Brunton ECLIPSE 8099 User manual

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BRUNTON ECLIPSE
INSTRUCTION MANUAL
MANUEL D'INSTRUCTIONS

Printed in U.S.A.
form 62-8099 rev 9951
Copyright 1998, The Brunton Company
A subsidiary of Silva Production, AB

ECLIPSE
8099
INSTRUCTION MANUAL
Section 1 – ORIENTATION (Brunton Eclipse 8099) Page(s): 1 - 3
Section 2 – MAGNETIC DECLINATION 4 - 6
Section 3 – 1° GRADUATED DIAL 6
Section 4 – FIELD BEARING (Forward & Reverse Sighting) 6 - 7
Section 5 – DIRECTION OF TRAVEL 7 - 8
Section 6 – TOPOGRAPHIC MAP 8
Section 7 – MAP BEARING (Map & Compass Alignment) 8 - 12
Section 8 – TRIANGULATION 12 - 14
Section 9 – BACK BEARING 14
Section 10 – COORDINATE POSITIONING (UTM & Lat./Lon.) 14 - 18
Section 11 – INCLINATION (Hinge, Card & Graduated Dial) 19 - 21
Section 12 – HEIGHT MEASUREMENT (Level & Sloping Ground) 22 - 23
Section 13 – ADDITIONAL INFORMATION 23
Section 14 – ECLIPSE 8099 SPECIFICATIONS 23
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1 – Orientation: Brunton Eclipse 8099
The Eclipse 8099 compass is a sighting instrument which uses the Earth’s magnetic field to display
a bearing (direction) in degrees. The Eclipse 8099 also contains three clinometer scales to meas-
ure angles from horizontal (0°).
The orientation section provides a description of important Eclipse 8099 parts. A detailed
description of Eclipse 8099 operation is provided throughout the instruction manual.
1.1 Sight Cover (Fig 1)
The sight cover opens to three pre-measured angles – 45°, 90° and 120°. Use 45° for forward
mirror sighting and 120° for reverse mirror sighting.
1.2 Vial (Fig 1)
The vial is a clear fluid filled extrusion containing a needle disk with a red circled "N" (described
in 1.3), blue orienting circle (described in 1.9) and a green clinometer arrow (described in 1.10).
The fluid inside the vial stabilizes the needle disk and clinometer arrow.
1.3 Needle Disk – RED circled "N" (Fig 1)
The needle disk contains a permanently magnetized ferrous material which orients the red
circled "N" to magnetic north. Also printed on the needle disk are "E", "S" and "W", for quick
directional reference.
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1.4 Rotating Azimuth Ring (Fig 1)
The rotating azimuth ring includes a graduated dial (described in section 1.7). The blue
orienting circle and the graduated dial rotate with the rotating azimuth ring.
1.5 Index Lens (Fig 1)
The bubble shaped index lens magnifies the graduated dial (described in 1.7). Also, notice the
green index line in the center of the index lens. Read bearing and inclination at this line.
1.6 Rubber Shoe (Fig 1)
The removable rubber shoe encloses and protects the Eclipse 8099 and a set of quick refer-
ence cards (described in 1.11). Also, the rubber shoe can be used as a pencil eraser for maps.
1.7 Graduated Dial (Fig 2)
The graduated dial is graduated 0° through 360° *, incremented by 1°. Read compass bearing
and inclination at the green index line in the index lens. Note the green and black scales for
forward and back bearing, respectively.
1.8 Viewing Lens (Fig 2)
Use the viewing lens to magnify small writing on a map.
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*0° = 360° (one complete revolution)

1.9 Orienting Circle – BLUE (Fig 2)
Printed on the bottom of the vial, the adjustable blue orienting circle is used in bearing and
clinometer measurements as well as magnetic declination adjustments. Additionally, the blue
orienting line extending across the vial allows for precise bearing and clinometer measurments,
as well as map alignment.
1.10 Clinometer Arrow – GREEN (Fig 2)
Located inside the vial, the weighted green clinometer arrow points to the ground when the
Eclipse 8099 is positioned on its side. Use the green clinometer arrow in combination with the
blue orienting circle, to measure angle of inclination.
1.11 Quick Reference Information Cards (Fig 3)
The quick reference cards supply quick, valuable information on navigation, formulas and scales
for field use.
1.12 Magnetic Declination Scale (Fig 3)
Magnetic declination is the difference between true north and magnetic north, at a position. The
magnetic declination scale, located on the bottom of the azimuth ring, is used in combination
with the adjustable blue orienting circle to set the Eclipse 8099 for magnetic declination.
1.13 Clinometer Index Mark (Fig 3)
Use the clinometer index mark in combination with the green clinometer arrow and the blue
orienting circle to measure angles up or down from the horizon.
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2 -- Magnetic Declination
The Earth is completely surrounded by a magnetic field, and an unobstructed magnetized object
will orient itself with magnetic north and south poles. Magnetic declination (or magnetic variation) is
the difference between true geographic north (north pole) and magnetic north (in northern Canada),
with respect to your position. It is important to note magnetic declination at your position, because
magnetic declination varies and fluctuate slowly at different rates, around the world. (Fig 4)
Contact Brunton for current information at [phone], or e-mail us at [email protected].
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Figure 4

The isogonic chart shows North America, only. Use an isogonic chart, or a current United States
Geological Survey (USGS), Bureau of Land Management (BLM), or another map to determine
magnetic declination at your position. Declination can be east, west or even 0°, from your current
position. At 0° declination, true north and magnetic north are aligned.
Example: If magnetic declination at your position is 15° east, then
magnetic north is 15° east of true geographic north – Figure 5 displays
true geographic north and magnetic north, as indicated in the legends
of USGS and BLM maps.
Most maps use true north as a reference. When adjustment for mag-
netic declination is complete, a bearing measurement will be with
respect to true north, same as the map.
2.1 Magnetic Declination Adjustment
1. Find the magnetic declination at your current position, from a map or chart.
2. Remove rubber shoe, and open both covers.
3. Position the Eclipse 8099 with bottom of clear base facing you. (Fig 6)
Figue 5
True North
Magnetic North
15oE
Your Position
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Figure 6

4. Locate declination scale.
5. Grasp azimuth ring in one hand, and the vial in the other. (Fig 6)
6. Hold azimuth ring stationary, and rotate vial until the arrow on the blue orienting circle points
to the value of magnetic declination at your current position.
· Make sure declination is correct (east or west).
3 – 1 Degree Graduated Dial
The 1° graduated dial has two scales, a green and a black scale and both are incremented by 1°.
(Fig 7) The green scale is for forward sighting and the black scale is for reverse sighting. The
scale increments from 0° to 360°, where 0° & 360° are the same value, and both indicate north.
In addition, 90° indicates east, 180° is south and 270° is west.
4 – Field Bearing
There are two methods to sight a field bearing – forward mirror sighting
and reverse mirror sighting. Since there are two methods and two
scales, please follow instructions carefully for each method.
4.1 Forward Mirror Sighting
This is the most accurate method of sighting a field bearing.
1. Find and set the magnetic declination at your position.
· Refer to section 2.1, Magnetic Declination Adjustment, for help.
2. Open sight cover to 45°.
3. At eye-level, sight object through sight hole, and align sighting
lines and peep sight. (Fig 8) 6
Figure 7
180
0
10
20
30
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
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10
20
30
40
50
60
70
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90
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110
120
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150
160
170
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50
60
70
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90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
Figure 8

4. Rotate azimuth ring until reflection of blue orienting circle
outlines the red circled "N".
· Make sure base is level and sighting lines and peep
sight are aligned.
5. Position Eclipse 8099 close enough to read field bearing
in magnified index lens.
· Read bearing from green scale at the green index
line – 170°, Figure 9.
4.2 Reverse Mirror Sighting
Reverse mirror sighting is another method of sighting a
field bearing.
1. Find and set magnetic declination at your position.
2. Open sight cover to 120°.
3. Hold Eclipse 8099 at waist-level, with sight cover
pointing at you. (Fig 10)
4. Sight object in the mirror and align mirror line with the
reflection of the cover line.
5. Rotate azimuth ring until blue orienting circle
surrounds the red circled "N".
· Make sure mirror line and reflection of cover line are
aligned with sighted object.
6. Read field bearing from the black scale in the magnified
index lens – 170°, Figure 11.
5 – Direction Of Travel
When field bearing to a destination is already known, set
compass to the known field bearing, sight and travel to the
destination. The bearing you travel is known as the direction
of travel. The following example uses forward mirror sighting.
1. Set magnetic declination.
2. Open sight cover to 45°.
3. Rotate azimuth ring until compass is set to known field bearing, using green scale.
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Figure 9
Figure 10
Figure 11

4. Position Eclipse 8099 at eye level and sight
through the sight hole.
5. Pivot your body until reflection of the blue
orienting circle outlines red circled "N".
(Figures 12 & 13)
· Do not rotate azimuth ring.
6. Sight destination or object through sight hole.
7. Travel to destination or object.
Always sight a destination or object in the distance.
Do not follow compass bearing by watching the
compass. If final destination is too far away to see,
sight a tree, mountain or something else and walk
to the object. At object, re-sight compass bearing to another object.
Repeat until final destination is reached.
6 – Topographic Map
A topographic map (topo-map) is a 2-dimensional drawing of 3-dimensional terrain. Hills, valleys,
ridges, cliffs and other terrain are represented through a series of contour lines. Each line
represents constant elevation in meters or feet above sea level. The contour interval (vertical
distance) between each line is indicated in the legend of the topographic map. Lines positioned
close together indicate a rapid change in elevation, while lines further apart indicate a more gradual
change in elevation. With practice, you’ll begin to rec-
ognize many different contours
on a topo-map, and identify the
best possible route from one
position to another. (Fig 14) In
addition, by studying the map it
will be possible to identify
landmarks and determine
positions, bearings and
distances.
7 – Map Bearing
Whether in the field or at home, it is possible to determine a bearing from one position to another
directly from a map. The Eclipse 8099 provides two methods of finding map bearings – map
alignment and compass alignment.
7.1 Map Alignment
Align a topo-map to true north, then find a map bearing.
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Figure 13
Figure 12
Figure 14

This is a popular method because it is possible to compare the map to the actual terrain. The
following examples use a USGS topographic map.
1. Remove rubber shoe.
2. Adjust for magnetic declination.
3. Rotate azimuth ring until compass bearing reads 0° --
green scale, figure 15.
4. With mirrored end of compass pointing to true north on
the map, place the clear base along the map’s margin
(edge of printed map). (Fig 16)
· On maps other than a USGS or BLM, true north-
south may not be aligned with the map’s margin, so
it may be necessary to place the clear base next to
the true north indicator.
5. Rotate map until blue orienting circle outlines the red circled "N". (Fig 16)
· The compass base should remain along the map’s margin.
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Figure 16
Figure 15

The topo-map is now aligned with true north. In the field, it is possible to compare the map to
the actual terrain. Now, find the map bearing from one position to another.
6. Place a "point" at a starting position and an "X" at a destination.
7. Draw a line connecting the "point" and the "X".
8. Open cover and sight cover as far as possible.
9. With both covers pointing to the "X", position clear base next to the line. (Fig 17)
· Do not move the map.
10. Rotate azimuth ring until blue orienting
circle outlines the red circled "N". (Fig
18)
11. Read bearing at the magnified index
line from the green scale. (Fig 18)
This bearing is the map bearing from the starting "point" to the destination.
7.2 Compass Alignment
Another way of finding a map bearing is using the compass alignment method. This method
allows for quick bearing determination, without aligning the map to true north. Use this method
for pre-planning at home, or in the office. The following example uses a USGS topo-map,
where the margin is aligned to true north.
1. Remove rubber shoe.
2. Adjust for magnetic declination, shown on topo-map.
· If your map does not have magnetic declination, adjust to 0° declination.
3. Set a long straight edge next to the map’s margin line (running true north-south).
4. Using a pencil, draw a true north-south line from the bottom to the top of the map.
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Figure 17 Figure 18

· Fill map with additional true
north-south lines, spaced
approximately 1 inch apart,
parallel to map’s margin. (Fig
19)
5. On the map, mark a start position
with a "point" and a destination
with an "X".
6. Draw a line connecting both
marks.
7. Remove the rubber shoe and
open both covers to 180°.
8. With both covers pointing to the
"X", place clear base next to the
line. (Fig 20)
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Figure 19
Figure 20

9. Keeping clear base stationary on the map,
rotate azimuth ring until blue orienting circle
points in a northerly direction, and the red lines
on graduated circle are aligned with the drawn
true north-south lines. (Fig 21)
10.Read bearing from the green scale in magnified
index lens. (Fig 21)
If using a map other than a USGS or BLM map,
check that the map’s margin is aligned to true
north. If not aligned, it is necessary to draw true
north-south lines from the true north indicator
(indicated by an arrow with an "N" or a star).
Then, find map bearing.
8 -- Triangulation
In this section, you will determine field bearings to
three visible landmarks and plot them as map bearings.
The intersection of the bearing lines indicate your approximate position. A landmark can be a
mountain peak, a cliff, or any visible object displayed on your map. The following example uses a
USGS 7.5 minute topo-map, and forward mirror sighting for bearing determination.
1. Adjust for magnetic declination.
2. Find three prominent landmarks in the field.
3. Orient the map to true north.
· See Section 7.1, Map Alignment, for help.
4. Find all three landmarks on the map, place an ‘X’ at the positions and label them ‘1’, ‘2’ & ‘3’.
(Fig 22)
Figure 21
Figure 22
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5. Sight a field bearing to
landmark ‘1’ – 320° (green
scale), this example.
· See Section 4.1, Forward
Mirror Sighting, for help.
6. With both covers open to
180°, place clear base of
8099 next to landmark ‘1’,
on the map.
7. With green scale set to
320°, pivot compass around
landmark ‘1’ until blue
orienting circle outlines red
circled "N". (Fig 23)
8. Draw the 320° map bearing
line using the side of the
base, passing through
landmark ‘1’.
· Your position is some
where along this line.
(Fig 23)
9. Repeat process for
landmarks ‘2’ (50°) and
‘3’ (90°).
Either a point or a small
triangle will form at the
intersection of the three
lines. Your position is at
the point, or within the
small triangle. (Fig 24)
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Figure 23
Figure 24

It is also possible to determine three map bearings using the compass alignment method (section
7.2, Compass Alignment). This method uses the map’s true north, so the map can be positioned
any direction while bearings on a map are determined. With compass set at sighted bearing, rotate
compass about position until the blue orienting circle is in a northerly direction, and red lines on the
graduated dial are aligned with the map’s true north-south lines.
9 – Back Bearing
A back bearing is 180° from another bearing. If you face true north (0° bearing) a back bearing is
directly behind you, or 180°. Another example: If you sight a field bearing of 320° the back bear-
ing will be 140° (320° – 180° = 140°).
When using the Eclipse 8099 there is no
need to add or subtract because there are
two scales (Fig 25). When sighting a bearing
using the green scale, simply determine the
back bearing by reading the black scale. If
you read the black scale for your bearing,
read the green scale for the back bearing.
Figure 25 – Forward and Back Bearing In
Magnified Index Lens
10 – Coordinate Position
Global Positioning System (GPS) receivers
are becoming a valuable navigation tool with
map and compass. GPS receivers require an understanding of coordinate systems to locate a
position. This section explains positioning on a 7.5 minute topographic map using Universal
Transverse Mercator (UTM) grid (grid coordinate system) and latitude and longitude (spherical
coordinate system). The Eclipse 8099 provides Universal Transverse Mercator (UTM) gird scales
on the clear base and reference card 6.
10.1 UTM Coordinate System
Universal Transverse Mercator (UTM) is a grid
coordinate system measured from the Equator (0°
latitude) and a zone meridian. UTM flattens and
divides the Earth into 60 zones, each zone 6° wide
and each with a zone meridian down the center (Fig
26). Since UTM grid is a flat representation of
Earth, grids above 84° N. and below 80° S. latitude
are considerably distorted, and are excluded from
maps. 14
Figure 25
174
oE Long. 180 oE Long.
Zone 60 Zone 1Zone 59
Meridian
Equator
84oN Lat.
80 oS Lat.
Figure 26

A UTM position is measured
using an easting and a northing
from a known reference point
called a datum. If using a Global
Positioning System (GPS)
receiver, document the zone
number and map datum, since
not every map uses the same
local geodetic datum. (Fig 27)
The following example uses a
1:24,000 scale, 7.5 minute topo-
map, with 1,000 meter grid tick
marks, indicated by the 3 small
zeros in the label (4790000mE).
10.1.a -- UTM Grid Coordinate Positioning
This example uses a 1:24,000 map & roamer scale.
1. Locate UTM roamer scales on reference card 6.
2. Identify and document the zone number and map datum (zone 11 & North American
Datum 1927, this example).
3. Identify UTM grid tick marks and labels around the map’s margin.
4. Draw lines connecting equal valued UTM tick marks. (Fig 28)
· A 1,000 meter by 1,000 meter square grid will form.
5. Identify and mark a position on the map with an ‘X’.
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47
91
47
90
47
91
599000m E 601
601 600
600
47
90000m N
599
Northing
Increases
Easting
Increases
Scale:1:24,000
zone11
NAD-27
Figure 28
Mapped, edited, and published by the Geological Survey
Control by USGS and USC&GS
Topography by photogrammeteric methods from aerial
photographs taken 1966. Field checked 1968
Polyconic projection. 1927 North American datum
10,000-foot grid based on Wyoming coordinate system,
west zone
1000-meter Universal Transverse Mercator grid ticks,
zone 12. shown in blue
Fine red dashed lines indicate selected fence lines
Where omitted, land lines have not been established
Figure 27

6. Place corner of roamer scale ("0") at the ‘X’, with scale increasing left and down. (Fig 29)
· Make sure roamer scale is parallel to the UTM grid lines.
7. Count from the ‘X’ to the nearest left easting line – 100, 200, … 500, 600 and 650 m.
8. Add 650 meter to the nearest left easting line.
· 650 m E + 599000mE = 599650mE
9. Count from the ‘X’ to the nearest northing line, below – 100, 200, …600 and 700 m.
10. Add 700 m to the nearest northing line below the ‘X’.
· 700 m N + 4790000mN = 4790700mN
The final UTM coordinate is:
599650mE, 4790700mN (zone 11, NAD-27)
The 1:24,000 roamer scale, in the illustration above, has 50 meter resolution (50 meters
between marks), where the 1:24,000 roamer scale on the 8099 base and quick reference
card 6provide 20 meter resolution.
The grids change with respect to the scales. So, identify the grid values and grid resolution
when using a UTM grid scale other than 1:24,000.
With UTM grid it is possible to identify a position within 100 meters of the actual position,
without a scale. After identifying tick marks around the map’s margin, and drawing the grid
lines, simply estimate the distance from the lower left-hand corner of the grid that surrounds the
‘X’. Remember, eastings always increase to the right, and northings always increase up.
10.2 Latitude And Longitude Coordinate System
Latitude and longitude scales are not provided with the Eclipse 8099, but determining a position
using a latitude and longitude scale, or a ruler is an essential navigation skill.
Latitude and longitude is a spherical coordinate system measured from the Earth’s center point
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47
91
47
90
47
91
599000m E 601
601 600
600
47
90000m N
2
1:24k
(50 meters)
4
6
8
1k
4
6
8
1k
599
Figure 29

to locations on its surface. A position on Earth is measured in degrees ( ° ), minutes ( ‘ ) and
seconds ( " ), where 60 second = 1 minute & 60 minutes
= 1 degree. Very similar to time on a clock. Measurements
begin at the Equator (0° latitude) and the Prime Meridian
(0° longitude).
In Figure 30, the position is read:
45° 00’ 00" N. Lat. = 45 degrees, 0 minutes and 0
seconds north latitude
60° 00’ 00" W. Long. = 60 degrees, 0 minutes and 0
seconds west longitude.
10.2.a -- Latitude And Longitude
Coordinate From A Topo-Map
All 7.5 minute USGS topo-maps are
bound by 7.5 minutes of latitude and 7.5
minutes of longitude. The four corners
of the map are identified by coordinates
in latitude and longitude. In addition, tick
marks are placed every 2’ 30" around
the margin of the map, with crosses in
the middle. The 4 crosses identify the
intersections of the 2’ 30" tick marks.
(Fig 31)
10.2.b -- Map Preparation
1. Identify the tick marks, and draw lines
connecting the tick marks. (Fig 32)
· The lines produce 9 small
rectangles.
2. Identify and mark a position on the
map with an ‘X’.
3. Use a 1:24,000 latitude-longitude
scale to determine the coordinate
position of the ‘X’ (not available with
the Eclipse 8099).
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60o40o20o0o
20o
40o
60o
60oW.
45oN.
45o00' 00" N. Latitude
60o00' 00" W. Longitude
80o
W
E
Longitude
Increase
Latitude
Increase
N
S
Figure 30
43o00'
108o22' 30"
43o00'
108o30'
25'
27' 30"
27'30" 25'
2' 30"
5'
5'
2' 30"
108o22' 30"108o30' 43o07' 30"
43o07' 30"
Figure 31
43o00'
108o22' 30"
43o00'
108o30'
108o22' 30"108o30' 43o07' 30"
43o07' 30"
Figure 32