The Case for Visual Observing
The Case for Visual Observing

The Case for Visual Observing

Photo's of the moon never do it justice.
Photo’s of the moon never do it justice.

At most star parties you’ll find two groups of people. They don’t hang out together. There’s the visual crowd, and there are the imagers. The visual crowd is very social, there’s lots of sharing and laughing, and when permitted, a beer or two.

Imagers are hard at work. Leave them alone. Do not walk up to them, do not shine your big red light at their telescope, and do not talk to them. During the day they will show you their equipment and tell you more than you care to hear about it, but in the dark…. they are focused and dangerous when they are at work, and they are always serious. Imaging is no laughing matter.

Of course I’m exaggerating;  imagers in a group are quite social, and I always have a great time imaging with friends. There is no denying though that the two crowds have a different approach to the night, and rarely do they cross over. This is too bad really. I started life out as a visual observer, and evolved into an “Imager”, but I must say, I do still enjoy the stroll through eyepiece alley sometimes. The imaging bug takes hold the first time you take a picture of _anything_ and find you can get more detail out of a camera than you can from the eyepiece. From thenceforth, EVERYTHING must be imaged!

The accepted wisdom is that a camera captures more than the human eye ever can so…. wait a second. Is that really true? Well, sort of.

Galaxy Images Trump Eyepiece Views. Always.
Galaxy Images Trump Eyepiece Views. Always.

When it comes to galaxies, yes, there is no galaxy ever anywhere that I have ever seen through any telescope eye piece that was not surpassed by a view of the same object taken with a camera. When it comes to astrophotography, galaxies rule. Through an eye piece, galaxies look like comets without a tail, just a fuzz ball. Could be a tiny cotton ball hung up in my optics somewhere. Oh, it’s COOL to think of the millions or billions of years the light has traveled to my eye, but that euphoria doesn’t last for me. I do recall the first time I spotted some spiral structure in M51 through someone else’s big dobsonaian, and that was thrilling… a little. The first time I took a picture of M51, it was HORRENDOUS, noise dominated, and out of focus, but BY GOD IT’S A GALAXY! You could see what it was clearly, and thrilling? I believe I jumped up and down.

Nebula are in a similar boat, with one exception. I remember too the first time I took a 10 second exposure of M42, the great nebula in Orion. I AM NOT SEEING THIS I shouted to my father-in-law who was standing nearby. It was amazing. Almost everything looks better, more defined, more color, more detail, larger, and deeper, when seen with a camera. Almost…

I’ll start my derailing of the thesis that images are better than visual by stating that I’ve never seen a photograph of M42 that actually looks like a view of M42 through a telescope. Well, that’s the point isn’t it? I’m not so sure with M42. There is a dark beauty to M42 in the eyepiece, it’s soft and smokey, your just there floating in space. When I look at M42 in an eye piece, the world around me melts away and falls silent. Sirens, gunfire, women screaming, babies wailing… it all falls away muffled by the deep cold silence of space.

Some things do just look better through an eyepiece.

An image I'm proud of. Still looks better in an eyepiece though.
An image I’m proud of. Still looks better in an eyepiece though.

Globular clusters are another clear eye piece winner. I have never seen a globular cluster image that matched the view through an eye piece. Crushed diamond, snow balls, fine ice crystals. The detail that can be resolved is far greater than most camera’s can render. Even if you have theoretically very tiny pixels that resolve far beyond what the human eye can, there is still the problem of dynamic range. The range of brightness in a globular cluster far exceeds what can be represented on current computer screens.

I think dynamic range is really the killer argument here for visual over photographic. The moon is another such target. I have seen some amazing lunar photographs by people talented far beyond what I may ever be able to achieve. Crisp sharp images that look like they were taken from orbit. But when you look at the moon through an eyepiece, there is a creamy subtlety to the surface, the rocky mountains, the rilles, and it’s the contrast and the stark changes in brightness across the surface that cannot be represented by modern imaging technology. The real view is just sublime in a way that cannot be matched by a computer monitor.

All things change of course, and this may not be true for much longer. Modern imaging technology is actually capable of capturing far more dynamic range than modern DISPLAY technology can deliver. I’ve seen some high dynamic range display prototypes at event’s like SigGraph (A computer graphics practitioners conference), usually though in the emerging technologies pavilion. We’ll see if in ten years time I can still say I still prefer the view through an eyepiece to the view on a computer screen. The irony is of course, if we can’t make more people aware of the problems of light pollution, we may well not have any dark skies left in 10 years anyway. Food for thought.

Richard