How long to image the M14 with the DwarfLab DWARF mini

From a Bortle 6 suburban sky, the DwarfLab DWARF mini needs about 23 min (91 subs of 15 s) for a solid image of the M14. A quick look takes 6 min; a showpiece 1 h 30 min. Under a Bortle 3 rural sky the solid figure drops to 10 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 15% of the frame’s short side.

M14 with the DwarfLab DWARF mini: 15 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site3 min10 subs9 min37 subs36 min145 subs
Bortle 2Typical dark site3 min10 subs9 min38 subs38 min152 subs
Bortle 3Rural3 min11 subs10 min42 subs41 min165 subs
Bortle 4Rural / suburban transition3 min13 subs12 min49 subs49 min195 subs
Bortle 5Suburban4 min16 subs15 min61 subs1 h 01 min243 subs
Bortle 6Bright suburban6 min23 subs23 min91 subs1 h 30 min361 subs
Bortle 7Suburban / urban transition9 min37 subs37 min147 subs2 h 26 min586 subs
Bortle 8City15 min59 subs58 min234 subs3 h 54 min936 subs
Bortle 9Inner city26 min106 subs1 h 45 min421 subs7 h1,681 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 29 min of run time. The DWARF mini’s battery (rated about 3 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 mini →

How it frames

The M14 is 11′ across. The DWARF mini frames 2.13° × 1.20° at 3.99″ per pixel, so it fills 15% of the frame’s short side.

Longer subs

Auto mode caps subs at 15 s; 30 s and longer need EQ mode, and 90 s is the ceiling. Time for a solid image by sub length:

Sub lengthBortle 3Bortle 5Bortle 7
15 s10 min42 subs15 min61 subs37 min147 subs
30 s15 min30 subs15 min30 subs36 min72 subs
60 s30 min30 subs30 min30 subs35 min35 subs
90 s45 min30 subs45 min30 subs45 min30 subs

Leave the dual-band filter out for the M14. It is a globular cluster, 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 11 times slower.

About the M14

A fainter, more distant globular in Ophiuchus. Takes longer than its neighbours to resolve.

NGC 6402 · Globular cluster in Ophiuchus · magnitude 7.6 · 11′ · best in May, Jun, Jul. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Globular clusters are point sources packed tight, so they come quickly: the core resolves into stars within a handful of minutes on any smart scope. More time deepens the halo and pulls in the faint outer members. Use short subs so the core does not saturate into a white blob, and no filter.

About the DwarfLab DWARF mini

DwarfLab’s answer to the Seestar S30: same sensor and focal length, big pixels, dual-band filter built in, and 90 s subs in EQ mode. Sensitivity over megapixels.

Auto mode caps subs at 15 s; 30 s and longer need EQ mode, and 90 s is the ceiling. Built-in Astro (430 to 690 nm), dark-frame and dual-band Hα / OIII filters; no plain VIS filter on the tele camera.

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 90 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 M14 with your DWARF mini? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the M14 from a DWARF mini? Email it with your total time and sky to [email protected] and it goes here, credited.

Same target, other telescopes

All telescopes for the M14 · All targets for the DWARF mini