Comet 3I/ATLAS Can Be Seen From Home — Picking The Right Telescope To Spot It

Comet 3I/ATLAS is now visible from Earth, offering a unique chance to witness a spectacular celestial object right from your own backyard.

You don't need to be an expert astronomer to see this icy visitor; with the right gear and knowledge, anyone can spot it.

A Visitor from Beyond the Sun

Comet 3I/ATLAS (officially called C/2025 N1) was found on 1 July 2025 by the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey, a project funded by NASA and based in Chile.

This object marks the third verified visitor from interstellar space to enter our solar system. Its path, known as a hyperbolic orbit, proves it came from outside the Sun's gravitational pull, setting it apart from comets originating within our planetary neighbourhood.

The comet passed its perihelion (its nearest point to the Sun) on 29 October 2025, at a distance of about 1.36 astronomical units (AU). It made its closest pass by Earth on 19 December 2025, sitting roughly 1.8 AU away. That distance is equivalent to about 269 million kilometres.

Where to Look and What to Expect Now

As of 14 December 2025, 3I/ATLAS can be found within the Leo constellation, making it visible in the morning sky just before the Sun rises. Current sightings indicate its apparent brightness is between 11 and 12. Its coma (the hazy shell of gas and dust surrounding the core) appears tiny, usually covering only a few arcminutes, and long-exposure pictures sometimes reveal a dim tail.

The comet is showing signs of activity, including a tail and a coma made of dust. There is also evidence of carbon dioxide being released as a gas, along with occasional plumes of material. However, the comet is still quite dim because it is a considerable distance from both our planet and the Sun.

Can I See It Without a Telescope?

3I/ATLAS cannot be spotted with the naked eye. The human eye can generally pick up things only as faint as magnitude 6, and that is only when the sky is perfectly dark. Even large binoculars (such as 10x50 models) are not enough to reliably find the comet at its current level of brightness. Reports all agree that, even when the comet is at its most active, it is best seen with a telescope.

Regarding viewing the comet from Earth, NASA states that 3I/ATLAS is visible in the sky before dawn, even with a small telescope. Furthermore, it should remain observable until spring 2026.

Choosing the Right Telescope for Your Home

Amateur stargazers using backyard telescopes can see 3I/ATLAS if they observe under dark conditions (a Bortle scale 4 or higher is best, meaning far from city light pollution). The following suggestions are based on reports of what has been seen and how bright the comet is:

Minimum Recommended Size (Aperture):

You will generally need a telescope with an aperture of 150-200mm for a clear, visual sighting. At this size, the comet will look like a hazy, indistinct patch with a moderately brighter central area (condensation). Common examples that fit this are well-known 6-inch or 8-inch Dobsonian reflectors or Schmidt-Cassegrain telescopes.

Larger Telescopes for Superior Views:

Instruments with an aperture of 250mm (10 inches) or more will offer more detailed observations. These can show the coma much more clearly and may even reveal faint parts of the tail. With perfect viewing conditions, observers have reported brightness levels of 10-11 with instruments, making longer viewing sessions possible and enabling simple astrophotography with stacked exposures.

Smaller Telescopes (80–150 mm):

These may find the comet, but only if the skies are extremely dark and the observer is experienced. The view will be dim and difficult to see. Automated or 'smart' telescopes (like computerised GoTo models) can be very helpful for finding its exact location.

Essential Viewing Checklist

• To successfully view the comet, you should:
• Find spots that have minimal light pollution and unobstructed horizons.
• View during the pre-dawn hours, as this is when the comet reaches its highest point in the sky (currently appearing in the east-southeast).
• Use a low to medium level of magnification (20-80x) to improve how well the comet stands out from the dark background sky.

It is recommended to use finder charts from sites like TheSkyLive or various astronomy applications for accurate positioning. This is important because the comet moves quickly when compared to the fixed background stars.

The comet is now slowly dimming as it moves farther from the Sun and Earth, and it is expected to drop below magnitude 13 early in 2026. Current sightings confirm that it is an accessible target for committed amateur astronomers with properly equipped, moderate-sized telescopes, offering them a unique chance to observe material that originated in another stellar system.

In short, while 3I/ATLAS is not bright enough to be seen with the naked eye or binoculars, it is visible from home with telescopes with 6–8-inch or larger apertures. This presents a rewarding challenge for enthusiasts throughout its short journey passing through our solar system.