| Target: |
NGC6888, bright nebula. Also known as the Crescent nebula |
Date: | 16.9.2004 |
| Time: | - | ||
| Location: | Vantaa, Finland | ||
| Conditions: | - | ||
| Telescope: | N150 f5 | ||
| Camera: | SC2 webcam (PCVC840K) in prime focus. Raw color mode |
Filters: | Baader #2459207 UV/IR-cut |
| Exposure: |
Mosaic of 4 images. 80 x 15s on each of the 4 (out of 684 total), dark frame and synthetic flat fields |
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| Processing: | Stacked in K3CCDTools. Adjusted in Photoshop. | ||
| Notes: | Clearly the exposure time was too short to capture this nebula well. I also had problems building this mosaic since the partial pictures tended to have different background levels and faint details did suffer when trying to process the background even. The variations were caused by stray light entering the telescope tube, and as the RA axis turns slowly during and between exposures the amount varies. I think it can be remedied by using an additional stray-light shield in front of the telescope in future. | ||
