Sunspots, which change from day to day, and — on a good film filter — the mottled granulation of the surface. It is the one object that is different every single day and the only one reliably available in the middle of the afternoon.
The Sun is the object most amateur telescopes never point at, and it is the one that changes fastest.
Sunspots
Dark regions that appear, move across the disc as the Sun rotates, change shape and disappear over days. Sketching or photographing the same group across a week is one of the few observing projects that needs no dark sky at all.
Granulation
A fine mottling across the whole disc, visible when the seeing is good and the filter is a good one. It is the top of the convective layer, and it is a genuinely difficult observation that rewards a steady morning.
The limb
The edge of the disc appears slightly darker than the centre. It is a real effect and easy to see once pointed out.
What a white-light filter does not show
Prominences and the detailed chromosphere, which need a different and much more specialised kind of instrument. A full-aperture white-light filter shows the visible surface, which is plenty.
If this page and the manufacturer’s own documentation disagree, follow the documentation. Every aperture, focal length, payload rating, field, eye relief, transmission figure and thread size on this page comes from the maker’s own published figures, with the unit as printed and the source named. None of it is measured here, and no figure is converted into another convention, because a converted number is a different number. And the limit this page does not cross: no filter, no pair of eclipse glasses and no mounting described here makes an observation safe. The page reports what a maker specifies for its own product — the standard the listing cites, the construction, the fitting, the inspection asked for before use — and what applies to your own equipment is decided by those instructions and by the condition of the filter in your hands.
The questions that keep arriving
Does the filter colour matter?
Only for appearance. A coated film usually gives a neutral or bluish disc and a glass filter a yellow or orange one; many observers find granulation easier to see on the first and the overall view more natural on the second.
Is seeing a problem during the day?
Very much so. Ground heated by the Sun produces strong local turbulence, so mornings are usually steadier than afternoons, and observing over grass rather than tarmac makes a visible difference.
Last reviewed 17 September 2026