How long to image the M94 with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 1 h 53 min (1,701 subs of 4 s) for a solid image of the M94. A quick look takes 28 min; a showpiece 7 h 34 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 18 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 33% of the frame’s short side.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 19 min279 subs | 1 h 14 min1,116 subs | 4 h 57 min4,462 subs |
| Bortle 2Typical dark site | 19 min284 subs | 1 h 16 min1,134 subs | 5 h 02 min4,534 subs |
| Bortle 3Rural | 19 min292 subs | 1 h 18 min1,168 subs | 5 h 11 min4,670 subs |
| Bortle 4Rural / suburban transition | 21 min313 subs | 1 h 23 min1,250 subs | 5 h 33 min4,999 subs |
| Bortle 5Suburban | 23 min346 subs | 1 h 32 min1,381 subs | 6 h 08 min5,522 subs |
| Bortle 6Bright suburban | 28 min426 subs | 1 h 53 min1,701 subs | 7 h 34 min6,803 subs |
| Bortle 7Suburban / urban transition | 39 min578 subs | 2 h 34 min2,312 subs | 10 h9,245 subs |
| Bortle 8City | 54 min815 subs | 3 h 37 min3,260 subs | 14 h13,037 subs |
| Bortle 9Inner city | 1 h 28 min1,321 subs | 5 h 52 min5,281 subs | 23 h21,123 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 2 h 27 min of run time. The Odyssey’s battery (rated about 5 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 power bank 20000mAh 5V 2.4AUnistellar says plain 5 V 2.4 A and warns against fast or adaptive chargers.
- red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
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Everything that fits the Odyssey →
How it frames
The M94 is 11′ × 9′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it fills 33% of the frame’s short side.
About the M94
A galaxy with a blazing inner ring and a very faint outer one. The core arrives fast; the outer ring is a long-integration project.
NGC 4736, Cat’s Eye Galaxy · Galaxy in Canes Venatici · magnitude 8.2 · 11′ × 9′ · 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 Unistellar Odyssey
Unistellar’s compact 85 mm with autofocus and tiny pixels. Sharp, but the fine sampling costs time on faint extended targets. The Odyssey Pro is the same telescope with an eyepiece added, so these figures apply to both.
Fixed 4 s subs in Enhanced Vision; they cannot be changed. No filter option; Unistellar says third-party filters cannot be fitted to the Odyssey.
The Odyssey uses fixed 4 s subs, so the only levers you have are the sky you shoot from, the filter, and total time.
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.
Have an image of the M94 from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M94 with the ZWO Seestar S50: 28 min from Bortle 6
- M94 with the ZWO Seestar S50 Pro: 31 min from Bortle 6
- M94 with the ZWO Seestar S30: 30 min from Bortle 6
- M94 with the ZWO Seestar S30 Pro: 33 min from Bortle 6
- M94 with the DwarfLab DWARF 3: 41 min from Bortle 6
- M94 with the DwarfLab DWARF mini: 28 min from Bortle 6
- M94 with the DwarfLab Draco: 23 min from Bortle 6
- M94 with the DwarfLab DWARF II: 1 h 35 min from Bortle 6
- M94 with the Vaonis Vespera II: 28 min from Bortle 6
- M94 with the Vaonis Vespera Pro: 1 h 03 min from Bortle 6
- M94 with the Vaonis Vespera 3: 27 min from Bortle 6
- M94 with the Vaonis Vespera Pro 2: 1 h from Bortle 6
- M94 with the Unistellar eQuinox 2: 25 min from Bortle 6
- M94 with the Celestron Origin: 8 min from Bortle 6
- M94 with the Celestron Origin Mark II: 10 min from Bortle 6