The weather and local smog didn’t cooperate this weekend. It was raining or cloudy early in the weekend, and later when it was clear the humidity was high and transparency was zilch. At one point I stepped out and was pleased to see the Summer Triangle overhead. I waited for my eyes to adapt so I could see more stars, and waited, and waited…well, I was pleased to see the Summer Triangle overhead. That was it. Even Mars was hard to spot — the murk rose to 60 or even 70 degrees altitude, and it wasn’t much better above that. Looking outside my office right now the sun is shining but I can’t see the horizon, so I won’t expect much tonight. Oh well, more time to read books – I still haven’t read the last two Lindsey Davis mysteries, and with the Rome show being hyped everywhere they’ll at least feel apropos.

There are times I really wish I could win the lottery. Tonight is one of those times. I woke around 1.45 am and decided to stick my head out the door. Big mistake.

The moon is very bright, the sky is crystal clear. The sky brightness meter shows 16.90 with the moonlight, but as soon as I angle the meter to avoid the direct light of the moon the reading jumps to 18.04, the best I’ve seen since I began taking readings from the city. Looking up at Lyra I can see Zeta1 by averted vision at 4.3 but not Epsilon at 4.6. There’s moonlight, so this is actually a superb night for the city.

I have to work tomorrow, so there’s not much point in opening up the observatory. And so, to bed.

According to the Clear Sky Clock for right now it should be clear but with lousy transparency. It’s clear, but the transparency is not as bad as I expected. On the other hand the Moon is very bright, and deep sky objects are a write-off. I was hoping to be able to set up for M101 and M51 (there’s a supernova I want to capture), but the sky glow is too damn bright. The Moon is currently worse than my bright light neighbour, so there’s little to be done. I’ll see what Mars is up to, I suppose.

The Ground Truth page has the readings from the Sky Brightness meter. Surprisingly, tonight’s reading actually improves the average — I guess it’s not quite as bright as I suppose, it’s just that the Moon is screwing up my night vision (I don’t need a flashlight to walk around the garden, though).

(Later) Mars was behind a pine tree for quite some time, so I pulled out the 3mm Radian and browsed the Moon for a while (so it’s good for something, even as it screws up the observing session). Seeing was quite chancy — moments of superb clarity were interspered with (longer) moments when I was sure I was out of focus. I set for the optimum moments, and carried that focus over to Mars reasonably well once it cleared the trees.

The view was rather puzzling, and I thought I was having problems with my vision — the planet appeared to be banded. I followed up on calsky.com and navigated to the Mars apparent view page, and all was explained. The position of Mars right now is such that the main features are lined up and appear as a band in my 110 mm scope. Even the apparent view of the polar cap turned out to be brighter features in one hemisphere compared to the other – the polar cap wasn’t well-sited for viewing tonight.

For the hell of it I took a look at Uranus, but it’s a dull object at the moment (and indeed, at most moments in a small scope), and barely registered as a planet – if I didn’t have other pinpoint stars to compare to, I would probably have dismissed it as an out-of-focus star. No wonder it wasn’t recognised until the 18th century! I may try to image Titania, Uranus’ largest moon, but not tonight….

By 1.30 am clouds were coming in and I called it a night.

One of the few good things to come out of the major blackout of August 2003 was the way it showed the stars to people in major cities. Unfortunately it doesn’t seem to have changed behaviours appreciably, and we still routinely see lights glaring out into the night sky pumping up the light domes over every urban centre. Some nights it almost seems as though you can read in the soft glow in an urban backyard. Some nights there’s no almost about it.

How bad is it? Well, tonight is actually a pretty dark night in my backyard, considering the moon is within a few percent of full. I can see the Summer Triangle, but much of the northern sky seems to be washed out, and I can’t find Polaris right away. To put a number on it, the sky brightness is 17.34 magnitudes per square arc-second, according to my Sky Quality Meter. That’s not too good, but I’ve seen it as high as 16.5 on a nominally clear night with poor transparency. by way of contrast, the best skies get down to 22 magnitudes / sq.arc-second.

For more recent readings of the local sky brightness, check out the Ground Truth page from the right sidebar.

I got back from Starfest on Sunday. It was a very enjoyable session though I only imaged for one of the three nights. On Thursday night we had a considerable cloudburst which took up most of the night, so most people turned in early, and on Saturday night I spent time walking around with friends looking at and through some of the Monster scopes (25″!), but on Friday night the sky was clear and dark (about 21.4 magnitude/sq.arcsec, though I didn’t record it and may be off a little), so I spent several hours puttering about with the scope and camera. I aligned the scope very roughly by levelling the mount and synching on the sun, then adjusting the mount position to minimise the telescope shadow. This worked well enough for visual observing, and surprisingly well for imaging. I had neglected to prepare my computer adequately for shielding others from the display, so I worked the imaging from my camera’s LCD screen. That led to a few oohs and ahs as I reviewed the captured images in the camera, but reviewing them on the computer screen later was disappointing.

The image shown here is a composite of two 30-second images of M8, the Lagoon Nebula (lower) and M20, the Triffid Nebula. Processing consisted of level adjustment and the removal of a dark frame. There is no stacking to reduce noise as I only captured one image of M20, but I will process M8 again as I think I have a couple of decent images of this object.

I also tried five minute captures, but at that point the lack of alignment (sounds familiar!) shows up objectionably. I suspect the alignment was out because I left the scope unattended briefly while putting the computer away, and there were a couple of folks hanging around when I got back. The images still looked ok on the camera LCD, so I kept going. Next time I’ll be sure to have some sort of red screen for the laptop. The images do show that five minutes was a reasonable exposure, and that longer exposures could be attempted with autoguiding in place or at least a guide scope so that the scope could be guided manually.

Speaking of guiding, I have picked up a ToUCam and an Orion 80mm f/6 which I hope to set up to control the scope. More info on this as things develop.