NGC 5544/5545 (Arp 199, VV 210, KPG 422)

Bootes
14 17 04
+36 34 24

NGC 5544
13,0vmag; 1,0’x1,1’; SB0-a

NGC 5545
15,0vmag; 1,0’x0,3’; Sbc

First known observation came from William Herschel 1785 with his Speculum 18,7-inch telescope. He saw and catalogs only one object but it was his son John who suggests a separation into two objects. William Parsons confirmed this separation 1852 with his 72 inch Leviathan and noted “either a double nebula or two knots of one nebula”.

Later, the both famous catalogs for interacting and abnormal galaxies Vorontsov-Velyaminov and Arp enter the pair as numbers 210 or 199. Arp’s classification is “material ejected from nucleus” with his notes “spirals appear disturbed”

Astrophysical both galaxies have the same distance of around 44 Mpc and their different radial velocities shows the interaction between them. Although the galaxies seems to be a collision pair photographs shows no strong interaction structure. Only very deep photos shows big HII and blue star burst regions in NGC 5545 and shows some dark zones in the overlapping region. This is also the topic of a new paper of Donovan L. Domingue et al. 1999

Visually the pair is more difficult than the NGC designation looks like. First target in mid size telescopes is to separate both galaxies. With 16” it was not a problem to see both as single objects - NGC 5545 as a fainter 3:1 elongated strip which sits directly NE on the small but brighter NGC 5544. In mid size telescopes the “exclamation marc” appearance is best. With bigger telescopes the periphery of NGC 5544 started to be visible – NGC 5544 becomes bigger, with a brighter part in the NW. NGC 5545 started to be structured also – the brightest spiral arm segment becomes visible at the NE end.

But, what do you see?

big_arp199.jpg
200-inch Palomar plate
- Dr. Barry F. Madore; Caltech and Carnegie; Pasadena, California, USA -

n5544s_11.jpg
32-inch Schulman Telescope
- Adam Block/Mount Lemmon SkyCenter/University of Arizona-

NGC5544_NGC5545.jpg
27-inch, 586x, NELM 7m+, Seeing I
(inverted version)

“GIVE IT A GO AND LET US KNOW”
GOOD LUCK AND GREAT VIEWING!