(March 14, 2013 at 4:58 am)teaearlgreyhot Wrote: In pictures like these, when you see the edges of the stars, is that the actual edge of the star or is that the intense light of the star making it look bigger than it is?
The star spikes are diffraction spikes caused by light diffraction around the secondary mirror support of the telescope. In order to obtain images of the faint nebula, long exposures must be taken, and in doing so, the stars, particularly the brightest ones, become over exposed. There isn't much that can be done about that. What's worse, in order to bring out these faint nebula, one must stretch the image in such a way that the stars tend to develop halos around them. There are methods that minimize this, but I'm still working on that issue. It's one of the most difficult issues to deal with when processing astrophotographs. All astrophotographs are a compromise between the various elements. Stretch the nebula colors, and the star colors can be affected. There are ways to deal with that too, and I'm getting better at it.
'The difference between a Miracle and a Fact is exactly the difference between a mermaid and seal. It could not be expressed better.'
-- Samuel "Mark Twain" Clemens
"I think that in the discussion of natural problems we ought to begin not with the scriptures, but with experiments, demonstrations, and observations".
- Galileo Galilei (1564-1642)
"In short, Meyer has shown that his first disastrous book was not a fluke: he is capable of going into any field in which he has no training or research experience and botching it just as badly as he did molecular biology. As I've written before, if you are a complete amateur and don't understand a subject, don't demonstrate the Dunning-Kruger effect by writing a book about it and proving your ignorance to everyone else! "
- Dr. Donald Prothero
-- Samuel "Mark Twain" Clemens
"I think that in the discussion of natural problems we ought to begin not with the scriptures, but with experiments, demonstrations, and observations".
- Galileo Galilei (1564-1642)
"In short, Meyer has shown that his first disastrous book was not a fluke: he is capable of going into any field in which he has no training or research experience and botching it just as badly as he did molecular biology. As I've written before, if you are a complete amateur and don't understand a subject, don't demonstrate the Dunning-Kruger effect by writing a book about it and proving your ignorance to everyone else! "
- Dr. Donald Prothero
