StarAlignment with differnt image scale sets fails

[LarryC]

I understood that one could register images taken at different image scales against a common reference frame.  When I try I get up to 100 out of 200 images fail to register, but with fairly extreme adjustments to StarAlignment's star detection parameters I can get that down to about 30 or so.  All of the images look fine and each set registered 100% against a reference frame from within that image scale set using near default StarAlignment parameters.

Should this be possible to accomplish or am I asking too much from StarAlignment?

Larry

[vicent_peris]

Hi Larry,

It should be possible. In fact, SA is working; what's not working is probably the structure / star detection. Please, could you give us details on the OTA / camera combination for the reference and the target images?

V.

[LarryC]

Both sets were 120sec exposures taken with an AT6RC and ASI1600mm with an Ha filter.  The only difference in the sets is that one was taken at the RC6 native FL of ~1300 with an AT2FF Field Flattener and the other set was taken with the RC6 using a CCDT67 reducer spaced to be about 0.7x, so about 1000.  All images were Blinked before calibration and a few images culled with SFS, so both sets "look" good. Calibration used a properly matched common master flat and biases and had image-session specific flats.  The final corrected images look fine.

Thanks,

Larry

[Juan Conejero]

There should be no problem at all to register images from focal lengths of 1300 and 1000 mm.

As always, we cannot help without looking at the data. We are magicians, not fortunetellers