Once the division has no gaps in it, the next purchase is not another focal length.
A better diagonal
It sits in the path of every eyepiece you own. A dielectric mirror with a published reflectivity improves everything at once, and a compression ring stops the thumbscrew marking every barrel.
A nebula filter
A broadband one, not a narrow one. It is the accessory that changes what is visible rather than how it is framed, and it works at any magnification.
A chair
Named by experienced observers more often than any eyepiece. A seated observer is steady, and steadiness shows detail that standing hides.
A dew shield
Free performance on every refractor and folded tube: it extends the usable part of the evening, which is worth more than a marginal optical gain.
And the one that costs nothing
A darker site. Twenty minutes of driving does more for a faint object than any eyepiece in any catalogue.
The questions that keep arriving
Is a premium eyepiece worth it at this stage?
At the focal length you use most, often yes — that is where the comfort and edge performance are actually experienced. At one used twice a year it is not.
What about a second Barlow?
Almost never. One good Barlow covers what a second would, and the magnifications it adds are usually already in the case.
Last reviewed 17 September 2026