A Tapo C325WB Night Vision Camera has been employed for recording Aurora and other night time and daytime phenomena (like clouds, NLC etc) since the end of 2024.  The example below compares a Colour image taken with my NorthCam/Tapo C325WB Camera (top) with the B/W image taken with my Oculus AllSky Camera at the same time (2025-09-01).

The NorthCam Picture is produced by taking the raw Tapo image (which has a curved horizon) and generating a 'fisheye' corrected image in iSpy Software (which flattens the horizon).  My AstroNorthCam program picks on the 'corrected' image, where annotation is added,  stars counted, and saved to a session folder (where it is used for generating various videos).

The night vision / colour capability of the Tapo Camera is fantastic, but my usage of the camera has suffered from certain limiting issues.    

•  House walls on righthand side of image slope inwards, rather than being vertical
•  Aurora rays sloping inwards    (note how in the geometrically correct AllSkyCamera picture they are fanning outwards)  
• The natural FOV of the camera is ok but it is narrower than ideal and it is reduced by the iSpy's fisheye correction process
• Daytime pictures show artefacts in area of strong contrast/greatest fisheye correction.    

The problem of the inward sloping house walls and aurora rays that are not fanning outwards as they should can be see particularly well in the zoomed-in picture below:  

The problem of arfetacts in area of strong contrast/greatest fisheye correction is illustrated by this portion of an image taken 2026-06-26


After a bit of a battle I've finally resolved all of these issues, by taking uncorrected images from iSpy, and performing the image corrections in my own program (AstroNorthCam).

Things discovered along the way   

• The lens is a fisheye type, and needs no radial corrections  
•  It is a wide-angle lens which generates an essentially rectilinear picture
• The optical centre is not at the centre of the picture, but it is at the centre-top  
• The lens / optical line is not perpendicular to the camera sensor, but is purposedly tilted downwards, which results in the curved horizon
  and creates  a view that is well suited to the camera's primary role as a security camera

The following series of images illustrate the steps taken by the new processing pipeline going from raw image to final image. 

1) Raw Image - uncorrected, 1400 px wide (increased from previous 1080 px) 

2) Corrected Image, 1400 px wide

3) Cropped Image (1400 px wide)

4) Final Image (resampled to 1080 px wide)

Notice :
- how the house walls are now vertical (which means Aurora rays will now show their natural geometry)
- how the image is now seeing the Camera's maximum possible FOV.
- acquiring image with a higher resolution and then cubic resampling/rescaling avoids the artefacts in the earlier images.
 -process has also been speeded up using more efficient 1D arrays and bitLock methodologies.


The Image below shows an older daytime image with its narrower FOV              

           

The cropped images below compares the lower left of the older image (left) with the approximate equivalent area from the new image (right), showing that problem artefacts have been largely resolved.

  

The new pipeline/projection was useful for showing a wider view of the NLC display last Sunday (2026-06-28 / 2026-06-29)