Dobsonian Telescopes: How They Work, and 6, 8 and 10 Inch Options Compared
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If you want to see faint galaxies and nebulae, aperture matters. As Tele Vue's Al Nagler put it, for faint galaxies and clusters "there is no substitute for aperture." Here's how several models compare, from Sky-Watcher's product sheets and the listings. We haven't tested them.
How a Dobsonian works
Celestron's glossary describes it as "a type of Newtonian reflector alt-azimuth telescope with a more simplistic 'rocker box' mount." No counterweights, no polar alignment, no electronics on the classic versions. You nudge it up-down and left-right. The trade-off is that it doesn't track on its own, so at high power you'll give it a small push every so often.
6, 8 and 10 inch, compared
| Model | Aperture | Tube | Weight | Included eyepieces |
|---|---|---|---|---|
| Sky-Watcher Classic 150 | 6 in. | Solid | 40 lb assembled (listing) | 25 mm, 10 mm |
| Sky-Watcher Classic 200 | 8 in. (203 mm), 1200 mm, f/5.9 | Solid | 45 lb assembled | 25 mm (48x), 10 mm (120x) |
| Sky-Watcher Flextube 200 | 8 in., 1200 mm, f/5.9 | Collapsible struts | 50.2 lb assembled | 25 mm, 10 mm |
| Celestron StarSense Explorer 8 in. | 203 mm | Solid | See listing | See listing |
| Zhumell Z10 | 10 in. | Solid | See listing | 2 in. 30 mm, 1.25 in. 9 mm |
Sky-Watcher figures are from its product sheets (Classic 150 weight from the listing).
Sky-Watcher Classic 200 (8 inch)
Sky-Watcher says its mirror coatings reach 94% reflectivity and that the 8 inch is "816 times brighter than the human eye" (a maker claim). It comes with a 2 inch Crayford focuser, two eyepieces and a 9x50 finder. The tube is 43 inches long, per the sheet, so check it fits in your car.
Sky-Watcher Classic 200 Dobsonian (8 in.)
- 8 in. solid-tube Dobsonian, per the listing
- 2 in. Crayford focuser with 1.25 in. adapter
- 25 mm and 10 mm eyepieces; 9x50 finder
- About 45 lb assembled (20 lb tube, 25 lb base)
Sky-Watcher Flextube 200 (8 inch, collapsible)
Same aperture and focal length, but the tube collapses on struts, which Sky-Watcher says keeps collimation. Handy if storage or car space is tight.
Sky-Watcher Flextube 200 Dobsonian (8 in.)
- 8 in. collapsible strut-tube Dobsonian, per the listing
- 2 in. Crayford focuser with 1.25 in. adapter
- 25 mm and 10 mm eyepieces; 8x50 right-angle finder
Comparing the two? See Classic 200 vs Flextube 200.
Celestron StarSense Explorer 8 inch
An 8 inch Dob with Celestron's phone dock: the listing says the app analyzes star patterns overhead and shows on-screen arrows to your target. A good choice if star-hopping sounds intimidating.
Celestron StarSense Explorer 8 in. Dobsonian
- 203 mm (8 in.) Newtonian reflector, per the listing
- Manual alt-azimuth Dobsonian base
- Phone dock + StarSense app
Smaller: 6 inch and tabletop Dobs
The Classic 150 is lighter at 40 pounds assembled, per its listing. For something you can carry in one hand, tabletop Dobs like the Heritage 130 (13.3 lb, per Sky-Watcher) or Celestron's StarSense 150 mm tabletop sit on a table or stool.
Sky-Watcher Classic 150 Dobsonian (6 in.)
- 6 in. solid-tube Dobsonian, per the listing
- 2 in. rack-and-pinion focuser with 1.25 in. adapter
- 25 mm and 10 mm eyepieces; 6x30 finder
- About 40 lb assembled (15 lb tube, 25 lb base)
Sky-Watcher Heritage 130mm Tabletop Dobsonian
- 130 mm collapsible tabletop Dobsonian, per the listing
- Arrives fully assembled
- 10 mm and 25 mm eyepieces; starpointer finder
- 2-year warranty
Celestron StarSense Explorer 150mm Tabletop Dobsonian
- 150 mm (6 in.) Newtonian reflector, per the listing
- Tabletop Dobsonian-style base
- Phone dock + StarSense app
Bigger: 10 inch
The Zhumell Z10 has a 10 inch mirror and a built-in cooling fan to bring the mirror to outdoor temperature faster, per the listing.
Zhumell Z10 Dobsonian (10 in.)
- 10 in. primary mirror, per the listing
- Built-in mirror cooling fan
- 2 in. 30 mm and 1.25 in. 9 mm eyepieces; 8x50 right-angle finder
- Base has a carry handle
Want GoTo on a Dob?
Sky-Watcher's Virtuoso GTi tabletop Dobs add Wi-Fi GoTo; see computerized telescopes.
After you buy
Reflectors need occasional mirror alignment: see how to collimate a telescope. A wide-field eyepiece and a mid-power eyepiece are easy upgrades.
FAQ
What is a Dobsonian?
A Newtonian reflector on a simple rocker-box mount.
How heavy is an 8 inch?
About 45 lb assembled for the Classic 200, in two pieces.
Do they need collimation?
Yes, occasionally.