I've been attempting to stack two batches of M42 images and struggling to isolate what is causing star doubling in the finished product (shown in the attached image). The camera's (Z6ii, 400mm) orientation was changed between batches, causing the first set to be exif orientation 6 (rotate 90 cw) and the second set to be exif orientation 5 (mirror horizontal and rotate 270 cw), and further resulting in declination variance between the two sets. ASTAP has no issues with plate solving either set using the D80 star database.
I have done the following in an effort to avoid star doubling when stacking the entire set of images:
1) Manually corrected orientation of images in ASTAP and resaved them as new FITS files before attempting to stack
2) Stacked using calibration and alignment only in ASTAP, using the best quality images from either set as the appropriate reference image
3) Reduced the star count, hash code tolerance, and enabled the slow and calibrate prior solving options in the alignment tab
4) Attempted to align using star, astrometric, and manual alignment
5) Attempted to stack using various sigma factors
6) Attempted to stack using various de-mosaic methods
7) Attempted to stack each set separately using all of the foregoing variations, before stacking the two stacks
Despite this, I cannot seem to avoid star doubling, and would normally assume it is due to the shift in image angle and/or orientation, except for the fact that both DSS and Siril have no issues stacking the entire set without this star doubling in the final product.
a) The two images align easy in mode "star alignment. Select that mode.
b) Orientation is fully automatic. Manually is not required.
c) Conversion to FITS is also fully automatic.
1) Your problem could be caused by one bad image which is selected as reference image and marked with a little crown. (see attached) Inspect that image by double click. If bad just remove or rename to back.
2) Check your setting. See attached.
3) If this doesn't work, share your image set and I will have a look
I've been attempting to stack two batches of M42 images and struggling to isolate what is causing star doubling in the finished product (shown in the attached image). The camera's (Z6ii, 400mm) orientation was changed between batches, causing the first set to be exif orientation 6 (rotate 90 cw) and the second set to be exif orientation 5 (mirror horizontal and rotate 270 cw), and further resulting in declination variance between the two sets. ASTAP has no issues with plate solving either set using the D80 star database.
I have done the following in an effort to avoid star doubling when stacking the entire set of images:
1) Manually corrected orientation of images in ASTAP and resaved them as new FITS files before attempting to stack
2) Stacked using calibration and alignment only in ASTAP, using the best quality images from either set as the appropriate reference image
3) Reduced the star count, hash code tolerance, and enabled the slow and calibrate prior solving options in the alignment tab
4) Attempted to align using star, astrometric, and manual alignment
5) Attempted to stack using various sigma factors
6) Attempted to stack using various de-mosaic methods
7) Attempted to stack each set separately using all of the foregoing variations, before stacking the two stacks
Despite this, I cannot seem to avoid star doubling, and would normally assume it is due to the shift in image angle and/or orientation, except for the fact that both DSS and Siril have no issues stacking the entire set without this star doubling in the final product.
An example NEF file from each set is available here: https://drive.google.com/drive/folders/1to2mW4KHvz4kkYwnHDZs_G2-PRurodCj?usp=sharing Any ideas would be greatly appreciated. Thanks!
Hi,
a) The two images align easy in mode "star alignment. Select that mode.
b) Orientation is fully automatic. Manually is not required.
c) Conversion to FITS is also fully automatic.
1) Your problem could be caused by one bad image which is selected as reference image and marked with a little crown. (see attached) Inspect that image by double click. If bad just remove or rename to back.
2) Check your setting. See attached.
3) If this doesn't work, share your image set and I will have a look
Han
Thank you for the reply. I'll continue to tinker with it.