In January 2023, Mars was on its retrograde loop in the sky, and at the far end of this loop it came relatively close to the Pleiades. The perfect date for this alignment was January 11.
A Pleiades – Mars photo had been on my mind for quite a long time. I would actually have preferred a somewhat wider field of view, but the purchase of my full-frame camera still had to wait a little longer.
Unfortunately, it had been cloudy for weeks. On the ideal date, the sky cleared up somewhat, but the conditions were still rather poor:
Too much wind.
High, thin cirrus clouds.
The wind repeatedly blew off my dew shield. At the same time, my new configuration of the guiding camera didn’t work. Considering that a thick cloud cover was slowly approaching, I decided not to waste any valuable time and shot without guiding – quite manageable at a 135 mm focal length. However, this is probably the reason why a walking-noise pattern is visible in the final image. More on that another time.
Because thin clouds kept passing through from time to time, I chose to expose individual frames for only 45 seconds, so that – despite the high number of expected rejects – I could still achieve as much total exposure time as possible. Out of 270 images, I had to discard 200 due to clouds.
Nevertheless, some frames with residual clouds surely made it into the integration process. Combined with the dew shield being blown off repeatedly, there were several unfavorable conditions for an all-around perfect photo – yet I am still satisfied. All in all, luck seems to have been on my side.
Technical overview
| Telescope | Olympus Zuiko Auto-T MC 2.8 |
| Focal Length | 135mm |
| Aperture ratio | 5.6 |
| Erecting Lense | – |
| Filter | – |
| Mount | Skywatcher HEQ-5 |
| Goto-Control | EKOS |
| Mount Control | INDI |
| Guiding Scope Focal Length | – |
| Guiding Camera | – |
| Guiding Software | EKOS, INDI |
| Dithering | – |
| Camera | CANON EOS M100 |
| Method | focal projection |
| Camera angle | -30° (Stellarium) |
| Camera Control | EKOS, INDI, Gphoto2 |
| Photography Date | 01/11/2023 |
| Exposure-Time Lights | 88x45s |
| Correction frames | FLATS, BIASES |
| Sensitivity | ISO 800 |
| Post Processing Date | 01/12/2023 |
| Stacking, Integration | PixInsight |
| Processing | PixInsight |
| Capture Place | Koblenz, Germany |
| Lightpollution | Bortle 5 |
| Scattered light | strong |
