January 18, 2026 — Winter Silence and a Shadow on Jupiter

Observing Log — January 18, 2026

Cold air, mixed seeing, and a memorable transit on Jupiter

After several cloudy nights, January 18 finally offered an opportunity to spend some time under the stars. Conditions were not perfect, but the night still delivered a number of rewarding views—especially of Jupiter.

Observing Conditions

The sky quality was mediocre, with an SQM reading of 19.87, indicating noticeable light pollution or haze. I began observing around 21:25. At that time, the temperature was –0.7 °C, with a relative humidity of 73.1%.

As the evening progressed, the cold became more apparent. When I wrapped up the session around 23:00, the temperature had dropped to –2.1 °C, and humidity had increased to 81.4%. Seeing held up well initially but deteriorated toward the end of the session.

At the very beginning of the observing session, just after stepping outside and before settling in at the telescopes, I was treated to an unexpected highlight: a bright meteor streaking across the sky. It appeared suddenly, cutting a clear and luminous path for a brief moment before vanishing just as quickly. Its brightness easily caught my attention despite the less-than-ideal sky quality, and it served as a perfect reminder to always keep an eye on the naked‑eye sky, even when the main focus is telescopic observing. Moments like these add an extra sense of excitement and spontaneity to an observing evening, setting a special tone for the night ahead.

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Wide-Field Observing with the TS‑Optics PhotoLine 80 mm

I started the evening with some wide-field observing using the TS‑Optics PhotoLine 80 mm refractor.

M 45 – The Pleiades

At 21:25, my first target was M 45, the Pleiades. As expected, this open cluster was a stunning sight in the wide field of the PhotoLine. The entire cluster fit perfectly in both the Tele Vue 31 mm Nagler and the Tele Vue 21 mm Ethos, framed beautifully against the background sky. Even under less-than-ideal SQM conditions, the brightest stars of the cluster shone clearly.

Jupiter

Still using the 80 mm refractor, I then turned to Jupiter. The planet handled magnification surprisingly well. Using the Tele Vue 6 mm Ethos, Jupiter remained crisp, though still small in this small aperture. The two main equatorial belts were easily visible, providing a pleasing and sharp planetary view for such a compact telescope.

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Switching to the 18‑Inch Obsession

After these initial observations, I switched to my 18‑inch Obsession Dobsonian for deeper and more detailed views.

NGC 1817 – Open Cluster in Taurus

My first deep-sky target with the Obsession was NGC 1817, an open cluster in Taurus. The best view came with the Tele Vue 21 mm Ethos. I could clearly distinguish four brighter stars, and around forty fainter stars, forming a loose, circular appearance. A subtle but satisfying cluster, well suited to the aperture of the Obsession.

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Jupiter and Europa’s Shadow Transit

Partway through the session, I received a message alerting me to a transit of Europa across Jupiter. That was reason enough to immediately return to Jupiter with the Obsession—and it turned out to be the highlight of the night.

The seeing was quite good, and the amount of visible detail was truly impressive. The two main belts were filled with whirls, knots, and irregular structure, and fine details covered the entire disk of the planet.

Europa’s shadow was unmistakable: a small, perfectly round, black circle sharply defined against Jupiter’s bright clouds. Europa itself was not visible, but its shadow stood out beautifully.

To see the shadow clearly, I needed at least 180×, achieved with the Tele Vue 13 mm Ethos. Thanks to the steady seeing, I could push the magnification much further. With the Tele Vue 6 mm Ethos, delivering 394×, even more intricate planetary details became visible—a rare and rewarding experience.

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Additional Targets

NGC 40 – Planetary Nebula in Cepheus

Next, I observed NGC 40, a planetary nebula in Cepheus. In the Tele Vue 13 mm Ethos, the nebula was visible using direct vision, appearing as a fairly large and distinct nebulous disk. A fine example of how planetary nebulae benefit from larger aperture.

M 42 – The Orion Nebula

I also spent some time on M 42, the Orion Nebula. As always, it was spectacular—rich structure, bright nebulosity, and an ever-impressive sight, even after countless observations.

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A Final Look and Closing the Session

Before packing up, I returned once more to Jupiter. The shadow of Europa had now moved noticeably and was approaching the center of Jupiter’s disk, making the motion over time very apparent.

Unfortunately, the seeing deteriorated rapidly at this point, softening the details that had been so sharp earlier. With worsening conditions and rising humidity, I decided to end the session around 23:00.

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Final Thoughts

Despite the average sky quality, this observing evening turned out to be very satisfying. The combination of wide-field refractor views and high-powered planetary observing with the Obsession—especially the transit of Europa’s shadow—made the cold well worth enduring. Nights like these are a reminder that even imperfect conditions can still deliver truly memorable moments at the eyepiece.