Seeing is succeeding

Are you all set to go out and watch the not-total lunar eclipse tomorrow morning, i.e., a few hours from now? I plan to be down at a reasonably dark sky location to make the attempt, though at the moment, it’s not looking promising – we have scattered thin clouds here right now, but they’re patchy, so it’s impossible to predict which way they may go. It’s been notably clear here for the past several days, so it fits perfectly that the conditions will go yuerch for an astronomical event.

Well, this isn’t quite true; I checked last night, thinking I might make a second, and final, attempt at the Leonids meteor shower, and we had light haze across the entire sky. The moon was visible, with a bit of a halo, and of course almost full at that point and not setting until shortly before sunrise. The light haze would be illuminated by the moon perpetually, across most of the sky, so the haze itself would obscure the dimmer meteors (and stars) while the moonlight scattering through it would make it much worse. Not to mention the reflection of the city lights nearby. The seeing (which is what astronomers call the clarity of the sky – now you understand the post title) was far from optimal, and long exposures would be greyed out by all that light even before the camera registered most of the stars. I didn’t even bother.

Meanwhile, the eclipse will take place over the period of several hours, so even if initially, the seeing looks bad (or, for that matter, good,) it might change over the course of the eclipse. Which means I’ll be out there regardless. For your own plotting, Stellarium will work just ducky.

This will not be a total lunar eclipse, only close – the south pole of the moon will never vanish, though at this time and latitude, that’ll be the lower left edge. From my location, as it approaches maximum, the moon will eclipse a dim star on the upper left side, where the moon itself will be fairly dark (actually, very dim red.) The brightness of the star (HIP 16896) will be pushing magnitude 9 in the best of conditions, which is pretty dim – naked eye visibility in dark conditions runs around magnitude 6. The lower the number, the higher the visibility, so 9 is binocular/telescope range, and capturing it on the camera, even with the long lens, is highly questionable. I could do it with a longer exposure perhaps, but then I’d be contending with apparent motion. It’ll be an experiment, anyway – provided I can see anything when it occurs (which around here will be right at 4:01 AM.)

So, watch this space, is what I’m saying. I mean, after you watch the eclipse itself – I won’t be that fast getting it up. I’m old now.