Search found 2794 matches

by MichaelG.
Tue Jun 15, 2021 5:17 am
Forum: Pictures and Videos
Topic: HAB in the Saint Lucie River
Replies: 1
Views: 19

Re: HAB in the Saint Lucie River

Very beautiful … at that scale

But I read this yesterday: https://theconversation.com/climate-cha ... ife-156148

MichaelG.
by MichaelG.
Sun Jun 13, 2021 8:08 am
Forum: Introduce yourself
Topic: a new fungi friend
Replies: 1
Views: 85

Re: a new fungi friend

Welcome, Danny

... We have ‘much room’ for you !

MichaelG.
by MichaelG.
Sat Jun 12, 2021 7:02 am
Forum: Resources (online, books etc.)
Topic: Optical Design : MIL-HDBK-141
Replies: 1
Views: 85

Optical Design : MIL-HDBK-141

Here is the ‘Military Standardization Handbook’ in a convenient form for reference:

https://wp.optics.arizona.edu/jgreivenk ... -hdbk-141/

Dated 1962 ... but still useful

MichaelG.
by MichaelG.
Fri Jun 11, 2021 12:28 pm
Forum: Beginner's corner
Topic: which is the real DIN 160mm objective?
Replies: 11
Views: 349

Re: which is the real DIN 160mm objective?

75RR wrote:
Fri Jun 11, 2021 12:08 pm
.
Here is a linked image showing some of the terminology
.

Ah, yes ... I remember it well ;)
https://www.microbehunter.com/microscop ... din#p85168
by MichaelG.
Tue Jun 08, 2021 5:52 pm
Forum: Pictures and Videos
Topic: Alyssum Stem (Higher Magnification)
Replies: 3
Views: 95

Re: Alyssum Stem (Higher Magnification)

Superb ! ... as is the lower magnification image

Real sense of depth in both of them.

MichaelG.
by MichaelG.
Mon Jun 07, 2021 10:57 am
Forum: Microscopes and optics
Topic: OFR (OPTICS FOR RESEARCH)
Replies: 7
Views: 200

Re: OFR (OPTICS FOR RESEARCH)

UVB looks promising !

MichaelG.
.
Ref. https://en.wikipedia.org/wiki/Ultraviolet#Subtypes
by MichaelG.
Sun Jun 06, 2021 5:09 pm
Forum: Illumination Techniques
Topic: Overhead lighting for compound scope (T720Q)
Replies: 13
Views: 319

Re: Overhead lighting for compound scope (T720Q)

Greg Howald wrote:
Sun Jun 06, 2021 11:47 am
That's an interesting comment. The half ball would act as a parabolic to focus the light. Sounds cool.
Greg
.
Well actually, no ... a hemispherical surface makes a rather poor job of focusing

MichaelG.
.
https://en.wikipedia.org/wiki/Parabolic_reflector
https://youtu.be/djkBahaEHG4
by MichaelG.
Fri Jun 04, 2021 12:58 pm
Forum: Pictures and Videos
Topic: Lycopodium
Replies: 5
Views: 191

Re: Lycopodium

iconoclastica wrote:
Fri Jun 04, 2021 12:27 pm
(Various stains haphazardly applied)
That second image [stele 40x.jpg] is gorgeous !!

MichaelG.
by MichaelG.
Thu Jun 03, 2021 5:24 pm
Forum: Pictures and Videos
Topic: Actinosphaerium eichhorni
Replies: 9
Views: 271

Re: Actinosphaerium eichhorni

Wonderful work, Luis

MichaelG.
by MichaelG.
Wed Jun 02, 2021 11:05 am
Forum: Pictures and Videos
Topic: Classic cheek cells
Replies: 2
Views: 98

Re: Classic cheek cells

An impressive demonstration ... Thank You

MichaelG.
by MichaelG.
Wed Jun 02, 2021 5:26 am
Forum: Microscopy accessories
Topic: Reticle size?
Replies: 8
Views: 272

Re: Reticle size?

Thanks, Scarodactyl

MichaelG.
by MichaelG.
Tue Jun 01, 2021 11:35 am
Forum: My microscope
Topic: Tungsten needle for diatom manipulation.
Replies: 15
Views: 351

Re: Tungsten needle for diatom manipulation.

. Nice work, Phill I have tried the molten Sodium Nitrite method with reasonable results ... but yours looks superb. MichaelG. . Edit: __ from my notes: This appears to be the original description of the electrolytic method: https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC2555190&blobtype=pd...
by MichaelG.
Tue Jun 01, 2021 8:24 am
Forum: Microscopy accessories
Topic: Reticle size?
Replies: 8
Views: 272

Re: Reticle size?

Just to add to the pool of knowledge ... I’ve found another list : https://www.mecanusa.com/microscope/micrometer/Micrometer-Sizelist.htm MichaelG. . P.S. __ Can anyone confirm [or refute] my suspicion that Nikon’s E stands for ‘economy’ ? ... my limited personal experience finds CFW 12.5/16 eyepiec...
by MichaelG.
Mon May 31, 2021 8:21 pm
Forum: Beginner's corner
Topic: I need to buy phase contrast microscope
Replies: 8
Views: 214

Re: I need to buy phase contrast microscope

You will probably find this rather ‘heavy going’ Marius ... but it’s a good introduction to the various types of Phase Contrast:
https://www.microscopyu.com/techniques/ ... figuration

At least skim through it.

MichaelG.
by MichaelG.
Mon May 31, 2021 4:46 am
Forum: Illumination Techniques
Topic: Uniform Illumination Sphere Light Source (UIS-LS)
Replies: 7
Views: 502

Re: Uniform Illumination Sphere Light Source (UIS-LS)

It makes me think that the entire interior of the sphere must be a mirrored surface and that the light source must be precisely centered. A rather pricey item. Greg You might find these documents [from different suppliers] interesting, Greg https://www.ophiropt.com/laser--measurement/knowledge-cent...
by MichaelG.
Mon May 31, 2021 4:25 am
Forum: Home-made microscope adaptations
Topic: Making a negative meniscus lense ?
Replies: 22
Views: 1345

Re: Making a negative meniscus lense ?

That looks very tempting ... but I must resist !
  • Being in England, the total cost of purchasing it could be considerable.
  • Although I regret not having one, I’m not really ‘looking for’ an Axioskop.
  • My sign-off comment says it all really.
Many thanks for thinking of me though.

MichaelG.
by MichaelG.
Sun May 30, 2021 1:51 pm
Forum: Microscopy accessories
Topic: Reticle size?
Replies: 8
Views: 272

Re: Reticle size?

by MichaelG.
Sun May 30, 2021 8:48 am
Forum: Microscopes and optics
Topic: What are the quality criteria for stereo microscopes?
Replies: 16
Views: 680

Re: What are the quality criteria for stereo microscopes?

farnsy wrote:
Sat May 29, 2021 7:18 am
I would really like to purchase a stereo microscope, but I'm frustrated with the lack of availability of knowledge on the subject.
.
Have you read these ?

http://www.microscopy-uk.org.uk/mag/art ... tereo1.pdf

MichaelG.
by MichaelG.
Sat May 29, 2021 9:05 am
Forum: Microscopes and optics
Topic: What are the quality criteria for stereo microscopes?
Replies: 16
Views: 680

Re: What are the quality criteria for stereo microscopes?

The single most important feature of a stereo microscope must surely be the design of its binocular. The suitability of a particular design, for your eyes and your type of work , is difficult to judge from descriptions, specifications, and the experience of other people ... You really need to find w...
by MichaelG.
Sat May 29, 2021 7:25 am
Forum: Camera systems and imaging
Topic: Light waves when taking videos
Replies: 6
Views: 645

Re: Light waves when taking videos

Whatever the root cause [and 75RR mentions a likely suspect] the problem is often known as ‘strobing’ and it is evidence of a ‘beat frequency’ in the interaction of the lighting an the camera’s electronic shutter.

MichaelG.
by MichaelG.
Thu May 27, 2021 4:45 pm
Forum: Pictures and Videos
Topic: Predator and Prey Didinium versus Paramecium
Replies: 3
Views: 368

Re: Predator and Prey Didinium versus Paramecium

The blue DIC image is astonishing !

... not least because I see a large right-angle just above your text ‘Cilia bands’

MichaelG.
by MichaelG.
Wed May 26, 2021 9:29 pm
Forum: Microscopes and optics
Topic: First stereo scope!
Replies: 7
Views: 570

Re: First stereo scope!

Have a look at this page, and those hyperlinked from it:
http://www.alanwood.net/olympus/macrophoto-stand.html

You should soon find yourself lusting after those neat little hand rests !!

MichaelG.
by MichaelG.
Wed May 26, 2021 7:08 am
Forum: Camera systems and imaging
Topic: solvent information required
Replies: 32
Views: 1029

Re: solvent information required

... I tried cleaning off the residue with the standard lens cleaning solution I use but all it did was smear it around and turn a clear uneven residue into a milky smear. Next, I tried I.P.A. No or not much effect. Then 100% ethyl alcohol. No or not much effect. Then pure dish detergent. Kind of sm...
by MichaelG.
Wed May 26, 2021 6:55 am
Forum: Microscopes and optics
Topic: Bausch & Lomb ‘semi-objective’
Replies: 1
Views: 119

Bausch & Lomb ‘semi-objective’

I have just stumbled across this patent: https://worldwide.espacenet.com/patent/search?q=pn%3DUS3471218A ... which I am sharing as a small tribute to the Inventors, Benford and Rosenberger It covers, in considerable detail, the design of the 7.5x Apochromatic ‘semi-objective’ [ i.e. the 1.5x which w...
by MichaelG.
Tue May 25, 2021 10:52 pm
Forum: Introduce yourself
Topic: polyvar photo tube
Replies: 6
Views: 385

Re: polyvar photo tube

Scarodactyl wrote:
Tue May 25, 2021 10:18 pm
I didn't respond here since I responded to his identical query over in the amateur microscopy group on facebook, but didn't check back in there.

[…]
Thanks for sharing that
... I don’t use facebook

MichaelG.
by MichaelG.
Tue May 25, 2021 9:34 pm
Forum: Illumination Techniques
Topic: Brand new T490B - extremely yellow?
Replies: 21
Views: 1227

Re: Brand new T490B - extremely yellow?

I have to say: I think this is either a faulty camera, or faulty software settings.

Unless the bulb is being severely under-run, it should never produce that colour of light !

MichaelG.
by MichaelG.
Tue May 25, 2021 9:27 pm
Forum: Introduce yourself
Topic: polyvar photo tube
Replies: 6
Views: 385

Re: polyvar photo tube

Welcome, Steve ... I think you might want to chat with Dan : https://www.microbehunter.com/microscopy-forum/viewtopic.php?f=4&t=12844&p=103859&hilit=polyvar#p103859 My guess is that the optics in your custom photo-tube would be fine on the common breed of ‘scope, but are not flat enough to handle th...
by MichaelG.
Mon May 24, 2021 12:33 pm
Forum: Camera systems and imaging
Topic: Camera fov
Replies: 8
Views: 433

Re: Camera fov

Greg,

Given the range of cameras that you have available; I would suggest getting a C-Mount "'TV Lens" of simple design, and using "afocal imaging".

Something in the range of 12mm to 16mm focal length seems to work well.

MichaelG.
by MichaelG.
Mon May 24, 2021 8:05 am
Forum: Pictures and Videos
Topic: Insider photographic tricks for protozoa
Replies: 2
Views: 216

Re: Insider photographic tricks for protozoa

. To the best of my knowledge ... the only currently practical way to address [2] is to reduce the objective lens aperture and thereby increase depth of field. Unfortunately this also reduces optical resolution; so it’s a ‘trade-off’ :( MichaelG. . Edit : __ for a glimpse of the future ... have a lo...