by Chris Peterson » Fri Jan 09, 2009 3:40 pm
emc wrote:Your pointing out the directional disparity brings up a point I recall someone else mentioning here regarding the orientation of space images. I reckon it would be nice for us beginners to have standard views based from the northern hemisphere like our typical earth maps. But that's more complicated than asking everyone to use the metric system... (and we know how that goes) :wink: And I reckon northern perspective conformity would require the folks in the southern hemisphere to turn their cameras upside down. :?
It is conventional in astronomical imaging to present images north up, east left. This convention is applied regardless of whether the image was made in the north or south hemispheres.
However, many amateurs use self guided cameras. These have the guide sensor fixed in relation to the main image sensor, and it is often necessary to rotate the camera to some arbitrary position in order to find a guide star. Also, cameras used by amateurs usually have rectangular dimensions, so non-standard orientations are sometimes chosen for aesthetic reasons. Occasionally images are made with optics that reverse the image. This is particularly confusing when the image processor neglects to mirror the result.
IMO any image that doesn't follow the north up convention should have its orientation described in the explanatory text.
[quote="emc"]Your pointing out the directional disparity brings up a point I recall someone else mentioning here regarding the orientation of space images. I reckon it would be nice for us beginners to have standard views based from the northern hemisphere like our typical earth maps. But that's more complicated than asking everyone to use the metric system... (and we know how that goes) :wink: And I reckon northern perspective conformity would require the folks in the southern hemisphere to turn their cameras upside down. :?[/quote]
It is conventional in astronomical imaging to present images north up, east left. This convention is applied regardless of whether the image was made in the north or south hemispheres.
However, many amateurs use self guided cameras. These have the guide sensor fixed in relation to the main image sensor, and it is often necessary to rotate the camera to some arbitrary position in order to find a guide star. Also, cameras used by amateurs usually have rectangular dimensions, so non-standard orientations are sometimes chosen for aesthetic reasons. Occasionally images are made with optics that reverse the image. This is particularly confusing when the image processor neglects to mirror the result.
IMO any image that doesn't follow the north up convention should have its orientation described in the explanatory text.