How long to image the Sunflower Galaxy with the Vaonis Vespera II

From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 1 h 39 min (593 subs of 10 s) for a solid image of the Sunflower Galaxy. A quick look takes 25 min; a showpiece 6 h 35 min. Under a Bortle 3 rural sky the solid figure drops to 38 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.

Sunflower Galaxy with the Vaonis Vespera II: 10 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site8 min49 subs33 min196 subs2 h 10 min782 subs
Bortle 2Typical dark site9 min52 subs35 min208 subs2 h 18 min831 subs
Bortle 3Rural10 min58 subs38 min231 subs2 h 34 min923 subs
Bortle 4Rural / suburban transition12 min72 subs48 min287 subs3 h 11 min1,147 subs
Bortle 5Suburban16 min94 subs1 h 03 min376 subs4 h 10 min1,502 subs
Bortle 6Bright suburban25 min149 subs1 h 39 min593 subs6 h 35 min2,371 subs
Bortle 7Suburban / urban transition42 min252 subs2 h 48 min1,007 subs11 h4,028 subs
Bortle 8City1 h 09 min413 subs4 h 35 min1,651 subs18 h6,601 subs
Bortle 9Inner city2 h 06 min756 subs8 h 24 min3,023 subs34 h12,089 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 2 h 08 min of run time. The Vespera II’s battery (rated about 4 h) 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 Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 15% of the frame’s short side.

Longer subs

10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only, no EQ mode. Time for a solid image by sub length:

Sub lengthBortle 3Bortle 5Bortle 7
10 s38 min231 subs1 h 03 min376 subs2 h 48 min1,007 subs
20 s33 min99 subs57 min171 subs2 h 42 min487 subs
30 s31 min62 subs55 min111 subs2 h 40 min321 subs

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 Vaonis Vespera II

A 50 mm quadruplet on an 8 MP sensor with Vaonis’s mosaic mode for wide fields. Same optics class as the Seestar S50, four times the pixels.

10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only, no EQ mode. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar; the app detects which is fitted.

Longer subs matter most under dark skies, where read noise rather than skyglow sets the floor. From a city the difference between 10 s and 30 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 Vespera II? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Sunflower Galaxy from a Vespera II? 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 Vespera II