Disclaimer
Last updated 2026
Solar observing, the one that matters
Never observe the Sun through a telescope, finder, binocular or camera viewfinder without a certified full-aperture solar filter fitted securely over the FRONT of the instrument.
Filters that thread onto the eyepiece end sit at the focus, where all the collected heat is concentrated into a few square millimetres. They can crack without warning while you are looking through them, and the retina has no pain receptors, so the resulting blindness is instant, silent and permanent. If a telescope came with a small dark filter that threads onto an eyepiece and is labelled for sun use, throw it away rather than store it. Cap or remove the finder scope as well, because it focuses enough heat to burn skin and to ignite finder crosshairs. Solar eclipse glasses are for naked eye use only and are never safe to hold behind any optic.
General information only
Everything on telescopesetup.com is published for general information. It is not professional advice, and no relationship of professional reliance is created by reading it. Decisions about what to buy and how to use it remain yours.
Equipment safety
Telescopes and mounts carry ordinary physical risks that are easy to underestimate. Tripods tip when a heavy tube is slewed to one side. Counterweights fall if a clutch is released before the load is balanced. An 8 inch Dobsonian tube weighs enough to injure somebody if it rolls off a table. Follow the manufacturer instructions supplied with your own equipment, which govern, and supervise children around any telescope.
Accuracy of figures
Specifications are taken from manufacturer publications and change without notice. Derived figures, such as focal ratio, maximum useful magnification, exit pupil and the Dawes resolution limit, are calculated from published aperture and focal length using standard formulas. Where a specification could not be verified it is omitted rather than estimated, so a missing row means we had no source we trusted.
Calculator results
The calculators return the output of standard optical formulas for the values you enter. They cannot account for atmospheric seeing, sky brightness, the collimation and cleanliness of your optics, your own visual acuity, or how long you have been dark adapted, all of which change what you will actually see. Treat every result as a starting point and trust the view through the eyepiece over any number on a screen.
What you will see
Descriptions of what a given aperture shows are typical outcomes under reasonable conditions, not guarantees. Human night vision is nearly monochrome, so nebulae appear grey-green rather than in the colours of a photograph, and galaxies appear as faint grey ovals. Sky darkness frequently matters more than aperture for faint objects.
External links and products
Links to retailers and other sites are provided for convenience. We do not control them and are not responsible for their content, pricing, availability or practices. Some are affiliate links, as set out on the affiliate disclosure page.
Limitation of liability
To the fullest extent permitted by law, TelescopeSetup.com accepts no liability for any loss, injury or damage arising from use of this site, from reliance on any information published here, or from any purchase made through a link on it.
Questions
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