RE: NGC 7000, in Cygnus
February 5, 2015 at 1:41 am
(This post was last modified: February 5, 2015 at 1:44 am by orogenicman.)
(February 4, 2015 at 8:12 pm)Cthulhu Dreaming Wrote: Nice work. That's one of my favorite areas of sky, and you really captured the contrast very nicely.
I know many refractor guys look down on Newtonians, but I actually think the diffraction spikes in photos taken through newts look cool. :p
The correction looks pretty good, the off-axis abberations are less significant than what I'd expect from an f/5 primary. What are you using to correct off-axis coma? (I had a 12" f/4.5 and the coma would be very noticeable in that scope.)
I am using a Baader MPCC coma corrector in front of the camera. It can be used for photography or for visual use with the proper adapters. It makes a big difference as it acheives a flat field for both uses. With a small focal ratio on a Newtonian, collimation of the mirrors is critical. I collimate my scope before each session and make sure the scope has cooled down to ambient temperature prior to use.
Thanks, Alex. I used a Hutech-modified Canon T1i. It has a clear filter on the sensor instead of the manufacturer's infrared cut filter. That gives the camera full spectrum capabilities. Then I use a Baader UV/IR cut filter that allows hydrogen alpha spectrum (the reddish color you see in the image) to pass through but cuts the infrared and uv dispersed in the atmosphere.
'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
