by Chris Peterson » Thu Nov 12, 2020 2:46 pm
Ann wrote: ↑Thu Nov 12, 2020 11:25 am
Lasse H wrote: ↑Thu Nov 12, 2020 10:13 am
Am I right in assuming that the photo is "upside down" – referring to how Orion is normally shown?
This is Orion as seen from the southern hemisphere. So yes, it's "upside down" from a northerner's point of view. :wink:
No, not really. Look at Orion when it is rising (from northern mid-latitudes) and his "head" slightly leads his "feet", and his belt is perpendicular to the horizon. At setting, his feet are below the horizon, the belt lines up with the horizon and his head is rotated to the east.
Like most of the sky, what we see depends much more on when we see it than it does where we see it from. Because Orion has a negative declination, it appears to rotate through a greater angle from the southern hemisphere than the northern, but that is all.
This is "upside down" for the reason suggested: the constellation represents a person, so we represent it with the head up. But we don't see it in the sky that way most of the time, from either hemisphere.
In terms of astronomical convention, images are usually presented with north up, whichever hemisphere they are imaged from. This image is presented with southwest up.
[quote=Ann post_id=308019 time=1605180322 user_id=129702]
[quote="Lasse H" post_id=308018 time=1605176027 user_id=123973]
Am I right in assuming that the photo is "upside down" – referring to how Orion is normally shown?
[/quote]
This is Orion as seen from the southern hemisphere. So yes, it's "upside down" from a northerner's point of view. :wink:
[/quote]
No, not really. Look at Orion when it is rising (from northern mid-latitudes) and his "head" slightly leads his "feet", and his belt is perpendicular to the horizon. At setting, his feet are below the horizon, the belt lines up with the horizon and his head is rotated to the east.
Like most of the sky, what we see depends much more on when we see it than it does where we see it from. Because Orion has a negative declination, it appears to rotate through a greater angle from the southern hemisphere than the northern, but that is all.
This is "upside down" for the reason suggested: the constellation represents a person, so we represent it with the head up. But we don't see it in the sky that way most of the time, from either hemisphere.
In terms of astronomical convention, images are usually presented with north up, whichever hemisphere they are imaged from. This image is presented with southwest up.