tail and antitail. Images were stacked using Deep Sky Stacker with both stars and comet fixed.
Comet C/2022 E3 (ZTF) with tail and antitail. Images were stacked using Deep Sky Stacker with comet fixed but stars allowed to move.
Comet C/2022 E3 (ZTF) with tail and antitail. Images were stacked using Deep Sky Stacker with comet fixed but stars allowed to move.

And here is a time-lapse movie of the motion of the comet during the period 0359 through 0435 MST.

Time-lapse video of Comet C/2022 E3 (ZTF) from 0358–0454 MST 22 January 2023.

A few days later I was able to capture both the dust tail and the ion tail. Stacking was done using Deep Sky Stacker. This was shot with the Nikon NIKKOR ED 180mm f/2.8 AI-S manual focus lens.

Comet C/2022 E3 (ZTF) showing both the dust trail and ion trail on 28 January 2023.
Comet C/2022 E3 (ZTF) showing both the dust trail and ion trail on 28 January 2023.

On 10 February the comet appeared near both the planet Mars and the Pleiades star cluster. Also visible are the dark dust lanes of the Taurus Molecular Cloud. Photos shot with Nikon 85mm f/1.8 AF-S G. Stacking was done using Starry Sky Stacker.

Comet C/2022 E3 (ZTF) with Mars and Pleiades star cluster.
Comet C/2022 E3 (ZTF) with Mars and Pleiades star cluster.
A closer view of Comet C/2022 E3 (ZTF) with Mars and Pleiades star cluster and the Taurus Molecular Cloud.
A closer view of Comet C/2022 E3 (ZTF) with Mars and Pleiades star cluster and the Taurus Molecular Cloud.

Time-lapse video of Comet C/2022 E3 (ZTF) and Mars from 1926–2029 MST 10 February 2023.

Lastly, a time-lapse video of the motion of the comet also shows a plethora of satellites moving across the sky.

Later this week the comet will pass close to the Hyades star cluster. If skies are clear I’ll be back out shooting more photos of the comet.

Note: Both of the videos incorrectly label the comet ZTH rather than ZTF.

Venus and Pleiades Conjunction—April 2020

During the first few days of April 2020 the planet Venus moved towards and then through the Pleiades star cluster. Venus and Pleiades have a conjunction every year but every eight years the conjunction is at its closest. This year, Venus moved right through the star cluster.

Conjunction of Venus and Pleiades
Conjunction of Venus and Pleiades

I shot images of Venus and Pleiades on three nights: 01 April, 03 April, and 05 April. Venus and Pleiades were closest on the night of 03 April. I then did a composite image of the three nights showing the progression of Venus past the star cluster. These were all shot at 8 seconds, f/4, 180mm, and ISO 800.

Additionally, I overlaid another image taken 13 February 2020. This is a stacked composite with 11 images shot at 120 seconds, f/4, 180mm, and ISO 1600. The images were stacked using Starry Sky Stacker. The stack was then post-processed using rnc_color_stretch. This composite image was used because it shows the nebulosity and color within the Pleiades better than the shorter exposures captured that show the motion of Venus.

Composite image of Venus and Pleiades.
Composite image of Venus and Pleiades.

The image above shows the composite from the three nights without the additional layer showing the nebulosity.

Photographing the North America Nebula

The North America Nebula has been on my To-Photograph list for a while. I had made one quick attempt previously to see whether I could actually resolve it with my Nikon 85mm f/1.8 lens. That was successful so I was ready to try again when the situation permitted.

I finally found the time, the right weather, and the right conditions. I shot a sequence of seven, 120-second exposures.

There are many star-stacking software packages available and I’ve often used DeepSkyStacker (DSS). More recently I’ve been testing StarrySkyStacker (a macOS-only app). The results have been pretty good.

The stacking complete, it was time to work on the histogram. Again, there are many histogram stretching packages. I’ve been evaluating rnc-color-stretch, available from Clarkvision.com. rnc-color-stretch is a set of scripts that calls the davinci application (not to be confused with the DaVinci Resolve video editing software).

North America Nebula (NGC 7000)
North America Nebula (NGC 7000)

The result is shown above. My next attempt at shooting this Deep-Sky Object (DSO) will be with my recently acquired Nikkor 180mm f/2.8 AIS manual focus lens.

Milky Way Closeup

Most of my Milky Way photographs are shot using a wide-angle (24 or 28 mm focal length), or ultra-wide-angle lens (16 mm focal length). These create an image that shows a large portion of the Milky Way. But sometimes it’s fun to zoom in a bit and focus (no pun intended) on a much smaller section of the sky.

Milky Way.
Milky Way.

A few days after the full Moon provided a great opportunity to do this. The Moon would not rise until about an hour after astronomical twilight ended and, more importantly, there were very clear skies.

I used a Nikon D750 body with a Nikon 85mm f/1.8 lens for this session. This is designed to be a portrait lens but I find it makes a pretty good astrophotography lens as well because of the excellent light-gathering f/1.8 aperture and the corner-to-corner sharpness resulting in nice round stars. At least, that is, when I get sharp focus and accurate tracking.

I shot 10 images of 120 seconds exposure time and used Long Exposure Noise Reduction (LENR). I was unable to use the 10th exposure because the sky was already getting brighter even though the Moon was still below the horizon. The result was 9×120 seconds or 18 minutes of light gathering.

I have several different applications (both Mac and Windows) for star stacking and alignment and chose to use Starry Sky Stacker this time with good results. Once I had the stack completed I used rnc-color-stretch for histogram stretching with final postprocessing done in Lightroom 6/Photoshop CS6.

Milky Way with annotations.
Milky Way with annotations.

This is the final result. I think the colors might be a bit too saturated—but I don’t dislike the result. Artistic license invoked here.