Quasars are among the brightest and most distant objects in the universe. Many are visible in amateur scopes if you know just where to look. We'll help you track them down.

Quasar model
This artist’s impression of a quasar shows the spinning accretion disk where matter is heated as falls into the black hole (center). Beams of particles and radiation focused by the disk's powerful magnetic field blast away from the quasar at near-light speeds.
ESO / HST / NASA / M. Kornmesser

This week we'll visit 12 of the season's brightest quasars. A quasar or quasi-stellar object (QSO) is an exceptionally luminous and active galactic nucleus powered by a black hole billions of times more massive than the Sun.

Stars, dust and gas caught in the black hole's gravitational grasp swirl into an accretion disk where they're heated to millions of degrees by friction and the release of  gravitational potential energy. As it all literally goes down the drain into the black hole, copious amounts energy are released across the entire electromagnetic spectrum, making quasars the brightest objects in the universe.

Other particles are focused by powerful magnetic fields arising from the disk into twin jets of high-speed particles and energy that can extend for millions of parsecs above and below the accretion disk. The most energetic quasars are found in distant galaxies, where we see them in their youth, a time when there was still a lot of material in the galactic core for the quasar to feed on. Older galaxies like the Milky Way harbor more sedate QSOs.

Quasars are so bright they outshine their host galaxies, most of which are so incredibly distant they're invisible except in the very largest telescopes. When observing a QSO all you see is a pinprick of light that looks exactly like a faint star. Appearances are deceptive, though. I have to remind myself that tiny glimmer is pure energy radiating from an ongoing cosmic cataclysm.

Black hole twins
This diagram shows that quasars and blazers are essentially the same phenomena but are viewed from different angles from our vantage point on Earth.
NASA (left) / JPL

Quasars, along with their relatives, the blazars, steadily crank out the equivalent of 10 to 100,000 Milky Ways worth of light. Both are essentially the same phenomenon, the difference between them is just a matter of perspective. Quasars are active nuclei viewed from the side. In a blazar we stare almost directly into the jet, like looking into the beam of a powerful LED flashlight. Blazars are also called BL Lacertae objects after BL Lacertae, one of the first of its class discovered.

Brighter than its host
The Hubble Space Telescope image at left shows the brilliant quasar 3C 273 in Virgo and one of its long, snaking jets. The diffraction spikes demonstrate the quasar is truly a point-source of light because the black hole's "central engine" is so compact. Once the blinding "headlight beam" of the quasar is blocked, the host galaxy pops into view (right). If 3C 273 were 30 light-years from the Earth, it would shine as brightly as the Sun.
NASA / A. Martel (JHU) / ACS Science Team / J. Bahcall (IAS) / ESA

Quasars add depth to deep-sky observing in a big way, coaxing adventurous souls out into the dark of night as if drawn by the pull of their supermassive black holes.The first quasar discovered, 3C 273 in Virgo, is also one of the closest, lying 2.5 billion light-years from Earth or 1,000 times more distant than the Andromeda Galaxy. Yet, at magnitude ~12.9, you can see it in a 6-inch telescope from a reasonably dark sky. It was my first quasar, and no kidding, I tracked it down with my old 6-inch Edmund reflector back in 1980.

Quasar finders
This is a high-resolution file with all the wide-field finder maps for locating the featured quasars. Some plot more than one per field. Use these in conjunction with the detailed maps below. Charts are shown in order of increasing right ascension from upper left to lower right. If you prefer an inverted version with black stars on a white background, click here.
Stellarium

Quasars have a reputation of being wickedly faint and difficult, but many aren't particularly so. Most of those featured here currently shine around magnitude 14. Two are brighter: Markarian 421 at magnitude 13.4 and 3C 273 at 13.0. Only RX J1230.8+0115 appeared faint in my 15-inch at 14.8 magnitude. With the exception of the last, all should be visible in a 10-inch scope, several in an 8-inch, and at least one in a 6-inch.

Sketch a black hole's dinner
The telescopic appearance of a typical quasar.
Bob King

In one sense, spotting a 14th-magnitude quasar is much easier than digging out a similarly faint galaxy. If you know exactly where to look, seeing a point of light is considerably easier than trying to make out a distended tuft of haze.

Not all quasars are naked stellar pips, though. Two on our list gleam from within distant but visible galaxies. Keep in mind when seeking these objects that their magnitudes can vary, sometimes dramatically, due to variations in the flow of material through the accretion disk and down the pipe of no return. The magnitudes given here are my estimates made during the past week and a half. If you see a change of light, count yourself lucky. Despite their variable nature I've only seen a couple get winky on me.

I've made two types of charts — a panel of wide-field maps to get you in the neighborhood and then much more detailed maps with stars down to about 15th magnitude so you can waltz right up to your target. Each wide-field map has a bright field star circled. That same field star is circled on the detailed map. Find that star in your finderscope, center it in your eyepiece, then use the detailed map to star hop to the quasar. Make sense?

Quasar detail chart
An example of one of the 12 detailed maps showing the shared guide stars (circled) and a figure I traced out to help point you to the quasar in the galaxy Markarian 478. The object's R.A. and Dec. are given at top. North is up and west right on all charts (ignore the chart's own direction indicator). Magnitudes are written without decimals, so 73 = mag. 7.3. The galaxy was very small but relatively easy to see at 242× in my 15-inch telescope, with the quasar appearing as a bright, stellar nucleus.
Chart created with MegaStar5 by Emil Bonanno, Copyright 1992-2002 by E.L.B. Software, Distributed by Willmann-Bell, Inc.

Right ascension and declination, field size, and other details are shown along the edge of each detailed map. I'm grateful to Perry Remaklus, publisher of Willman-Bell, for allowing me to share the maps which I created using MegaStar, my favorite deep-sky plotting software.

Here's our list of targets. Click a name for a detailed map. For more information and additional maps for each object, check out Stefan Karge's superb Frankfurt Quasar Monitoring site, one of the best resources out there for quasar hunters. Bookmark it and you'll have enough black holes for a lifetime. Several years back, Sky & Telescope's Tony Flanders compiled this excellent list of resources you'll also find useful.

By the way, the first half of this blog's title is taken from a delightful rhyme by Russian-American physicist George Gamow. He penned it in 1964 when we were only beginning to understand the nature of quasars. Here's the whole thing, titled Quasar:

Twinkle, twinkle quasi-star
Biggest puzzle from afar
How unlike the other ones
Brighter than a billion suns
Twinkle, twinkle, quasi-star
How I wonder what you are.

Let us know how you do and whether you break your own personal distance record. Good luck and clear, deep skies!

Rare visible galaxy
The quasar Markarian 501 in Hercules lights up the center of its host galaxy.
DSS2

List of QSOs and Blazars (All charts created with MegaStar5 by Emil Bonanno, Copyright 1992-2002 by E.L.B. Software, Distributed by Willmann-Bell, Inc.) The AAVSO also has excellent charts of 3C 273, Mrk 421, and S5 0716+71 at different scales with star magnitudes included. Key in the name under Pick a Star, then select Create a Finder Chart.

  • HS 0624+6907 / Quasar in Cam (mag. 14.0) / Distance: 4.56 billion light-years — wow!
  • S5 0716+71 / Blazar in Cam (14.3) / 3.76 billion l.y.
  • B3 0754+394 / Quasar in Lynx (~14.3) / 1.27 billion l.y.
  • PG 0804+761 / Quasar in Cam (14.1) / 1.3 billion l.y.
  • He 1029-1401 / Quasar in Hydra (14.0) / 1.14 billion l.y.
  • Markarian 421 / Blazar in UMa (13.4) / 411 million l.y.
  • PG 1116+215 / Quasar in Leo (14.4) / 2.3 billion l.y.
  • PG 1211+143 / Quasar in Com (14.0) / 1.1 billion l.y.
  • 3C 273 / Quasar in Virgo (13.0) / 2.5 billion l.y.
  • RX J1230.8+0115 / Quasar in Virgo (14.8) / 1.5 billion l.y.
  • Markarian 478 / Quasar in Boötes (~14.5) / 1 billion l.y. (Host galaxy visible in 15-inch)
  • Markarian 501 / Blazar in Hercules (14.0) / 447 million l.y. (Host galaxy visible in 15-inch)

Comments


Image of Tom-Reiland

Tom-Reiland

April 3, 2019 at 2:18 pm

Thanks for another interesting article, Bob. I've observed 8 Quasars, Blazars or QSOs. One was thanks to your article about CTA 102 more than two years ago. The others from this list include: 3C 273, Markarian 421 and S5 0716 +71. The most distant object that I observed is PG 1634 +706 at 9 Billion Light Years in Draco. I observed it the night I finished observing the Herschel Catalogue in April of 2017. I'll have to search for the rest of the objects on this list when the weather improves and I get over a scratchy throat.

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Bob King

April 5, 2019 at 11:24 am

Thanks, Tom. And I'll have to check my lists to see if I've spotted PG 1634+706. I like going back in time!

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Tom Hoffelder

April 9, 2019 at 1:04 pm

Tom R, PG 1634 is on my list also, but I haven't seen any except 3C 273. The information I found for PG is 14.2 to 14.7 mag and a distance of 12.9 billion light years, which I didn't/don't believe. What is the source for the 9 billion?

Tom H

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Tom Hoffelder

April 4, 2019 at 1:04 pm

Bob, great list - thanks for reminding me that I created a similar list a few years ago and then forgot about it, probably because it wasn't clear for a month or so after, which can happen in Maine! At least it seems that way sometimes. Since all these are currently brighter than 15th mag, I should be able to see them in our C14 from our driveway, except trees could be a problem for some.

3C 273 is the only one I've seen and in a scope as small as our 8 inch Newtonian. It's been a very long time (back in the good old days when Tom Reiland and I did some observing together in the Pittsburgh area) since I've had a six; I knew about quasars but didn't know that 3C could be seen in a six so never tried.

My list of 12 objects is different (includes only two of yours) because the purpose is to try to view ones more distant than 3C 273 and therefore covers my entire sky, not just spring. And I selected ones that have a peak brightness greater than 15, so if they never reach that, I won't see them. What I do know is that I need to be looking for the first two on your list, which are nice and high so trees won't be a problem.

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Bob King

April 5, 2019 at 11:26 am

Hi Tom,
Thanks! I'm sure you'll see the two in Cam. As a visual observer I've always found this area of the sky challenging to navigate from its dearth of bright stars, but at least it's at a convenient altitude.

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Tom Hoffelder

April 9, 2019 at 12:49 pm

Hello Bob, I agree, Cam is no man's land. Luckily the best object, NGC 2403, isn't too far from omicron UMa. From 2403 (H400 object) I sweep to three other galaxies that are on the Herschel II list.

The distance winner quasar in Cam could be rather easy to find. It is near L Cam (HIP 29997, mag 4.7), which is exactly 10.3 degrees north of 2 Lyn (mag 4.4), a star conveniently pointed out by the triangle on "top of" Auriga. It will be an easy eyepiece sweep from 2 to L, with an equatorial mount not all that closely aligned, which is how I do all my object location. All of my scopes are equatorial but of course not everyone's is. No comment on go-to, except that for me finding an object is half the enjoyment of observing.

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Joe Stieber

April 9, 2019 at 1:39 pm

We had a Public Star Watch in the New Jersey Pines on Saturday night, 06-April-2019, and amazingly, we had clear skies for it. Pursuing one’s own observing agenda can be diffcult at a public event, but before the night was over, I made it a point to find 3C 273 with my 12.5-inch reflector. It’s been some years since I’ve seen 3C 273, so I’m thankful for Bob’s article prompting me to do it (and soon, work on some of the other quasars in the article).

Anyway, using SkySafari on my tablet and the article’s finder chart, I was able to find and verify 3C 273 without much difficulty. Nice! (I use just a reflex finder on my strictly manual scope.)

Also, while in that neck of the woods, check out the reddish carbon star, SS Virginis. It’s a degree-and-a-half southwest of 3C 273, roughly midway between 3C 273 and Zaniah (Eta Virginis).

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Bob King

April 10, 2019 at 1:34 am

Excellent, Joe. Glad you found the quasar again. Sometimes I forget about SS Vir being close — thanks for the reminder.

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Gordon Hommes

April 26, 2019 at 7:26 pm

I observed 3C 273 last night with my 8-inch SCT in a Bortle 3 sky north of Two Harbors, MN. Your excellent finder chart, Bob, made finding the quasar very easy. The quasar is the brightest of the three "stars" that make a tiny right triangle. The third star is VERY dim ( mag 14.2 -14.5?) and floated in and out of visibility. Then, I dove into the Realm of Galaxies for the next couple of hours...

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Gordon Hommes

May 7, 2019 at 9:45 am

Limiting myself to a single challenge on a work night, I was able to track down 3C 273 with my 4-inch refractor last night. Definitely WAY more challenging than with the 8-inch due to image scale and dim field stars for star-hopping, but it was visible, along with stars as faint as 13.5 at 76x.
Darkness and transparency are critical.

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