For astrophotography and long exposure sequences, the Svbony SV164 Dark filter (2") will come in handy.
While in operation, the camera's sensors not only react to incoming light, but also capture stray signals (noise) due to heating. This is a kind of error in imaging that can be reduced by using cooled cameras, but not completely eliminated. Fortunately, by taking corrected images, some of the errors can be removed from the raw images.
The Svbony SV164 Dark filter, as it is called, is designed for dark correction images. It's not really a filter, but rather a dark sheet in a socket compatible with filters. It completely blocks the path of light from the sensor, so that the sensor only captures signals containing "noise"
Dark images should always be exposed in the same circumstances as the actual raw (light) images were taken. Correction images should be taken at the same ISO (gain) setting, with the same shutter speed, under the same temperature conditions to ensure that the correction is as accurate as possible. The aforementioned conditions, the causes of noise generation will vary, and the amount of noise will vary.
As sensors age, sensor behavior may change, so it is a good idea to update the correction images saved in our Dark library annually.
The Svbony SV164 Dark filter is practical to use in a filter changer or fold filter holder. Of course, as usual with Svbony, it comes with a storage box.