This image comprises of 4 x 3.3 degree full frame stacked images along the length of comet C/2023 A3 Tsuchinshan-ATLAS taken with a RASA 11.
Notes:
1. From an orbital perspective, we are looking up towards the comet with the sun to our bottom right. Therefore we are seeing the dust heavily smeared towards the left of the comet and its orbit. Above the comet seems to indicate very little dust present.
2. No gradient process was employed in any of the frames, so what you see is what was imaged gradient-wise.
3. The anti - tail is still viewed along the comet's previous orbital position.
4. As usual, SpectrophotometricColorCalibration process was applied to the stars (G5V star as white reference) rendering a truer color to the stars and comet. I added saturation to make all more apparent.
5. The total horizontal reach of the mosaic yields a little over 13.3 degrees. The comet stretches closer to 15 degrees.
6. When deciding on the panel size and orientation, judging the look of the comet from an individual sub makes this decision difficult. Individual subs can't possibly show where stacking will bring out areas of faint nebulosity. Framing was a bear!
7. There isn't enough time to include all panels for the mosaic to be rendered properly. Comets move too quickly and their positions in the sky rarely cooperate lengthy imaging times. Here I attempted 12.5 minutes per frame!
8. The full size of the PixInsight XISF file of the finished mosaic exceeded 10GB! I had to resample 2x2 in the final images.
9. Processing time of four panels in this mosaic is shorter than processing four different comet images. But not by much!
10. A fun process to render a large comet in nearly its entirety keeping with a closeup of details.
Full resolution link:
https://astrob.in/iqt9w1/B/
Observational Notes:
scope: RASA11 fl620mm F/2
Seeing: 4.5/5
Transparency: 9/10
Observer: DEBartlett
Place: JuneLake California USA (Altitude +2357m)
Image Info (all ):
All panels have been down sampled 2x2 (CMOS = BIN 2x2)
(All images processed solely using PixInsight)
Panel1 (right)
C2023_A3_Tsuchinshan_ATLAS_25x30sec_017_10C_2024_10_22193013local_JuneLake_California_USA_DEBartlett
Projection ............... Gnomonic
Projection origin ........ [4607.558821 2946.961189] px -> [RA: 17 02 55.553 Dec: +3 05 19.13]
Resolution ............... 2.506 arcsec/px
Rotation ................. 0 deg
Reference system ......... ICRS
Observation start time ... 2024-10-23 02:12:24 UTC
Observation end time ..... 2024-10-23 02:39:41 UTC
Geodetic coordinates ..... 119 04 46 W 37 46 30 N 2357 m
Focal distance ........... 619.00 mm
Pixel size ............... 3.76 um
Field of view ............ 3d 12' 25.7" x 2d 3' 4.7"
Image center ............. RA: 17 02 55.554 Dec: +3 05 19.13 ex: +0.010681 px ey: -0.005261 px
Image bounds:
top-left .............. RA: 17 09 28.109 Dec: +4 04 07.54 ex: -1.515641 px ey: -1.093032 px
top-right ............. RA: 16 56 36.601 Dec: +4 09 22.48 ex: +0.734460 px ey: -0.959096 px
bottom-left ........... RA: 17 09 13.627 Dec: +2 01 07.09 ex: -1.054358 px ey: +0.383582 px
bottom-right .......... RA: 16 56 23.652 Dec: +2 06 19.70 ex: +1.957235 px ey: +0.370478 px
Panel2:
Projection ............... Gnomonic
Projection origin ........ [4607.527976 2946.933375] px -> [RA: 17 14 13.552 Dec: +4 06 57.51]
Resolution ............... 2.506 arcsec/px
Rotation ................. 0 deg
Reference system ......... ICRS
Observation start time ... 2024-10-23 02:41:59 UTC
Observation end time ..... 2024-10-23 03:12:33 UTC
Geodetic coordinates ..... 119 04 46 W 37 46 30 N 2357 m
Focal distance ........... 618.99 mm
Pixel size ............... 3.76 um
Field of view ............ 3d 12' 25.8" x 2d 3' 4.8"
Image center ............. RA: 17 14 13.553 Dec: +4 06 57.51 ex: -0.021007 px ey: +0.014289 px
Image bounds:
top-left .............. RA: 17 20 46.709 Dec: +5 05 44.48 ex: -0.923596 px ey: -1.183630 px
top-right ............. RA: 17 07 54.068 Dec: +5 10 59.54 ex: +0.778939 px ey: -0.996525 px
bottom-left ........... RA: 17 20 31.936 Dec: +3 02 43.94 ex: -0.971016 px ey: +0.689367 px
bottom-right .......... RA: 17 07 41.246 Dec: +3 07 56.31 ex: +1.933133 px ey: +0.277018 px
Panel3:
Projection ............... Gnomonic
Projection origin ........ [4607.533109 2946.906860] px -> [RA: 17 24 55.445 Dec: +4 48 13.57]
Resolution ............... 2.506 arcsec/px
Rotation ................. 0 deg
Reference system ......... ICRS
Observation start time ... 2024-10-23 03:14:48 UTC
Observation end time ..... 2024-10-23 03:42:20 UTC
Geodetic coordinates ..... 119 04 46 W 37 46 30 N 2357 m
Focal distance ........... 618.89 mm
Pixel size ............... 3.76 um
Field of view ............ 3d 12' 27.8" x 2d 3' 6.1"
Image center ............. RA: 17 24 55.444 Dec: +4 48 13.57 ex: +0.016027 px ey: +0.001520 px
Image bounds:
top-left .............. RA: 17 31 29.183 Dec: +5 46 59.83 ex: -1.563659 px ey: -1.309504 px
top-right ............. RA: 17 18 35.476 Dec: +5 52 15.34 ex: +0.593655 px ey: -1.027461 px
bottom-left ........... RA: 17 31 14.087 Dec: +3 43 58.54 ex: -1.088602 px ey: +0.655376 px
bottom-right .......... RA: 17 18 22.739 Dec: +3 49 11.07 ex: +1.981160 px ey: +0.370250 px
Panel4:
Projection ............... Gnomonic
Projection origin ........ [4607.440637 2946.907996] px -> [RA: 17 34 46.295 Dec: +5 33 07.11]
Resolution ............... 2.506 arcsec/px
Rotation ................. 0 deg
Reference system ......... ICRS
Observation start time ... 2024-10-23 03:44:20 UTC
Observation end time ..... 2024-10-23 04:08:19 UTC
Geodetic coordinates ..... 119 04 46 W 37 46 30 N 2357 m
Focal distance ........... 618.84 mm
Pixel size ............... 3.76 um
Field of view ............ 3d 12' 28.6" x 2d 3' 6.6"
Image center ............. RA: 17 34 46.294 Dec: +5 33 07.10 ex: -0.008609 px ey: -0.156318 px
Image bounds:
top-left .............. RA: 17 41 20.671 Dec: +6 31 53.12 ex: -1.587901 px ey: -0.946681 px
top-right ............. RA: 17 28 25.776 Dec: +6 37 07.49 ex: +0.702570 px ey: -1.741797 px
bottom-left ........... RA: 17 41 05.330 Dec: +4 28 51.08 ex: -0.997398 px ey: +0.087708 px
bottom-right .......... RA: 17 28 13.075 Dec: +4 34 02.87 ex: +1.702710 px ey: +0.092197 px |
Page last updated: Tue 30 Sep 22:01:01 BST 2025