Brunton Eclipse 8097 User manual

E C L I P S E
8097
INSTRUCTION MANUAL
Section 1 – ORIENTATION (Brunton Eclipse 8097) Page(s): 1 - 2
Section 2 – MAGNETIC DECLINATION 2 - 4
Section 3 – FIELD BEARING 4 - 5
Section 4 – DIRECTION OF TRAVEL 5
Section 5 – TOPOGRAPHIC MAP 5 - 6
Section 6 – MAP BEARING (Map, Compass & Protractor Alignment) 6 - 8
Section 7 – TRIANGULATION 8 - 10
Section 8 – BACK BEARING 10
Section 9 – COORDINATE POSITIONING (UTM Grid) 10 - 12
Section 10 – CLIP + ANIMAL ALERT / RESCUE WHISTLE 13
Section 11 – POCKET / MAP CLIP 13
Section 12 – ADDITIONAL INFORMATION 13
Section 13 – ECLIPSE 8097 SPECIFICATIONS 13
i

1 -- Orientation: Brunton Eclipse 8097
The Eclipse 8097 compass is a sighting instrument which uses the Earth’s magnetic field to display
a bearing (direction) in degrees, with respect to true or magnetic north.
The orientation section provides a description of the important Eclipse 8097 parts. A detailed
description of 8097 operation is provided throughout the instruction manual.
1.1 Vial (Fig 1)
The vial contains a needle disk with a red circled "N" (described in 1.2) and a blue orienting
circle (described in 1.3). The fluid inside the vial stabilizes the needle disk.
1.2 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.
1.3 Orienting Circle – BLUE (Fig 1)
Use the adjustable blue orienting circle for bearing measurement and magnetic declination
adjustment. Additionally, the blue line allows for accurate map alignment.
1.4 Graduated Dial (Fig 1)
The graduated dial is graduated 0° through 360°, incremented by 1°.
1.5 Rotating Azimuth Ring (Fig 1)
The rotating azimuth ring includes the graduated dial (described in 1.4). The blue orienting
circle and graduated dial rotate with the azimuth ring.
1
1.2
1.1
1.3
1.11
1.4
1.6
1.7
1.8
1.10
1.9
1.5
Figure 1

Use the isogonic chart (Fig 3), or 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.
1.6 Index Lens (Fig 1)
The bubble shaped index lens magnifies the graduated dial. Also, notice the green index line in
the center of the index lens. Read bearing at this line.
1.7 Viewing Lens (Fig 1)
Use the viewing lens to magnify small writing on a map.
1.8 Double Prism Alignment System (Fig 1)
With a partner, use the double prism alignment system to sight an object or destination.
1.9 Clip + Animal Alert / Rescue Whistle (Fig 1)
The lanyard clip provides hands-free storage of the 8097 around your neck, wrist, etc. Also,
use the whistle for a rescue signal or animal alert.
1.10 Pocket / Map Clip (Fig 1)
The detachable pocket/map clip fastens to the 8097, clips to maps, pockets, etc.
1.11 Map Scales (Fig 1)
The map scales on the clear base allow for quick position and distance calculations.
1.12 Magnetic Declination Scale (Fig 2)
Use the magnetic declination scale, on the bottom of the azimuth ring, with the adjustable blue
orienting circle to adjust for
magnetic declination at your
position.
1.13 Protractor (Fig 2)
Use the protractor and the center
ing template (1.14) to determine
angles and map bearings.
1.14 Centering Template (Fig 2)
The centering template allows for
accurate use of the protractor.
2 -- Magnetic Declination
Magnetic declination (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 fluctuates slowly at different
rates, around the world. (Fig 3) Contact Brunton for most recent information at [phone], or
e-mail us at [email protected].
23
Figure 3
Figure 2
1.14
1.12
1.13

Example: If magnetic declination at your position is 15° east, then
magnetic north is 15° east of true geographic north. Figure 4 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 magnetic 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. Locate declination scale on the bottom
of the azimuth ring. (Fig 5)
3. Grasp azimuth ring in one hand, and
the vial in the other. (Fig 5)
4. Hold azimuth ring stationary, and
rotate vial until the arrow on the blue
orienting circle points to the value
of magnetic declination, at your
position.
· Make sure declination is correct
(east or west).
3 – Field Bearing
For the best accuracy, have a partner stand directly above the Eclipse 8097 and adjust the azimuth
ring, while you sight an object through the double prism.
3.1 Forward Sighting With Partner
1. Adjust 8097 for magnetic declination at your position.
· Refer to section 2.1, Magnetic Declination
Adjustment, for help.
2. Sight object between the double prism alignment
system. (Fig 6)
· To align the sight with center of the vial, make
sure all four triangles are the same size.
3. Have partner rotate azimuth ring until the blue
orienting circle surrounds the red circled "N".
(Fig 7)
4
Figure 4
Figure 6
Figure 5

4. Read bearing -- 170°. (Fig 7)
To guarantee accuracy, switch with your partner
and have your partner re-sight the object. Both
bearings should be within 1° of each other.
You can sight a field bearing without a partner,
but the accuracy diminishes.
4 – Direction Of Travel
When field bearing to a destination is already
known, set compass to known field bearing,
sight bearing and travel to the destination. The
bearing you travel is known as the direction of
travel.
1. Adjust 8097 for magnetic declination.
2. Rotate azimuth ring until set at known field bearing. (Fig 8)
3. Pivot your body until vial displays “circle over circle”. (Figs 9 & 10)
4. Sight distant object or destination at field bearing, and
travel to it.
Do not travel 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.
5 -- 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. Find the contour interval in the
legend of the topographic map.
5
Figure 7
Figure 8
Figure 9
Figure 10

7. Position clear base next to the
line. (Fig 14)
· Do not move the map.
8. Rotate azimuth ring until vial dis
plays “circle over circle”. (Fig 15)
9. Read bearing.
6.2 Compass Alignment
The compass alignment method allows for quick bearing determination, without aligning the
map to true north. This is not as
accurate as the map alignment
method, but it can be used for
pre-planning at home or in the office.
1. Adjust for 0° magnetic declination.
2. Draw true north-south lines on a
map, spaced approximately 1 inch
apart. (Fig 16)
3. Mark a start position with a "point"
and a destination with an "X".
4. Draw a line connecting both marks.
5. Place clear base next to the bearing line.
(Fig 17)
7
With practice, you’ll begin to
recognize many different contours
on a topo-map, and identify the
best possible route from one
position to another. (Fig 11)
6 – 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 8097
provides three methods of finding map bearings - map, compass and protractor alignment methods.
6.1 Map Alignment
Map alignment is the most accurate method. Align map to true north, then find a map bearing.
Using this method, it is possible to compare the map to the actual terrain.
1. Adjust 8097 for magnetic declination.
2. Rotate azimuth ring until compass reads 0°. (Fig 12)
3. Place clear base along the map’s true north-south margin (edge of
printed map). (Fig 13)
· 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.
4. Rotate map until vial dis
plays “circle over circle”.
(Fig 13)
The topo-map is now aligned
with true north, and it is
possible to compare the map
to the actual terrain. Now, find
the map bearing.
5. Place a "point" at a starting
position and an "X" at a
destination.
6. Draw a line connecting
both marks.
Figure 16
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 17
6

6. Rotate azimuth ring until blue orienting circle points to the
map’s true north. (Fig 18)
· Align blue line in vial and red lines on graduated dial with
drawn true north-south lines.
7. Read bearing.
6.3 Protractor And Centering Template
Use the centering template and the protractor to determine a map
bearing.
1. On the map, place a "point" at a starting position and an "X" at a destination.
2. Draw a bearing line connecting both marks.
3. Determine true north from the map’s legend.
4. Draw a true north-south line through the "point".
5. Place the centering template directly over the point".
6. Draw an outline around the "point". (Fig 19)
6.3.a -- 0° to 180° Map Bearing
1. With 0° on the protractor pointing north, position
center of needle disk within the outline.
2. Using the 0° to 180° scale, read bearing where
the bearing line intersects the protractor. (Fig 20)
6.3.b -- 181° to 360° Map Bearing
1. With 0° on protractor pointing south,
position center of needle disk within the
outline.
2. Using the 181° to 360° scale, read bearing
where the bearing line intersects the
protractor. (Fig 21)
7 – Triangulation
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.
8
Figure 18
Figure 19
Figure 20
Figure 21
N
N

1. Adjust for magnetic declination.
2. Find three prominent landmarks in the field.
3. Orient map to true north. See section 6.1, Map Alignment, for help.
4. Find and mark all three landmarks with an ‘X’, and label them ‘1’, ‘2’ and ‘3’. (Fig 22)
5. Sight a field bearing to landmark ‘1’ (320°). See
section 3.1, Forward Sighting, for help.
6. Place clear base next to landmark ‘1’, on the map.
7. With bearing at 320°, pivot compass around land-
mark ‘1’ until “circle over circle”. (Fig 23)
8. Draw map bearing passing through landmark ‘1’,
using the clear base.
· Your position is somewhere along this line.
9. Repeat process for landmarks ‘2’ (50o) and ‘3’ (90o).
Either a point or a small triangle
will form at the intersection of the
three lines. Your position is
within the triangle. (Fig 24)
It is also possible to determine
three map bearings using the
compass alignment method (6.2,
Compass Alignment). This
method uses the map’s true north,
so the map can be positioned any
9
Figure 22
Figure 24
Figure 23

The following example uses a 1:24,000 scale, topo-map, with 1,000 meter UTM grid tick
marks, indicated by three small zeros in the easting label, 4790000mE.
9.1.a -- 1:24,000 scale UTM Grid Coordinate Positioning
1. Identify and document the zone number, map datum and scale.
(zone 11, North American Datum 1927 & 1:24,000, Figure 27).
2. Identify UTM grid tick marks and labels around the map’s margin.
3. Draw lines connecting equal value UTM tick marks. (Fig 27)
· 1,000 meter by 1,000 meter grid will form.
4. Identify and mark a position on the map with an ‘X’.
5. Place "0" of 1:24,000 UTM scale at the ‘X’, with scale increasing left . (Fig 28)
· Make sure UTM scale is parallel to the northing grid lines.
6. Count from the ‘X’to the nearest left easting line – 100, 200, … 500, 600 and 650 m.
7. Add 650 meter to the nearest left easting line.
· 650 m E + 599000mE = 599650mE
direction while bearings on a map are determined. With magnetic declination set at 0°, and
compass set at sighted bearing, rotate compass about position until the red lines on the graduated
dial and the blue line in the vial are aligned with the map’s true north-south lines. Then, draw
bearing lines.
8 – 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°. Keep all bearings between 0° and 360°, and follow the steps below
to determine back bearing.
Calculate back bearing:
1. If the bearing is from 0° to 180°, add 180° to calculate back bearing.
2. If the bearing is from 181° to 360°, subtract 180°.
9 – Coordinate Position
Global Positioning System (GPS) receivers are becoming valuable navigation aids 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 topo-
graphic map, using the 1:24,000 Universal Transverse
Mercator (UTM) grid scale, on the clear base.
9.1 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 25) UTM grid above 84° N. and below 80° S.
latitude is considerably distorted,
and is excluded from maps.
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
(Fig 26), then enter into your GPS
receiver.
10 11
4791
4790
4791
599000m E 601
601 600
600
4790000m N
599
Northing
Increases
Easting
Increases
Scale: 1:24,000
zone 11
NAD-27
Figure 27
4791
4790
4791
601 600 599
599000m E 601
600
4790000m N
1:24k
(50 meters)
4
6
8
1k 20
Figure 28
174 oE Long. 180 oE Long.
Zone 60 Zone 1Zone 59
Meridian
Equator
84 oN Lat.
80 oS Lat.
Figure 25
Mapped,edited,andpublishedbytheGeologicalSurvey
Control by USGS and USC&GS
Topography by photogrammetric methods from aerial
photographstaken 1966. Fieldchecked 1968
Polyconicprojection.1927 North American datum
10,000-footgridbasedonWyomingcoordinatesystem,
west zone
1000-meterUniversalTransverseMercatorgridticks,
zone 12. shown in blue
Finereddashedlinesindicateselectedfencelines
Whereomitted,landlineshavenotbeenestablished
Figure 26

10 – Clip + Animal Alert / Rescue Whistle
An animal alert / rescue whistle is included with the Eclipse 8097. Remove whistle from 8097 by
depressing and holding retaining latch on the bottom of the
whistle, and pull.
To use whistle, position horizontally with retaining latch
opening up. (Fig 30) Cover retaining latch opening with a
finger. Be careful not to cover the airway exit hole,
underneath. Completely cover the airway entry hole and blow.
Vary frequency by changing finger pressure over retaining
latch opening, while blowing.
11 – Pocket / Map Clip
An additional feature of the Eclipse 8097 is the pocket / map clip that fits into the same terminal as
the lanyard clip. Clip compass to shirts, pant pockets, or maps for orienteering or route determina-
tion. (Fig 31) Remove the pocket / map clip by depressing and holding the retaining latch on the
bottom of the clip, and pull.
12 – Additional Information
Before heading into the field, practice
using the Eclipse 8097 and a map in
a familiar area. Also, carefully re-read
the instruction manual to gain a full
understanding of 8097 applications.
Become an expert with a map and
compass, and educate yourself on
survival techniques.
13 – Eclipse 8097 Compass Specifications
Magnetism: NdFeB needle disk
Accuracy: Bearing -- ± 1° accurate reading (0.5° readable)
Size: Length – 4.6 in. (11.8 cm)*
Width – 2.6 in. (6.7 cm)*
Weight – 1.6 oz (45 g)*
*-- Excluding lanyard, pocket / map clip and animal alert / rescue whistle
8. Rotate clear base until the "0" is at the ‘X’, and scale increases down. (Fig 29)
· Make sure UTM scale is parallel to the easting grid lines.
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:
zone 11 599650 mE 4790700mN datum: NAD-27
The 1:24,000 UTM scale, in Figures 28 & 29 , have 50 meter resolution (50 meters between
marks), where the 1:24,000 UTM scale on the 8097 base provides 20 meter resolution. Also,
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 grid lines,
simply estimate the distance from the lower left-hand corner of the square grid that surrounds
the ‘X’. Remember, eastings always increase right and northings always increase up.
9.1.b -- Metric UTM Grid Coordinate Positioning
If using the metric version 8097, use the cm / mm scale for position determination.
1:25 000 scale 1:50 000 scale 1:250 000 scale
4 cm = 1000 m 2 cm = 1000 m 4 cm = 10 000 m
1 mm = 25 m 1 mm = 50 m 1 mm = 250 m
12 13
4791
4790
4791
601 600
4790000m N
599
599000m E 601
600
4681k
2
0
1:24k
(50 meters)
Figure 29
Figure 30
Figure 31