How long should I image the Jellyfish Nebula with the Vespera Pro from a Bortle 6 sky?

About 15 h of total integration for a solid image, or 59 h for a showpiece. A quick look takes 3 h 43 min.

How many subs is that on the Vespera Pro?

At the default 10 s sub length, 5,344 subs for a solid image from Bortle 6 and 2,127 from Bortle 3.

Does a dual-band filter help on the Jellyfish Nebula?

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 15 h to 10 h.

How long to image the Jellyfish Nebula with the Vaonis Vespera Pro

From a Bortle 6 suburban sky, the Vaonis Vespera Pro needs about 15 h (5,344 subs of 10 s) for a solid image of the Jellyfish Nebula. A quick look takes 3 h 43 min; a showpiece 59 h. Under a Bortle 3 rural sky the solid figure drops to 5 h 54 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 51% of the frame’s short side.

Jellyfish Nebula with the Vaonis Vespera Pro: 10 s subs.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	1 h 16 min454 subs	5 h 02 min1,813 subs	20 h7,251 subs
Bortle 2Typical dark site	1 h 20 min481 subs	5 h 20 min1,921 subs	21 h7,684 subs
Bortle 3Rural	1 h 29 min532 subs	5 h 54 min2,127 subs	24 h8,505 subs
Bortle 4Rural / suburban transition	1 h 49 min656 subs	7 h 17 min2,624 subs	29 h10,493 subs
Bortle 5Suburban	2 h 22 min853 subs	9 h 28 min3,411 subs	38 h13,644 subs
Bortle 6Bright suburban	3 h 43 min1,336 subs	15 h5,344 subs	59 h21,374 subs
Bortle 7Suburban / urban transition	6 h 16 min2,257 subs	25 h9,026 subs	100+ h36,104 subs
Bortle 8City	10 h3,686 subs	41 h14,744 subs	160+ h58,974 subs
Bortle 9Inner city	19 h6,735 subs	75 h26,938 subs	300+ h107,750 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 19 h of run time. That is more than one night: over 3 nights, about 6 h 26 min each. The Vespera Pro’s battery (rated about 11 h) should cover each night; a power bank still keeps the phone running the app alive. (Bortle 6, solid image; we allow 30% over the integration time, and 30% off the battery for a January night.)

USB-C PD power bank 20000mAh 30WExtends the 11 h battery; 30 W PD per Vaonis.
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red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
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How it frames

The Jellyfish Nebula is 50′ × 40′ across. The Vespera Pro frames 1.62° × 1.62° at 1.65″ per pixel, so it fills 51% 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 length	Bortle 3	Bortle 5	Bortle 7
10 s	5 h 54 min2,127 subs	9 h 28 min3,411 subs	25 h9,026 subs
20 s	4 h 47 min861 subs	8 h 21 min1,503 subs	24 h4,311 subs
30 s	4 h 24 min529 subs	7 h 58 min957 subs	24 h2,829 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	5 h 54 min2,127 subs	9 h 28 min3,411 subs	25 h9,026 subs
dual-band (Dual Band filter), clip-on	7 h 36 min2,735 subs	8 h 41 min3,128 subs	13 h4,847 subs

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

About the Jellyfish Nebula

A supernova remnant beside Propus in Gemini, with a bright rim like a jellyfish bell. Faint; dual-band and hours.

IC 443, Sh2-248 · Supernova remnant in Gemini · magnitude 12.0 · 50′ × 40′ · best in Dec, Jan, Feb. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Supernova remnants are emission-line objects, strong in both hydrogen-alpha and OIII, and their filaments are thin, so pixel scale matters as much as aperture. A dual-band filter is essential from any lit sky and still helps under a dark one. These are long-integration targets; plan on several sessions and stack across nights.

About the Vaonis Vespera Pro

The square-sensor Vespera with 2 µm pixels. Higher resolution than the II, and correspondingly slower per pixel: expect around double the time for the same per-pixel SNR. Run-out in 2026 and replaced by the Vespera Pro 2.

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.

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

Have an image of the Jellyfish Nebula from a Vespera Pro? Email it with your total time and sky to [email protected] and it goes here, credited.

Same target, other telescopes

All telescopes for the Jellyfish Nebula · All targets for the Vespera Pro