Cepheus is a traditional constellation known for thousands of years, at least since the time of Ptolemy, on whose list it appeared in the 2nd century.

The name of the constellation comes from Greek mythology and is derived from Cepheus, the king of Ethiopia, who was the father of Princess Andromeda and the husband of Cassiopeia. In the sky, these three constellations (Cepheus, Cassiopeia, and Andromeda) are located next to each other.

It is interesting that in traditional Romanian rural astronomy, this constellation was known and shaped like a Scythe:
"The stars alpha, gamma, and a smaller star between them, aligned in a straight line, form ... the handle of the scythe. The star Vita forms the grip... while the stars mu, zeta, and delta form the blade of the scythe.", cf. The Romanian Peasant’s Beliefs About the Sky and Stars by Ion Otescu. You can see the scythe representation here.

Due to the precession cycle of approximately 26,000 years, the star Gamma Cephei, which can be seen at the pointed tip of the constellation directed roughly toward Polaris, will itself become the North Star (the North Celestial Pole) around the years 3800–4100.
Thus, in over 2,000 years, those practicing astrophotography will perform polar alignment toward Gamma Cephei... :)

Being a circumpolar constellation, Cepheus is relatively easy to photograph in almost any season from our latitude. Only one important aspect must be considered: the subject should not be too low, too close to the horizon during the imaging session, in order to avoid obstructions and to minimize atmospheric turbulence or excessive light pollution.

Visually, the constellation is easy to recognize when looking north, relatively close to the North Star. From an astrophotography perspective, it contains many interesting targets, both for beginners (e.g., Elephant’s Trunk Nebula) and for advanced imagers (e.g., SH2-129, OU4).
Some of these have already been photographed, and for several I have also written short articles in the form of astrophotography projects, where numerous technical details are presented. You can see them below.

Spectacular targets for amateur astrophotographers in the Cepheus constellation:

• Elephant’s Trunk Nebula (IC 1396)
• Wizard Nebula (NGC 7380)
• Lion Nebula (SH2-132) – a fairly complex target that requires many hours of integration
• Flying Bat Nebula (SH2-129) and Squid Nebula (OU4) – a fascinating but extremely difficult target, where the nebulae overlap and require many hours of integration and special processing techniques
• Iris Nebula (NGC 7023)
• NGC 7822 Nebula
• Fireworks Galaxy (NGC 6946) together with the open cluster NGC 6939 (both can be framed in the same image)
• Cave Nebula (SH2-155) – a relatively easy target to photograph
• LDN 1235 – The Shark Nebula, a dark nebula with a distinct shark-like shape
+
• Bubble Nebula (NGC 7635) together with the spectacular Lobster Claw Nebula (Sh 2-157) and the open cluster M52. These targets are included even though they belong to Cassiopeia, because visually they lie very close to the Cepheus constellation, essentially at the boundary between the two constellations.

Proiecte de astrofotografie și imagini cu subiecte din constelația Cefeu

---

Elephant’s Trunk Nebula (IC 1396)

Astrophotography project

Wizard Nebula (NGC 7380)

Astrophotography project

Bubble Nebula and Lobster Claw Nebula

Astrophotography project

Bubble Nebula (NGC 7635)

Image

There are two main ways to photograph the entire constellation: either you shoot it in sections and then stitch them together like a panorama (a more complex method), or you capture it using a widefield lens, which is what I did (a simpler method).

I photographed the Cepheus constellation on August 29, 2022, on a warm night, from my backyard in a village in Oltenia, under a Bortle 4 sky. The seeing was acceptable, and the guiding was quite good, allowing me to take 5-minute exposures.

I used a ZWO ASI 533 MC-PRO color astro camera, paired with a Canon EF-S 10-22 lens at 22 mm focal length and f/7.1 aperture. The camera was cooled to -5°C, while the outside temperature was around 24°C.
To combat light pollution and enhance nebulae (especially emission nebulae), I used a dual narrowband filter (Ha+OIII), the Optolong L-eXtreme 1.5".
A very important component was the ASIAIR+, which acts as the brain of the entire setup, handling most operations:
- focus checking
- identifying the sky position the lens is pointed at using plate-solving algorithms
- camera control (number of frames, exposure time, gain)
- semi-guiding (SkyGuider Pro can correct tracking only on the RA axis, not on DEC)
I also used an ASI 120 MM guide camera, a Manfrotto CX PRO3 tripod, and two dedicated batteries (Omegon Pro Powerbank 96k LiFePO4 307Wh 12V + Celestron Powertank Lithium Pro LiFePO4 159Wh).

Using the ASIAIR plate-solving algorithms, I was able to point the lens toward a relatively central area of the constellation (RA: 22hr 54' 30"; DEC: 65º 15' 30"), which I had previously calculated using the website telescopius.com/telescope-simulator.

In the end, I captured 64 light frames of 5 minutes each, 10 dark frames, and 100 bias frames. Total integration time: 5 hours and 20 minutes.

Photographing this constellation can be a great project for beginners who have a simple star tracker (like mine), a DSLR modified for astrophotography (or even an unmodified DSLR), and a narrowband filter similar to the one I used. The filter is essential, along with the mount (star tracker). The advantage is that tracking precision does not need to be extremely high, since this is a very widefield composition (using an ultra-wide lens).

The first step is loading the frames (Light, Flat, Bias, etc.) into PixInsight using Script >> Batch Processing >> WeightedBatchPreprocessing in order to stack the frames, after which the software exports a single final image that we will work on. I prefer this simpler method, with fewer settings, although there are many other more advanced stacking options (including within PixInsight). There are also several other software tools: DeepSkyStacker (most commonly used on Windows), SIRIL (Windows, Linux, and Mac), or Starry Sky Stacker (Mac).

Below you can see several frames:
- a single 5-minute unprocessed frame (.FIT), captured with ASI 533 MC-PRO
- the master frame resulting from stacking all images together with calibration frames in PixInsight
- the unprocessed frame with stars removed using STARNET2
- the processed starless frame
- the unprocessed starless frame
Then, to generate the final images, I added the stars (reduced using MorphologicalTransformation) over the starless image using PIXELMATH. Recently, new methods for star reduction in PixInsight have appeared (see this video), which I have successfully tested and found to be extremely simple, effective, and configurable.