Cygnus on the Milky Way
| Polish version is here |
The Milky Way refers to the barred spiral galaxy in which our own Solar System is located. It is often simply called the Galaxy. According to older estimates, it contains around 100 billion stars, while newer estimates suggest up to 400 billion stars. It has a diameter of approximately 100,000 light-years and a thickness of about 1,000 light-years.
In the night sky, the Milky Way appears as a bright band stretching across the sky; however, to observe it clearly, one must be in an area with low light pollution. The Milky Way shines brightest in the direction of its center, near the constellation Sagittarius. Its luminous band extends northward to the constellation Cassiopeia and southward to the constellation Crux.
Originally, the term "Milky Way" referred to the band of light visible in the night sky, formed by stars located along the galactic plane—ancient observers had no knowledge of the Galaxy's structure. According to Greek mythology, the Milky Way was created from droplets of Hera's spilled milk when she pushed Heracles away, refusing to nurse him.
Observations
June 18, 2022, around 10:00 PM – Jaworzno (Poland)
suburban conditions, high level of light pollution
The clear, warm night encouraged me to admire the beautiful view overhead. In addition to visual observations, I decided to test the capabilities of my Xiaomi Redmi Note 8 Pro smartphone camera. I used the DeepSkyCamera app (beta version), which allows a series of exposures with customizable settings. The phone was mounted on a standard lightweight tripod and aimed at the region of the constellation Cygnus. By capturing a sufficient number of 20-second light exposures, as well as dark frames and bias frames, and then stacking the material, I obtained Photo 1.
Surprisingly, the smartphone camera captured the Milky Way even under urban conditions with significant light pollution, where it is impossible to see it with the naked eye. The photograph is dominated by the Cygnus constellation.
Cygnus is one of the most prominent constellations of the northern sky, easily visible to the naked eye and known since antiquity. The number of stars visible to the naked eye in this constellation is estimated to be around 150. In Poland, Cygnus is visible from spring through autumn. Since its brightest stars form a cross-like shape, similar to the Southern Cross, it is sometimes referred to as the Northern Cross. The constellation lies within the Milky Way. High in the summer northern sky, Cygnus helps locate the most spectacular part of the northern Milky Way, specifically the so-called Cygnus Star Cloud. Deneb, the alpha star of the constellation (α Cygni), forms a well-known asterism—the Summer Triangle—together with Altair from Aquila and Vega from Lyra.
Deneb is a blue-white supergiant and a first-magnitude star, despite being about 1,500 light-years away. This is because its luminosity is approximately 60,000 times that of the Sun. However, it is important to note that the distance measurement is subject to considerable uncertainty, which can lead to significant errors in estimating its actual brightness. Interestingly, although Deneb in Cygnus is the most famous star with this name, it is not the only one—other examples include Deneb Kaitos in Cetus (also known as Diphda, β Ceti), Deneb Algedi in Capricornus (δ Cap), and Denebola in Leo (β Leonis). All of these names refer to the "tail" of the figure represented by the constellation.
Albireo, or Beta Cygni (β Cyg), is a well-known double star. Even with a small telescope, one can observe a pair of stars with distinctly different colors. The brighter component, β Cyg A, has an amber hue, while the fainter component, β Cyg B, has a distinct bluish hue. It is still uncertain whether this is merely an optical double or if the components are gravitationally bound.
Delta Cygni (δ Cyg), also known as Fawaris, is another multiple star system. Its two dominant components are separated by only 2.4 arcseconds, requiring a larger telescope to distinguish them.
Epsilon Cygni (ε Cyg), known as Aljanah, is an orange giant located approximately 72 light-years from Earth.
The region of the night sky occupied by Cygnus is rich in various deep-sky objects, such as the Crescent Nebula, the Pelican Nebula, the Tulip Nebula, and the X-ray binary system Cygnus X-1, which is known to contain a black hole. Surrounding Cygnus are many smaller constellations. In Lyra, for example, a suitable telescope can reveal the stunning Ring Nebula (M57).
To help readers visualize Cygnus within the Milky Way, I have illustrated its figure (based on Uranographia by Johannes Hevelius), as shown in Photo 2.
Photos 1 and 2 Parameters:
- Total exposure time: 20 minutes (stack of 60 RAW frames at 20s each, using an appropriate number of dark, bias, and flat frames)
- Xiaomi Redmi Note 8 Pro + DeepSkyCamera (beta)
- ISO: 800
- Mount: photographic tripod
Marek Ples