Royal Astronomical Society of Canada
- Toronto Centre -
(Originally published in Scope, Summer 1996)
On the evening of March 16, 1996 we embarked on a “dusk till dawn” astronomical event called the Messier Marathon. The “runners” were Toronto Centre Members Stephen Keefer, Guy Nason, and myself. We were joined for the first few hours by member, Sal Merola and his friend. For Stephen and myself this would be a second attempt at the Marathon -- back in March 1992 we saw 100 objects (see Scope May/June 1992).
A Messier Marathon is only possible in late March or early April, a time when the Sun is located in a part of the sky devoid of Messier objects. Within this span of time it is also preferable not to have the Moon in the sky as it may it may interfere with some of the fainter objects. Our choice of March 16 was based on the following facts: it was a Saturday night, it was two days before new Moon, it was close enough to that special time of the year, and we expected a clear sky all night.
This year I prepared a little better for the event. The previous weekend I went scouting for a good site east of Toronto within a one hour drive. Site selection is probably the most important factor in a Messier Marathon. It is imperative that the observing site allows for a completely clear view of the western, southern, and eastern horizons. Even if you have one tree blocking part of your sky, chances are a Messier object will be hiding behind it just before setting for the night. You should also be as far away from light pollution as possible, especially in the western and eastern horizon.
I did find a good site, or at least it seemed good during the day time, called Richardson’s Lookout - a small park on top of a hill at an altitude of about 850 feet. The park is about half-hour north-west of Port Hope near the small village of Garden Hill. Although the sky was quite dark, we quickly found out that the site was not the greatest because the many street and house lights from Garden Hill were shining right in our eyes even from a distance.
Sun data for March 16 and 17: Sunset 6:25 pm End of Twilight 8:10 pm Beginning of Twilight 4:45 am Sunrise 6:30 am
We planned to begin observing at 8 pm and end at 5 am, giving us a total of 9 hours to find the 110 Messier objects. This equated to an average of one object every 4.9 minutes! Several days before the event I decided to make it a little more challenging for myself by trying to observe a couple of dozen NGC objects that I had not seen before.
We arrived at the site at scattered times during the evening, some as early as 5 pm and others as late at 7:30 pm. As twilight faded in the west, the night looked quite promising, but first we had to get our equipment from the parking lot to the top of the hill where we nearly had a 360 degree view of the horizon. Lugging the equipment up the gentle, but very long slope proved to be quite a challenge. I had an 8-inch Schmidt-Cassegrain telescope, Guy had a 10-inch Newtonian on a very solid and heavy equatorial mount, and Stephen had a 16-inch Dobsonian! Just before 8 pm we were ready to begin observing.
The critical evening Messier objects we observed first are listed below:
Object Type Mag. Altitude at 8 pm Time Observed Altitude when observed M74 Galaxy 9.2 13 deg. not seen M77 Galaxy 8.8 14 deg. 8:03 14 deg. M79 Globular Cluster 8.0 16 deg. 8:39 12 deg. M31 Galaxy 3.4 21 deg. 8:42 15 deg. M32 Galaxy 8.2 21 deg. 8:42 15 deg. M110 Galaxy 8.0 21 deg. 8:42 15 deg. M33 Galaxy 5.7 22 deg. 8:35 16 deg.
The first object we all spotted was M77. I am not sure why, but we started with the second object on the list, perhaps sabotaging ourselves. This galaxy was not terribly difficult to see in the telescopes, however it took some effort to star-hop to it as few guiding stars were visible at such low altitude. Next was M74 which was not seen for certain. The exact position was at first difficult to determine because there were such few visible stars to use for star-hopping. We even thought a blazing Venus was blocking the view, but that was not the case since the planet was a generous 12 degrees east of M74. Eventually we all arrived at the correct part of the sky and began sweeping the area. We spent a good half-hour looking for M74, and eventually we all though we could see something there - a slightly brighter patch of light in the field of view best seen with averted vision. But then again, we were not one hundred percent sure. Did we really see M74 or was averted imagination getting the better of all of us?
I would not hesitate in labeling M74 as the most difficult object in the Messier Catalogue - it was in fact the very last object I observed in completing my Messier list due to its difficulty. Although The Observer’s Handbook labels it magnitude 9.2, I have seen it listed at 10th magnitude in other sources, and as faint as 11th magnitude in Burnham’s Celestial Handbook, which describes it as “one of the faintest and most elusive of the Messier objects.” The reason this face-on galaxy is so difficult to spot is because it is quite large and its total brightness, may it be magnitude 9 or 10 or 11, is spread among a large area, giving it a low surface brightness. Furthermore, at low altitudes the effects of atmospheric extinction become quite relevant, making the object appear even dimmer, probably by one magnitude or more. In hindsight I am not surprised we did not see M74.
By 8:30 pm M74 had sunk to just 8 degrees above the western horizon and that was when we thought it was time to move on. The remaining critical evening objects were not that critical after all, especially M31,32,33 and 110 which were all visible in my 8X50 finder scope.
From this point forward the Marathon took on a more relaxed and steady pace. The order in which we observed Messiers was not really important as long as we observe them from West to East so that none were missed before setting. Because Messier objects are fairly bright and large, a small telescope is quite adequate and easier to use when rushed for time. In fact, of the 103 Messiers I viewed through my telescope, 60 were visible in the 8 X 50 finder!
The night remained clear and cold with a low temperature of minus 7. A sharp easterly wind did not let up for most of the night. Starting around 12:30 am we had a nice view of Comet Hyakutake while still only 3rd magnitude in Libra. I also spent a couple of minutes looking at a couple of bright stars in Centaurs. These were only 3 degrees above the horizon given their declination of - 42 degrees. Omega Centauri was only a few degrees south of those stars, but I knew it would never make it above the horizon. By 2 am we started feeling the effects of the previous long and cold six hours. I could have taken several breaks throughout the night, but whenever I had a few minutes to spare in between Messiers I opted to keep busy by hunting down unseen NGC objects.
By 4 am we entered the home stretch. It was a tense 45 minutes until the beginning of twilight. We knew that the whole night had come down to the last few objects as listed below.
* M2 observed only through 10-inch and 16-inch scopes.
Object Type Mag. Altitude at 4:30 am Time Observed Altitude when observed M15 Globular Cluster 6.4 13 deg. 4:14 10 deg. M2* Globular Cluster 6.5 3 deg. 4:30 3 deg. M75 Globular Cluster 8.6 3 deg. not seen M72 Glob. Cluster 9.4 2 deg. not seen M73 Open Cluster 9.0 1 deg. not seen M55 Globular Cluster 7.0 0 deg. not seen M30 Globular Cluster 7.5 -13 deg. not seen
M15 was not difficult to see, in fact I had to use 16 X 50 binoculars because a lonely tree in the east was blocking my telescope’s view. M2 however was a little more difficult to spot, mostly because there were hardly any stars visible that could be used for star-hopping to it. I did not find M2 in my 8-inch scope, but fortunately Guy and Stephen did spot it around 4:30 at an altitude of only three degrees. The last five objects were not seen and in hindsight I do not think there was much hope of seeing them. M30 was definitely out of the question because by 4:30 am it was still 13 degrees below the horizon. M75 was at the same altitude as M2, however it was two magnitudes fainter. M72 and M73 were barely above the horizon at magnitude nine and fainter, while M55 was still right on the horizon. Atmospheric extinction made the effort even more difficult. We waited an extra half-hour till 5 am but anything we had gained in altitude we had lost in the brightening dawn sky. By 5:05, twenty minutes into morning twilight, the stars in the east had vanished and we unwillingly crossed the finish line. We had seen 104 of the 110 Messier objects.
Quite exhausted after being on site for more than 10 hours, we spent a little over one hour packing and transporting all the equipment back to our cars. Shortly after leaving the site, driving westbound back home, the sun rose casting long shadows ahead of us.
Would I do a Messier Marathon a third time? You bet! And here are the things I would do differently.
Only one object was missed in the evening sky, while five were missed in the morning sky. The solution could be to do the Marathon later in the spring, perhaps during the first week of April. But in such case more objects in the evening sky would not be visible. Fortunately M31, 32 and 110 rise again in the morning sky if missed, so the net effect may still be positive. If the Marathon were done April 1, for example, I would expect to miss M74, M77, and M33 in the evening sky, and M30 in the morning sky, resulting in 106 objects. Not much better, but worth a try. Of course, by early April the night will grow shorter, perhaps canceling out the advantages mentioned above. My conclusion remains the same as after the 1992 Messier Marathon - I seriously doubt anyone can see more than 106 Messier objects during a Marathon from Toronto’s northerly latitude.
So, if you want to make it more challenging you will have to add a few of your own NGC objects. That was exactly what I did this time by observing 27 previously unseen NGC objects to give me a total of 130 deep sky objects for the night.
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