| Telescope | Tuorla 70cm f2.5 Schmidt-Vaisala |
| Date | Dec 2004 |
| Instrument | SBIG - ST 8 |
| Filter | N/A |
| Exposure Time |
0 s (bias frame) |
| Other |
Suspected Problem:The bright feature is caused by some light source that leaks light into the camera. This image is a bias frame (0s exposure time), so all light on the image was recorded during the readout of the CCD. Even very faint lights, like LEDs, can cause signatures like this, especially when the exposure time is greater than 0s. |
Fix:Make sure no unwanted light can get into your setup. This frequently means taping up all the potential light leaks with black tape. All lights that can be switched off should obviously be switched off. It is often hard to find the problem light since it is most likely very faint (otherwise it would totally obliterate any image). A good start is to look on the 'bright side' of the CCD, i.e., the side that has a higher count (like north, south, etc), which only works if the light source is not some reflection of something inside the optical path. |
See example of light leak in Filter Wheel
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