Draco Trio (NGC 5981, 5982, 5985)

Telescope: Planewave 17" CDK reflector, 1940 mm FL
Camera: FLI-PL6303E, 3072 x 2048 pixels
Exposure: Lum: 6 x 4 minutes. Seeing 1.5 FWHM. Limiting mag about 21. Processed with StarTools and Photoshop.
Location: Mayhill, New Mexico (Elevation 7380')
Image Center (J2000): RA 15h 38m 44s, Dec 59° 21' 30"
Image Size: 23' x 18'

From left to right NGC 5981, NGC 5982 and NGC 5985 - an edge-on spiral, an elliptical with an unusual star-like core and a Seyfert face-on barred spiral galaxy all within a 20' field of view. Too small to be considered a galaxy cluster and too wide apart to be considered a compact galaxy group. Many faint background galaxies are also in this image. The arrowed object is a 19.0 mag high redshift quasar almost perfectly in line with the 3 nearer low redshift galaxies. Halton Arp called attention to the Draco Trio and other alignments like it as proof that the interpretation of an expanding universe as measured by redshift was incorrect. It has since been shown that the frequency of an alignment like this is no more common than would be expected by chance.


Draco Trio (NGC 5981, 5982, 5985), From left to right NGC 5981, NGC 5982 and NGC 5985 - an edge-on spiral, an elliptical with an unusual star-like core and a Seyfert face-on barred spiral galaxy all within a 20' field of view. Too small to be considered a galaxy cluster and too wide apart to be considered a compact galaxy group. Many faint background galaxies are also in this image. The arrowed object is a 19.0 mag high redshift quasar almost perfectly in line with the 3 nearer low redshift galaxies. Halton Arp called attention to the Draco Trio and other alignments like it as proof that the interpretation of an expanding universe as measured by redshift was incorrect. It has since been shown that the frequency of an alignment like this is no more common than would be expected by chance. , acquired with a remote telescope at Mayhill, New Mexico (Elevation 7380')

Object Label Identifier Notes
Galaxy G1 2MASX J15383273+5924022 Galaxy
Galaxy G10 SDSS J153829.83+592601.8 Galaxy, mV=20.4
Galaxy G2 SDSS J153929.78+592518.8 Galaxy, mG=16.5
Galaxy G3 SDSS J153845.39+592351.5 Galaxy, mV=19.3
Galaxy G4 SDSS J153742.22+592543.5 Galaxy, mV=18.8
Galaxy G5 SDSS J153943.53+592730.2 Galaxy, mV=18.2
Galaxy G6 SDSS J154004.15+591741.1 Galaxy, mV=18.4
Galaxy G7 SDSS J153815.00+591945.4 Galaxy, mV=18.3
Galaxy G8 SDSS J153929.78+592518.8 Galaxy, mV=16.5
Galaxy G8 GALEXMSC J153828.06+592707.4 Galaxy
Quasar Q1 QSO B1537+595A Quasar, z=2.125, mV=19.0

Click on the plate solved image to display annotations. 4' across NGC 5985 is about 115,000 light years.