Sky and Telescope - March 2018 - 59

Flavors of AGN
Object

Type

Redshift (z)

Distance (million l-y)

Mag(v)

Size

Dec.

NGC 660

Seyfert

0.003

11.2

8.3′ × 3.2′

01h 43.0m

13° 39′

NGC 5548

Seyfert

0.016

230

12.6

1.4′ × 1.3′

14h 18.0m

25° 08′

1ES 2344+51.4

BLL

0.044

615

15.5

36″ × 28″

23h 47.0m

51° 42′

3C 66A

BLL

0.444

4,800

15.2

02h 22.7m

43° 02′

UGC 1841

Seyfert

0.021

300

14.0

3.3′ × 2.3′

02h 23.2m

43° 00′

KUV 18217+6419

Quasar

0.297

3,500

14.2

18h 22.0m

64° 21′

PG 1718+481

Quasar

1.083

8,300

14.6

17h 19.6m

48° 04′

QSO 0957+561

Lensed quasar

1.41

9,300

16.9

10h 01.3m

55° 54′

QSO 2237+0305

Lensed quasar

1.695

10,000

16.8

39″ × 22″

22h 40.5m

03° 22′

J014709+463037

Lensed quasar

2.341

11,000

01h 47.2m

46° 31′

Angular sizes and separations are from recent catalogs. Visually, an object's size is often smaller than the cataloged value and varies according to the aperture and
magnification of the viewing instrument. Right ascension and declination are for equinox 2000.0. Look-back distances are computed from redshifts according to current cosmological models.

tively easy to ﬁnd. The star-like object,
situated at 8.3 billion light-years, formed
a small arc with two foreground stars.
The ﬁrst lensed quasar was discovered in 1979. QSO 0957+561, or the
Twin Quasar, is in Ursa Major and can
be found easily by star-hopping less
than ½° northwest from NGC 3079
via asterisms shaped like a triangle,
a pentagon, and ﬁnally a trapezoid -
the quasar is located off the top-right
corner of the trapezoid. I made two
attempts to observe this object, the ﬁrst
under excellent skies (NELM 6.3) at
Cherry Springs State Park, Pennsylvania. However, I wasn't able to split it.
Six years later, I made a second attempt
from another dark-sky site (NELM 5.9).
This led to success; the split was easily
observed. The light from this quasar,
traveling 9.3 billion light-years, is gravitationally lensed by a foreground galaxy,
YGKOW G1, a mere 4 billion light-years
away. Why could I not split the lensed
quasar the ﬁrst time? Looking back at
my notes it appears that the object was
quite low in the sky the ﬁrst time and
more favorably placed the second.
The capstone object for me was QSO
2237+0305, also known as the Einstein

Cross in Pegasus, that I observed twice
over several attempts. Again, looking
back at my notes, I can see that success
depended upon high magniﬁcation,
steady seeing, and good transparency. Initial views showed granularity,
while observing it for several minutes
revealed the four points of light. The
foreground galaxy CGCG 378-15 (PGC
69457) presented itself variously as a
small, elongated glow; a hazy glow with
a stellar nucleus; or as a compact and
solid-looking galaxy, depending upon
sky conditions, aperture, and location.
If you detect a stellar nucleus, try higher
magniﬁcation to snag these ancient
photons from nearly 10 billion lightyears away.
More recently, the lensed quasar
J014709+463037 was discovered
serendipitously by PanSTARRS and
shortly thereafter given the moniker
Andromeda's Parachute by Kate H. R.
Rubin (San Diego State University) and
others. Three of its four components,

FINDER CHARTS
º For more ﬁnder charts on the AGNs
covered here, visit https://is.gd/ch_agn.

with grizy magnitudes between 14.9
and 18.1, lie in a small arc with an even
fainter fourth component underneath.
Several amateurs have observed one or
more of the components. I viewed the
two brightest components, split in brief
moments of steady seeing, at 770×. Its
redshift translates into a distance of
around 11 billion light-years!

Final Words
The Big Bang occurred over 13 billion
years ago. Imagine capturing light that's
been traveling through space for over
half that time. Imagine as well how
unique it is to have that light stimulate your retina or imaging chip. Those
thoughts can be mind-numbing and
humbling. The endeavor also makes you
appreciate ever more so the wonders
that are up there just waiting for you to
capture them. So how deep and far back
in time can you go?
¢ AL LAMPERTI has been going deep
since 1985 when he acquired his first
light bucket. He and other members of
the Delaware Valley Amateur Astronomers developed the AGN Observing Program for the Astronomical League.
sk yandtelescope.com * M A RCH 2 018

https://www.is.gd/ch_agn http://www.skyandtelescope.com

Sky and Telescope - March 2018

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