IC 4704, IC 4705, IC 4712 – A trio of galaxies in the constellation Pavo
On paper, this trio of galaxies in the constellation Pavo (the Peacock) seems rather unspectacular: no NGC number, no known proper names. With a little patience (and sufficient exposure time), however, three fundamentally different types of galaxies become visible in a single field of view: a gravitationally shaped barred spiral, a quiet elliptical galaxy, and a classic spiral galaxy.
The barred spiral galaxy IC 4705, “deformed” by gravity, is located about 155 million light-years away. The most fascinating feature of the galaxy is the tidal streams that extend outward from the center. The original spiral arms were torn from their orbits by gravitational forces and distorted far outward. The trigger was most likely another galaxy that has since merged with IC 4705. What remains is a morphology that reminds me of the outstretched tentacles of a jellyfish.
A few more figures: The brightest central region spans just under 1.5 arcminutes in the sky, which corresponds to an absolute diameter of about 70,000 light-years. The tidal streams extend the galaxy’s diameter to nearly 7 arcminutes, corresponding to 300,000 light-years.
In the upper right corner of the image, northwest of IC 4705, lies the elliptical galaxy IC 4704. At just under 200 million light-years away, it is even farther from us. Its appearance shows no signs of dust lanes or a spiral structure, as is typical for elliptical galaxies. Its yellowish color is caused by an old population of stars, since there is no longer any significant material left for the formation of new stars. With a diameter of about 340,000 light-years, it is significantly larger than our Milky Way.
The spiral galaxy IC 4712 is located in the left, eastern half of the image. Of the three galaxies shown here, it is the one most similar to our own galaxy. It is about 175 million light-years away and has a diameter of 125,000 light-years.
| Date: | 20.08.-25.08.2025 |
| Optics: | Planewave CDK 14 with Televue 0.8x reducer |
| Aperture: | 350 mm |
| Focal Length: | 2050 mm |
| Camera: | QHY268M |
| Exposure: | L:R:G:B 60:33:31:30 x 600s |
| Location: | Gemsbock Observatory, Rooisand Desert Ranch, Namibia |
| Processing: | PixInsight, Photoshop |
| Diameter: | 340,000 light years (IC 4704) 300,000 light years (IC 4705) 125,000 light years (IC 4712) |
| Distance: | 200 million light years (IC 4704) 155 million light years (IC 4705) 175 million light years (IC 4712) |
