Tuesday, 23 February 2010

Weird Wild

Here's Comet Wild from 01:30 20/2/10 looking particularly weird. There are two tails, one of which is curved in a strange way from this line of sight. The sub-frames looked like the coma was smeared out left-right. I fiddled a bit with the processing to reveal more of the faint tail at the expense of the coloured background, which is probably the result of a light pollution gradient, or an out of date flat field. It is 9 x 30" pics on the 20". Wild is visible in the morning sky in the constellation Virgo.

Comet Schwassmann-Wachmann 1

Here's a current shot of Comet Schwassmann-Wachmann 1, which has been in 'outburst' recently. It looks a bit like Holmes did, as it has an expanding shell. The image was taken at about midnight on 20/2/10, is linear and results from 19 x 15" + 1 x 30" stacked light frames at f/3 ish on the 20". It is currently about 11th magnitude in W Leo.

Saturday, 20 February 2010

IC 342

For those of you that are checking this blog to see how well the 20" telescope performed after it's mini-service, then the answer is ... pretty well. It may be a little louder and a play a slightly different tune while it's working but it is much smoother and hasn't been this easy to image on for a long while. We had what most telescope users expect, stars that keep pretty still for 10 30 second frames. There was some trailing, but not much, and not all that dancing about that I've been used to recently. So thanks - we got a lot of interesting pics taken last night. Here's one of them - a far out IC object called IC 342. It is a faint face-on galaxy in Camelopardalis and it is seen dimmed through the milky way's dust. So it may be close and 21 arc minutes across, but is only 9.2 magnitude. Only the middle spot showed up on the 30-second sub frames. So it was a bit of a swine to find; we successfully used a 14.2 magnitude galaxy as a GOTO/reference object!!

Monday, 15 February 2010

IC 289

Here I am pointing out an overlooked object. It's not in the Herschel 400, the Caldwell catalog, nor the original New General Catalogue. It lies less than 3º from the easily visible (4.2m) star CS Camelopardalis, which is itself a ridiculously overlooked (double) star in the 'unfashionable' constellation of the giraffe. CS Cam doesn't have a Bayer letter designation, or even a Flamsteed number and lies an unmeasurable distance away. Still, IC 289 is a lovely little(!) 12th magnitude planetary nebula - the same magnitude technically as the Owl nebula in Ursa Major, which I find a bit hard to reconcile. The nebula itself is actually over the border in Cassiopeia. There are some lovely coloured stars in the field. There is a weird pattern over to the left, which is the Southern side, centred on a 9th magnitude brightish star. Moving slightly toward the corner, there appears to be a streak or 'hair' next to the 14th magnitude star. This is actually a little row of 5 stars, all in a neat line, that are just unresolved. Just below the 9th magnitude star is a faint reddish galaxy, looking a little smudgy. I find this image an exciting little exploration of space! Details: 20" @ f/3, ISO1600, 2½' on Canon EOS 350D, linear.

Sunday, 7 February 2010

Comet Siding Spring

On another frustrating night trying to control a confused telescope with a very rigid operating system I still somehow managed a few shots of Comet Siding Spring. We got a visual sighting of the comet before imaging. I had to star-hop to it through northern Boötes. It was not obvious at first that it was in the field of view and I may well have gone past it a couple of times. But this process was made much easier with the charts from heavens-above.com. The view was later improved greatly by putting in the zoom eyepiece. I find it very interesting that undermagnification causes the perception of less contrast, and even contrarily makes objects invisible while more light is reaching the back of your eye. The tracking was a serious problem, we corrected it for a few minutes using drift correction, but later on the scope ended up thinking it was about 25 degrees from where it was and nearly knocked over the step ladder. The frames were 6x15 and 2x30 seconds at f/3 ish on the 20" and I still had to be detrail by 2 or 3 pixels after stacking. Not bad for a low altitude comet dimmer than 10th mag and a slightly misty night.

14 Tauri occultation

Update from below...
I drove out to the observatory at midnight on a working weekday night, set up my tripod outside and pointed at the star 14 Tauri. I took continuous 10 second exposures around 00:56 am, while I watched the star through binoculars to see if there was an occultation by the asteroid below. Frustratingly, some high cloud drifted past just at the wrong minute, and made the star hard to see clearly, and it could well have disappeared for a second or so without me noticing. I was on the northern edge of the possible error limit of the occultation 'shadow' and as was likely, saw no disappearance of the star. After reviewing the camera shots there was no noticeable dimming of the star on 'film', but of course, it could have disappeared between shots. Also, unusually, during the crucial minute, some chatty cyclists came by. This disturbed me to look away from the binoculars and then I had to refind the star, so I can't say for sure it didn't disappear! Here's a picture with 14 Tauri labelled. It is quite impressive that Flamsteed could see this star without optical aid.

Monday, 1 February 2010

Asteroid occults 6m star...tonight! (Feb 2)


Just a one-off alert for astronomers across UK to test the accuracy of this little asteroid's orbit. (no picture, sorry!)
1248 Jugurtha, mag 14.6 astreroid will rapidly obliterate the light from the sixth magnitude star 14 Tauri (HIP 17408), which is just below the Pleiades. The event will occur at about 12:56 a.m to a few select areas across Wales, the Midlands, and East Anglia, possibly including London.