Pixinsight - star alignment HELP

[Sternfreund]

Hey,

Last night i shot 21x10min with ED90/500 + 400Da and 21x10min with ED100/900+0,85 red+550Da.

i calibrated and debayered everything already.

now i wanted to star align the Files with pixinsight.

but it only aligned the Files of one Camera and few of the other...

Need a Guide through it...

thanks

[Space Bat]

Harry page is your man - and has excellent tutorials on his site...http://www.harrysastroshed.com/pixinsighthome.html

Also if you message him am sure he can quickly point you down the right road to what you are having a problem with

[SkyGibbon]

Could it be the difference in focal length between the two sets on the detection? You can try to set  a higher focal length shot as your reference image, or vice versa, as it probably just aligned the images that coincided with your reference image. You can also try the other methods available to see if it makes a difference.

[lensman57]

Hey,

Last night i shot 21x10min with ED90/500 + 400Da and 21x10min with ED100/900+0,85 red+550Da.

i calibrated and debayered everything already.

now i wanted to star align the Files with pixinsight.

but it only aligned the Files of one Camera and few of the other...

Need a Guide through it...

thanks

Use the high resolution capture as reference,  PI should rescale and align the others to this one. I have other problems with this Star Align routine such as failing to pick up alignment stars.

A.G

[Sp@ce_d]

Must admit, whilst PI has got a lot better at this I tend to still use RegiStar for the wildly differing scales

[harry page]

Hi

Are you using the script or the registration module ?

Harry

[Physicist13]

different image scales, so I'd say reg each batch separately with distortion correction then mosaic merge.

I've found PI reg to be pretty perfect so far...sub pix.

Patrick

[Sternfreund]

Short update:

the frames from the ED100/900+0,85 red+550Da  have a 5 times higher S/N ratio than the frames with ED90/500 + 400Da. 

so the solution was to increase the "noise reduction" at "star detection" to 2. 

Everything works now.

BUT:

even if i stack all 42 frames together i get a much worse stacked image than if i stack just the 21 frames from ED100/900+0,85 red+550Da alone….

​i don't get it why the S/N ratio is that higher… the ED with f5,5 must perform much better with the same exposure time and iso than the f7 system. 

maybe the 400Da is that much worse...

[lensman57]

Short update:

the frames from the ED100/900+0,85 red+550Da  have a 5 times higher S/N ratio than the frames with ED90/500 + 400Da. 

so the solution was to increase the "noise reduction" at "star detection" to 2. 

Everything works now.

BUT:

even if i stack all 42 frames together i get a much worse stacked image than if i stack just the 21 frames from ED100/900+0,85 red+550Da alone….

​i don't get it why the S/N ratio is that higher… the ED with f5,5 must perform much better with the same exposure time and iso than the f7 system. 

maybe the 400Da is that much worse...

I can only guess that the 100ED @ F7.6 goes a lot deeper with that much less of the reduced noisy sky in the capture, the camera has something to do with it too for sure. 

A.G