Two images of the same diatom

[75RR]

Planapo 63x/1.4, 100µm, DIC, 14 and 15 image stacks in Photoshop

[kit1980]

Both images are good, but I like the second one much more - very nice!

[mrsonchus]

Wow 75', these images are simply stunning old chap. Such detail and such fine lines! A real treat for the eyes. Your DIC technique is excellent. Lovely images - I don't know where I've seen more detail from diatom images.

[exmarine]

Where is the raphe and the striae do not show up well do they?
Nice photos.

[75RR]

Thanks kit1980, mrsonchus and exmarine

Where is the raphe ...

Do not think it is visible from from this side. One can see the indentations halfway up on both sides that seem to indicate the central nodule position.

Had hoped to take more images at different angles but my rotating stage was not centered, I think I must have inadvertently de-centered it, what with turning all those knobs and dials just by feel, which made changing the angle of the diatom somewhat of a challenge.
Have placed the slide in the slide holder (an optimistic step as it is oiled) and will center the stage and try again later today.
Hope to get 4 views 22.5 degrees apart (from 0 to 90) which should give a range of details.

[gekko]

Excellent, beautiful, sharp images (both).

[zzffnn]

Very very nice!

[rnabholz]

Beautiful DIC and great stacks. Really pretty images.

[75RR]

Many thanks gekko, zzffnn and rnabholz

[KurtM]

Hope to get 4 views 22.5 degrees apart (from 0 to 90) which should give a range of details.

Why 22.5 degrees apart?

One of the benefits of being an old astronomer is I can re-center the rotating stage in about 5 seconds. I'm forever grabbing the stage centering screw instead of the condenser centering screw, which, while ARGHHH-inspiring, keeps me in practice.

Seriously GREAT image!! The second one was especially had my jaw dropping. Bravo!

[75RR]

Thanks KurtM :)

Why 22.5 degrees apart?

Thought an image half way between 0 and 45 degrees and half way between 45 and 90 would show some differences.
Actually just realized that that would be 5 images: 0˚, 22.5˚, 45˚, 67.5˚ and 90˚

I'm forever grabbing the stage centering screw instead of the condenser centering screw, which, while ARGHHH-inspiring, keeps me in practice.

Drives me crazy too, but love having all those controls.
One can fine tune to one's heart's content :)

[JimT]

Seriously beautiful!

[KurtM]

love having all those controls

I know the feeling! In my opinion there are two controls that all advanced microscopes should at least offer, but are seldom - if ever - seen:

1. Rotating stage
2. Oblique condenser

At least I finally got one of the two...

[actinophrys]

Do not think it is visible from from this side. One can see the indentations halfway up on both sides that seem to indicate the central nodule position.

The stacks show beautiful detail but of course make things seem kind of flat, and while many diatoms are genuinely flat-topped, this looks like a Rhopalodia which are not. Instead the 3-D shape is sort of like a kayak, with the brace-shaped valves tilted up to make the left and right sides of its deck. So viewing it from above as here, what seems like the centre of one valve is actually the girdle between them. Each has its raphe along the outer edge forming the perimeter of the image.

[KurtM]

The stacks show beautiful detail but of course make things seem kind of flat, and while many diatoms are genuinely flat-topped, this looks like a Rhopalodia which are not. Instead the 3-D shape is sort of like a kayak, with the brace-shaped valves tilted up to make the left and right sides of its deck. So viewing it from above as here, what seems like the centre of one valve is actually the girdle between them. Each has its raphe along the outer edge forming the perimeter of the image.

I agree it is Rhopalodia. Are you saying, then, that Rhopalodia is one of those few that are most often seen in girdle view? I have often wondered about this. This form is fairly common, often sizable, and always quite a challenge to make visual sense of.

[75RR]

Many thanks JimT and many thanks for the ID and the explanation actinophrys

I had no idea what it was. After looking it up and seeing its shape I can see why you described it as a kayak.
If the two ends are tilted up then given the shape of the side it is lying on, is the diatom angled like a child's see saw?

[75RR]

1. Rotating stage
2. Oblique condenser

At least I finally got one of the two...

Looked up Oblique condenser, a rare animal indeed. Still I like the idea.

[rnabholz]

Many thanks JimT and many thanks for the ID and the explanation actinophrys

I had no idea what it was. After looking it up and seeing its shape I can see why you described it as a kayak.
If the two ends are tilted up then given the shape of the side it is lying on, is the diatom angled like a child's see saw?

The first image here has a "kayak" featured

viewtopic.php?f=6&t=3722

[rnabholz]

1. Rotating stage
2. Oblique condenser

At least I finally got one of the two...

Looked up Oblique condenser, a rare animal indeed. Still I like the idea.

Here is a beautiful classic Spencer with an oblique condenser. Image #8 shows it nicely.

Look at this on eBay http://www.ebay.com/itm/262603529049

[75RR]

Thanks rnabholz, so the diatom is lying like my diagram (red line represents the floor) angled like a see saw?

Neat image of the side moving diaphragm!

[rnabholz]

Thanks rnabholz, so the diatom is lying like my diagram (red line represents the floor) angled like a see saw?

Neat image of the side moving diaphragm!

Yes, like your see saw.

Isn't that a pretty and interesting scope? The seller is a friend that I have bought many things from. I can say without any fear that it has been gone through and is ready to use. I have to keep telling myself that I am out of room.....

[actinophrys]

The see-saw is right but to be clear the valves are as much "top" as "sides", so while it is a girdle view it is not the usual perpendicular from valve view. Instead of my analogy, I guess it would be better to give a picture. Here is an SEM I found from Western Diatoms; the cell is shorter and more oval but should illustrate the general boat shape:

[75RR]

The see-saw is right but to be clear the valves are as much "top" as "sides", so while it is a girdle view it is not the usual perpendicular from valve view.

Ok, see what you mean now. Thanks

[billben74]

Fantastic diatom images and great thread.
I don't have either a rotating stage or an oblique condenser but I can definately see the point of them.

[McConkey]

Great image comparison! What did you do differently to get such a difference in the images?

Thanks for sharing!

[75RR]

Many thanks billben74 and McConkey

I don't have either a rotating stage or an oblique condenser but I can definitely see the point of them.

Can't speak for a Oblique Condenser but a Rotating Stage, provided you have it centered, is particularly useful in photography if you can not rotate you camera. It is also very useful with diatoms as each angle one views them at shows up different features.

What did you do differently to get such a difference in the images?

There were two different things, one is the rotation of the diatom which therefore shows different facets and the other was that I had to remove the camera as the card was playing up and did not want to connect to my computer. This effectively meant two distinct sessions, starting with refocusing the camera, setting up the illumination etc ...

[KurtM]

...a Rotating Stage ... is also very useful with diatoms as each angle one views them at shows up different features.

This is true with DIC, and wouldn't be the case otherwise, right?

[75RR]

This is true with DIC, and wouldn't be the case otherwise, right?

It holds true for oblique as well.

[rabitt]

Wonderful images, thank you for the explanation on how the images where done.
Also the information about the Diatom shape itself.
The continuing education of a Newbie.