This past week I got serious about orienting my camera so that the image results in NCP:Up and East:Left. I snapped an image of Albireo and asked astrometry.net and All Sky Plate Solver for its opinion. You can see my image here .

Both astrometry.net and ASPS agreed with the orientation: "Up is -178 degrees E of N". I thought: what? I worked hard to ensure that North was Up. Why are you telling me that South is Up? I uploaded a JPG file not a FITS file, so my theory is that the plate solvers assumed that my telescope optics inverted the image. OK I can understand that.

Information is not easy to come by on the Internet about this topic, so I thought long and hard about it. Perhaps when the plate solvers refer to "UP" they are not referring to the top of the image -- instead they are referring to the top of the sensor. Does that make sense?

Also, FITS files contain metadata whereas JPG and PNG files do not. I am wondering if I should expect different results from the plate solvers if I capture my images in FITS files instead. I can certainly understand that getting the orientation of the sensor is important when applying darks, flats, and bias frames.

Would you recommend that I always capture to FITS?

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