M46 & M48 – wide field images

Again taking the opportunity of a half-hour imaging session, here is M46 in Puppis from the window-sill. Since it is a wide field view, the included planetary nebula, NGC 2438, (a line-of-sight effect, it isn’t in the cluster) appears pretty small, but after a bit of processing you can see it just above centre and slightly to the left. For those of you trying to see it visually, here is a quote from Stephen James O’Meara’s splendid book “The Messier Objects”:

“There is yet another illusion with M46. It appears to contain a tiny planetary nebula. NGC 2438 – – –  But the cluster and nebula are not physically associated because the cluster is 5.300 light years distant, whereas the nebula is 6,250 light years away. Positioned just a few arc minutes north of the cluster’s centre, this 11th magnitude planetary measures only about 1’ in diameter. I suspected it at 23X but 72X shows it clearly as a ghostly mote among the multitude”

(I see from my notes that I observed it visually and sketched it at 01:10 UT on 23/12/2001 with my 8″ SCT at X266)

Since there was no moon, I had another go at M48, showing a few more stars than the last one I posted.

For completeness with the Messiers in that region I have also included the recent wide-field image of M47

Looking for Tardigrades in St Michaels Churchyard, Lichfield

Tardigrades are water-dwelling, eight-legged, segmented micro-animals. They were first discovered by the German zoologist Johann August Ephraim Goeze in 1773. The name Tardigrada was given three years later by the Italian biologist Lazzaro Spallanzani. They have been found everywhere: from mountain tops to the deep sea and mud volcanoes (Wikipedia).

Tardigrades, often called water bears or moss piglets, are near-microscopic animals with long, plump bodies and scrunched-up heads. They have eight legs, and hands with four to eight claws on each. While strangely cute, these tiny animals are almost indestructible and can even survive in outer space. Tardigrade is a phylum, a high-level scientific category of animal. (Humans belong in the Chordate phylum — animals with spinal cords.) There are over 1,000 known species within Tardigrade. Water bears can live just about anywhere. They prefer to live in sediment at the bottom of a lake, on moist pieces of moss or other wet environments. They can survive a wide range of temperatures and situations (https://www.livescience.com/57985-tardigrade-facts.html)

I went looking for tardigrades today in St Michael’s church graveyard in Lichfield, Staffordshire, UK. No success – sadly – so you won’t see tardigrades in the photo and video below. However, the samples I obtained from moss on gravestones, some lichen off trees and a sample from a wood chipping pile, revealed a range of life shown in the video below.


Photo x32 objective:

Video x32 objective:


Wider angle view of M47

Managed a 10-minute observing session from the window-sill before the clouds rolled in. M47 is quite large so this time, in order to get a good context, I used a focal reducer. Using a reducer on an f/5 refractor is not optically very good – and it was rather hazy, so the image is not brilliant. You can compare it with the one without the reducer at http://roslistonastronomy.uk/m46-and-m47

Delamination of Zeiss Standard Optovar

The following pictures show this problem on an example of a Zeiss Standard Optovar. The lens elements are separating and this leads to the rainbow effect. I have slightly rotated the Optovar on the spot in same lighting between pictures and you can see that the inner edge of the rainbow rotates with the rotation of the whole instrument. This would not occur if it was due to defraction of light from the glass only.


Delamination in top lens

Delamination in bottom lens:

Various out of print Zeiss manuals, brochures and price lists

Below is a list of manuals, brochures and price lists for Zeiss microscopes and associated equipment which are no longer in print.







Zeiss Use Care1927


Zeiss Optical Systems




Zeiss Model-W-Brochure


Zeiss Katalog188918931902














Zeiss Universal microscope manual for use with transmitted light(II)

Zeiss Universal microscope manual for use with transmitted light(I)

Zeiss Standard POL microscope manual

Zeiss Standard microscope with Lucigen illuminator manual

Zeiss Standard Lab 6 microscope manual

Zeiss Standard Junior 2 microscope manual Z

Zeiss Photomicroscope 3 manual for use with transmitted light

Zeiss Photomicroscope 3 manual for use with incident light

Zeiss Photomicroscope 1 manual

Zeiss ICM405 microscope part of manual

Zeiss dark field condensers brochure





Microscope Illuminator 100

Microscope Illuminator 60

MC 100

MC63A Camera

Invertoskop D

Invertoscope ID03 g


Epi-fluorescence Condensor IIIRS




Continuous Filter Monochromator-B-Bulletin

Carl Zeiss Katalog 1889 Microscope Catalogue

Carl Zeiss Jena 1937 Microscope Catalogue

Carl Zeiss 1893 Optical Measurment Instruments

Second attempt at oblique dark field illumination of algae from neighbour’s pond using halogen swan-neck illuminator on Zeiss Standard microscope

This time I used my centrifuge to concentrate the sample – snow outside/cold means number algae per ml in the water low.

Bright field images of algae x40 objective – unfortunately they show that I have some work to do aligning the optics as lot of colour fringes…there is also quite a lot of dust on the optics of this microscope – I need to give it a good clean! However, not all out of focus rings are dust – much of it is algae in different planes on this live sample.

I particularly like the second and third pictures as they show long cilia from the spherical organism.

Video from this session showing motile organisms:

Dark field using oblique illumination – set up with Zeiss Standard microscope:

I have found that the best dark field is when the fibre-optic tips are placed on the stage pointing virtually horizontally at the end of the objective.

Dark field with x10 objective, using above equipment – looks like a star field in the telescope! Can you recognise the constellations?

The above two images came directly from the camera.

The following are the same two pictures but this time I have used curves in GIMP to remove part of curve below the data and hence blacken the background:

Dark field using x40 objective – this is where I am breaking new ground with success at dark field using x40 objective. So far, using my Zeiss IM microscope, I have been able to obtain excellent dark field images using the 10x non-phase objective and a phase annulus, but the higher power objectives don’t seem to work so well using that system. I think maybe the NA on the objectives is too high compared to the NA on the condenser, but am not sure of the reason.

I found that if I varied the position of the swan neck heads to direct the light more downwards (angled the lights to point down rather than horizontally) then this varied the lighting effect. The lighting is no longer true dark field but is still interesting! Example picture below: