Skip to main content

Firefighter Math: 6.3 Back Azimuth and Backsighting

A back azimuth is a projection of the azimuth from the origin to the opposite side of the azimuth circle. There are 360 degrees in the azimuth circle, so the opposite direction would be 180 degrees (half of 360 degrees) from the azimuth.

A back azimuth is calculated by adding 180° to the azimuth when the azimuth is less than 180°, or by subtracting 180° from the azimuth if it is more than 180°. For example, if an azimuth is 320°, the back azimuth would be 320° - 180° = 140°. If the azimuth is 30°, the back azimuth would be 180° + 30° = 210°.

Backsighting is a method of sighting that uses an azimuth reading taken backwards. Backsighting uses the azimuth sight and turns it around to find the way back to the original starting point.

Example 1 - Susan is at the lookout point and sights a fire at 100°. She starts out in the direction of the fire, but soon loses sight of the fire. Susan turns around and backsights to the lookout point. It is 260°. How many degrees off course is she? Which direction does Susan need to move to get back on course?

Step 1. The azimuth, 260°, is more than 180°, so subtract 180° from the azimuth. 260°– 180°= 80°

Step 2. Subtract the calculated backsight reading from the original azimuth reading.
100° - 80° = 20°

Susan is 20 degrees off course. 

Because the new azimuth (80°) is less than the original (100°), Susan needs to move to the left to make the back azimuth larger by 20°. When the lookout line of sight back azimuth of 280° is read, she can proceed along the line toward the fire. 

Susan needs to move to the left by 20 degrees. 

NWCG Latest Announcements

Quarter Three Materials for the 2025-2026 Wildland Fire Leadership Campaign Now Available

Date:  April 1, 2026
Questions? 
Please contact: Leadership Committee

NWCG is excited to announce that Quarter Three materials for the 2025/2026 Wildland Fire Leadership Campaign are now available. This annual initiative offers all students of leadership and wildland fire management an opportunity to engage with essential leadership skills and knowledge needed to lead effectively in dynamic environments.

Quarter Three materials focus on Leadership Level 3: Leader of People (Develop Intent). Leadership Level 3 is where your values, your team, and your influence come together. Leaders of People put their teams first, build trust, and lead with authenticity. They mentor future leaders and shape decisions up and down the chain.

References:

2025/2026 NWCG Leadership Campaign - Leadership Levels

Wildland Fire Leadership Development Program

Leadership Committee

WFSTAR 2026 Core Components Module Package and 2025 Fire Year in Review Now Available

Date:  March 23, 2026
Questions? 
Please contact: Joe Schindel

The 2026 Core Components Module Package for RT-130, Wildland Fire Safety Training Annual Refresher (WFSTAR) and the 2025 Fire Year in Review are now available on the NWCG website. The 2026 Core Components Module Package provides all content needed to deliver RT-130.

References:

2026 Core Components Module Package

2025 Fire Year in Review Module

NEW! S-490, Advanced Fire Behavior Calculations (Blended) Available Now

Date:  March 17, 2026
Questions? 
Please contact: Fire Behavior Subcommittee

NWCG is pleased to announce that the new S-490, Advanced Fire Behavior Calculations (Blended), 2026 course is now available.

This training includes performance-based activities that allow students to apply the knowledge and concepts required for the Fire Behavior Analyst (FBAN), Long Term Fire Analyst (LTAN), and Prescribed Fire Burn Boss Type 1 (RXB1) positions. It supports individuals working towards these incident qualifications.

This blended course begins with a self-paced online training (OLT) in the Wildland Fire Learning Portal (WFLP), followed by an in-person instructor-led training (ILT).

References:

S-490, Advanced Fire Calculations (Blended)

NWCG Fire Behavior Analyst (FBAN) Position Page

NWCG Long Term Fire Analyst (LTAN) Position Page

NWCG Prescribed Fire Burn Boss Type 1 (RXB1) Position Page

2024 Paul Gleason Award Winners Announced

Date:  March 13, 2026
Questions? 
Please contact: Leadership Committee

The NWCG Leadership Committee is proud to announce the recipients of the 2024 Paul Gleason "Lead By Example" awards. Award categories include Initiative and Innovation, Mentoring and Teamwork, Motivation and Vision, as well as a Lifetime Achievement Award.

Congratulations to the awardees:

  • Justin Baxter, National Unmanned Aerial System (UAS) Operations Specialist, with the U.S. Forest Service — Initiative and Innovation
  • Kelly Woods, Director of the Wildland Firefighting Lessons Learned Center — Mentoring and Teamwork
  • Doug Booster, Instructor, ProHealth Net, Inc. — Motivation and Vision
  • Pam McDonald, Writer-Editor for the National Interagency Fire Center — Lifetime Achievement Award

References:

Paul Gleason Lead By Example Award

Wildland Fire Leadership Development Program (WFLDP)

Leadership Committee