Author: Andrew

An electrical engineer, amateur astronomer, and diver, living and working on Mauna Kea, Hawai'i.

Unsafe Solar Filters on EBay

I though these things were gone!

Eyepiece mounted solar filter
DO NOT USE! A Solar filter meant to thread into a 0.956″ telescope eyepiece.
But no, in the world of cheap e-commerce, any product can be found, even those that are notably unsafe.

What are we discussing? Eyepiece style solar filters that screw into the threads on the bottom of the eyepiece, not at the front of the telescope like proper solar filters.

I actually have one of these things, found in a kit of equipment I was given. A bright red and very cheap pot metal casting with a small glass filter. I have never attempted to actually use it, I keep it as a example of the bad and the ugly. It is a vintage bit of gear, the type that was included with inexpensive Japanese refractors of the 60’s and 70’s, sized to be used with the small 0.965″ eyepieces of the era.

An eyepiece style solar filter available on EBay
An eyepiece style solar filter available on EBay
To my surprise I find out these things are still around… I was shopping for an inexpensive solar filter for a small telescope when I came across these eyepiece style filters on EBay. They are cheap too, less than $10 with shipping, just the sort of thing to attract a young or novice telescope user into trying a product that is potentially very dangerous.

Given that the risk you are taking involves irreplaceable eyesight, this is very serious.

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A Moonlit Hike to Lake Waiau

Sublime… One word in the English language that comes close… A frozen world of snow and ice, dark rock, illuminated by ethereal moonlight. A place more of the arctic than a tropical island. Recent storms have again created such a place on the summit of Mauna Kea. Just need to make a point to get out there and enjoy it.

Moonset Over Lake Waiau
A nearly full Moon setting over lake Waiau near the summit of Mauna Kea
The plan? Set the alarm clock for 2am, out of the house before 2:30am, arrive at the trailhead about 3:45am. I would take a walk with a camera, then drive back down to Hale Pōhaku for breakfast, then join the crew for a normal day working on the summit. A good plan, if somewhat exhausting. A plan that was executed exactly as originally envisioned.

It was the timing that was the factor here. A few things to come together to make this work… A good covering of snow, the summit road open to the public, and good weather with clear, starry skies. Clear skies have been in rare supply lately, a succession of winter storms bringing weeks of clouds.

The road being open to the public is also an important bit. While I could drive past the roadblock, the rangers know me, we are forbidden to engage in non-work activities on the summit if the road is closed to the public.

The needed factors came together this particular morning and I set the plan into action.

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