Messier 51: The Whirlpool Galaxy
The smaller galaxy, NGC5195 has suffered extensive disruption following a gravitational encounter with the much larger M51 spiral galaxy.
Two tiny galaxies can also be seen - edge-on spiral IC 4277 is just under and to the right of NGC 5195 and IC 4278 is an irregular class galaxy to the right of the junction between M51 and NGC 5195.
Imaged over 18th and 19th March 2025.
Technical Card
900/120mm f/7 Skywatcher Esprit 120 triplet refractor.
0.85 x Field corrector with 2 inch IDAS P3 LPS filter
ZWO ASI2600MC; 60 x 300 second subs, Gain 100, Offset 25, Temp = -15c.
EQ6 R pro mount . EQMOD control.
Pegasus Astro FocusCube 2 electronic focuser.
Session control; SharpCap 4.1 on laptop.
Controlled from inside house with iPAD
Automated plate solving GOTO and focusing. 8 secs at gain 635.
60 dark frames
50 flat frames (electroluminescent panel A, 3500ms exposure @ 0 gain).
Post processed in PixInsight 1.8.9.
Light Pollution and Weather:
Night 1: SQM (L) =19.98 m/as2
Clear throughout - stopped at Moonrise
Night 2: SQM (L) =20.03 m/as2
Session stopped by cloud
Polar Alignment:
Error measured by PHD2= 0.5 arc minute.
RA drift - 0.04 arcsec/min
Dec drift - 0.10arcsec/min
Guiding:
PHD2 guiding with ZWO ASI290mm/WO GuideStar 61.
Every 6th sub dithered.
RA RMS error 0.53 arcsec
Dec RMS error 0.39arcsec
Astrometry
Resolution ............... 0.900 arcsec/px
Observation start time ... 2025-03-23 20:52:58 UTC
Observation end time ..... 2025-03-24 02:35:13 UTC
Focal distance ........... 861.81 mm
Pixel size ............... 3.76 um
Field of view ............ 1d 33' 42.7" x 1d 2' 38.1"
Image center ............. RA: 14 03 25.884 Dec: +54 19 13.67
Messier 51: The Whirlpool Galaxy
The smaller galaxy, NGC5195 has suffered extensive disruption following a gravitational encounter with the much larger M51 spiral galaxy.
Two tiny galaxies can also be seen - edge-on spiral IC 4277 is just under and to the right of NGC 5195 and IC 4278 is an irregular class galaxy to the right of the junction between M51 and NGC 5195.
Imaged over 18th and 19th March 2025.
Technical Card
900/120mm f/7 Skywatcher Esprit 120 triplet refractor.
0.85 x Field corrector with 2 inch IDAS P3 LPS filter
ZWO ASI2600MC; 60 x 300 second subs, Gain 100, Offset 25, Temp = -15c.
EQ6 R pro mount . EQMOD control.
Pegasus Astro FocusCube 2 electronic focuser.
Session control; SharpCap 4.1 on laptop.
Controlled from inside house with iPAD
Automated plate solving GOTO and focusing. 8 secs at gain 635.
60 dark frames
50 flat frames (electroluminescent panel A, 3500ms exposure @ 0 gain).
Post processed in PixInsight 1.8.9.
Light Pollution and Weather:
Night 1: SQM (L) =19.98 m/as2
Clear throughout - stopped at Moonrise
Night 2: SQM (L) =20.03 m/as2
Session stopped by cloud
Polar Alignment:
Error measured by PHD2= 0.5 arc minute.
RA drift - 0.04 arcsec/min
Dec drift - 0.10arcsec/min
Guiding:
PHD2 guiding with ZWO ASI290mm/WO GuideStar 61.
Every 6th sub dithered.
RA RMS error 0.53 arcsec
Dec RMS error 0.39arcsec
Astrometry
Resolution ............... 0.900 arcsec/px
Observation start time ... 2025-03-23 20:52:58 UTC
Observation end time ..... 2025-03-24 02:35:13 UTC
Focal distance ........... 861.81 mm
Pixel size ............... 3.76 um
Field of view ............ 1d 33' 42.7" x 1d 2' 38.1"
Image center ............. RA: 14 03 25.884 Dec: +54 19 13.67