My Dream of Asaph Hall

A dream that came true in 2003.

When I was a wee lad someone--I'm no longer sure who--noted my fledgling interest in astronomy and bought me some books. One of these books became my guide to astronomy as a science (Introduction to Astronomy by Cecila Payne-Gaposhkin). The other became my guide to practical observing (The Telescope Handbook and Star Atlas by Neale E. Howard). And so began my lifelong journey with one foot firmly planted in the science of astronomy and the other equally planted in amateur observing.

I read Howard's book from cover to cover many times.  I learned about different types of telescopes, mounts, eyepieces, and the observation of various objects. The section entitled "The Martian Moons" particularly caught my fancy:

"Certainly the strangest little objects in the whole solar system, the two moons of Mars will rarely be seen by the amateur unless he possesses a 16-inch telescope, and then only at favorable oppositions."

I never imagined owning a 16-inch telescope at the time. It was something so large and expensive that such a thing never entered my head. Instead, in my mind's eye I imagined what Asaph Hall has seen when he discovered Deimos on August 12, 1877; I saw a speck of light in the glare of the planet and felt his jubilation.

I first had a half-hearted try at observing the moons of Mars in the late 70's using my newly acquired 6" f/8 Meade Newtonian. Of course, I knew from my reading that such a small telescope should not reveal them. Not a real confidence builder, that. But I was also far too inexperienced.

I tried again at many later oppositions, using different telescopes, but never really putting in any serious effort. Having moved to Cloudcroft, New Mexico in 1998, where the sky is clear and dark, for the first time I put some serious effort into detecting the moons using the only telescope I still had access to--that same old 6-inch. But to no avail. At least that time it wasn't from lack of trying.

During the 2001 opposition I added another distinct advantage. Not only was I in Cloudcroft, but I had my newly completed home-crafted 18-inch Dob. Unfortunately Mars was low in the sky and the weather horrible. In order to see it over the trees in my yard I had to go to great lengths (literally) and the position of the telescope was good for little else. I went so far as to make an occulting bar that time, but still came up empty. The dreams of Asaph Hall faded once again.

Somewhere in there I wrote an article about observing the moons of Mars for my web site. The most recent incarnation was originally posted at the beginning of August, 2003. I didn't really realize until one wonderful morning just how flat and uninteresting that article was.

As August 2003 wore on our monsoon season was in full swing. Clouds built all day and it wasn't possible to predict if it would be clear or raining cats and dogs at any time during the night. Even the Clear Sky Clocks, which are usually spot on, had been useless. When it cleared late it hadn't been practical to take my 18-inch out due to sleeping kids and cool down time. So I'd been taking my old familiar 6-inch out instead. It gave me some pretty good views of the planet, although not nearly as often as I'd have preferred..

On the night of August 19/20 I hauled the old girl out around midnight. After a struggle I was about 75% sure that I had finally glimpsed Deimos. If I had, I guess it was pretty fitting that it happened in the old scope. That afternoon I read a message from Russ Lederman describing his view of Phobos and Deimos in his 20 inch where he saw both moons without all that much difficulty and with Mars in full view. That was a confidence builder.

The next night (August 20/21) the weather pattern changed. It looked like a little high pressure area--of all things--had built around my location during the late afternoon. With much better weather I was confident enough to bring out Skyhound (my 18-inch) at dusk. I collimated it, started the fan, then went indoors and carefully cleaned my eyepieces. I knew mars would first rise above the trees just before midnight. No deep sky observing this night; I had other things on my mind: two of them.

At around midnight I finally set out, feeling a little like a soldier on a mission. I had a good idea this was going to be the night. Mars was so bright that it dominated the night, much as it had dominated my observing thoughts that month.

I didn't fool around, putting in what has become my "goto" eyepiece: my 8mm Radian. Compared to the previous night's view in the 6-inch I was at first overwhelmed by the brightness of Mars and all the scattered light surrounding it. I remember thinking that there was no way I'd be able to make out two faint specks in all that glare. Phobos was nearing elongation so I concentrated on the eastern side of the planet, about one Mars diameter away from the edge of the disk. Nothing. I took a deep breath and decided to enjoy Mars itself for a while. The seeing suddenly improved and I was trying to tease more detail out of the southern features. In all of this I only slowly realized that I was seeing a tiny speck of light to the east of the planet. I turned my attention to it and it disappeared. Moving my eye up and away a bit it came back into view and I was able to hold it plainly visible. Phobos! I let out the customary "Oh... my... god!" and felt the strain on the skin around my eye from the big grin I was wearing.

It was sort of an emotional moment--a huge wave of serene satisfaction. Sure, just about anyone could probably see Phobos in a well designed 18-inch scope with the right eyepiece from Cloudcroft New Mexico at 9000ft on a night of good seeing during the most favorable opposition. But none of those things just happened; I didn't arrive at this time and place by chance. It was the result of hundreds of conscious choices; choices that I had made. Standing there by the scope looking up at bright old Mars, well, it was a moment--a private, personal, moment. This victory gave me pause to think about who I am and and about the long journey that brought me to this time and place, and to the realization of how lucky and contented I am.

Back at the eyepiece I found Phobos to be easy to spot; every time I looked, there it was shining away. I finally tracked down Deimos way off to the west of the planet. I found it the more difficult of the two, mostly because it was way out there in no man's land where there were few guideposts to get to it. Comparatively, Phobos was right there just off the equator of the planet. Phobos gave the appearance of a larger, more turbulent dot, powering through the bright glare, while Deimos appeared more as a tiny faint speck lost in a sea of haze.

I soon came to the point where I could spot each moon easily, requiring only a short eye movement between the two. They were too far apart to see simultaneously, but after a while I had the same impression one would have observing Saturn--ho mum, there are those pesky little moons, always hanging about.

I thought of my "observing the moons of mars" web page and suddenly realized that I had an opportunity to do some experimentation that could possibly help others looking to see these two illusive objects. I tried many things: different eyepieces, a Barlow, occulting bar, Mars off the edge, etc.

Don't think this is for 16-inch scopes only! I would not be surprised if Deimos could be glimpsed in a 4-inch under just the right conditions. Unfortunately it won't be until 2014 that Mars is again large enough to try in smaller instruments. 

Other articles about mars:

Observing the moons of mars

Observing mars in 2010