The Celestron Travel Scope 70, model number 21035, is a small, lightweight refractor sold with its own backpack. This page brings together three earlier posts on this site about the same telescope into one guide, covering the verified specifications, what you can realistically see, and how to get the best from it.
What it is
A refractor uses a lens at the front of the tube to collect and focus light, the classic “spyglass” design. The Travel Scope 70 has a 70 mm (2.8 in) front lens and comes on a lightweight photo-style tripod with a simple altazimuth mount that moves up-down and left-right. The tube and tripod fit into the included backpack. The kit arrives largely preassembled, so setup is quick and needs no tools.
Because it includes an erect-image diagonal, the view is the right way up and correctly oriented left to right. That makes it usable as a spotting scope for birds and landscapes during the day, not just for the night sky.
Verified specifications
From Celestron’s product page and instruction manual:
- Optical design: refractor with fully coated glass optics
- Aperture: 70 mm (2.8 in)
- Focal length: 400 mm; focal ratio f/5.7
- Eyepieces: 20 mm (20x) and 10 mm (40x), 1.25-inch
- 45-degree erect-image star diagonal
- Finderscope: 5×24
- Highest/lowest useful magnification: 168x / 10x
- Limiting stellar magnitude: about 11.7
- Light-gathering power: about 100 times the dark-adapted human eye
- Optical tube length: about 43 cm (17 in); tube weight about 0.68 kg (1.5 lb)
- Total kit weight: about 1.5 kg (3.3 lb)
- Two-year warranty when bought new
Earlier kits shipped with The SkyX First Light Edition software; current kits include Starry Night Basic Edition and access to the SkyPortal app. Note that the Travel Scope 70 does not include a Barlow lens (the smaller Travel Scope 50 does).
What you can see
A 70 mm refractor is a genuine astronomical instrument, but it’s worth setting realistic expectations:
- The Moon looks superb: craters, mountain ranges and the dark “seas” (maria) are all clear even at 20x.
- Jupiter shows as a small disc with its four largest moons lined up beside it, and on steady nights a hint of its two main cloud belts.
- Saturn’s rings are visible as a tiny ring around the planet at 40x and above.
- Venus shows phases like a tiny Moon.
- Bright star clusters such as the Pleiades and the Double Cluster in Perseus look excellent thanks to the wide field.
- The Orion Nebula and Andromeda Galaxy appear as soft glows from a dark site.
The short 400 mm focal length gives a wide field of view, ideal for sweeping star fields, but it also means bright objects can show a faint purple fringe of false colour. That is normal for this type of short refractor.
Getting more magnification
Magnification equals the telescope’s focal length divided by the eyepiece’s focal length, so the 10 mm eyepiece gives 400 / 10 = 40x. For closer views of the planets, a 2x Barlow lens or a 6 mm eyepiece (around 67x) is a sensible first add-on. Higher powers are possible in theory, but the light photo tripod becomes the limit: at high magnification, every touch makes the image shake.
Tips for steadier views
- Keep the tripod legs short and spread wide; extend the centre column as little as possible.
- Hang your backpack from the tripod’s centre to add weight and damp vibrations.
- After focusing, let go and wait a couple of seconds for the shaking to settle.
- Align the finderscope with the main telescope in daylight, using a distant treetop or pole.
Buying used
One of the original posts on this site described a secondhand 21035 sold untested. If you buy used, check the front lens for scratches or haze, make sure both eyepieces and the diagonal are included, and confirm the tripod’s locking knobs work. A missing diagonal is easily replaced with any standard 1.25-inch diagonal.
Who it suits
The Travel Scope 70 suits beginners, families and anyone who wants a telescope that can be packed for a holiday, a camping trip or a dark-sky site. Experienced observers often keep one as a quick “grab-and-go” scope. If you mainly want detailed views of faint galaxies, a larger-aperture reflector will show more, but it will not fit in a backpack.
Safety note
Never point the telescope at the Sun without a certified solar filter covering the front lens, and keep it supervised around children during daytime use.
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