Where to get microscope slides for measurements?

Discussion in 'Plants: Science and Cultivation' started by Kada, Oct 3, 2008.

  1. Kada

    Kada Active Member 10 Years

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    i wanted to post this in the plant sourcing area, but i cant seem to post there...hope this is ok to post.

    what i want are some slides that i can use to measure small things (like spores and pollen, up to seeds). When i search for "stage micrometers" all i can find is $150+ slides!

    is this normal? are there any alternatives? all i need is a simple glass slides with etched measurements....i dont get why so expensive.

    any help would be GREATLY appreciated!!!!
     
  2. bjo

    bjo Active Member 10 Years

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    Hi,

    stage micrometers are very expensive, but unless you are doing scientific work requiring a very high degree of accuracy + precision you probably do not need one. To make measurements with the microscope, you do need (and may already have ) an eyepiece graticule (=reticule = reticle) - a scale built into the eyepiece. If you do not have one they are relatively cheap. One potential source is someone selling an eyepiece on EBay - they often contain a graticule - check the listing.

    Having got the graticule (which will normally have a scale of 0 - 100), you need to calibrate it against a known length. Ideally this would be a "stage micrometer", but at low magnifications, using the x4 objective and using the x 10 objective you can use a normal millimetre ruler.

    You will probably find that using the x4 objective, 25 graticule units corresponds (more or less) to 1 millimetre. In this case each graticule unit = 40 micrometres.

    Similarly, you will probably find that using the x10 objective, 100 graticule units corresponds (more or less) to 1 millimetre. In this case each graticule unit = 10 micrometres.

    In each case, the relationship may not be exact because of small differences in the optical system of your microscope - this is why you need the stage micrometer for exact work.

    You cannot calibrate the higher power objectives directly in the way I suggest with a ruler, but the calibration follows the magnification so:

    x40 objective 1 graticule unit ~2.5 micrometres
    x100 objective 1 graticule unit ~ 1 micrometre

    You might like to read the following article:

    http://www.microscopy-uk.org.uk/mag...microscopy-uk.org.uk/mag/artdec99/cwnano.html

    You only need to calibrate your microscope once, therefore another option would be to see if you can borrow a stage micrometer from a university, college etc or bring your mike into the college and calibrate it there.

    Good Luck
    BrianO
     
  3. Kada

    Kada Active Member 10 Years

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    excellent thanks a lot! i need pretty exact measure as it is for plant and fungus identification and study. guess there is no cheap way to do it...at least i know they are expensive and i dont find out after they were cheap.

    thanks again.
     

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