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Live Star Chart -- Messier Slide Collection -- NGC Slide Series

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Get Polaris transit times at the U.S. Naval Oceanography Portal

Tuesday, July 6, 2010

Messier 8, the Lagoon Nebula remix

Okay, once again trying my hand at this beautiful deep sky object. Of all my shoots, this has seemed to be the most troublesome; my recent attempts thwarted by cloud pirates and processing gremlins. This time the odds are better with significant improvements:
  • polar alignment using setting circles and computed transit time
  • better dynamic range and less noise than previous DSLR
  • IR-cut filter removed
  • field flattener lens adapter
  • images normalized prior to stacking
  • new DDP algorithm rather than traditional "stretching"
  • nearly doubled the number of exposures taken

You be the judge. 300 x 15-sec. unguided JPEG frames, nearly 75 minutes of overall exposure, modified-Canon XTi, field flattener, calibrated, and processed with DDP.

Monday, July 5, 2010

Messier 23

Back in Tucson under a beautiful night sky for the Fourth of July! Here is Messier 23, an open cluster in the constellation of Sagittarius; one more in my quest to capture every Messier object.

This is very close, cosmologically speaking, only a couple thousand light-years away and upwards of 20 light-years across. Taken with DSLR @ 1600 ISO, unguided, 190 x 15 sec. JPEG frames, calibrated 200/200 bias/flat, and finished processing without "stretching". Instead, out of curiosity, the Digital Development Processing (DDP) feature of Nebulosity was used.

From what I've read, DDP makes digital images more like film and was invented by Kunihiko Okano, a physicist and amateur astronomer. I compared my results with some manual stretching and found I preferred the DDP output. Threw in a some sharpening and color balance - voila.