April 2026
I finally managed to find time to photograph the Aperture Iris Diaphragm that I acquired at the Quekett Spring Sale last month.
Aperture Iris Diaphragm
It fits the trans-illuminator base that was available for several Olympus stereo microscopes in the 1970s and 1980s. This is the same base as the X-DE Trans-Illuminator Base that was part of the OM macrophoto group, but Olympus did not mention the Aperture Iris Diaphragm in their OM literature. I tried to attach it on top of the base, before realising that it has to be attached underneath the top. The four threaded holes in the top of the base and the small hole in the front of the top have puzzled me for years, and now I know what they are for.
Aperture Iris Diaphragm attached to X-DE base
The iris has 17 blades and can be adjusted from 2 mm to 40 mm. It can also be offset by up to 5 mm for oblique illumination.
March 2026
It is a long trip by public transport to the Quekett Spring Sale, about 3½ hours, but it is a good opportunity to catch up with old friends and to meet real people who I have previously only met on Facebook. I managed to sell the stage plates, an Olympus CT-4 phase telescope and the Zeiss centring slide. I bought a blue Olympus KB-4 filter as originally supplied with the BHT, BHS and early BX microscopes. I don’t really need it, but it was only £1, and I have added it to my box of small BHT accessories. It is only for viewing, not for photography. I also found an Aperture Iris Diaphragm (an obscure accessory for the X-DE Trans-Illuminator Base), so now I need to photograph it for my website.
For the Quekett Spring Sale (which has replaced the Reading Convention) at Sonning Common Village Hall, I sorted out a few items that I no longer need. My Olympus SZ4045 stereo and Macrophoto Stand VST-1 take the same 100 mm stage plates, and I found that in addition to good sets for each, I had a couple of spares. In my box of oddments, I found two centring slides, one by Lomo and one by Zeiss. I don’t know what to do with them, but perhaps someone will want them. I will have another go at selling an Olympus PM-ADF eyepiece adapter for £5 and a Leitz Periplan eyepiece with 28 mm thread for £15, far less than they fetch on eBay.
Surplus items for sale at Sonning Common
At the Home Counties Meeting in Cobham, Robert Ratford arrived with a huge Olympus BX51M metallurgical microscope. I had a PDF of the instruction manual, so now Robert can work out how to use it.
Olympus BX51M metallurgical microscope
February 2026
I went to the workshop on contrast enhancement, led by Chris Thomas, so that I could take notes and photos for the meeting report. It is not easy to make accurate circular stops for dark-ground and Rheinberg illumination, and I was surprised how well the octagonal and square stops that Chris demonstrated worked.
Dark-ground stop and Rheinberg filter
There is no time at workshops to take stacked images, so I took some specimens home to photograph:
Down feather using dark-ground illumination (BH2-DCD condenser, 10× SPlanApo objective, 56 images at 0.002 mm steps)
Teased toilet tissue using crossed polarisers plus makeshift retarder (10× SPlan objective, 27 images at 0.01 mm steps)
I have decided to dispose of some of the books and equipment that I no longer use, so on fine days I have been carrying loads of non-microscopy books to my local Oxfam bookshop and British Heart Foundation charity shop. I posted photos of the microscopy books, a dissecting microscope and an illuminator for a stereo microscope in the QuekettMicro group on Facebook.
Free books
I was surprised and disappointed that the books were not snapped up. Many people don’t seem interested in books these days.
Free Spencer Dissecting Microscope No. 82
The dissecting microscope was claimed in a few minutes, and will be going to a youngster at the Anglian Microscopy Group.
Free Olympus LSG illuminator and TE-II transformer
I didn’t think anyone would want this illuminator, which is less bright and much heavier than an LED ring-light, but three people were interested.
January 2026
The Quekett’s 2026 outreach programme started on a freezing winter day at the “Life Under a Microscope” session of the Wimbledon Common Nature Club. It is run by Auriel Glanville and her assistants (Jen Long, Luci Teuma and Alexander and Oliver Mallett) and welcomes children from 6–14 years old to come and discover the world of nature on the Common. They meet for 2 hours each month in the Information Centre, the same venue as used by Quekett members on excursions, the Weekend of Nature and the Open Day. I took my Olympus SZ4045 stereomicroscope with an LED ring-light, a small and simple stereomicroscope, and some slides and specimens.
Alan Wood [by Auriel Glanville]
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