SkyBox
This is a SkyBox. It's an 8x8x6 ft. box made out of ¾ EMT pipe and wrapped with 2x 6x10’ high density tarps secured with 6” ball bungee cords. A very simple yet effective device that helps protect the telescope from wind as well as stray light.
Note: The tarps are meant to go on the outside of the frame. In the above image theyre on the inside because I did a poor job at measuring and cutting the EMT so the tarps would have left huge gaps. I remedied this with longer tarps.
How effective is it you ask? Well I’ve imaged in 20mph+ winds with short (sub-60s) sub-exposures. In fact if it weren’t for the SkyBox I wouldn’t have gotten any imaging done during Fall or Winter of 2021 due to wind. In some short tests I ran with handheld anemometer I measured gusts of 10-15mph outside the box while only reading 1-3 mph inside the box. For those that don't know anything up to 5 mph is basically a very gentle breeze. When you use large telescopes it doesn't take much to ruin exposures. This thing isn’t a miracle device. You definitely won’t be doing long sub-exposures in extreme wind but the box will allow for decent imaging on a very windy day. Seeing won't be great but I’d rather image in bad seeing than not at all. It is a great thing that CMOS cameras don’t require very long exposures to begin with.
Depending on the situation you can save some time by only setting up 2-3 walls as I do on nights where there isn't supposed to be much wind. Though I must admit that I find the 2 wall configuration to be borderline in terms of helpfulness so I would only use it in that config if it's to block stray light. For blocking wind I would use at least 3 sides which is what I do most of the time. I leave the east side open because where I image, east winds are almost unheard of during the night. Most wind comes from the N, NW, and occasionally SW.
2 wall configuration for blocking headlights from the highway to the North.
3 wall configuration for blocking the West wind.
As mentioned above, blocking stray light is the second most useful function of the SkyBox. At my mag 21 dark site I am fortunate to have zero stray light. I mean zero stray light with one exception.. My SUV. An SUV that unfortunately flashes all 6 turn signal lights every time the car is locked or unlocked. There is no way to turn this functionality off so that used to leave me with only a few choices:
Only unlock/lock car during a dither or autofocus run (inconvenient)
Park car far from mount (highly inconvenient)
Resign myself to ruining a sub ever time I need to get in or out of the car (sadface.jpg)
Thanks to the SkyBox, it doesn't matter what's going on on the outside, none of that stray light is making it to the telescope's aperture. That means I’m free to lock/unlock the car, use a headlamp, or whatever else I need to do with complete peace of mind. Anyone who images in an urban environment would benefit similarly by being able to block streetlights, porch lights, or vehicle headlights. Anyone who images in the field or in windy conditions really should consider building one of these. With the right size EMT they can be made as tall or wide as the user desires.
