The Leo Triplet (Rollover with Labels)

Leo Triplet
All Images
Copyright Steve Cannistra

For a better view of galaxy details, please click here for a large size image (unlabeled).
Please click here for a medium size image (unlabeled).

RA (J2000): 11h 19m 34s
Dec (J2000): +13 degrees 15' 56"
Position Angle: 90 degrees
Field of View:  Approximately 1 degree

Note:  For a better view of galaxy details, please click here for a large size image (but without rollover).

The Leo Triplet is a famous and photogenic target for astrophotographers.  The three main galaxies that comprise the triplet are NGC 3628 (the "Hamburger Galaxy", lower left), M65 (top), and M66 (lower right), labeled in the rollover shown above.  These spiral galaxies are approximately 35 million light years away, with NGC 3628 being seen edge-on and showing an intricate pattern of central dust, while both M65 and M66 being tilted to reveal their spiral structure.   The galaxies of the Leo Triplet have been influenced by intense gravitatational interactions, most notably between NGC 3628 and M66, leaving each galaxy with tidal tails and misshapen spiral arms.  A faint tidal tail associated with NGC 3828 can be seen in the lower left of the image, and the diffuse and misshapen spiral arms of M66 are plainly visible as well.  M66 (lower right) in particular shows many regions of new star formation, as evidenced by the predominance of blue light emitted by newly formed star clusters coursing through its spiral arms (best appreciated in the larger size image), a testimony to the gravitational interactions it has had with NGC 3628 (lower left).  In contrast, M65 (top) shows a very well organized spiral structure with much less blue, indicating that it has experienced less disturbance from the other two members of the trio.  More detail about this region may be found on Rob Gendler's website.

Photographic Details:
Dates:  February 3 thru 6, 2024.
Scope:  Takahashi FSQ106 at f5 on the Takahashi NJP Mount.
Autoguider:  ASI178 autoguider with SvBony 30mm guidescope, focal length 120mm.
Camera:  ZWO ASI294MM at -10C, with 7 position ZWO filter wheel.  Pixel size is 2.3 microns (Bin 1x1), yielding an image scale with the FSQ (530mm focal length) of 0.90 "/pixel (well matched for my seeing of  3 arcseconds).  Camera gain set to 50 (e-gain 2.13 electrons/ADU), offset 25. Read noise at this gain level was 2.18 electrons rms.
Baader LRGB filters; 2 inch.
Image acquisition software:  MaximDL for camera control and autoguiding; CCD Commander for automation.
Exposures:  Total exposure 11 hours (LUM 4 hours, 60 second subs; Red 2 hours, 120 second subs; Green 2 hours, 120 second subs; Blue 3 hours, 120 second subs ).
Processing:  Calibration, integration, Spectrophotometric Color Calibration (SPCC), deconvolution (BlurXTerminator), noise reduction (NoiseXTerminator) in Pixinsight; subsequent processing in Photoshop.

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