Question about camera rotation, Telescopius and shooting mosaics

[900SL]

I'm going to try get a 3 panel mosaic of the Lion, the Witch and the Wardrobe the Wizard and the Lobster on holiday. No Goto but I have platesolving

I'll be using a Star Tracker and platesolving to get accurate RA/Dec location. 533MC Pro/Samyang 135

Am I correct in assuming that the camera framing shown in Telescopius is based on the date, time and location, and assumes a home position pointing at the NCP with the camera frame horizontal?

I've rotated the camera 50 degrees here to give a 3 x 1 panel, and I am assuming that if I do the same in the field, and take successive 3 hour panels with the appropriate central RA and DEC, I will get this kind of view?

 

 

[vlaiv]

26 minutes ago, 900SL said:

camera frame horizontal?

I think it will be like that.

In your case - you don't even have to worry about horizontal / vertical aspect - as you have square sensor so it does not matter if RA is aligned with horizontal or vertical side of the image.

Only thing to pay attention to would be rotation direction.

I would personally do the following - find a pair of stars that are bright enough and are horizontal / vertical (line going thru them is either parallel with horizontal or vertical edge of the frame) in your wanted orientation. Then in field, after rotating camera for 90 and taking frame / focus shots (or plate solving) - check to see if those stars are in fact as expected.

If you rotate to -50 degrees - then stars will be at an angle of 10 degrees to the edge.

[Starflyer]

It's been a long time since I've done a mosaic so correct me if I'm wrong.  I seem to remember that if you don't have the sensor aligned with RA & DEC and do a meridian flip then the angles are really screwed up.

I may be misremembering this, as I say, it's been many years.  It's easy to test before you go away, take an image close to the meridian, do a flip, take another and look at the angles.

[vlaiv]

5 minutes ago, Starflyer said:

I seem to remember that if you don't have the sensor aligned with RA & DEC and do a meridian flip then the angles are really screwed up.

Nope.

After meridian flip - only thing that happens is frame "flip" - or 180 degree rotation of the frame.

Sometimes there is small deviation from this - like few degrees, and I'm not sure what is consensus on that one - if it's orthogonality issue or cone error, or maybe both.

[900SL]

On 09/07/2023 at 14:17, vlaiv said:

I think it will be like that.

In your case - you don't even have to worry about horizontal / vertical aspect - as you have square sensor so it does not matter if RA is aligned with horizontal or vertical side of the image.

Only thing to pay attention to would be rotation direction.

I would personally do the following - find a pair of stars that are bright enough and are horizontal / vertical (line going thru them is either parallel with horizontal or vertical edge of the frame) in your wanted orientation. Then in field, after rotating camera for 90 and taking frame / focus shots (or plate solving) - check to see if those stars are in fact as expected.

If you rotate to -50 degrees - then stars will be at an angle of 10 degrees to the edge.

Thanks Vlaiv, much appreciated

[900SL]

22 hours ago, Starflyer said:

It's been a long time since I've done a mosaic so correct me if I'm wrong.  I seem to remember that if you don't have the sensor aligned with RA & DEC and do a meridian flip then the angles are really screwed up.

I may be misremembering this, as I say, it's been many years.  It's easy to test before you go away, take an image close to the meridian, do a flip, take another and look at the angles.

Thanks, I'm using a tracker over a few nights so won't be flipping, which simplifies things