Ngc 6946(Fireworks galaxy) & Ngc 6939

 

Telescope : SW Esprit 100ED

Mount : SW EQ6-ri 

Camera : ZWO 533mc

Guiding : 8x50 SW finder with QHY 5IIL

Filters:   Total exposure time :100x180min (5 hours) with ir-cut 2' filter SVBony

Programs I have used : Nina 3.0 _ PixInsight 1.8.9-3

 

NGC 6946, sometimes referred to as the Fireworks Galaxy, is a grand design, face-on intermediate spiral galaxy with a small bright nucleus, whose location in the sky straddles the boundary between the northern constellations of Cepheus and Cygnus. Its distance from Earth is about 25.2 million light-years or 7.72 megaparsecs, similar to the distance of M101 (NGC 5457) in the constellation Ursa Major.  Both were once considered to be part of the Local Group,^[6] but are now known to be among the dozen bright spiral galaxies near the Milky Way but beyond the confines of the Local Group. NGC 6946 lies within the Virgo Supercluster.

The galaxy was discovered by William Herschel on 9 September 1798. Based on an estimation by the Third Reference Catalogue of Bright Galaxies (RC3) in 1991, the galaxy has a D₂₅ B-band isophotal diameter of 26.77 kiloparsecs (87,300 light-years).^[1][3] It is heavily obscured by interstellar matter due to its location close to the galactic plane of the Milky Way.  Due to its prodigious star formation it has been classified as an active starburst galaxy.  NGC 6946 has also been classified as a double-barred spiral galaxy, with the inner, smaller bar presumably responsible for funneling gas into its center.

 NGC 6939 is an open cluster in the constellation Cepheus. It was discovered by William Herschel in 1798. The cluster lies 2/3° northwest from the spiral galaxy NGC 6946. The cluster lies approximately 4,000 light years away and it is over a billion years old. 

NGC 6939 is located near the border of the constellations Cepheus and Cygnus, at the southwest corner of Cepheus. The open cluster is located two degrees southwest of Eta Cephei and 2/3° northwest from the spiral galaxy NGC 6946, which has visual magnitude 8.7. They appear as two patches of haze with 10x50 binoculars. NGC 6939 can be seen and glimpsed with 7x35 binoculars where as 25x200 binoculars are required to start resolve the cluster.The cluster can be glimpsed with 4 inches telescope and is resolved at x72 magnification. NGC 6939 is included in the Herschel 400 Catalogue.

NGC 5906 Splinter Galaxy

 

Telescope : SW Esprit 100ED

Mount : SW EQ6-ri 

Camera : ZWO 533mc

Guiding : 8x50 SW finder with QHY 5IIL

Filters:   Total exposure time :9hours & 30minutes with IR-Cut filter from 2nights

Programs I have used : Nina 3.0 _ PixInsight 1.8.9-3

 

NGC 5907 (also known as NGC 5906, Knife Edge Galaxy, or Splinter Galaxy) is a spiral galaxy located approximately 46.5 million light years from Earth German-British astronomer William Herschel discovered the galaxy on 5 May 1788.Its most notable features are its large stellar stream and ultraluminous X-ray source 

 

NGC 5907 has an anomalously low metallicity and few detectable giant stars, being apparently composed almost entirely of dwarf stars. It is a member of the NGC 5866 Group.

NGC 5907 has long been considered a prototypical example of a warped spiral in relative isolation. In 1998, a faint ring structure, likely caused by a disrupted dwarf spheroidal galaxy, was first observed around the galaxy.This challenged the assumption of isolation and suggests the gravitational perturbations induced by the stream progenitor may be the cause for the warp. Then, in 2008, an international team of astronomers announced the presence of an extended double loop tidal stream coiling around the galaxy.  The existence of part of these tidal streams has been recently challenged by some deeper surveys, which show only a single knee-shaped stream as opposed to the full double loop structure.  This shorter stream has a length of 45′ in the sky (or a physical size of 220 kpc) and has a surface brightness ranging from 27.6 mag/arcsec² at its brightest to 28.8 at its faintest.

An ultraluminous X-ray source, NGC 5907 ULX-1, is located in the galaxy.  This source is also called an ultraluminous X-ray pulsar (ULXP) because it exhibits a rapid pulsation effect. This pulsation has a period of 5.7 days and is caused by a rotating neutron star orbiting a high mass companion.  The neutron star itself has a spin period of 1.13 seconds and seems to be accelerating; its period ten years prior was 1.43 seconds. It is one of the brightest such source yet discovered with a luminosity over 10⁴¹ erg/s (7 orders of magnitude more luminous than the Sun). Notably, its peak luminosity is over 1000 times greater than the Eddington luminosity for a neutron star.

from Wikipedia