How long should I image the Ghost of Cassiopeia with the Vespera 3 from a Bortle 6 sky?

About 2 h 43 min of total integration for a solid image, or 11 h for a showpiece. A quick look takes 41 min.

How many subs is that on the Vespera 3?

At the default 10 s sub length, 976 subs for a solid image from Bortle 6 and 369 from Bortle 3.

Does a dual-band filter help on the Ghost of Cassiopeia?

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 2 h 43 min to 1 h 42 min.

How long to image the Ghost of Cassiopeia with the Vaonis Vespera 3

From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 2 h 43 min (976 subs of 10 s) for a solid image of the Ghost of Cassiopeia. A quick look takes 41 min; a showpiece 11 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 01 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 11% of the frame’s short side.

Ghost of Cassiopeia with the Vaonis Vespera 3: 10 s subs.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	13 min78 subs	51 min309 subs	3 h 26 min1,236 subs
Bortle 2Typical dark site	14 min83 subs	55 min330 subs	3 h 40 min1,318 subs
Bortle 3Rural	15 min93 subs	1 h 01 min369 subs	4 h 05 min1,473 subs
Bortle 4Rural / suburban transition	19 min116 subs	1 h 17 min462 subs	5 h 08 min1,848 subs
Bortle 5Suburban	25 min153 subs	1 h 42 min611 subs	6 h 47 min2,442 subs
Bortle 6Bright suburban	41 min244 subs	2 h 43 min976 subs	11 h3,901 subs
Bortle 7Suburban / urban transition	1 h 10 min418 subs	4 h 38 min1,671 subs	19 h6,681 subs
Bortle 8City	1 h 55 min688 subs	7 h 38 min2,750 subs	31 h10,997 subs
Bortle 9Inner city	3 h 30 min1,263 subs	14 h5,051 subs	56 h20,202 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 3 h 31 min of run time. The Vespera 3’s battery (rated about 11 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 30WVaonis says an external bank extends sessions; 30 W PD as for the II and Pro.
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 3 →

How it frames

The Ghost of Cassiopeia is 10′ × 3′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it fills 11% 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; CovalENS mosaic widens the field to 4.3° × 2.4°. Time for a solid image by sub length:

Sub length	Bortle 3	Bortle 5	Bortle 7
10 s	1 h 01 min369 subs	1 h 42 min611 subs	4 h 38 min1,671 subs
20 s	52 min157 subs	1 h 33 min278 subs	4 h 29 min808 subs
30 s	49 min99 subs	1 h 30 min180 subs	4 h 26 min533 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	1 h 01 min369 subs	1 h 42 min611 subs	4 h 38 min1,671 subs
dual-band (Dual Band filter), clip-on	1 h 11 min426 subs	1 h 23 min501 subs	2 h 17 min825 subs

The Vespera 3 has no built-in dual-band filter. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar. The new optical baffle is not a substitute for a CLS filter. On an emission target like this it is the single biggest upgrade you can make.

About the Ghost of Cassiopeia

A small emission and reflection wisp being eroded by the star Gamma Cassiopeiae. Keep the bright star's glare under control.

IC 63 · Emission nebula in Cassiopeia · magnitude 10.0 · 10′ × 3′ · best in Sep, Oct, Nov. 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 3

The 2026 Vespera: same 50 mm quadruplet class as the II on an 8 MP IMX585, with a 24 MP mosaic mode and 11 hours of battery. Per pixel it behaves like a Seestar S50 Pro without the built-in dual-band filter.

10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only; CovalENS mosaic widens the field to 4.3° × 2.4°. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar. The new optical baffle is not a substitute for a CLS filter.

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 3Vaonis 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 Ghost of Cassiopeia with your Vespera 3? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Ghost of Cassiopeia from a Vespera 3? Email it with your total time and sky to [email protected] and it goes here, credited.

Same target, other telescopes

All telescopes for the Ghost of Cassiopeia · All targets for the Vespera 3