How long to image the Tulip Nebula with the Vaonis Vespera II

From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 3 h 51 min (1,388 subs of 10 s) for a solid image of the Tulip Nebula. A quick look takes 58 min; a showpiece 15 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 25 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 19% of the frame’s short side.

Tulip Nebula with the Vaonis Vespera II: 10 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site18 min106 subs1 h 10 min422 subs4 h 41 min1,686 subs
Bortle 2Typical dark site19 min113 subs1 h 15 min452 subs5 h 01 min1,805 subs
Bortle 3Rural21 min127 subs1 h 25 min508 subs5 h 38 min2,029 subs
Bortle 4Rural / suburban transition27 min161 subs1 h 47 min644 subs7 h 09 min2,574 subs
Bortle 5Suburban36 min215 subs2 h 23 min859 subs9 h 33 min3,436 subs
Bortle 6Bright suburban58 min347 subs3 h 51 min1,388 subs15 h5,552 subs
Bortle 7Suburban / urban transition1 h 40 min599 subs6 h 39 min2,396 subs27 h9,583 subs
Bortle 8City2 h 45 min991 subs11 h3,961 subs44 h15,843 subs
Bortle 9Inner city5 h 04 min1,825 subs20 h7,298 subs81 h29,192 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 5 h 01 min of run time. The Vespera II’s battery is rated at about 4 h, so the session needs an external power bank. (Bortle 6, solid image; we allow 30% over the integration time.)

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How it frames

The Tulip Nebula is 16′ × 9′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 19% 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 s1 h 25 min508 subs2 h 23 min859 subs6 h 39 min2,396 subs
20 s1 h 11 min213 subs2 h 09 min389 subs6 h 26 min1,157 subs
30 s1 h 06 min133 subs2 h 05 min250 subs6 h 21 min762 subs

With and without the dual-band filter

Solid quality, default sub length.
FilterBortle 3Bortle 5Bortle 7
No filter1 h 25 min508 subs2 h 23 min859 subs6 h 39 min2,396 subs
dual-band (Dual Band filter), clip-on1 h 37 min585 subs1 h 55 min693 subs3 h 14 min1,163 subs

The Vespera II has no built-in dual-band filter. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar; the app detects which is fitted. On an emission target like this it is the single biggest upgrade you can make.

About the Tulip Nebula

A compact hydrogen bloom in Cygnus near the black hole Cygnus X-1. Small and moderately faint; dual-band.

Sh2-101 · Emission nebula in Cygnus · magnitude 9.0 · 16′ × 9′ · best in Jul, Aug, Sep. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Emission nebulae glow in a few narrow lines, mostly hydrogen-alpha (deep red) and doubly ionised oxygen (teal). A dual-band filter passes those lines and blocks most skyglow, which is why it cuts the time needed from a suburban sky so dramatically. Use it. From a genuinely dark site the gain is smaller because there is less skyglow to block, and read noise becomes the limit, which is where longer subs (EQ mode, or Expert Mode on a Vespera) earn their keep.

Stars lose colour through a dual-band filter; a short broadband stack blended in fixes that if you care.

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 Tulip Nebula with your Vespera II? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Tulip Nebula 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 Tulip Nebula · All targets for the Vespera II