How long to image the M96 with the DwarfLab DWARF 3

From a Bortle 6 suburban sky, the DwarfLab DWARF 3 needs about 2 h 21 min (563 subs of 15 s) for a solid image of the M96. A quick look takes 35 min; a showpiece 9 h 22 min. Under a Bortle 3 rural sky the solid figure drops to 52 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 8% of the frame’s short side.

M96 with the DwarfLab DWARF 3: 15 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site11 min44 subs43 min174 subs2 h 54 min695 subs
Bortle 2Typical dark site12 min47 subs46 min186 subs3 h 06 min743 subs
Bortle 3Rural13 min53 subs52 min209 subs3 h 28 min833 subs
Bortle 4Rural / suburban transition16 min66 subs1 h 06 min263 subs4 h 23 min1,052 subs
Bortle 5Suburban22 min88 subs1 h 27 min350 subs5 h 50 min1,399 subs
Bortle 6Bright suburban35 min141 subs2 h 21 min563 subs9 h 22 min2,250 subs
Bortle 7Suburban / urban transition1 h242 subs4 h 02 min968 subs16 h3,871 subs
Bortle 8City1 h 40 min400 subs6 h 39 min1,598 subs27 h6,389 subs
Bortle 9Inner city3 h 04 min735 subs12 h2,940 subs49 h11,758 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 3 h 03 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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Everything that fits the DWARF 3 →

How it frames

The M96 is 7.6′ × 5.2′ across. The DWARF 3 frames 2.93° × 1.65° at 2.75″ per pixel, so it fills 8% 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 s52 min209 subs1 h 27 min350 subs4 h 02 min968 subs
30 s49 min98 subs1 h 24 min169 subs3 h 59 min478 subs
60 s47 min48 subs1 h 23 min83 subs3 h 57 min238 subs

Leave the dual-band filter out for the M96. 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 M96

The brightest of the M95/M96/M105 group, a slightly asymmetric spiral.

NGC 3368 · Galaxy in Leo · magnitude 9.2 · 7.6′ × 5.2′ · best in Feb, Mar, Apr. 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 M96 with your DWARF 3? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the M96 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 M96 · All targets for the DWARF 3