Sky and Telescope - March 2018 - 58

+30°

What You Might See
Below is a sampling of my observing
notes on the more than 80 AGNs that

UGC 5435
3225
3238

Star magnitudes

3220
5
6
7
8
9
10

3206

5629

14h 40m

3079

+56°

3073

URSA MAJOR

10h 10m

10h 00m

9h 50m

IC 4397
IC 4381

5548

5523

14h 30m

14h 20m

t NGC 5548 As with all AGNs, a supermassive black hole is responsible for powering this
Seyfert galaxy. Turn your telescope toward this
object in March - you won't see the black
hole, but you will observe photons that have
traveled 230 million years. For clarity, galaxies
have been omitted in the top left of the chart.

were seen visually. I relied mostly on
20- and 22-inch reﬂecting telescopes.

Seyfert Galaxies
NGC 660, an 11th-magnitude polarring galaxy located a mere 43 million
light-years away in Pisces, was best
seen at 77× with a galaxy-contrastenhancement (GCE) ﬁlter. The nucleus
appeared stellar or mottled. I found this
hazy glow in the middle of a triangle

formed by two pairs of wide double
stars and a single star.
NGC 5548 in Boötes, the Herdsman,
is 230 million light-years distant and
showed as a slightly elongated galaxy
with a central brightening.

BLL
1ES 2344+51.4 in Cassiopeia was easy
to ﬁnd, but I needed 416× to recognize
the star ﬁeld that resembled the one
found in the printed chart. This BLL,
at some 615 million light-years distant, was small yet relatively bright.
Since it was adjacent to a ﬁeld star, the
pair looked like a double star, oriented
southeast-northwest, at ﬁrst glance.
3C 66A in Andromeda, with a z of
0.444 corresponding to a distance of 4.8
billion light-years, was stellar in appearance. It makes a right triangle with a
ﬁeld star and UGC 1841 (also known as
3C 66B), a foreground Seyfert galaxy at
300 million light-years. A veritable twofor-one special!

u DOUBLE VISION Astronomers observing

Quasars

QSO 0957+561, or the Twin Quasar, were suspicious of the two objects' similarity. When they
discovered that the two sources had identical
spectra, they soon realized they were witnessing gravitational lensing - light from the distant
quasar was being gravitationally distorted by a
massive foreground object.

KUV 18217+6419 in Draco was a faint
dot whose light has traveled some 3.5
billion light-years. Nearby, the planetary nebula PK 94+27.1 was undetectable in any ﬁlter.
PG 1718+481 in Hercules was rela-

M A RCH 2 018 * SK Y & TELESCOPE

4
5
6
7
8
9
10

5610

+24°

QSO 0957+561

UGC 9101

5635

+26° B O Ö T E S

+58°

3188
3214
3164

+28°

3182

10h 20m

3043

G A L A X Y: ESA / HUBBLE / N ASA; T WIN Q UASA R: ROBERT G ENDLER

capabilities can prepare a list of AGNs
to upload into your device. Whether
using Go To or star-hopping from a
nearby object to your target, having a
detailed sky chart will help you differentiate the AGNs from any foreground
stars in the eyepiece. Observing Variable
Galaxies by Alvin Huey (https://is.gd/
huey_ovg) can well serve this purpose
for the 65 objects he lists. Several online
lists are available in addition to those
on the Astronomical League website,
such as the one provided by Wolfgang
Steinicke, https://is.gd/steinicke. High
magniﬁcation is a key factor in your
success, as is better-than-average seeing
and transparency from dark skies. Jotting down the distance of your object
beforehand adds to the joy once you've
captured it with your eye or digitalimaging setup. Published redshifts (z
values) can be converted to light-years
with online calculators; note that the
resulting distance depends on which
cosmological model is adopted.

Star magnitudes

MARCH 2018 OBSERVING
Going Deep

https://www.is.gd/huey_ovg https://www.is.gd/huey_ovg https://www.is.gd/steinicke

Sky and Telescope - March 2018

Table of Contents for the Digital Edition of Sky and Telescope - March 2018