While today a picture of a serious looking person peering into a microscope may suggest “science” to the general public, we noted in our last column that this was not always so. In the early 19th century, for example, the microscope was seen by many as a hobby, interesting yes, but not as worthy of respect as an amateur's telescope.

Microscopes improved and soon, through the insight of the likes of Ernst Abbe, reached a state of perfection which was not greatly improved upon until recently. Once aberrations were well corrected for and glasses of high refractive index commonly utilized, further improvements in numerical aperture became increasingly difficult to receive. The only way to improve resolution seemed to be to decrease the wavelength of light used to illuminate the sample.

Slow-scan CCD (charge-coupled device) cameras (SSCs) are based on optical image detection technology introduced in the seventies and first used in astronomy in the eighties. When they are properly configured for the detection of medium energy electrons rather than photons, they are able to capture images that exceed the quality of images recorded on photographic film. Here we discuss aspects of their operation pertinent to routine biological TEM.

Compared to the TV-rate CCD sensors that have become ubiquitous in miniature camcorders, scientific (astronomy-grade) CCDs have several unique characteristics: 1) their pixels are typically 20-27 urn in size rather than the 6 urn typical of TV rate CCDs, 2) their read-out amplifiers are optimized for low noise at read out rates of 1/10 to 1/100 of TV rate, 3) they do not have a separate frame-transfer buffer for CCD read-out, and 4) they are available in large total sizes (up to 2048 x 2048 pixels).

Let's face it, nobody became a microscopist because they wanted to become an expert in Vacuum Science. The fact is that most of us were shown the proverbial “fly's eye” micrograph and fancied ourselves as the Ansel Adams of Electron Microscopy. As a consequence, during the progress of our careers, we have had to come to grips with Vacuum Science, usually on a “need to know” basis. Specifically, when the system has broken down, we need to know who can fix it … when they can fix it … and why they can not fix it sooner…

Nevertheless, the fact is that we ignore vacuum science at our peril. Although microscopes can withstand a lot of abuse before they catastrophically fail, they respond to poor vacuum practice with poor vacuum quality. In the final analysis ifs extremely valuable to have some “Vacuum sawy”.

1992 was certainly a banner year for microscopy in terms of an incredible total of nearly 3000 presentations given world-wide - at the largest ever joint (E)MSA/MAS/MSC meeting in Boston and at the 3 IFSEM-sanctioned Regional Conferences in Spain, China and Venezuela. Several of the local affiliate societies also mounted well-attended symposia and contributed to the outpouring of words and images. The apparently continuously growing volume of microscopy-related presentations has impacted both conference organizers and publishers.

Poster presentations are being used to an increasing extent to avoid an excessive number of parallel sessions. There is also an economic incentive as a poster session probably costs the organizers less than half that of a platform session of contributed papers. The poster trend draws a mixed response. Most microscopists love to look at posters but hate to prepare them as they are much more work to put together and are costly. They are awkward to carry and often have a one-time use whereas slides are for ever.