…continuedImaging a Solar Eclipse
The Hi-8 and S-VHS formats offer better resolution than the old 8-mm, VHS, or VHS-C formats. The compact size and light weight of 8-mm camcorders make them ideal for travel. There are dozens of models and prices to choose from, with features such as flip-out LCD viewfinders and image-stabilized optics.
All camcorders have zoom lenses, some with up to 32x optical and 330x (or more) "digital" magnification. Optical zoom is what matters, since it increases the image scale on the detector. (Digital zoom simply crops in on the center of the view, reducing resolution.) The easiest way to determine the approximate size of the Sun in your camcorder is to shoot the Moon, zooming in from lowest to highest power. If your camcorder doesn't have enough magnification, consider adding a teleconverter (2x or more) to the front of the lens. Or shoot through a telescope's eyepiece.
As with still cameras, you need a proper solar filter over your camcorder or scope when recording the partial phases. You can take 2- to 3-second clips every five minutes or so to produce a time-lapse sequence that compresses the hours-long partial phases into just minutes. High-end camcorders have manual controls for adjusting the gain, f/stop, and "shutter" speed so you don't overexpose the bright inner corona or cause blooming (streaking) of the image. Again, it's best to test your setup on the full Moon well in advance. On eclipse day, be sure to use a battery freshly charged at least a half hour before totality. Keep a spare one as backup.
The Digital Darkroom
Recording the corona's full range of brightnesses and details in a single view has been the Holy Grail of eclipse imagers. In the past astronomers have used different techniques, including special radially graded filters, to suppress the bright inner corona and capture the solar atmosphere's full shape and structure. They have also spent countless hours in the darkroom stacking negatives and using sophisticated dodging and masking techniques to bring out subtle coronal details.
Each exposure is digitized and processed with an unsharp mask. With just a few mouse clicks, you can easily retouch any film defects (dust specks, scratches, or fingerprints) and adjust the image contrast, brightness, and hue. A half dozen or more images can be processed this way and then sequentially coadded to improve the image quality and produce a smooth composite, which can be printed on a high-quality photo printer or sent to a photo lab to produce prints or slides.
Based on my previous eclipse expeditions, here are some suggestions worth keeping in mind:
- Use a pocket tape recorder to document your observations and reactions.
- During the March 1988 eclipse in Mindanao, Philippines, the umbra was so dark it was difficult to read the camera's shutter dial. On the other hand, the July 1991 eclipse in Baja California was so bright it was possible to read a newspaper during totality! Be prepared and keep a small pocket flashlight handy.
- When packing your things, put delicate equipment like cameras, telephotos, and camcorders in your carry-on baggage to ensure safe handling. Commercial airlines are now restricting the amount and size of carry-on baggage, so be sure to check with them or your travel agent to avoid problems during boarding.
- New, more powerful security X-ray machines are in use at many airports. These can damage film. Even lead-lined film pouches are no longer impenetrable. So ask that your films be hand-inspected.
- For safety, ask your photofinishing lab to leave your developed (slide) films uncut. You don't want the lab accidentally slicing your best shot in half because the separation between frames is difficult to see.
I know it's difficult, but take a few moments to leave your gear alone and enjoy totality with your unaided eyes or through binoculars. I've often heard tales of people so engrossed with their imaging that they missed seeing the eclipse visually. In all my eclipse chasing, I've always made it a point to catch (between exposures) good glimpses of the spectacle going on above me. No photograph or video can compare with the real thing.