Decent 400mm flat panel?

I’ve been using a large tracing panel for a couple years now and I too share the issue of it being too bright. I generally put two t-shirts minimum as well as a couple sheets of paper to get it dim enough. I do see the banding occasionally, but since it’s never in the same spot, it doesn’t bother me.

What I will say, (and what I would do in your situation) is start using a white t-shirt and doing skyflats this way. Heck, you could even design a 3D printed ring to hold the shirt taut. Drop it over the end and shoot sky flats. I’ve done this quite a few times now and my flats have been perfect without worry. It’s miles cheaper and honestly kinda faster anyways. With a t-shirt over the end you don’t have to be quite as picky for sky conditions either, and can honestly shoot the second the sun goes over the horizon.

I use a clear/white garbage bag tied lightly with a piece of string, then a piece of perspex thrown on the top. Cheap light panel with 4 adjustments that I found on Amazon. The panel can be used both ways if too bright etc. Obviously for home use.

Sky flats and I have yet to get a bill…

Brian Puhl · Jul 21, 2026, 10:54 AM

I’ve been using a large tracing panel for a couple years now and I too share the issue of it being too bright. I generally put two t-shirts minimum as well as a couple sheets of paper to get it dim enough. I do see the banding occasionally, but since it’s never in the same spot, it doesn’t bother me.

What I will say, (and what I would do in your situation) is start using a white t-shirt and doing skyflats this way. Heck, you could even design a 3D printed ring to hold the shirt taut. Drop it over the end and shoot sky flats. I’ve done this quite a few times now and my flats have been perfect without worry. It’s miles cheaper and honestly kinda faster anyways. With a t-shirt over the end you don’t have to be quite as picky for sky conditions either, and can honestly shoot the second the sun goes over the horizon.

The a2 tracing panel is unwieldy for dark site transport (yes, I take my 12”, welded pier, and cem70 mobile — not too much hassle!) and after 6 months it's developed weird zones of splotchiness when on. So the tracing panel needs to be retired.

Sky flats are not consistent and do not give me the control that is needed. The window I have to be outside for sky flats, taking all 6 slots in that appropriate window of time without missing it or having the last 2 slots start to take minutes per exposure because the window is too late, etc, it's not reliable. Getting to the dark site slightly after sky flats time, then needing to leave before dawn, it just doesn't work.

Does no one have an opinion on the flat panel themselves? Yes I can make a hoop to dim whatever panel, but I still need a panel. The a2 panel is too large and has splotches on it now, much less the other issues mentioned.

Tom Boyd · Jul 21, 2026, 06:06 PM

I use the 10” version of these:

https://ellumiglow.com/collections/astrophotography

Work great, fully brightness adjustable…

Oh yes, that reminds me, the cheaper 2 options would be that one or the bare cheapest being a “EL Flat panel” bare from aliexpress for around $100. My only concern with those was illumination profile and flicker.

So I guess this is where I’ve been at the decision crossroads for a while, if the wanderer is materially safer in terms of illumination profile, non-flickering, or if the gemini or even bare flat panel/diy options are also safe and won’t end up in an unknown headache. I guess I am not sure how to judge what is material.

I think there’s nothing wrong with using the wandererastro White Dwarf Flat Panel, I have the 350mm version, not used it yet but have friend that use their panels. I even made a sticker for the dimmer so I can keep a record of what works for each filter.

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