One of the first things an astronomy newcomer hears is that astrophotography is prohibitively expensive. That is not altogether true. There is no reason why someone operating on a low budget can't begin without spending a small fortune, particularly if they begin in their own neighborhood, so to speak. For our purposes, astrophotography can be divided ito two easily separated categories: deep space and solar system. This article will address only the latter aspect of astrophotography.

Why is it more expensive to photograph certain objects?

The most difficult and most expensive type of astrophotography involves the long-exposure imaging of objects so distant that very little of their light reaches us. These objects include galaxies, globular star clusters and diffuse nebulae. Due to the earth's rotation and the time necessary to capture their light, extreme tracking precision is required in the telescope's mount. When putting together such an imaging system, more thought and money should be directed to the mount than any other component, including the telescope. Spending six to ten thousand dollars on the mount alone is not at all uncommon.

The learning curve for this type of photogrphy is very steep. It takes most people several years to master. The equipment necessary is so expensive that many aspiring deep space photographers start out with gear that is barely adequate for the job, working their way up and replacing components and telescopes as they learn.

Fortunately, planetary and lunar imaging is comparatively cheap. Moreover, beginning with the brighter objects within our solar system is a more practical starting point. And for a number of reasons, this range of targets is not as limiting as it sounds. It is more than just a matter of nine planets and a moon. Jupiter, for example, constantly changes, not only from hour to hour, but from year to year, as well. The ring tilt of Saturn goes through eight-year cycles. Simply taking high magnification images along the moon's terminator strip can take a lifetime.

But, even if deep space photography is your end goal, it is probably best to pick up the basics closer to home. For one thing, you're a lot better off discovering that the hobby doesn't interest you as much as you initially thought, before spending 10 to 20 thousand dollars on mounts and cameras. The equipment for solar system imaging isn't nearly as costly.

Since the target objects are so bright, they don't require long exposures to capture their light. This means that you don't need a mount that tracks with extreme precision. The Chinese CG5 clones, or motorized alt/az (fork mounts) systems will work just as well.

Additionally, dedicated CCD cameras are not necessary. Believe it or not, amateurs using slightly modified webcams attached to relatively small telescopes have been taking pictures from their back yards that exceed the efforts of the biggest earth-bound telescopes from the best equipped observatories in the world.

Seeing is everything!

Seeing conditions vary on a nightly basis, but they can also change within the space of an evening, an hour, or even within a single second. It is for this reason that webcams are better suited for the high contrast, highly detailed planetary and lunar work. By capturing frames at the rate of 10 or fifteen frames per second, your camera effectively freezes those brief moments of clarity that happen too fast for the human eye to register. Software programs such as Registax enable you to eliminate the bad frames and stack the remaining shots into an individual image that captures all of the detail that revealed itself during that time period.

I can't stress enough the importance of seeing conditions. For this type of photography light pollution doesn't really matter; the objects are bright enough to image, even on full moon nights. Transparency doesn't matter much either. In the images below are two shots of Saturn taken within a month of each other by the same telescope, a Celestron 9.25 SCT, using a Philips toUcam Pro. The difference was that, in the first image the seeing conditions were considerably sub par, while the seeing was better than average on the night the second image was captured. If the conditions are bad it doesn't matter what kind of telescope or camera you have. You won't get good images. Equipment and skill do contribute to great images, but seeing is of more importance.

 

 

 

 

 

 

 

Which brings us to perseverance. If I suggested earlier that planetary imaging was easy, then I apologize. It's not easy, it only seems than way in comparison to deep space astrophotography. But, once you've mastered the basics, a lot of it has to do with the time you are willing to invest in getting a great picture. Good pictures take a lot less time. Great pictures require a willingness to squat next to a telescope in the middle of the night, staring into a laptop screen, while gripping a mouse with a half-frozen hand, waiting for just the right moment to click and begin the capture sequence. Even on a good night I usually capture at least twenty avi video sequences.

Some areas of the world have consistently better seeing conditions than others. Living in an area with worse than average conditions doesn't mean you can't get good pictures. It just means that you may have to spend a little more time trying. Take advantage of every good night and make the most of it. Take as many sequences as possible. Get as much raw footage as possible and worry about processing later. If you are willing to put some work into it, you can get decent images.

If you live in the United States, check the Clear Sky Clock frequently. You can even put the code for your area in the html of your webpage. It won't take long before you can sense when the seeing will be good, based on conditions in the past, the amount of moisture you can feel, etc. One good indication of calm conditions is a sky with stars that do not appear to "twinkle."

Barlows, Focusers, etc.

There are a lot of accessories that will make the imaging process easier. Don't get too upset if you have a tough time getting Jupiter or Saturn to show up in your webcam chip's field of view on the laptop screen. When I was putting my setup together I thought I would save $150.00 by opting not to buy a flip mirror. On my first night out, it took me at least 45 minutes to place Jupiter on screen. That very night I ordered a Meade flip mirror, and would have done so even if it cost twice that amount.

The problem is that a toUcam, when used without a barlow, will magnify your view roughly equivalent to using a 4mm eyepiece. With my 9.25" SCT at f/10 that means a magnification level of around 588x. With a 2x barlow I get 1175x, and so on. If you have ever observed a planet at high magnification with an undriven dobsonian telescope, you know how difficult it can be to keep the object within the field of view. To use a webcam for imaging you first have to locate the object in a lower power eyepiece, then switch to an eyepiece that will give you as much magnification as possible, at least 1000x, then very carefully remove the eyepiece and replace it with the webcam, taking care not to bump the telescope or move it even a fraction of an inch. Once you lose it with the webcam in place it will be extremely difficult to find it again, without beginning the process again.

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