Registration scale

Software Siril
1

Hi,
I assume that Siril can cope with some minor scaling between frames (as well as offset & rotation) at the registration step?

If this assumption is correct how much scale difference is acceptable?

Thanks
Ed

2

Hi Ed,

sure Siril can deal with some (not so minor) scaling/offset/rotation between frames at registration step. My most “extreme” attempt to date was aligning same field imaged with both 420mm and 1000m scopes (same camera). I had to adjust a bit the field of view as described here: Siril 0.99.6 crashes - #5 by cissou8
What is the scale difference you have in mind?

Cheers,

C.

1 Like
3

Thanks C. Nothing as dramatic as your example. I want to combine some RGB data taken with a 16MP DSLR with Ha taken with a different full spectrum modified 12MP DSLR on the same scope. From what you wrote this shouldn’t be to much of an issue.
Ed

4

Hi,

My case is very simple. Scales are 1x and 0.8x respectively.

I thought using 0.8x image as reference frame might cause a crash, as there will be stars in it which will not be in the 1x frame due to the wider field of view. But, it doesn’t seem to matter maybe because the difference is so small, and so no issues in registering :slight_smile:

Different question - depending upon the reference frame chosen, I get the stacked image at 0.8x (so the1x images are downsampled), or at 1x (so the 0.8x images are upsampled).

Is there a general rule on whether it is better to downsample or upsample in such situations with Siril?

Thank you