Brunton ECLIPSE 8099 User manual

ECLIPSE8099
INSTRUCTION MANUAL
Section 1 – ORIENTATION (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./Long.) ......... 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°) to overhead (90°).
The orientation section provides a description of important compass parts. A detailed description of
Eclipse 8099 operation is provided throughout the instruction manual.
1.1 Sight Cover (Figure 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 (Figure 1)
The vial is a clear, fluid-filled extrusion containing a needle disk with a red circled "N" (described
in 1.3), a 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" (Figure 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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50

1.9 Orienting Circle – BLUE (Figure 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 measurments and map align-
ment in some instances.
1.10 Clinometer Arrow – GREEN (Figure 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 (Figure 3)
The quick reference cards supply quick, valuable information on navigation, formulas and scales
for in-field use.
1.12 Magnetic Declination Scale (Figure 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 adjust the compass for magnetic declination.
1.13 Clinometer Index Mark (Figure 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 (0°).
1.4 Rotating Azimuth Ring (Figure 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 (Figure 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 (Figure 1)
The removable rubber shoe encloses and protects the compass and a set of quick reference
cards (described in 1.11). Also, the rubber shoe can be used as a pencil eraser for maps.
1.7 Graduated Dial (Figure 2)
The graduated dial is graduated from 0° through 359°, in 1° increments. Read compass bear-
ing 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 (Figure 2)
Use the viewing lens to magnify small writing on a map.
1.9 - Orienting Circle (Blue)
Map Scales
1.8 - Viewing Lens
1.7 - Graduated Dial
Cover
Figure 6
1.10 - Clinometer Arrow (Green)
2 3

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 compass with bottom of clear base facing you (figure 6).
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 (figure 4).
Visit the National Oceanic and Atmospheric Association (NOAA) on the Internet at
www.ngdc.noaa.gov/cgi-bin/seg/gmag/fldsnth1.pl for current magnetic declination values.
Figure 5
True North
Magnetic North
15oE
Your Position
Figure 6
4 5
ISOGONIC CHART
East Declination West Declination
Figure 4
0°

4. Locate declination scale.
5. Grasp black azimuth ring in one hand, and the vial in the other (figure 6).
6. Hold black 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.
· Adjust orienting circle toward “EAST” for east declination and “WEST” for west declination.
3 – 1 Degree Graduated Dial
The 1° graduated dial has two scales, a green scale and a black scale (figure 7). The green scale
is for forward sighting and the black scale is for reverse sighting. The scale increments from 0° to
359°, where 0° indicates north. In addition, 90° indicates east, 180° is south and 270° is west.
4 – Field Bearing
The following instructions describe two methods of sighting a field bear-
ing – 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. Determing 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, look through sight hole, and align object with the
sight hole, cover line and peep sight (figure 8).
0
350
340
330
320
130
230
310
240
120
300
290
110
250
280
260
100
90
270
220
140
150
210
160
200
170
190
180
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20
30
40
50
60
70
80
4. Rotate azimuth ring until reflection of blue orienting circle,
in the mirror, outlines the red circled "N".
· Make sure base is level and sighting lines and peep
sight are aligned.
5. Position the compass 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 compass at waist-level, with sight cover pointing
towards you (figure 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 – 50° (figure 10).
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. This example uses forward mirror sighting.
1. Set magnetic declination.
2. Open sight cover to 45°.
3. Rotate azimuth ring until compass is set to a known field bearing ( 270° ), using the green scale
in this example.
Figure 9
Figure 10
Figure 11
Figure 8
350
170
Figure 7
50
230
50
Cover Line
Mirror Line
6 7
Peep Sight
Cover Line
Sight Hole

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 - figure 16).
· On maps other than USGS or BLM, true north may
not be aligned with the map’s margin, so it might be
necessary to place the clear base next to the true
north indicator, on the map.
5. Rotate map until blue orienting circle outlines the red circled "N" (figure 16).
· The compass base should remain along the map’s margin.
4. Position compass 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 the 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 (figure 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 following instructions provide two methods of finding map bearings – map
alignment and compass alignment.
7.1 Map Alignment
Using this method, you align a topo-map to true north, then it is possible to find a map bearing.
Figure 13
Figure 12
Figure 14
Figure 16
Figure 15
90
270
180
0
0
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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 the cover and sight cover as far as possible.
9. With both covers pointing to the "X", position clear base next to the line (figure 17).
· Do not move the map.
10. Rotate azimuth ring until blue orienting
circle outlines the red circled "N"
(figure 18)
11. Read bearing at the magnified index
line from the green scale (figure 18).
This bearing is the map bearing from the starting "point" (Camp) to the destination (Carrie’s
Cave). Use this compass bearing, in the field, to find Carrie’s Cave from the Camp.
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, at base camp, or in the office. The following example uses a USGS
topo-map, where the left and right margins are aligned to true north.
1. Remove rubber shoe.
2. Adjust compass for magnetic declination.
3. Set a long straight edge next to the map’s margin line (running true north-south).
4. Using a pencil, lightly draw a true north-south line from the bottom to the top of the map.
Figure 17 Figure 18
220
40
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· Fill map with additional true
north-south lines, spaced
approximately 1 inch apart,
parallel to map’s margin
(figure 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 (figure 20).
11
Figure 19
Figure 20

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
compass 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" (figure 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
(figure 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 (figure 24).
9. Keeping the 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 (figure 21).
10.Read bearing from the green scale in magnified
index lens (figure 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 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’
(figure 22).
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Figure 21
Figure 22
Figure 23
Figure 24
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1
2
3

A UTM position is measured
using an easting (E) and a north-
ing (N) from a known reference
point called a datum. If using a
GPS receiver, document the zone
number and map datum, indicat-
ed on the map, since not every
map uses the same local geo-
detic datum (figure 27).
The following example uses a
1:24,000 scale, USGS, 7.5
minute topo-map, with 1,000
meter grid tick marks. The 1,000
meters is 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 & a 1:24,000 roamer scale.
1. Locate the 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 value UTM tick marks (figure 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’.
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 (figure 25). When sighting a bearing,
using the green scale (forward mirror sight-
ing), simply determine the back bearing by
reading the black scale. If you read the black
scale for your bearing (reverse mirror sighting,
read the green scale for the back bearing.
Figure 25 – Forward and Back Bearing
10 – Coordinate Position
Global Positioning System (GPS) receivers
are becoming a valuable navigation tools
which compliment a map and compass. GPS receivers require an understanding of coordinate
systems to locate a position. This section explains positioning on a USGS 7.5 minute, topographic
map using Universal Transverse Mercator (UTM) grid (grid coordinate system) and latitude and lon-
gitude (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
(figure 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 15
Figure 25
174 oE Long. 180 oE Long.
Zone 60 Zone 1Zone 59
Meridian
Equator
84 oN Lat.
80 oS Lat.
Figure 26
4791
4790
4791
599000m E 601
601 600
600
4790000m 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 11. shown in blue
Fine red dashed lines indicate selected fence lines
Where omitted, land lines have not been established
Figure 27
140
320