Run the larger telescope through these five questions honestly. If it fails two of them, buy the smaller one.
Can one person carry the heaviest single piece?
Not the total weight — the heaviest half. A telescope that needs two people or two trips gets used on the evenings when it was clearly going to be worth it, which is a much smaller set of evenings.
Does it fit where it will live, and through the door?
Measure the storage space and the doorway, including the dew shield and the finder. A telescope stored somewhere awkward is a telescope brought out less often.
Does it fit in the car you actually own?
With the boot half full of other things, which is how boots usually are. Measure rather than estimate.
How long does it take to cool?
More glass means a longer wait before the image settles. If it lives indoors, that wait happens every session, and it is where the larger instrument quietly gives back part of its advantage.
What are you actually going to look at?
Planets and the Moon are less affected by aperture than the specification suggests, because the atmosphere caps the detail anyway. Faint galaxies are where the larger mirror earns its keep — and they also need a darker sky than an upgrade provides.
The questions that keep arriving
How much difference does one size step make?
Measurably more light and finer resolution, and how much of that reaches you depends on your sky. Under bright suburban skies, faint extended objects gain less than the arithmetic suggests.
Does the larger one need more accessories?
Often yes, and they are rarely costed in: a heavier mount if it is not a Dobsonian, a longer cool-down, sometimes a chair because the eyepiece sits higher.
Last reviewed 17 September 2026