Posts tagged 'Comet'

Observing Report 3rd-4th August 2011 (Garradd through the cloud-gaps)

Posted by on August 8th 2011 in Astrostuff, Observing Reports, Pics
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An odd night - a lot of isolated clouds but with crystal-clear dark skies beyond. I'd got my night-pass from my better-half and wasn't going to waste it, so I got set up for imaging Comet C/2009 P1 Garradd which was up there in the constellation Pegasus, visible as a fuzzy white patch through the binoculars. I set up the scope for a 50-shot run of 300s exposures and let the kit run on auto while I got on with other stuff.

As I expected, most of the exposures were rejected due to the clouds, and I ended up with just three useful frames. Then it rained stair-rods.

No matter, I've stacked and processed them anyway and the result's fair if not brilliant. Give me a clear night for this target and I reckon I could get a much better image. I'll wager that it won't happen soon though, what with all this glorious summer weather. I'll see what I can do in the coming months.

Anyway, it looked something like this:

Comet C/2009 P1 Garradd (04/08/2011 @ 01:09 approx), in the constellation Pegasus.
Subs: 3 light @ 300s, darks and bias frames, ISO400.
1000D on the 6" R-C, guided with PHD.

Observing Report 16th-17th October 2010 (First light for the new scope)

Posted by on November 1st 2010 in Astrostuff, Observing Reports, Pics, Shiny new kit
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Sorry this is a bit late but I'm playing catch-up here.

Saturday night was forecast reasonably clear so I grabbed the chance to point the baby R-C scope skywards to see what it could do. Although this scope is built primarily for imaging, I wanted to try some visual observing first to see how it compared to the 8" Newt.

I'd been told that aside from the reduced light-grasp due to the reduced aperture, the contrast would be reduced due to the relative size of the secondary obstruction. Well, I believed that until I looked at Jupiter's clearly-defined belts through the 8mm eyepiece. It looked good, and there were no issues with holding the planet and its moons in focus at the same time. I had a look at some Messier objects through various eyepieces and was similarly impressed.

After that I removed the eyepiece and put the webcam in at prime focus and went back to Jupiter and its moons. The scope has a larger native magnification than the Newt, so it was hard to gauge the differences, but it was certainly no worse, I reckon it'll make a fair grab 'n go planetary webcamming scope.

Finally I set it up with the D50 at prime focus and took some guided long exposures of a few objects - M1 (The Crab Nebula), Comet 103P/Hartley again,  M33 (The Triangulum Galaxy) again, M67 (an open cluster in the constellation Cancer) and M74 (a face-on spiral galaxy in the constellation Pisces). Hartley was really motoring - in the pic the comet's elongation gives an indication of how far it was moving during each 300s exposure.

The data for the last two was dumped due to it being affected by high-level thin clouds, but I processed the rest and got some reasonable results bearing in mind the small amount of data that was used. I'm sufficiently encouraged by these to plan ahead for a decently-long session with M33 when the skies eventually clear here, I reckon I could get much better results with more data at better settings. It that works, I'll go for M74 which is supposed to be the most difficult Messier object for amateur astronomers to observe.

Anyway, the pics are as follows:

103P/Hartley, currently in the constellation Auriga.
Subs: 10 light @ 300s, darks, flats, ISO200.
D50 and AT2FF on the 6" R-C, guided with PHD.

 M33 (aka NGC 598), a spiral galaxy in the constellation Triangulum.
Subs: 12 light @ 300s, darks, flats, ISO200.
D50 and AT2FF on the 6" R-C, guided with PHD.

 M1 (aka NGC 1952), The Crab Nebula in the constellation Taurus.
Subs: 12 light @ 300s, darks, flats, ISO200.
D50 and AT2FF on the 6" R-C, guided with PHD.

By the time I'd finished taking flat-frames, packed away and locked up, it was getting light. I was knackered but happy. For such a small scope, the baby R-C has proved to be good and I'm glad that I bought it.

Observing Report 29th-30th September 2010 (Much wetness)

Posted by on October 1st 2010 in Astrostuff, Observing Reports, Pics
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Wednesday evening was unexpectedly clear after several days and nights of grotty weather, and I wasn't going to miss the opportunity to get a look in so yet again I got set up after our weekly evening shopping trip. The seeing was reasonable and there wasn't a hint of a breeze but the humidity was high - it was a battle against the dew all night long. It's a good job that I'd been planning for such conditions - I'd recently acquired a set of anti-dew tapes and a controller-box and I'd made a decent power-pack. Again, the aim was to get some more views of Messier objects, image a few, and to return to Comet 103P/Hartley which is getting brighter and faster.

After a few hours I'd looked at 103P/Hartley and at a few Messiers, but many of them were difficult targets as they were drowned-out by the light of the rising Moon. Bearing in mind the condensation that kept forming on the scope's secondary mirror, I managed to get fairly good digital data for the comet and for M33 (The Triangulum Galaxy). The resultant (clickable) images are as follows:

103P/Hartley, currently in the constellation Cassiopeia.
The bright star to the left of the comet is Lambda Cassiopeiae.
Subs: 30 light @ 200s, darks, no flats, ISO200.
D50 and MPCC on the C8N, guided with PHD.

 M33 (aka NGC 598), a spiral galaxy in the constellation Triangulum.
Subs: 17 light @ 200s, darks, no flats, ISO200.
D50 and MPCC on the C8N, guided with PHD.

After that I did quite fancy a good look at the Moon but I was too knackered to carry on and it was beginning to get light so I ended the session and closed the roof. Packing away was a nightmare as everything was covered with condensation - not good when there's so much electrical stuff in use!

Observing Report 15th-16th September 2010 (Clusters and Comets)

Posted by on September 17th 2010 in Astrostuff, Observing Reports, Pics
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It was generally nice and clear here on Wednesday evening so I got set up pretty sharpish after our weekly evening shopping trip. The seeing was quite good although there was the threat of isolated showers. The aim was to get some more views of Messier objects and to image them if possible, and then to find Comet 103P/Hartley which is increasing in brightness for the next few weeks, and which is currently above the horizon all night long.

Despite having to shut the roof a couple of times due to spitting rain, after a few hours I'd looked at a fair range of Messiers (M31, M32, M34, M35, M36, M37, M38, M45 and M110) with the 8" scope and had acquired images of the M37 and M38 with the D50. The resultant (clickable) images are as follows:

M37 (aka NGC 2099), an open cluster in the constellation Auriga.
Subs: 8 light @ 200s, darks, no flats, ISO200.
D50 and MPCC on the C8N, guided with PHD.

 M38 (aka NGC 1912), an open cluster in the constellation Auriga.
Subs: 11 light @ 200s, darks, no flats, ISO200.
D50 and MPCC on the C8N, guided with PHD.

Then it was time to have a look-see at the comet. It was just a faint smudge visible through the binoculars and through the scope, but the D50 and scope combo picked it up quite well with 200s exposures. I stacked 10 frames and, after a lot of post-processing, ended up with this pic:

103P/Hartley, currently in the constellation Andromeda.
Subs: 10 light @ 200s, darks, no flats, ISO200.
D50 and MPCC on the C8N, guided with PHD.

 As previous but cropped and enlarged a bit.

The comet's poorly-defined and quite dim at the moment, but it should develop a better tail and become much brighter in the coming weeks - it's closest to Earth on 20th October and closest to the Sun on 28th October, and is predicted to reach naked-eye visibility around those dates. If you want to know where and when to stare, have a look at http://www.calsky.com/cs.cgi/Comets/1

Observing Report 17th-18th April 2010 (A night with a Wild Thing)

Posted by on April 19th 2010 in Astrostuff, Observing Reports
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With the absence of air-traffic Saturday night was looking good for observing. There was no wind, stable air, clear skies and hardly any sign of the dreaded Icelandic dust. The plan was to have a look for comets, and to see if I could bag one with the camera. A quick look on the CalSky site indicated that Comet 81P/Wild (pronounced Vilt) might be worth a shot. It's a tiny target - currently in the constellation of Virgo, it's low down, quite dim and well beyond the capability of my binoculars - so it was a scope-job. 81P/Wild is quite a significant comet - NASA targeted it for one of their missions - see here and here.

It took me ages to find the target with the 8" Newt even with the GOTO, primarily because the software's datafile for comets is wrong, leading to a huge positional error. Undeterred, I opted for Plan B - I got the comet's true coordinates from CalSky and plugged them into the software, and soon found the required bit of sky. A thorough look through the eyepiece revealed hardly anything, so I ditched that idea and slapped on the D50 at prime-focus with the intent of taking a series of long exposures. I wanted to be taking frames with exposures in the 5-10 minutes range, so I needed to use the other scope and the webcam as an autoguider, but there was no suitably bright and well-positioned guide-star anywhere near the target. Typical. No matter, I'd just have to make do with shorter exposures, but more of them. It wasn't an ideal situation, but it was better than nothing.

After a few hours I'd got what I needed, having taken a series of light and dark frames for the stacking-software to mull over. By that time a haze had started to develop which meant that the session was over. I packed up and started to process the data before heading in for some shut-eye.

So, here are the results:

(Mouseover for the annotated version, click for the biggie)

Comet 81P/Wild (the bluish smudge) in the centre, NGC5493 (a galaxy) to the left of centre, the other labelled items are stars.
53 light and 45 dark frames restricted to 60 second exposure times due to the lack of guiding.
Stacked in DSS and post-processed with PSCS3.

 

Here's a cropped and enhanced version. This is about the best I can get it, no doubt others could do much better with the data:

 

 

I'm quite pleased with that. I don't usually have the patience to deal with the slow pace of imaging the faint fuzzy things up there, but I'm glad that I persisted. If I get another chance, I'll try to get some longer, guided exposures to see how much improvement can be achieved.
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