7-panel mosaic in 110 minutes
Posted: Mon Mar 08, 2021 8:59 pm
From Melotte 111, a bright Open Cluster in Coma Berenices, to NGC 4565, the Needle Galaxy.
It is an odd shape, but my plan is to use it in a video presentation. I'll be using some video processing techniques to make it more accessible.
The image size is 7515 x 854 pixels. The image height is approximately the height of my sensor: 1040 pixels. I had to crop it down to 854 pixels since the mosaic is curved.
The total time to capture was 3.5 hours from 9pm to 12:30am, all east of the meridian. I don't have a go-to mount or auto-focus, so I had to devise a plan. I knew that I needed to minimize the number of filter changes, so I decided on this:
1. Plate solve to the westward end of the mosaic.
2. Select luminance filter (actually a Wratten #12).
3. Focus.
4. Capture 12x 25-second frames for Panel #1.
5. Turn off the RA drive for exactly 3 minutes.
6. Capture 12x 25-second frames for Panel #2.
7. Turn off the RA drive for exactly 3 minutes.
8. Capture 12x 25-second frames for Panel #3.
9. Turn off the RA drive for exactly 3 minutes.
10. Capture 12x 25-second frames for Panel #4.
11. Turn off the RA drive for exactly 3 minutes.
12. Capture 12x 25-second frames for Panel #5.
13. Turn off the RA drive for exactly 3 minutes.
14. Capture 12x 25-second frames for Panel #6.
15. Turn off the RA drive for exactly 3 minutes.
16. Capture 12x 25-second frames for Panel #7.
17. Turn off the RA drive for exactly 3 minutes.
18. Luminance completed.
19. Repeat steps 1-18 for the Red filter but use a 34-second exposure.
20. Repeat steps 1-18 for the Green filter but use a 20-second exposure.
Next came processing in APP:
21. Create 7 RGB composite images for each panel using my technique for transforming W12, R, G data into LRGB.
22. Use HSL Selective Color to push Cyan to Blue and Orange to Red.
23. Do a minor stretch and saturation.
24. Export the panels.
Next came Affinity Photo:
25. APP refused to create a mosaic using noisy panels, so I had to denoise the panels first.
Back into APP:
26. Create the mosaic using the denoised panels.
27. Export the mosaic.
Back into Affinity Photo:
28. Crop.
29. Adjust curves.
30. Export.
William Optics 71mm f/5.9
Atik 314E CCD
GSO Wratten #12
Optolong Red and Green
U235-Pro Web App
Brian
It is an odd shape, but my plan is to use it in a video presentation. I'll be using some video processing techniques to make it more accessible.
The image size is 7515 x 854 pixels. The image height is approximately the height of my sensor: 1040 pixels. I had to crop it down to 854 pixels since the mosaic is curved.
The total time to capture was 3.5 hours from 9pm to 12:30am, all east of the meridian. I don't have a go-to mount or auto-focus, so I had to devise a plan. I knew that I needed to minimize the number of filter changes, so I decided on this:
1. Plate solve to the westward end of the mosaic.
2. Select luminance filter (actually a Wratten #12).
3. Focus.
4. Capture 12x 25-second frames for Panel #1.
5. Turn off the RA drive for exactly 3 minutes.
6. Capture 12x 25-second frames for Panel #2.
7. Turn off the RA drive for exactly 3 minutes.
8. Capture 12x 25-second frames for Panel #3.
9. Turn off the RA drive for exactly 3 minutes.
10. Capture 12x 25-second frames for Panel #4.
11. Turn off the RA drive for exactly 3 minutes.
12. Capture 12x 25-second frames for Panel #5.
13. Turn off the RA drive for exactly 3 minutes.
14. Capture 12x 25-second frames for Panel #6.
15. Turn off the RA drive for exactly 3 minutes.
16. Capture 12x 25-second frames for Panel #7.
17. Turn off the RA drive for exactly 3 minutes.
18. Luminance completed.
19. Repeat steps 1-18 for the Red filter but use a 34-second exposure.
20. Repeat steps 1-18 for the Green filter but use a 20-second exposure.
Next came processing in APP:
21. Create 7 RGB composite images for each panel using my technique for transforming W12, R, G data into LRGB.
22. Use HSL Selective Color to push Cyan to Blue and Orange to Red.
23. Do a minor stretch and saturation.
24. Export the panels.
Next came Affinity Photo:
25. APP refused to create a mosaic using noisy panels, so I had to denoise the panels first.
Back into APP:
26. Create the mosaic using the denoised panels.
27. Export the mosaic.
Back into Affinity Photo:
28. Crop.
29. Adjust curves.
30. Export.
William Optics 71mm f/5.9
Atik 314E CCD
GSO Wratten #12
Optolong Red and Green
U235-Pro Web App
Brian