Another strange anomaly…or not..??

[Stuart1971]

Imaging last night and had a go at M81 and M82, in the FOV of my QHY268c sensor the two galaxies were side my side, as I thought they should be, then I guide with an ASI174m which had a decent size oblong sensor, and I noticed that the two galaxies were one above the other, in the image on PHD2, hmmm but both cameras are orientated with the long sides of the sensors right to left, yet the guide camera needed to be rotated by 90 degrees clockwise for the images to match which would mean that it would have the short sides of the sensor top and bottom, this can’t be correct can it…??

I know this makes no odds for guiding purposes, but was intrigued to know why…

Imaging scope Tak FSQ85 and guide scope Tak FS60cb

Any ideas…?

[ollypenrice]

We assume you're not using a diagonal anywhere?

How are you defining the chip orientation? If you look down the scopes from the front you'll be able to see the chips. That's the sure-fire, software-free way to know that they are aligned the same way relative to the mount's saddle plate.

Once they are, the read-out software may do two things to confuse you: it can present you with an image rotated by 180 degrees or even a flipped (mirrored) image. I don't see how it can make the long side the short side, though!

Olly