| Target: |
M31, the Andromeda galaxy | Date: | 13.9.2008 |
| Time: | 22:43 .. 23:09 [UTC] | ||
| Location: | Frankfurt am Main, Germany | ||
| Conditions: | T +11°C, RH 77%, windy. Almost full moon @ alt ~29°, the sky was not very dark. | ||
| Telescope: | Newton 150mm, f5 (GSO) | Mount: | Sky-Watcher EQ6 Pro with SynScan Controller |
| Camera: | Canon EOS 400D. ISO800. In-Camera dark frame subtraction. |
Filters: | None |
| Exposure: |
9min (15s and 30s sub-exposures) Guided with 70/500mm achromatic refractor, modified webcam (SC2) and PHD Guiding v1.9 |
||
| Processing: | - | ||
| Images: |
 | ||
|
Notes: |
My first astrophoto with DSLR & telescope -combination. This one is a bit out of focus, especially at the bottom edge. The upper part of the frame seems to have much better focus. This might be because the focuser my 150mm Newtonean is a simple rack and pinion unit (altough metal and quite solid) and has some sloppiness; the camera must have been a bit non-perpendicular, causing the focus variation thru the frame. Also, vignetting occurs because the telescope has a fully illuminated view of about 9mm which is just enough for my Art-429 cooled CCD-camera, but not enough for crop-cell DSLR that requires approx 27mm. This is a common problem with Newtonean telescopes that are not specifically designed for photography. In this case the vignetting appears to be off-center which might be an indication of a misaligned secondary (not centered, wrong offset). | ||