NGC 5422 and NGC 5471
Posted 22 September 2012 - 05:36 PM
Posted 22 September 2012 - 05:41 PM
Posted 22 September 2012 - 07:35 PM
Posted 22 September 2012 - 09:43 PM
Is there a dark lane along the top right (must be SW) edge of NGC 5422? Is there a dark lane on the top right side of NGC 5471 as well?? So it appears on my screen. The galaxy is supposed to be pretty much exactly edge on, and it is a lenticular. So any dark lanes would be a little unexpected.
5471 is indeed completely detached visually. It is not even on the same line as the nearest NGC patches. It is at the end of a different arm, which is invisible for 1/4 revolution around the core leading up to NGC 5471. Closer to the core it is probably the most massive arm visually, though. I have an annotated drawing here: http://ivm-deep-sky....11/05/m101.html
Incidentally, that's an expressive M51 in your avatar.
Posted 22 September 2012 - 10:14 PM
They are artifacts that have escaped my detection until you said something. The "lane" in 5422 is on my original sketch, so it's a mistake in my smudging. I think the one in 5471 was introduced by the camera.
Is there a dark lane along the top right (must be SW) edge of NGC 5422? Is there a dark lane on the top right side of NGC 5471 as well?? So it appears on my screen.
Thank you for posting a link to your observation of M101, there is a lot of good information there.
Posted 23 September 2012 - 01:18 AM
Posted 23 September 2012 - 09:18 AM
As regards 5471, I imagine slight warping of the original may introduce a bright area like this (dark when inverted -or vice versa) from the flash if you are photographing. Scanning is not necessarily better though.
These defects may be less noticeable on many other screens; I am on a "gaming" computer with a glossy screen.
In any case, as I already said, nebulosity is masterfully captured here.
Posted 24 September 2012 - 02:42 PM
Very good sketches of NGC 5422 & NGC 5471 .