How long to image the Sunflower Galaxy with the DwarfLab DWARF 3

From a Bortle 6 suburban sky, the DwarfLab DWARF 3 needs about 2 h 24 min (575 subs of 15 s) for a solid image of the Sunflower Galaxy. A quick look takes 36 min; a showpiece 9 h 34 min. Under a Bortle 3 rural sky the solid figure drops to 50 min. At Bortle 6 the limit is skyglow, so a darker site or a filter helps more than longer subs. In this scope's field it fills 13% of the frame’s short side.

Sunflower Galaxy with the DwarfLab DWARF 3: 15 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site10 min42 subs41 min165 subs2 h 45 min660 subs
Bortle 2Typical dark site11 min45 subs44 min178 subs2 h 58 min711 subs
Bortle 3Rural13 min51 subs50 min202 subs3 h 21 min806 subs
Bortle 4Rural / suburban transition16 min65 subs1 h 05 min259 subs4 h 19 min1,036 subs
Bortle 5Suburban22 min88 subs1 h 28 min351 subs5 h 50 min1,401 subs
Bortle 6Bright suburban36 min144 subs2 h 24 min575 subs9 h 34 min2,297 subs
Bortle 7Suburban / urban transition1 h 03 min251 subs4 h 10 min1,001 subs17 h4,003 subs
Bortle 8City1 h 44 min416 subs6 h 56 min1,664 subs28 h6,653 subs
Bortle 9Inner city3 h 12 min769 subs13 h3,076 subs51 h12,304 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 3 h 07 min of run time. The DWARF 3’s battery (rated about 5 h 30 min) should cover it; a power bank still keeps the phone running the app alive. (Bortle 6, solid image; we allow 30% over the integration time.)

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How it frames

The Sunflower Galaxy is 12.6′ × 7.2′ across. The DWARF 3 frames 2.93° × 1.65° at 2.75″ per pixel, so it fills 13% of the frame’s short side.

Longer subs

Auto mode caps subs at 15 s; 30 s and longer need EQ mode, and 60 s is the ceiling on the tele camera. Time for a solid image by sub length:

Sub lengthBortle 3Bortle 5Bortle 7
15 s50 min202 subs1 h 28 min351 subs4 h 10 min1,001 subs
30 s47 min95 subs1 h 24 min169 subs4 h 07 min494 subs
60 s45 min46 subs1 h 23 min83 subs4 h 05 min246 subs

Leave the dual-band filter out for the Sunflower Galaxy. It is a galaxy, and it shines right across the spectrum. A dual-band filter keeps two emission lines and throws the rest away, so most of the light you came for is being stopped along with the sky. From a Bortle 6 sky it would be roughly 10 times slower.

About the Sunflower Galaxy

A flocculent spiral whose arms break into patches like sunflower seeds. Bright core, subtle outer disc.

M63, NGC 5055 · Galaxy in Canes Venatici · magnitude 8.6 · 12.6′ × 7.2′ · best in Mar, Apr, May. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Galaxies are broadband targets: their light is mostly starlight spread across the spectrum, so a dual-band filter throws most of it away and makes things slower, not faster. Shoot without a filter (or with a plain UV/IR cut) and rely on total time and a dark sky. The core of a galaxy is usually many times brighter than its outer disc, so a short stack shows the nucleus long before the arms; the figures here are for the arms and disc, not the core.

Field rotation in Alt-Az mode crops the edges of the stack over a long session, so on a big galaxy re-centre now and then or use EQ mode where your scope supports it.

About the DwarfLab DWARF 3

Small pixels on a 35 mm f/4.3 lens give a sharper image than its aperture suggests, and EQ mode with 60 s subs makes it the read-noise winner in dark skies.

Auto mode caps subs at 15 s; 30 s and longer need EQ mode, and 60 s is the ceiling on the tele camera. Three built-in filters: VIS, Astro (430 to 690 nm) and dual-band Hα 656 nm / OIII 501 nm.

Longer subs matter most under dark skies, where read noise rather than skyglow sets the floor. From a city the difference between 15 s and 60 s subs is small; from a rural site it can halve the total time, especially with a dual-band filter in place.

Stack across nights. Every smart scope app can continue a stack or you can combine the saved frames on a computer; the figures here are totals, not single-session limits.

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Imaged the Sunflower Galaxy with your DWARF 3? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Sunflower Galaxy from a DWARF 3? Email it with your total time and sky to [email protected] and it goes here, credited.

Same target, other telescopes

All telescopes for the Sunflower Galaxy · All targets for the DWARF 3