Sunflower Galaxy M63 Visual Guide: Comparing It with the Black Eye Galaxy

Two galaxies, one season

Both galaxies are best observed in late spring, so you can plan a single session that includes both. M63 lies in Canes Venatici, and M64 lies in the neighboring constellation Coma Berenices, to the south-southwest. You will need to move your telescope some distance between them, so plan the route before you start.

The comparison teaches two different skills. M63 rewards patience with a faint, even glow, and it teaches you how a telescope renders low-contrast light. M64 rewards careful attention to structure, because a dark band cuts across its bright center. Working through both in one session shows you how your eye responds to different kinds of detail.

How they differ in appearance

M63 looks like an oval glow with a brighter core. In a 200 to 300 mm Dobsonian reflector from a suburban sky, that core is the most obvious feature. The outer disk fades gradually into the background, so the edge of the galaxy is hard to pin down. The spiral arms are too faint to see by eye from most suburban locations, so do not expect to trace them. What you see is the brighter central region and the soft, rounded outline around it.

M64 has a different character. Its bright center is crossed on one side by a dark dust lane, which gives the galaxy its name. At medium power, this dark band is the feature that separates M64 from a plain glow. In a telescope, you will often see the bright core first and then notice the dark lane once your eye settles. Give the lane time to appear, and avoid moving the eyepiece while you look for it.

When you compare the two, note the overall shape, the brightness of the center, and whether any dark structure is visible. M63 shows a rounded glow with a bright core. M64 shows a bright core with a dark lane across one side. These observations are simple, but they are the basis for recognizing each galaxy at the eyepiece.

Difficulty and what to expect from a suburban sky

M63 has a visual magnitude of 8.6, which is far fainter than anything you can see with the naked eye from a suburban sky, where the limit is about magnitude 5. You need a telescope to see it at all. Its apparent size is 12′ by 7.2′, but its light is spread across that area, so the surface brightness is low. This is why the glow is faint even though the galaxy is large in the sky.

Suburban light pollution reduces contrast further. A 200 to 300 mm Dobsonian will show the oval glow and brighter core under reasonable conditions, but the outer parts of the galaxy will blend into the sky background. If you can observe from a darker location, the galaxy's outline becomes easier to judge. Do not expect the arms or fine detail that appear in photographs. Those require much larger instruments, longer exposures, or darker skies.

The same caution applies to M64. Both galaxies are faint surface-brightness targets, so both reward a careful approach. A good view of M63 shows a steady, even glow. A good view of M64 shows the core and the dark lane. Neither view will look like a photograph.

Timing across the year and the hemispheres

The best months for M63 are May and June. In these months the galaxy is high in the evening sky, and the view is steadier because you are looking through less atmosphere than you would at low altitude. At 35° N the galaxy reaches about 83° above the horizon, and at 50° N it reaches about 82°. At these latitudes, it passes nearly overhead, so you can observe it comfortably from a reclining or upright position at the eyepiece.

From 35° S the picture is very different. The galaxy reaches only about 13° above the northern horizon, so you see it low and through a thick layer of air. Look for a clear northern horizon with no buildings or trees blocking the view. Expect a brief observing window and a view that is affected by haze and atmospheric turbulence. If you observe from the southern hemisphere, consider using a longer session in May or June, when the galaxy is best placed for your location, and accept that the view will be less steady than it is from northern latitudes.

M64 is also a spring target for northern observers, so the two galaxies share a season. If you observe from the south, plan carefully, because the galaxies' positions in the sky may require different routes and altitudes.

Technique at the eyepiece

Start with a finder and a low-power eyepiece. Locate Cor Caroli, the bright star in Canes Venatici, and use a finder sweep to move a few degrees to the northeast. Look for a faint, fuzzy patch among the field stars. Once you have it in the finder, move to your telescope and center the glow in a wide-field eyepiece. Low power, about 50x to 80x for a 200 to 300 mm reflector, gives a bright, wide view with good contrast.

Use averted vision. Look slightly to the side of the galaxy's center so that the light falls on the more sensitive parts of your retina. Hold your gaze for a few seconds, then move your eye slightly and look again. Faint, even light often appears more clearly this way. Avoid staring straight at the center, because the glow tends to disappear under direct gaze.

Allow your eyes to dark-adapt for at least 15 to 20 minutes before you start. Avoid looking at white light, including phone screens, during this time. A red-filtered flashlight is useful for reading charts or adjusting the telescope. Keep a dew shield on the tube, and let the telescope cool to the outdoor temperature before you judge the view.

To move from M63 to M64, return to a wide field and star-hop across the sky toward the southwest. Use a star chart or a planetarium program on a red-filtered screen to plan the route before you move. Once you reach M64's region, switch to a medium-power eyepiece to look for the dark lane. The change in power helps you see structure that the wide field may hide.

What each galaxy teaches

M63 teaches you how low surface brightness appears through a telescope. The galaxy is large but faint, and its glow is spread across a wide area. Learning to see it with averted vision builds the patience that many faint deep-sky objects require. It also shows how the outline of a face-on galaxy is harder to define than its core.

M64 teaches you how dark structure can change the appearance of a galaxy. The dark lane is a contrast feature, not a bright one, so it is visible only when your eye and the telescope are working well together. Comparing it with M63 shows that two galaxies of similar spring visibility can present very different kinds of detail.

Together, the two galaxies show that a telescope view depends on both the object and your method. Record what you see in a simple log. Note the shape of the glow, the brightness of the core, the presence or absence of the dark lane, and the sky conditions. Over several sessions, these notes help you see what changes with altitude, sky darkness, and eyepiece power.

Observing checklist

1. Check the weather and the altitude of M63 for your latitude, and plan a May or June session when the galaxy is high.
2. Dark-adapt your eyes for 15 to 20 minutes, and keep white light away from them.
3. Find Cor Caroli and sweep the field a few degrees to the northeast to locate M63.
4. Begin at low power with a wide field, and center the glow.
5. Use averted vision to confirm the oval glow and the brighter core.
6. Note the outline of the galaxy, and record where the glow fades into the sky background.
7. Move to M64 in Coma Berenices, and switch to a medium-power eyepiece to look for the dark lane.
8. Write a short log entry for each galaxy, including the eyepiece used and the sky conditions.