Galaxies M77 and NGC1055

UPDATE AUG 2025

Informed wisdom has it that the background in this and other images was too dark, so I have re-processed this in PixInsight (using the original data) and at the same time looked to improve the detail in the outer spiral arms of M77. The result is shown here with the original image below for comparison.

M77 (NGC1068) is the face-on spiral at upper left, while NGC1055 is at lower right. The galaxies appear in the constellation Cetus. North is to the right in this image.

The bright core of M77 identifies it as a Seyfert galaxy, whose extremely bright central region is due to an accretion disk of matter falling towards a supermassive black hole at its centre. The energy source is the same as that of quasars, the difference being that, unlike with a quasar, we can see the host galaxy’s surrounding structure in Seyferts. M77 was the first Seyfert galaxy to be so categorized.

NGC1055 is an edge-on spiral with a prominent dust lane. It is a member of the same group that includes M77. They lie about 50 million light years away.

The small galaxy near the top of the image is NGC1072, another spiral galaxy at mag 14.27, an estimated 370 million ly away.

There are a few other small distant galaxies visible: to upper left of NGC1055 is PGC 1164535 at mag 16.56, 310 million ly away; and at bottom centre is PGC 135658, another spiral at mag 17.26, 370 million ly distant.

Exposure times were 13hrs through red, 12hrs through green and 14hrs through blue filters.

Equipment: Planewave CDK-14 corrected Dall-Kirkham scope, FLI Proline P09000 CCD camera and Astrodon E-series filters. Autoguided using a Monster MOAG off-axis guider and Starlight Xpress UltraStar Pro guide camera.

Acquisition software: Maxim DL, ACP Expert Scheduler. Image processing: Pixinsight.