Category Archives: ARP Object

The Hickson 93 Galaxy Group in Pegasus

The Hickson 93 Galaxy Group, also referred to as Arp 99, can be found in the constellation Pegasus. From the Atlas of Compact Groups of Galaxies (1993), Paul Hickson stated, “This group (Arp 99) consists of an accordant quartet plus a fainter high-redshift galaxy. The bright spiral galaxy has two long plumes which result from tidal interaction. It is a radio and infrared source. The bright elliptical galaxy is also a radio source.”

This grouping is about 265 million light years away, five main galaxies are shown in the image, but only four are thought to be gravitationally bound and strongly interacting. You can see in the image how NGC 7549 is distorted by gravity, slowly pulling away strings of stars and gas.

The particulars on the galaxies shown are:

  • NGC 7549, magnitude 13.8, barred spiral galaxy.
  • NGC 7550, magnitude 13.6, lenticular galaxy.
  • NGC 7547, magnitude 14.7, barred spiral galaxy.
  • NGC 7553, magnitude 15.3, elliptical galaxy.
  • NGC 7558, magnitude 16.0, spiral galaxy.

Tech Specs: This image is composed of 192 x 15 second images at ISO 5,000 with 10 x 15 second darks and 10 x 1/4000 second bias frames using a Meade LX90 12” telescope and Canon 6D camera mounted on a Celestron CGEM-DX mount. Imaging was done on November 6, 2016 and November 22, 2016 from Weatherly, Pennsylvania.

Online resources:

…Tom

NGC 7448 – A Strange Looking Galaxy in Pegasus

NGC 7448 is a spiral galaxy in the constellation Pegasus and also appears in the Arp List of Peculiar Galaxies under the “Spiral galaxies with detached segments” group as ARP 13. You can see from my image what Halton Arp was referring to – you can see the small knobs or bumps on the spiral arms of this galaxy about 100 million light years away.

Tech Specs: This image is composed of 60 x 15 second images at ISO 3200 with additional dark and bias frames using a Meade LX90 12” telescope, Antares Focal Reducer, and Canon 6D camera. Imaging was done on September 27, 2016.

ngc7448_15min_092716_b-1

Online Resources:

Cseligman.com (http://cseligman.com/text/arpatlas.htm)

Wikipedia (https://en.wikipedia.org/wiki/Atlas_of_Peculiar_Galaxies)

Arpgalaxy.com (http://arpgalaxy.com/)

Carpe noctem!

…Tom

The Pisces Galactic Cloud – Arp 331

The Pisces Cloud, also known as Arp 331, is a small chain of elliptical galaxies in the constellation Pisces between the Andromeda Galaxy and the Triangulum Galaxy that are roughly around magnitude 13.0 and lower.  This group is actually part of the Perseus-Pisces Supercluster. The photo contains many more galaxies than are shown, I have identified just easily identifiable galaxies.

This image is composed of 100 x 15 second images at ISO 3200 with additional dark and bias frames. Tech Info: Meade LX90 12” telescope, Antares Focal Reducer, and Canon 6D camera. Imaging was done on September 1, 2016.

piscescloud_25min_090116f

Sources for additional information:

SpaceBanter.com (http://www.spacebanter.com/showthread.php?t=144276)

Astronomy-Mall (http://www.astronomy-mall.com/Adventures.In.Deep.Space/peculaut.htm)

Carpe noctem!

…Tom

Galactic Tidal Forces in the Nautilus Galaxy

When I first imaged The Nautilus Galaxy (NGC 772/ARP 78) I was fascinated by its shape, one spiral arm stretched outward from the center. This is probably and effect of being tugged on by a satellite galaxy designated as NGC 770 (see the labeled image below). NGC 772 is also listed as ARP 78 in the ARP Atlas of Peculiar Galaxies. This catalog was compiled by Dr. Halton C. Arp and it has 338 peculiar galaxies detailed in it. An online version of this catalog is available HERE. If somebody has a copy of the original printing and no longer needs it, I have the perfect spot for it on my astronomy bookcase…..

It is estimated that NGC 772 is twice the size of our Milky Way Galaxy!

I photographed NGC 772 during three imaging sessions from November 2015 to January 2016. I used a Meade 12″ LX-90 telescope mounted on a Celestron CGEM-DX mount. At prime focus, I placed a Canon 6D DSLR camera right behind my trusty Antares focal reducer. Imaging was done using 20-second sub-frames using mixed ISO settings of 3200, 5000 and 6000. Images were stacked in DeepSkyStacker, stretched in ImagesPlus and final processing in Corel Paintshop Pro and Adobe Lightroom. The final images are presented below. I still struggle with good focus on my LX90 telescope, working on focus issues is one of my goals for 2016.

NGC 772 - 70 minute total exposure.

NGC 772 – 70 minute total exposure. DETAILS: Center (RA, Dec): (29.832, 19.006), Center (RA, hms): 01h 59m 19.775s, Center (Dec, dms): +19° 00′ 22.929″, Size: 17.2 x 15.4 arcmin, Radius: 0.192 deg, Pixel scale: 0.8 arcsec/pixel, Orientation: Up is 111 degrees E of N.

 

NGC 772 - labeled version.

NGC 772 – labeled version.

Tech Info from Wikipedia:

Observation data (J2000 epoch)
Constellation Aries
Right ascension 01h 59m 19.6s[1]
Declination +19° 00′ 27″[1]
Redshift 2472 ± 3 km/s[1]
Distance 130 Mly[citation needed]
Type SA(s)b[1]
Apparent dimensions (V) 7′.2 × 4′.3[1]
Apparent magnitude (V) 11.1[1]
Other designations
UGC 1466,[1] PGC 7525,[1] Arp 78[1]

Clear skies!

…Tom

Messier 77 (M77) Galaxy Observation

Messier 77, also known as ARP 37 (#37 in Arp’s Catalog Of Peculiar Galaxies) is a barred spiral galaxy about 47 million light-years away in the constellation Cetus. This was photographed on January 5, 2016.  Tech Specs: Canon 6D at prime focus of a Meade 12″ LX90, light frames included 60 x 20 seconds, 60 x 10 seconds, 5 x 5 seconds all at ISO 5000, dark frames were also included.

Messier 77, also known as ARP 37

Messier 77, also known as ARP 37

Clear skies!

…Tom

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