Archive for the ‘Quasars’ Category


Observing Report: Messier Marathon at the Salton Sea

May 11, 2011

Okay, clearly I am a little obsessed with Messier marathons. Last spring I got 98 of the 110 Messiers in my first marathon. Last month Andy and I only got 80, but that’s because we got clouded out for the nearly 30 predawn Messiers. I had planned to hang up my spurs and wait until next spring to try again, but I just had to have one more go. I really wanted to crack into triple digits, and checking Stellarium I saw that late April was not a bad time for marathoning, with at least 105 of the Messiers potentially visible. So on Friday, April 29, London and I headed down to the Salton Sea for another go.

Evening Rush

It was a much more relaxing start than my beginning-of-April marathon. That evening, I had been running around for about an hour trying to snag a bunch of fuzzies before they dipped below the horizon. This time I knew that some of the objects were just flatly impossible, and they tended to be the faint galaxies that one sweats over in a spring marathon: M33, M74, and M77. M79, the little glob in Lepus, was also out of the running. The only ones that were particularly timely were the nebulae in Orion (M42, M43, M78) and Taurus (M1). I started about 8:20 and in half an hour I had bagged all of the Messiers west of Leo–17 in total–so I could take a nice long break. I set out a lounge chair, London climbed up in my lap, and we spent an hour looking for satellites (we found 3) and shooting stars (9). Then I got him settled in his sleeping bag, had a snack and a big drink of water, and got started on the springtime galaxies.


I should break here and mention what tools I was using. For speed and ease of use, I made most of the observations with a 15×70 binocular (this one, in fact). Under dark skies, binos that size can reel in most of the Messiers without breaking a sweat, and the point-and-shoot simplicity and lack of stuff to fiddle with really makes the instrument disappear. For backup, and for hunting down some interesting non-Messiers, I had along the XT10. For finding, the Pocket Sky Atlas. To keep track of what I had seen, I used a one-page checklist and a map (both available here), noting the time of each observation and the instrument used (B or T) on the checklist and crossing out each object on the map.

Realm of the Galaxies

The Leo galaxies were a cinch, and I started in on the Virgo-Coma “clutter” at 10:36. Depending on how you draw the boundaries, there are at least 13 galaxies in this small patch of sky, and maybe more. I tend to count M49 and M61 in addition to the core 13 since they’re the next closest targets and also galaxies. I had never made it through the clutter with binos alone. Last year I got all of them but one with both binos and scope, but this time I really wanted to sweep the whole area without using the scope at all. And I did, although M91 and M98 were both devilishly hard. I had to pull my hood up around my face to block peripheral light and use averted vision to get them, but they were definitely there. M91 was my last object in this part of the sky, at 10:52. During my last marathon, the Realm of the Galaxies took an hour and a half. Last time out, I got through in what felt like a blistering 23 minutes, using a 5-inch reflector. This time I dropped my aperture considerably and still got through faster, in only 16 minutes.

(Before anyone chides me for not taking time to “appreciate” each beautiful and unique cosmic snowflake: I know, I know. This has been the perennial criticism of astronomical marathons. And here’s the perennial response: I have the other 364 nights of the year to savor every detail. The marathon is, explicitly, a race. Getting through 15 galaxies in 16 minutes is a personal achievement in celestial orienteering, not visual study. It means that next time out I’ll spend less time finding NGC Umptysquat and more time looking.)

To the Edge of Forever

One of the benefits of doing a “late season” marathon is that so much more stuff is up in the eastern sky. After getting through the Virgo-Coma galaxies I swept through all of the goodies in Ursa Major and Canes Venatici, the globs in Ophiuchus, and the northern reaches of the summer Milky Way. By a quarter after midnight I had 72 objects logged. Sagittarius was just starting to crawl over the eastern horizon and its Messiers wouldn’t be clear of the near-horizon murk for a while, and I had other things to try for. I wanted to see some quasars.

Er, say what now?

Yes, believe it or not, several quasars–the fiery hearts of long ago, far-off galaxies–are within reach of small-to-middlin’ amateur telescopes. Quasars were mysterious for decades, appearing as star-like points of light with highly redshifted spectra and usually massive output in the radio portion of the electromagnetic spectrum. They are now understood to be caused by energy emitted from the accretion disks that form around the supermassive black holes at the centers of most galaxies. As matter spirals into the accretion disk, there is tremendous friction. Imagine rubbing your palms together…at relativistic velocities! Friction in the accretion disk heats it to unimaginable temperatures, and that heat is radiated away as light and other electromagnetic waves.

The brightest quasar as seen from Earth is 3C 273 in Virgo. From a distance of 33 light years, it would shine as brightly as the sun in our skies. A planet in the core of the host galaxy would have at least two “suns”: the star around which it orbits, and the quasar shining equally brightly in the sky. I don’t know if anyone would be around to see it–it seems quite likely that any planets close enough to see the quasar as a sun would be heavily irradiated by it.

I didn’t know any of this just a month ago, beyond having a nodding acquaintance with the nature of quasars. I assumed that they were simply well beyond the reach of my telescopes. But a couple of posts at the blog Washed-Out Astronomy set me straight: “3C 273: Quasars are Easy” and “A Fist Full of Quasars“. Definitely worth checking out!

The aforementioned 3C 273 in Virgo is the brightest and easiest quasar, shining at magnitude 12.8. It’s also quite impressively distant, about 2.5 billion light years away. So the light from this quasar is more than half as old as the Earth itself; when these photons started their journey, our planet’s most advanced life-forms, bacteria, were still working up to producing an oxygen atmosphere, a task they would not complete for another 800 million years. Markarian 421 in Ursa Major and Markarian 501 in Hercules are magnitude 13.2 and 13.9, respectively, but they are much closer at 400 million and 500 million light years, respectively (why, our fishy ancestors had already evolved backbones by then!). Among the easy quasars, OJ 287 in Cancer is the most distant at 3.5 billion light years, but still not punishingly faint at magnitude 14.2. Finder charts for all four of these quasars are available at the links above.

3C 273 was an easy catch, just below an M-shaped asterism of faint stars not far from Porrima (Gamma Virginis, one of the bright stars of Virgo). Markarian 421, in Ursa Major, was even easier to find, since it sits right off the shoulder of a bright, 6th magnitude star. I made both observations with the XT10, but the quasars would have been visible in much smaller scopes; even a 4” ought to show them clearly. OJ 287 had set by the time I switched from Messier-hunting to quasar-hunting, and I skipped Markarian 501 because the rising wind was visibly rocking my vehicle and throwing sand horizontally through the air. It was time to get back to Messiers.

The Home Stretch

The string of clusters and nebulae that comprise the “steam” from the teapot of Sagittarius were easy prey for the 15x70s; it took more time to correlate the sky view with the atlas and figure out which was which, than it did to find them. The little globs along the bottom of the teapot–M54, M69, and M70, were tougher, and required the telescope, as did the globs and other Messiers just cresting the eastern horizon. At 2:25 I logged the last visible Messier–M15, a very nice glob off the nose of Pegasus–secured the telescope against the very impressive wind howling through the campground, and crawled into the back of the Mazda for some rack. M15 was my 100th Messier of the evening, so I knew that I had at least made my proximate goal of getting into triple digits. But there would be more Messiers up before dawn, and naturally I wanted to see how many of them I could add to the tally. I set an alarm for 4:00 and sacked out.

Knowing that I already had 100 in the bag dulled my ambitions a bit, and I snoozed until 4:30. I was not anxious to get back out in the wind–it was cold and uncomfortable. But needs must when the devil drives, so I dragged my tail out of the vehicle, parked a folding chair right up against the lee side, and got back to work. M30, a glob in Capricorn, was dead easy, as were the Andromeda galaxy, M31, and its satellite galaxy M32. I tried and tried for M110, M31’s dimmer satellite, and a couple of times I suspected a faint glow at about the right place, but it wasn’t good enough to log for certain. I gave up at 4:47–the sun wasn’t going to be up for almost another hour, but the eastern sky was already bright enough to make further observations impossible. So I finished with a total of 103.

Two more that might just have been possible are the open cluster M34 and the planetary nebula M76. Actually, I’m dead certain that M76 would have been possible in the XT10, but I didn’t fancy opening the scope and letting the wind sand-blast the mirrors, so I let that one go. M34 is iffy–it was definitely over the horizon before sunrise, but not by much, and I have real doubts about its visibility, scope or no scope. If M34 was not possible, then there were 105 Messiers visible that night, of which I found and logged 103, missing only M76 and M110.

Of the 103, I logged one with naked eyes only (M44, the Beehive cluster, in Cancer), one with the 9×50 finder on the telescope (M54, a glob in Sagittarius), 12 with the scope only, and 89 with the binos (I did go back and re-observe 19 of those 89 with the scope as well, just because I had time and wanted to see them). Except M74 and M77, I saw all of the Messier objects during the month of April. Also, I believe that M74 is the only Messier that I’ve never observed with binoculars–I should rectify that in a couple of months when it’s up before dawn.

What’s next? I should probably get back to the Herschel 400 one of these days. But part of me is already looking forward to next spring, and my next shot at getting all 110 Messiers. Stay tuned.