Magnitude

What is the lowest (highest?) magnitude that can be seen by the naked eye? A co-worked stated that "apart from Andromeda, everything we can see naked-eye is a part of our own galaxy".

Darryl

Darryl Simmons said:

What is the lowest (highest?) magnitude that can be seen by the naked eye? A co-worked stated that "apart from Andromeda, everything we can see naked-eye is a part of our own galaxy".

Darryl

Just thought I'd add that your observing site is the key. When the magnitude system was created, 6th magnitude stars were the faintest that could be seen.

Stephen James O'Meara (in his Deep Sky Companions: The Messier Objects) says that he can see stars as faint as mag 8.4 from his 9000-foot altitude observing site in Hawaii. Another person at the Texas Star Party saw stars as faint as mag 7.9.

If you've read any of O'Meara's books or his columns, you know he's all about pushing the limits 8O

Hi Darryl,

Interesting question! You already have some good answers, and it really is a case of your own eye sensitivity and the viewing conditions. It is also very important to preserve your night vision. Even when using a red torch, it should be as dim as possible as even a red light does interfere to some extent. In addition, dark adaption continues to improve over several hours as the chemical rapsodin (sp?) is removed from the eye. So you can see more after several hours in the dark.

M33 should not be all that difficult from a dark site for most people. Stephen O'Meara and Timo Kahula are 2 that I know of who have seen M81, which seems to be the most distant object visible to the naked eye from the northern hemisphere. From the southern hemisphere, myself and several of my friends (including Timo) have observed NGC 5128 with the naked eye, and this seems to be the most distant object for southern hemisphere observers.

One object that I have not found any naked eye observations for is NGC 253. I would have expected this one to be observable, but despite repeated attempts I have not been successful. I wonder if the problem is that it is close to the zodiac light and this brightens the background too much? Any thoughts anyone?

If anyone has observed anything more distant than M81 or NGC 5128 with the naked eye or knows of any confirmed reports, I would be interested to hear of them.

Regards,

Maurice