Crossed polarisation – variable positions of filters relative to each other.
Comparing plain vs crossed polarisation for various samples – all x3.5 magnification as currently this is only objective I have for this microscope – uses special clamp mechanism so my other objectives won’t fit.
For more information on the LOMO Polam P-113 Polarising Microscope, see a wide range of posts at: http://roslistonastronomy.uk/category/microscopy/equipment-for-microscopy/lomo-polam-p-113-microscope
Permian-floodplain-deposit-Robledo-New-Mexico-LOMO-Polam-P113-Crossed-Polars-120518: Excellent birefringement is shown here, and this can be seen varying between the images as polarised filter rotated (below).
Laminated-mudstone-LOMO-Polam-x3-5-plane-polar-120518: Some birefringence evident where crystals form in both images, more so in bottom as the two polarised filters approach 90 degrees orientation to each other (below).
Fossilised-palm-tree-LOMO-Polam-x3-5-plain-polar-120518: Even here some crystal deposition is evident, as shown by coloured areas of birefringence, more evident in second image where polars are crossed (below).
The following photos are from a slide of Ritland Impactite seen through the LOMO Polam P-113 Polarising Microscope. The four photos show the changing colour of the crystals as the polarising filter in the condenser is turned through 90 degrees. There is another polarising filter in the eyepiece assembly. Hence, this slide is being seen with “Crossed Polarising Filters”.
Information on the LOMO Polam P-113 Polarising Microscope can be found here, http://roslistonastronomy.uk/lomo-p-113-polarising-microscope
The following is a video of the same slide through this microscope – showing effect of rotating the polarising filter in the condenser, rotating the rotating stage, and X-Y movement of the stage.
The LOMO P-113 Polarising Microscope is an old Russian Federation microscope – solidly built, this one comes with an LED modification to the illuminator and a trinocular head and monocular head. I have used the monocular head in the trinocular port of the trinocular head to allow simultaneous photography and visual observation. There is lever on side of the trinocular head to change between visual and photographic use.
See also the following post where “first light” with this microscope, http://roslistonastronomy.uk/ritland-impactite-seen-in-lomo-polam-p-113-polarising-microscope
Having seen it done on BBC Sky at Night TV programme, I decided to have a go myself. For the last few weeks, I have put a strip of wood with neodychromium magnets screwed onto it in the gutter from our roof……in the hope of picking up these tiny visitors from the solar system. If I find them, they will be round/egg shaped from melting as they heat up in the Earth’s atmosphere during their fall to the ground (roof).
As you can see below, I washed off what was stuck to the magnets, then filtered it and used another neodychromium magnet to try and retrieve magnetic material from what remained. Most of it was organic debris (not sure why that stuck to the magnet!) – but resolutely stuck to magnet and difficult to remove was a reasonable amount metallic dust.
The photos show that sadly this is composed of small angular rust particles – I could not find the tell tale round structures that could be meteorites.
The magnets are back in the gutter.
Extracting possible micrometeorite (magnetic) particles from gutter collector:
What I found – tiny angular pieces of metal (totally opaque as metallic):
Helicon Focus 3D image and model:
On BBC Sky at Night TV show a few months ago, they collected micro-meteorites from roof collection at the Norman Lockyer Observatory in Sidmouth, UK. Rhys and I ordered some neodychromium magnetd and today we mounted them on a piece of spare wood using some small screws through their central holes. We put the wood and magnets, magnet side down, in the guttering on the front of our house in Lichfield, UK.
Hopefully, this will extra small metallic debris from the water running off the roof when it rains over the next few months. Again hopefully some of this will turn out to be micro-meteorites.
Andy and Rhys