MathML is a way of displaying mathematical and other formulae. As such it would be very useful to have in an astronomical context. Unfortunately I’m viewing on a Mac, and so far, MathML does not play well on a Mac. On a Mac, the default browser is ‘Safari’–and on Safari, the formulas show as in-line ASCII with a lot of detail missing, so try Firefox instead. Firefox has other problems, most notably so far being that square roots look incredibly ugly – and I’m sure others can point out more problems. Meanwhile, on a PC, IE 6 doesn’t play well either – again, go for Firefox/Mozilla.
Here’s a test. You should see the equation for the force of gravity between two objects M and m at distance r between centres:
[mathml] F_g = G (M m) / (r^2) [/mathml] (1)
For me, that looks ok in Firefox, but…
[mathml] x_(1,2) = -b +- (sqrt(b^2 – 4ac)) / (2a) [/mathml] (2)
has problems with a couple of missing minus signs as well as the square root symbol.
Trying to force the page feed to xml+xhtml didn’t work too well (and in the process I seem to have broken my Calendar. Again.). More work to follow…..
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.
The banner is now based on the Lagoon Nebula picture captured at Starfest. Someone from the Niagara Centre of the RASC posted a blog asking “who would you rather observe with?” which put me up against a considerably younger individual of the female persuasion, and I couldn’t stand the competition. Old fart vs. young woman = no contest! (Although I could make the case that I should win because I have the telescope, but perhaps observing wouldn’t really be on his mind….)
If you’re obsessive about it, the old banner background is here. I thought for a while about modifying the image of the David Dunlap Observatory’s 74-inch ‘scope which I used in a May 26 post, but it had already been used (in a b&w version) as the cover illo for the Starfest edition of Astrotent, and (probably a more significant reason) would take quite a bit of manipulation to fit in the banner format. I hope to be eclectic in choosing banners, using both my own and, with permission, those of other amateurs. In keeping with the irregular nature of this log, the banner will also change irregularly – no schedules, please, as I get enough of those at work!
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.
If you want to see the images on the blog, search for “jpg” in order to find the jpeg images which are linked in to the articles (this article will give a false positive). The search box is at the right side of the page.
Also at the right side of the page are links to the NYAA image Gallery site, plus links to my own Gallery site here at zerobyzero, and a further link to a pbase site which I use occasionally.
The banner picture is a detail from the Lagoon/Triffid Nebulae image elsewhere on the site.
I was checking out Noise Ninja for the Mac and was very happy with the product. I’ll be buying it — but not right away! On checking my bank balance I find I’ve been a little too enthusiastic in upgrading the toys in my observatory. What with Starfest, the Orion 80mm Express, the ToUCam, the Sky Quality Meter (I did mention that, didn’t I?), the replacement for the Illuminated Reticle Eyepiece (I traded up, but the new eyepiece ate a huge chunk of change I didn’t expect) and assorted supportive software, my wallet is a little flatter than usual. I’ll have to delay further purchases and upgrades until my bank balance looks a little healthier (and work needed around the house looks like that event will be delayed for a while longer than I might like). So Noise Ninja, Equinox, Keith’s Astroimager, iAstrophoto 1.2 — all of these will have to wait.
I have a lottery ticket…..
It’s a truism amongst amateur astronomers that whenever you get a new telescope the weather is bad for weeks. That certainly seems to be playing out for me: the weather was fine while I was still reassembling the FLT-110, but as soon as I started setting up the Orion 80 mm Express which I want to use for a guidescope, the weather turned ugly. We’ve had clear weather with zero transparency, torrential rain followed by clouds, and right now it’s cloudy with the occasional shower. I’ll post an image of the new configuration when I have time to take a snap, and I’ll keep working on selection of the right guide software – it has to be Mac OS X compatible as well as working with a ToUCam and the Gemini system.
Meanwhile, on a slightly different though related note, iAstrophoto 1.2 is coming, and will support Canon 20Ds — providing the OS is pre-Tiger — i.e., Mac OS X 10.3.9 and earlier. Apparently there is a bug/feature with Canon’s SDK which interacts with a feature/bug in Tiger and prevents the camera from being recognised. Canon’s example software doesn’t work either….sigh….
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.