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M106 is a Seyfert galaxy in Canes Venatici, approximately 23.7 million light-years from Earth. This M106 DWARF 3 project ran across three sessions, three cold nights, and one combined mega stack. This post documents 15 hours and 31 minutes of total integration on a target that rewards patience, with a surrounding field that contains four additional galaxies within the same DWARF 3 frame, including NGC 4226 at an estimated 340 to 394 million light-years, the farthest object captured on this site.

What You Will Learn

• What the exact capture settings were across all three sessions and how the mega stack was assembled
• How a gibbous moon affected broadband galaxy data and what was done about it in processing
• Why cold ambient temperatures improve data quality for an uncooled sensor
• What NGC 4226 at up to 394 million light-years represents as the farthest detection on this site
• How the Stellar Studio baseline compares to the finished Snapseed result

Run Card

Target	Messier 106 (NGC 4258)
Type	Seyfert galaxy
Objects in field	NGC 4217, NGC 4226, NGC 4248, NGC 4232
Sessions	3
Moon phase	Gibbous
Transparency	Excellent
Seeing	Excellent
Mode	Guided EQ mode
EQ deviation	1 degree
Sub Length	60 seconds
Gain	50
Filter	Astro
Dark frames	30 at 60s gain 50
Total Integration	15h 31m
Location	New England, Bortle 6
Post-Processing	Stellar Studio, Snapseed

Session breakdown

Session 1: New England, Bortle 6, ambient temperature 21 to 28°F. Guided EQ mode, 60-second sub-exposures, gain 50, Astro filter, 30 dark frames at matching settings. 279 frames stacked.

Session 2: Same location, same settings, ambient temperature 24 to 31°F. 420 frames captured. A portion were rejected during stacking due to satellite trails and one aircraft crossing during the run. Additional frames were manually deleted before stacking after review showed cloud cover affecting those subs.

Session 3: Same location, same settings, similar temperatures. 386 frames captured, adding 6 hours and 26 minutes to the project.

All three sessions combined into a single on-device mega stack via the DWARF app: 15 hours and 31 minutes total integration. Post-processing in Stellar Studio: denoise, star correction, then auto. Finishing in Snapseed.

Three cold nights, consistent conditions

All three sessions were conducted at ambient temperatures between 21 and 31°F. The uncooled Sony IMX678 sensor runs meaningfully cooler at these ambient temperatures than it does in summer. Cold ambient temperatures reduce dark current directly. Less heat in the environment means less heat reaching the sensor, which means fewer thermally generated electrons masquerading as signal. The practical effect is a cleaner background before any calibration is applied.

The dark frames still matter, since they remove the fixed-pattern noise the sensor produces regardless of temperature, but the baseline noise floor is lower across all three sessions than it would be in warmer months. Running the same target across three cold nights with consistent settings produced a dataset that behaves predictably through the entire processing chain.

When sessions at slightly different temperatures are combined in the mega stack, the dark frame library needs to cover the full range accurately. A single master dark from one temperature will not calibrate data taken at a meaningfully different temperature correctly. For this project, all sessions used 30 dark frames at matching exposure and gain settings, captured at temperatures consistent with each respective session.

What the gibbous moon did to the M106 DWARF 3 data

The moon was present during all three sessions. For a broadband galaxy target using the Astro filter, moonlight raises the sky background. The Duo-Band filter blocks it for emission nebulae, but galaxies emit broadband light at the same wavelengths the moon scatters, so the filter cannot selectively suppress it.

The effect in the final stack is a gradient. A brightness ramp across the background that becomes visible when the data is stretched. On this dataset the gradient was manageable. It did not invalidate any of the three sessions. The background required deliberate attention during Snapseed finishing, but the galaxy data itself was not compromised.

15 hours of signal from an imperfect sky is worth more than two hours from a perfect one. The gradient is a processing problem, not a capture failure.

Frame rejection: satellites, aircraft, and cloud cover

Not every captured frame makes it into the final stack. On this project frames were lost to three separate causes: satellite trails crossing the field during session 2, one aircraft crossing during the same run, and cloud cover affecting a portion of the captures that were identified and manually deleted before stacking.

The DWARF app handles satellite and aircraft rejection automatically during the on-device mega stack. Cloud cover requires a manual review step. Frames affected by cloud show a drop in overall brightness and a non-uniform background that stacking cannot fully correct for, so removing them before the stack runs produces a cleaner result than letting the algorithm attempt to compensate.

The discipline of reviewing frames before stacking rather than after is one of the less visible parts of the workflow. It adds time but the stack quality difference is material.

The field: M106 and four companions

NGC 4217 is an edge-on spiral galaxy at approximately 55 to 65 million light-years, more than twice the distance of M106. In the DWARF 3 frame it appears as a thin elongated disk. NGC 4248 and NGC 4232 are smaller, fainter companions at similar distances to M106.

NGC 4226 is the most distant object in this field and the farthest galaxy confirmed on this site. It is a barred spiral and radio galaxy in Canes Venatici at an estimated distance of 339 to 394 million light-years, based on measured heliocentric velocities of 7238 to 7260 km/s. Its apparent magnitude is approximately 14.4 and its angular size is about 1.0 by 0.5 arcminutes, which makes it a genuinely faint object. Detecting it at 15 hours of integration from Bortle 6 skies under a gibbous moon is the deepest reach of this project.

To put that distance in context: the light that formed this image left NGC 4226 between 339 and 394 million years ago. At that point in Earth’s history, the Devonian period was ending and the first land-based forests were taking root. The DWARF 3 captured photons from that era with a 35mm aperture telescope from a suburban backyard.

At 15 hours of integration all four companions are detectable. The degree to which their structure is resolved is documented in the images accompanying this post.

Processing: from Stellar Studio baseline to finished result

The mega stack output from the DWARF app is a linear dataset. It looks flat and grey before processing. Stellar Studio applies denoise, star correction, and auto stretch in sequence, producing a usable starting point. That result then goes into Snapseed for final contrast, saturation, and background work.

The before and after below shows the Stellar Studio auto output on the left and the finished Snapseed result on the right.

A note on the second session night

While the DWARF 3 ran on M106, the Nexstar 8SE was set up alongside it pointed at the Moon. The gibbous phase that added background noise to the galaxy data was working in favor of lunar detail. Copernicus crater at high magnification through an 8-inch Schmidt-Cassegrain is a different kind of observation from deep-sky imaging. The detail is immediate, unprocessed, and visible in real time.

My wife came out, looked through the eyepiece at Copernicus, and said wow. That reaction is worth recording. The DWARF 3 runs unattended for hours and produces results that take processing to understand. The visual telescope produces a reaction in seconds. Both instruments had their place on the same night.

What comes next

At 15 hours and 31 minutes, this is the deepest M106 dataset on this site. It is not the deepest project overall — the M81 mega stack has grown to over 37 hours of total integration, documented separately. But M106 has more to give. The companion galaxies are detectable at this depth, and additional sessions will push their structure further. NGC 4226 in particular is worth returning to. At 339 to 394 million light-years, it sits at the far edge of what the DWARF 3 can reach from suburban skies, and more integration time will determine how much of its structure the system can resolve.

The DWARF app Mega Stack will absorb any new sessions into the existing dataset without reprocessing from scratch. The approach is the same one that produced the UGC 5210 detection at magnitude 14.88 in the M81 project. Depth uncovers what shorter integrations cannot see.

Clear Skies!

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