Image orientation calculation

[Phillyo]

Good morning all,

So I'm considering making a mosaic with my Samyang and ASI533. Just around the Cygnus area for now, just as it's not something I've ever done before. So, in NINA I used to framing wizard to make a 3x4 panel mosaic and I used an image from the previous nights imaging that NINA plate solved to get the orientation of the sensor. It said 195 degrees.

However, when I popped the same image into Pixinsight and platesolved it, it said -15 degrees. What gives? Which one is right, and why are they different?

Thank you,

Phil

[scotty38]

I don't know why or how etc but it seems to me like it's the starting point that's the difference. One starts at the East and one at the West if you see what I mean... I'd look into that and you'll probably work it out from there. I have both apps so will have a look too 🙂

[scotty38]

Well I just tried one of my images that I know NINA told me was 95 degrees and PI just solved to 85 degrees, give or take. Just trying to work that one out but like yours is a similar amount either side of a "valid" point, again if you see what I mean 🙂

[ONIKKINEN]

Did you actually check that your camera had the right orientation on the night of shooting?

Unless you have an automatic rotator to rotate the camera to the desired orientation you have to manually do that before starting a run. Especially so with mosaics, as im sure you have just found out with the corners being out of place.

[Phillyo]

6 minutes ago, ONIKKINEN said:

Did you actually check that your camera had the right orientation on the night of shooting?

Unless you have an automatic rotator to rotate the camera to the desired orientation you have to manually do that before starting a run. Especially so with mosaics, as im sure you have just found out with the corners being out of place.

No I didn't start the mosaic yet. I just checked the orientation of an image from the night before so I could add that to the framer in NINA and see how to frame everything up. But NINA and PI are telling me two different things.

Phil

[Phillyo]

46 minutes ago, scotty38 said:

I don't know why or how etc but it seems to me like it's the starting point that's the difference. One starts at the East and one at the West if you see what I mean... I'd look into that and you'll probably work it out from there. I have both apps so will have a look too 🙂

Hmmm interesting. I'll look into that, thank you.

Phil

[tomato]

As I’m sure you know on the NINA framing wizard the orientation of your platesolved image is projected onto the sky survey image so you can see exactly what your mosaic panels will capture if you don’t change the camera orientation. I have found this to be 100% accurate.

[ONIKKINEN]

1 hour ago, Phillyo said:

No I didn't start the mosaic yet. I just checked the orientation of an image from the night before so I could add that to the framer in NINA and see how to frame everything up. But NINA and PI are telling me two different things.

Phil

Hmm, maybe its just a numbers thing. NINA reports orientation from 0 to 360, but maybe PI reports orientation from 0 to 180 and 0 to -180 to the other direction. Isnt this the same orientation in that case? 

15 degrees over 180 would in that case maybe be reported as -15?

[scotty38]

Yes I think we realise that and just trying to work out why the different "starting" position