National 156, 156-S, 157 User Instruction

National Optical & Scientific Instruments Inc.

6508 Tri-County Parkway

Schertz, Texas 78154

Phone [phone] Fax [phone]

INSTRUCTIONS FOR MODE LS

156, 156-S, 157

COMPOUND BIOLOGICAL MICROSCOPES

Copyright © 1/2/01

National Optical & Sc i ent i fic Instrument I nc.

Model 157 is illustrated below

Models 156 & 156-S Monocular Head

Base

Illuminator condenser

Iris diaphragm lever

Swing-out filter holder

Abbe condenser 1.25 N.A.

Revolving nosepiece

Objective lenses

Specimen holder

Viewing head of microscope

Interpupillary scale

Widefield 10x/18

Sliding interpupillary adjustment,

Mark on side of eyepiece tube

Head locking screw

Arm of microscope stand

Knobs controlling X and Y

Coarse focus knob

Fine focus knob

Power on/off switch and

fuse holder on back of base

Tension adjustment collar

Rack stop adjustment screw

Knurled locking screws for securing

eyepiece

Stage

Knurled diopter ring

grips located on both left and right

side of diopter scale

for indexing diopter reading

(mechanical stage)

specimen holder to stage

(behind focus knob on left side)

movement of mechanical stage

INTRODUCTION
Thank you for your purchase of a National microscope. It is a well built, precision instrument carefully checked to

assure that it reaches you in good condition. It is designed for ease of operation and years of carefree use. The
information in this manual probably far exceeds what you will need to know in order to operate and maintain your
microscope. However, is provided to answer questions which might arise, and to help you avoid any maintenance
expense that may be unnecessary.

Your new compound microscope is a high performance microscope with high quality Achromatic objective lenses
that provide good resolution and optical centering. The microscope is designed with a built-in mechanical stage
providing a travel range of 70mm x 32mm in the X and Y direction with graduation reading up to 0.1mm for
accurate positioning of specimen. Also included is a ball bearing quadruple nosepiece, separate coarse and fine
focus, with slip clutch, to protect focus mechanism, spiral mounted N.A. 1.25 Abbe condenser and built-in 5 watt
fluorescent light source.

Carefully read these instructions before operating microscope. They will permit you to use your new microscope to
its fullest capability. Nomenclature used to describe components and controls is identified by referring to diagram
on page 2.

UNPACKING
The microscope and accessories have been carefully packed to assure they reach you in the best possible

condition. Do not discard packing container or materials until all components are accounted for. Save packing
container in case microscope needs transporting to another location or shipped for repairs.

156 Monocular: Stand with head, one eyepiece, one rubber eyeshield, three objectives, condenser,

specimen holder, blue filter, dust cover, 0.9mm “L” type key wrench (for eyepiece socket
set screw and tension adjustment collar) and 2mm “L” type key wrench (for rack stop
adjustment).

156-S Monocular: Stand with head, one eyepiece, one rubber eyeshield, four objectives, condenser,

specimen holder, blue filter, dust cover, 0.9mm “L” type key wrench (for eyepiece socket
set screw and tension adjustment collar) and 2mm “L” type key wrench (for rack stop
adjustment).

157 Binocular: Stand wi th head, two eyepieces, two rubber eyeshields, four objectives, condenser,

specimen holder, blue filter, dust cover, 0.9mm “L” type key wrench (for tension adjustment
collar) and 2mm “L” type key wrench (for rack stop adjustment).

DESCRIPTION OF COMPONENTS

1. EYEPIECE (ocular lens): Lens closest to the eye, magnifies the primary image formed by the objective lens.

2. OBJECTIVE TURRET (nosepiece): Revolving turret which holds objective lenses, permits changes of
magnification by rotating different powered objective lenses into optical path. Reverse position permits easier
access to stage when positioning specimen slides.

3. OBJECTIVE LENS: Lens closest to the object being viewed, forms first magnified image of the specimen.

4. MECHANICAL STAGE: Permits precise, mechanical manipulation of the specimen slide.

5. STAGE: Platform of the microscope where the specimen slide is placed.

6. CONDENSER: A 1.25 N. A. Abbe condenser lens positioned under center of stage, condenses light rays from
substage illumination and fills the back lens element of objective lens to improve image resolution.

7. IRIS DIAPHRAGM: Attached to bottom of Abbe condenser, controls aperture of light by moving control lever
left or right.

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