Target guide · star group
M40 with a smart telescope
M40 is a star group about 1 arcminutes (0.02°) across, magnitude 8. It is highest around midnight in March, best placed for the northern hemisphere, and bright enough to image from a suburb or even a city. It is larger than every native frame we track, or too small to fill one, so plan a mosaic or a crop.
Key facts
| Catalogue | M40 |
|---|---|
| Type | star group |
| Apparent size | 1′ × 1′ |
| Magnitude | 8 |
| Position (J2000) | RA 12.37 h, Dec 58.1° |
| Highest at midnight | March (±2 weeks) |
| Sky needed | City-friendly |
In the best-matching frame
Imaging tips
Star clusters and star groups are bright and forgiving: they show well from a city and need only short sessions. A wider field of view shows the whole group with some surrounding sky. M40 is one of the easier targets from light-polluted skies.
Which smart telescope frames it best
| Telescope | Field of view | Fit |
|---|---|---|
| Unistellar Odyssey | 0.75° × 0.56° | small in the frame |
| Unistellar Odyssey Pro | 0.75° × 0.56° | small in the frame |
| ZWO Seestar S50 | 1.29° × 0.73° | small in the frame |
| Celestron Origin Mark II | 1.32° × 0.75° | small in the frame |
| DWARFLAB DWARF mini | 2.13° × 1.2° | small in the frame |
| ZWO Seestar S30 | 2.14° × 1.21° | small in the frame |
| ZWO Seestar S50 Pro | 2.45° × 1.38° | small in the frame |
| Vaonis Vespera II | 2.5° × 1.4° | small in the frame |
| Vaonis Vespera 3 | 2.5° × 1.4° | small in the frame |
| Vaonis Vespera Pro 2 | 1.6° × 1.6° | small in the frame |
| DWARFLAB DWARF 3 | 2.93° × 1.65° | small in the frame |
| ZWO Seestar S30 Pro | 3.99° × 2.24° | small in the frame |
How high it gets from where you live
Highest altitude above a flat horizon. Below about 20° the image suffers from haze and light pollution; trees and roofs often block it completely.
| Latitude | Highest altitude |
|---|---|
| Oslo, 60° N | 88° |
| Amsterdam, 52° N | 84° |
| Madrid, 40° N | 72° |
| Miami, 26° N | 58° |
| Equator | 32° |
| Sydney, 34° S | never rises |
Nearby in the sky
Objects close to M40 in the sky, so you can image them in the same session.
Questions and answers
- Can I photograph M40 from a city?
- Yes. It is bright enough to image from a suburb or even a city.
- Which smart telescope is best for M40?
- None of the smart telescopes we track frames it well in one frame; plan a mosaic or a crop.
- When is the best time to photograph M40?
- It is highest around midnight in March and best placed for the northern hemisphere. From 52° north it climbs to about 84° at most.