Total Station Telescope and Objective Lens Function, Care and Common Problems Malaysia
Total Station Telescope and Objective Lens Function, Care and Common Problems Malaysia
The telescope and objective lens are two of the most important optical components of a total station.
The telescope allows the surveyor to accurately sight a prism, reflector or survey target, while the objective lens collects and focuses light so the target can be viewed clearly.
When the telescope is difficult to focus, the crosshair appears unclear, or the objective lens is dirty or damaged, accurate aiming becomes more difficult.
For total stations used regularly on Malaysian construction and surveying sites, proper optical care is therefore essential.
What Is the Telescope on a Total Station?
The telescope is the main sighting system of the total station.
Surveyors look through the telescope to precisely aim the instrument toward a target.
Typical targets include:
Survey prisms
Reflective sheets
Control points
Building corners
Columns
Structural points
Boundary marks
Setting-out points
The telescope can rotate horizontally together with the instrument and vertically around its horizontal axis.
What Is the Objective Lens?
The objective lens is the large optical lens at the front of the telescope.
Its function is to collect light from the target and form an image that can be viewed through the eyepiece.
The condition of this lens directly affects how clearly the operator can see the target.
Dust, fingerprints, moisture or physical damage can reduce image quality.
Telescope vs Objective Lens vs Eyepiece
These three components work together.
Objective Lens → Telescope Optical System → Eyepiece → Surveyor's Eye
The objective lens receives the image.
The telescope optical system focuses it.
The eyepiece allows the surveyor to clearly see the image and crosshair.
All three need to function correctly for comfortable and precise target aiming.
How to Focus a Total Station Correctly
Correct focusing involves more than simply making the target look sharp.
Step 1 Focus the Crosshair
Look through the telescope toward a bright, plain background.
Adjust the eyepiece until the crosshair or reticle appears sharp.
The crosshair should remain clear without straining your eye.
Step 2 Aim Toward the Target
Locate the prism or target through the telescope.
Step 3 Focus the Target
Use the telescope focusing control until the target image becomes sharp.
Step 4 Check for Parallax
Move your eye slightly while looking through the telescope.
If the target appears to move relative to the crosshair, the focusing may not be correct.
Adjust again until apparent relative movement is minimized.
What Is Parallax in Total Station Surveying?
Parallax occurs when the target image and telescope reticle are not effectively focused in the same viewing plane.
When the operator moves their eye, the crosshair can appear to shift relative to the target.
This can lead to inconsistent pointing.
For accurate observations:
Focus the reticle first → Focus the target → Check for parallax
This is especially important when performing precise angle obsrvations.
Why Is My Total Station Telescope Blurry?
A blurry telescope does not automatically mean the total station needs repair.
Check the basic causes first.
Eyepiece Not Adjusted
If the crosshair itself is blurry, adjust the eyepiece.
Target Not Focused
If the crosshair is sharp but the target is blurry, adjust the telescope focus.
Dirty Objective Lens
Dust, fingerprints or contamination may reduce image clarity.
Environmental Conditions
Heat shimmer, rain, fog, dust and long sighting distances can reduce visibility.
Internal Optical Problem
If focusing cannot produce a clear image under normal conditions, the telescope may require professional inspection.
How to Clean a Total Station Objective Lens
The objective lens is a precision optical surface and should be treated carefully.
First remove loose dust using appropriate optical cleaning equipment.
If additional cleaning is necessary, use materials and methods suitable for precision optical lenses and follow the instrument manufacturer's recommendations.
Avoid:
Shirt sleeves
Rough cloth
Tissue paper not intended for optics
Dirty rags
Abrasive materials
Excessive pressure
Unknown cleaning chemicals
Incorrect cleaning can scratch or damage optical coatings.
Can I Use Alcohol to Clean a Total Station Lens?
Do not automatically apply general-purpose alcohol or cleaning chemicals to a total station lens.
Optical coatings and manufacturer recommendations can differ between instruments.
Use an appropriate optical cleaning solution specified or considered suitable for the equipment.
When uncertain, refer to the manufacturer's maintenance instructions or have the instrument professionally cleaned.
What If There Is Fungus Inside the Telescope?
Internal fungus, haze or contamination is different from surface dust.
Symptoms may include:
Cloudy image
Hazy viewing
Reduced contrast
Visible internal spots or patterns
Poor image quality despite external cleaning
Do not dismantle the telescope yourself unless you are properly trained and equipped.
Opening the optical system can affect alignment and introduce additional contamination.
Professional servicing is recommended.
Scratched Objective Lens Can I Still Use the Total Station?
A small surface mark does not necessarily mean the instrument will immediately stop measuring.
However, the effect depends on the location and severity of the damage.
A heavily scratched, cracked or damaged objective lens can affect optical performance and may indicate that the instrument has suffered an impact.
The instrument should be inspected if the damage is significant.
Does a Dirty Lens Affect EDM Distance Measurement?
The total station's EDM system sends and receives measurement signals through the instrument's optical system.
Heavy contamination, condensation or obstruction should therefore not be ignored.
If the total station has difficulty measuring distances, check basic conditions such as:
Objective lens cleanliness
Target visibility
Prism condition
Measurement mode
Prism constant
Atmospheric conditions
Distance to target
Persistent EDM problems may require professional testing.
Why Does My Total Station Crosshair Look Tilted?
If the reticle appears abnormal or observations suggest that the line of sight is not correctly aligned, the instrument may require checking.
Possible issues can involve:
Telescope alignment
Reticle alignment
Collimation
Horizontal axis relationship
Previous impact
Do not attempt internal adjustment without the correct procedure and reference equipment.
What Is Total Station Collimation Error?
In simplified terms, collimation error occurs when the telescope's line of sight does not maintain the correct geometric relationship with the instrument's measurement axes.
This can influence angular observations.
Survey procedures using observations in both telescope faces can help reduce or identify certain instrumental errors, but they do not eliminate the need for proper instrument adjustment.
If collimation is suspected, professional inspection and calibration are advisable.
Telescope Problem After Total Station Is Dropped
A dropped total station should receive more attention than a simple visual inspection.
Even if:
The screen works
The telescope still focuses
The EDM still measures
The instrument powers on normally
the internal alignment may have changed.
After a significant impact, important checks can include:
Telescope alignment
Collimation
Horizontal angle
Vertical angle
Compensator
EDM
Optical or laser plummet
Levelling system
For precision survey work, verification before returning the instrument to service is important.
How to Protect a Total Station Telescope
Good field practices include:
Keep the lens cap installed when appropriate
Avoid touching the objective lens
Keep the instrument away from heavy dust where possible
Dry the instrument properly after wet conditions
Transport it in its carrying case
Avoid leaving it unsecured on the tripod
Do not point the telescope directly at the sun
Inspect optics periodically
A small amount of preventive care can reduce expensive optical repairs.
When Should the Telescope Be Serviced?
Consider professional inspection when:
The telescope cannot focus properly
The image remains cloudy
Internal fungus is visible
The objective lens is damaged
Crosshair alignment appears abnormal
The telescope has excessive mechanical play
The instrument has been dropped
Angle measurements become inconsistent
EDM performance becomes abnormal
Optical problems and measurement problems should be diagnosed together when necessary.
Total Station Telescope Repair & Calibration Malaysia
MTM Precision provides total station inspection, calibration, servicing and repair in Malaysia.
Total station checks may cover relevant areas including:
Telescope condition
Objective lens
Telescope alignment
Horizontal angle
Vertical angle
Compensator
EDM distance measurement
Optical or laser plummet
Levelling system
If your total station has blurry optics, focusing problems, alignment issues or has suffered impact damage, professional inspection can determine whether cleaning, adjustment, repair or calibration is required.
Contact MTM Precision
MTM Precision Sdn. Bhd.
Showroom & Service Centre
No. 29-1 & 29-2, Jalan Bandar 18,
Pusat Bandar Puchong,
47160 Puchong, Selangor, Malaysia
🌐 Website: www.mtmpre.com.my
📧 Email: mtmpre@yahoo.com
📱 WhatsApp: +6016-660 7346
06 Sep 2026
