Telescopes / 400mm focal length
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400mm Telescopes

Checked 2026-10-24

Compact focal lengths ideal for portable travel telescopes 15 telescopes · 12 brands

For adults For beginners For kids Refractor For moon viewing Portable Tripod included For travel Budget With phone adapter Altazimuth mounts 90mm aperture 80mm aperture Equatorial mounts Reflector 70mm aperture Professional For bird watching For deep sky For astrophotography 600mm focal length Black Smart Digital Dobsonian 800mm focal length Monocular 400mm focal length White 50mm aperture STEM learning Tabletop mounts Maksutov-Cassegrain 130mm aperture 60mm aperture 900mm focal length 114mm aperture 300mm focal length Blue Waterproof 700mm focal length Red Green

Best 400mm Telescopes

# Item Level House Notes See listing
1 Compact 80mm refractor telescope for kids 8.7 Gskyer Compact 80mm refractor telescope for kids $143 Gskyer Refractor · For kids · Tripod included
$143 See listing
2 Portable 70mm travel refractor telescope for kids Koolpte Portable 70mm travel refractor telescope for kids $56.99 Koolpte Black · Refractor · For kids
$56.99 See listing
3 Silver 70mm portable refractor 400mm length 7.4 EACONN Silver 70mm portable refractor 400mm length $49.99 EACONN For adults · For beginners · Refractor
$49.99 See listing
4 Sky View 70mm refractor panhandle mount 6.9 Explore Scientific Sky View 70mm refractor panhandle mount $39.99 Explore Scientific For adults · Refractor · For kids
$39.99 See listing
5 Travel refractor telescope 70mm aperture 8.1 AOMEKIE Travel refractor telescope 70mm aperture $49.99 AOMEKIE For adults · For beginners · Tripod included
$49.99 See listing
6 Portable 70mm aperture refractor with carrying bag 8.4 YUANZIMOO Portable 70mm aperture refractor with carrying bag $59.99 YUANZIMOO For adults · For beginners · Refractor
$59.99 See listing
7 Compact Starwatcher refractor with tabletop tripod 8.1 BARSKA Compact Starwatcher refractor with tabletop tripod $69.89 BARSKA For beginners · Refractor · For kids
$69.89 See listing
8 Refractor telescope with 400mm AZ mount LunaVu Refractor telescope with 400mm AZ mount $79.99 LunaVu For adults · For beginners · Refractor
$79.99 See listing
9 Professional high power 70mm aperture refractor 8.8 Huanglininno Professional high power 70mm aperture refractor $19.99 Huanglininno For adults · For beginners · 70mm aperture
$19.99 See listing
10 White 70mm beginner refractor 400mm length 7.4 EACONN White 70mm beginner refractor 400mm length $49.99 EACONN For adults · For beginners · Refractor
$49.99 See listing
Before you buy

400mm questions

What can I see with a 400mm focal length telescope?

You can see the Moon in good detail, the rings of Saturn, Jupiter and its four bright moons, and wide star fields. Bright deep-sky objects like the Orion Nebula and the Pleiades are also within reach. It is best at low to medium power, not high magnification.

Is a 400mm telescope good for a child?

Yes, the short tube and light weight make it manageable for a child to carry and point. The wide field of view helps them find the Moon without frustration. A tabletop tripod version is often easier for small hands than a full-height tripod.

Can I use a 400mm telescope for looking at things on the ground?

Yes, a refractor with a 400mm focal length works as a spotting scope for daytime use. You will need to use a diagonal or an erect-image prism to get the view right-side up. The wide field makes it easy to follow birds or ships.

Why do most 400mm scopes come with two eyepieces?

The two eyepieces give you two magnification levels from the same short tube. A longer eyepiece gives a wide, bright view for finding objects, and a shorter one boosts power for the Moon or planets. It is a simple way to cover low and medium power without buying extra glass.

Short tubes for wide views and easy carrying

A 400mm focal length telescope is a compact instrument, usually a refractor with a tube short enough to hold in one hand or tuck into a carry bag. The short focal length gives a wide field of view, which makes it easy to find the Moon, bright planets, and terrestrial landmarks without hunting. These scopes are often sold as travel or beginner kits, and the whole package is light enough to take outside on a whim.

The aperture on these models is typically 70mm or 80mm, paired with a focal ratio around f/5.7 to f/6. That combination keeps the tube short and the image bright enough for low to medium power. You will not get high magnification out of a 400mm tube without pushing the optics past their useful limit, but for sweeping the sky and spotting craters, it works.

Mounts, eyepieces, and what comes in the box

Most 400mm scopes sit on an alt-azimuth mount, either a simple yoke or a panhandle head, sometimes on a tabletop tripod and sometimes on a full-height adjustable tripod. The mount is manual, so you point and follow by hand. A few models include a smartphone adapter or a carry bag, and the eyepieces are usually low-power Kellner or similar designs, often a 20mm and a 10mm or a K6 and K25 pair.

The tube finish is commonly black or white, and the tripod is usually aluminum or a lightweight composite. Because the focal length is short, the scope is forgiving of a light mount, but a shaky tripod will still show up at higher powers. The focuser is a basic rack-and-pinion, and the diagonal is a standard 90-degree prism or mirror.

Related
Refractor For beginners 70mm aperture For kids Budget For adults Tripod included For moon viewing