Big Dipper

SubjectUrsa Major
CameraNikon D-3000
LensAF-S Nikkor 20 mm, 50x5s, ISO 800

Last evening, the new moon was low and there were no clouds, so I tried again. On the forum, I was tipped not to expose more than 5 or 8 seconds per photo without a tracker, considering my chip and focal length.

First, I took fifteen pictures of the moon, all of which were completely overexposed. Then I took successively 75 lights and 10 darks at ISO 800 straight up, in which Sequator found too few stars, and then twenty-five of both types at ISO 3200 of the same thing, with the same result. Concluding the evening with fifty lights and 5 darks in the direction of the Big Dipper, appeared the only thing that yielded results.

I read that darks are actually not necessary if you do a limited number of short exposures because then the sensor doesn’t get warm enough for hot pixels and that it only takes time. The reason I made those darks was to check that. And indeed, I didn’t see anything on it.

On the forum, I got feedback on the picture above, stating that, contrary to what I found, there was quite a lot to see on it and that it wasn’t as bad as I thought. But I also got tips:

  • Longer exposure (15 seconds should be possible with this lens)
  • Better focusing
  • Longer wait for darkness
  • Distancing myself from light pollution

The latter means I can no longer use my backyard, which means more planning.

Categorised as: astro

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