I need to measure some Pollen grains.

[BKF Admin]

I collected some Pollen yesterday to see what the bees are bringing in.

So far I have worked out:

Aster
Sunflower
Sweetcorn
Ragwort (Yuck!)

The problem I have is I dont have an Ocular scale on any of my eyepieces.

I want to measure the Sunflower pollen@ 42um and the Michaelmas daisy(Aster)@27um.

I am finding it hard to tell the difference between the 2 types without a way of measuring.

 

[oliver90owner]

I know that some companies used to supply a given particle size in suspension (for standardising particle size counting instruments) in various sizes in days of old. Last time I used one was probably best part of 30 years ago.......

Regards, RAB

 

[Rosti]

Reference particles

o90o is right, they are still in use and available. Try Brookhaven (not sure of an address though)

 

[JCBrum]

The problem I have is I dont have an Ocular scale on any of my eyepieces.

I want to measure the Sunflower pollen@ 42um and the Michaelmas daisy(Aster)@27um.

I am finding it hard to tell the difference between the 2 types without a way of measuring.

If you unscrew the top of your eyepiece you can see whether there is a graticule shelf inside and maybe acquire a micrometer graticule.

You may also need a stage micrometer to calibrate the eyepiece graticule.

Neither is particularly expensive and may be obtained from Brunel Microscopes.

http://www.brunelmicroscopes.co.uk/accessory.html

See their guidance pages on micrometer use. Hope this helps. Apologies if you already know about it.

 

[BKF Admin]

Thanks JC.

My 1963 microscope box does have a note inside the door that say's that the 15x eyepiece lens had been calibrated for measurment,so I think someone over time must of removed the graticule.

I will go check Brunel.

Thanks
Mark.

 

[Bcrazy]

Admin.

Do you have the X&Y measurements on your stage?
If so you should be able to get an approximate size from that.

Regards;

 

[BKF Admin]

Yes I have x and y.
How is it done ?

 

[Bcrazy]

Re X&Y measurements I know there is a formula for working the size out but for the life of me do not know what it is. I have even tried 'Google' for help but to no avail.

Regards;

 

[oliver90owner]

X&Y measurements I know there is a formula for working the size out

This wil all be related to the pitch of the screw thread, will it not?

Regards, RAB

 

[Bcrazy]

This wil all be related to the pitch of the screw thread, will it not?

I don't think its anything to do with the mechanics of the micrometre readings but its a proper formula that allows measurements to be use using the graticule's on the stage.

Is there a professor that anyone might know who has worked with microscopes, as they will definitely know?

Regards;

 

[JCBrum]

In order to use the mechanical stage as a micrometer you still need a reference of some sort in the eyepiece. Cross hairs would suffice, and if you're careful (and have fine hair) you could put these into the eyepiece yourself, on the graticule shelf, using gum to fix.

Then, as o90o says, you need to know the pitch of the screw on your mechanical stage. You can measure this by traversing (using the stage) an object of known size past the cross hairs and counting the turns required.

Then by dividing the dimension of the object by the turns required you can find out the distance traversed per turn. You have now calibrated your stage screw for that particular eyepiece/objective combination.

You then put the slide with the unknown object on the stage, and see how many turns it takes to traverse past the cross hairs. You now know its real size.

Hope this helps. Good luck.

 

[JCBrum]

p.s. You could arrange with Brunel to meet up at one of the shows, and have them fit your microscope out with the necessary micrometers for you.

 

[BKF Admin]

One of the shows ?

Do they attend the national honey show ?

 

[JCBrum]

Dunno, ask 'em. They were at the spring convention/Stoneleigh.

 

[JCBrum]

I think they're in Chippenham,Wilts. How far is that from you ?

 

[Bcrazy]

Admin,
All you need is an eye (optical) graticule from 1 to 10 with sub divisions, and use that in conjungtion with the measurements sheet you have, and your worries will be over.

Regards;