How long should I image the Saturn Nebula with the Vespera II from a Bortle 6 sky?

About 12 min of total integration for a solid image, or 49 min for a showpiece. A quick look takes 3 min.

How many subs is that on the Vespera II?

At the default 10 s sub length, 75 subs for a solid image from Bortle 6 and 40 from Bortle 3.

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

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 12 min to 10 min.

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

From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 12 min (75 subs of 10 s) for a solid image of the Saturn Nebula. A quick look takes 3 min; a showpiece 49 min. Under a Bortle 3 rural sky the solid figure drops to 7 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 is small in the frame, about 18 pixels across.

Saturn Nebula with the Vaonis Vespera II: 10 s subs.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	2 min10 subs	6 min37 subs	24 min146 subs
Bortle 2Typical dark site	2 min10 subs	6 min38 subs	25 min150 subs
Bortle 3Rural	2 min10 subs	7 min40 subs	26 min159 subs
Bortle 4Rural / suburban transition	2 min12 subs	7 min45 subs	30 min180 subs
Bortle 5Suburban	2 min14 subs	9 min54 subs	36 min214 subs
Bortle 6Bright suburban	3 min19 subs	12 min75 subs	49 min297 subs
Bortle 7Suburban / urban transition	5 min29 subs	19 min114 subs	1 h 16 min455 subs
Bortle 8City	7 min44 subs	29 min175 subs	1 h 56 min699 subs
Bortle 9Inner city	13 min77 subs	51 min306 subs	3 h 23 min1,221 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 16 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.)

USB-C PD power bank 20000mAh 30WOnly four hours inside; Vaonis specifies a 30 W PD source. C-to-C cable not included.
Amazon UK Amazon US
Vaonis Vespera hygrometer sensorTriggers the built-in demister automatically; the correct dew accessory for the II.
Amazon UK Amazon US
red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
Amazon UK Amazon US

Affiliate links: the retailer pays us a small commission and you pay the same price. These are search links to the named product, not endorsements of a particular listing; check the listing matches your model.

Everything that fits the Vespera II →

How it frames

The Saturn Nebula is 0.7′ × 0.4′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it is small in the frame, about 18 pixels across. It is worth doing, but the result is a crop rather than a full frame; a longer focal length would resolve more of it.

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	7 min40 subs	9 min54 subs	19 min114 subs
20 s	10 min30 subs	10 min30 subs	18 min56 subs
30 s	15 min30 subs	15 min30 subs	18 min37 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	7 min40 subs	9 min54 subs	19 min114 subs
dual-band (Dual Band filter), clip-on	9 min52 subs	9 min56 subs	12 min74 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 Saturn Nebula

A bright planetary with ansae like Saturn's rings, tiny in a smart scope but very bright per pixel.

NGC 7009, Caldwell 55 · Planetary nebula in Aquarius · magnitude 8.0 · 0.7′ × 0.4′ · best in Jul, Aug, Sep. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Planetary nebulae are small but intensely bright per pixel in OIII and H-alpha, so they respond very well to a dual-band filter and do not need much time for the main shell. The faint outer halos most of them have are a different proposition and need hours. Keep subs short if the central region saturates.

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.

Where to buy the Vespera IIVaonis store Direct Amazon UK Amazon USThe Vaonis store link is a plain link; the others are affiliate links. As an Amazon Associate I earn from qualifying purchases, at no cost to you.

Imaged the Saturn 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 Saturn 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 Saturn Nebula · All targets for the Vespera II