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KEY TAKEAWAYS
- Sensor calibration, also known as taking a dark frame, is commonly used in digital photography, particularly in astrophotography.
- It helps improve your observations and the quality of the images you save to your smartphone and share with others.
- On a UNISTELLAR telescope, simply leave the dust cap in place and select “Sensor Calibration” in the telescope settings.
- Because sensor calibration depends on the telescope’s temperature, we recommend:
- leaving the telescope outside for 15 minutes before taking a dark frame;
- performing sensor calibration before each observation session.
In digital photography, calibrating the sensor, or taking a dark frame, consists of recording an image without a light signal. This process helps improve your observations and the quality of the images you capture. A dark frame allows the telescope’s onboard computer to identify and correct hot pixels and other image imperfections.
If your UNISTELLAR telescope does not have an accurate sensor calibration, you may notice “hot pixels” in Enhanced Vision images displayed in the app or through the eyepiece. These hot pixels appear as small red, green, or blue dots. This is normal. Here is an example of a blue hot pixel:
To prevent this, follow the steps below:
- Place your UNISTELLAR telescope outside for at least 15 minutes before starting your observation. This allows the telescope to adjust to the outdoor temperature.
- Turn on your UNISTELLAR telescope without removing the dust cap. Leave it in place for one to two minutes.
- Make sure your UNISTELLAR telescope is not directly exposed to streetlights or another light source. The darker the surroundings, the better.
- Open your telescope settings and tap “Sensor Calibration.” The process can take up to 1 minute and 20 seconds.
You can then monitor the progress of the operation:
If the operation is successful, the message “Calibration is successful” should appear.
Note: If an error message appears, try again in darker surroundings and make sure the telescope has been left outside for 15 minutes. Keep the dust cap on and, if necessary, cover the telescope with a dark piece of fabric. You should also check that the telescope’s storage is not completely full.
Tip: Sensor calibration is one of several steps you can take to improve the quality of the images saved during your observations. If you own an eVscope or an eQuinox, you should also make sure that the collimation is correct and that the focus is optimal. Where applicable, you should also adjust the eyepiece to your eyesight to obtain the best possible image quality.