Posts tagged 'Saturn'

Observing Report 8th-9th April 2011 Part 2 (Saturn and globs)

Posted by on April 15th 2011 in Astrostuff, Observing Reports, Pics
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Well, we waited a while for darkness to fall and for Saturn to become visible. I trained the scope on it only to find it hiding behind the topmost leaves of a bush. We waited a while longer and then found that it had gone behind a tree. More waiting ensued before it cleared all of the obstructions, and then the guests all got a view of it through the eyepiece. After they were all suitably impressed by the planet and by the few Saturnian moons that were visible, I swapped the eyepiece for the camera and we all watched it on the laptop for a while. As an added bonus those not glued to the screen got to see the ISS pass overhead.

Visit over and goodbyes said, I went back to pack away. Trouble was, the sky was incredibly clear and the seeing was much better than usual. It was too good an opportunity to miss...

Before long I'd got the 1000D set up on the 6" R-C and the DMK was back on the guide-scope. A fair few globular clusters were visible unaided so I took a few runs of images and did some visual observing over the next few hours. Intermittent high wispy clouds spoiled a lot of the data but I ended up with a few reasonable frames for stacking. At the end of the session I was fair knackered as I'd spent nearly 12 hours either behind the scope or in front of the lappy, but it was worth it.

M3 (aka NGC 5272), a globular cluster in the constellation Canes Venatici.
Subs: 11 light @ 300s, darks and bias frames, ISO400.
1000D on the 6" R-C with 2x PowerMate, guided with PHD.

M5 (aka NGC 5904), a globular cluster in the constellation Serpens.
Subs: 14 light @ 300s, darks and bias frames, ISO800.
1000D on the 6" R-C with 2x PowerMate, guided with PHD.

M92 (aka NGC 6341), a globular cluster in the constellation Hercules.
Subs: 11 light @ 300s, darks and bias frames, ISO400.
1000D on the 6" R-C with 2x PowerMate, guided with PHD.

Observing Report 3rd-4th April 2011 (Saturn in opposition)

Posted by on April 6th 2011 in Astrostuff, Observing Reports, Pics
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Once a year the Earth passes almost exactly between the Sun and Saturn, at this time Saturn is said to be in opposition (Saturn and the Sun are directly opposite each other relative to an Earth-bound observer). With the Earth being "piggy in the middle", it stands to reason that at that time Saturn will be illuminated almost exactly face-on from behind the Earth, and this causes an interesting phenomenon, The Seeliger Effect. This is an apparent relative brightening of Saturn's rings due to the fact that we don't see so many shadows between the rings and between the ring particles.

This year's opposition occurred at 01:00 BST (00:00 UTC) on the 4th of April. I managed to get several imaging runs of it during the period one hour either side of the actual opposition, typically at the exact time there were clouds in the way so time-wise the closest I could manage was at about 00:10 BST:

 

Saturn in opposition
8" Newtonian, SPC900NC webcam, eyepiece-projection.
300/5400 frames stacked with RegiStax6, post-processing with PSCS3

Observing Report 8th-9th January 2011 (Venus & Saturn)

Posted by on January 15th 2011 in Astrostuff, Observing Reports, Pics
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Nearly caught up!

It wasn't the clearest of nights, but it was the first half-decent chance for over a month so I took it.

The first half of the session was spent setting up the scope and mount and then getting good polar-alignment. It's always a good idea to do proper checks after either maintenance or extremes of weather - it's surprising how much the ground heaves when it's gone through long freeze/thaw cycles, and it does affect the position of the mount's pier. Setting-up also included re-registering the reference stars so that the thing can work out where it's pointing (and can then work out where to find other stuff)... a time-consuming job if done to a fair degree of accuracy.

The second half was given over to visual observation and planetary imaging. While waiting for Saturn to rise to an acceptable declination, I got the camera set up and had a few practice-sessions focusing on double-stars and then I sat back watching for meteors. When Saturn was in sight I found that I'd picked a night when the huge "Dragon Storm" was visible, so I grabbed some footage of it for processing later. After that I went over to visual for an hour or so while waiting for the next target, Venus, to gain some height in the pre-dawn sky. Eventually the bright crescent of Venus climbed far enough to be nabbed by the CCD. After that I should have packed away but I couldn't resist the temptation to wait and see if I'd be able to image Mercury too. I could see it through the binoculars, peeking through the branches of a tree, but as I waited for it to clear the obstruction the sky became too bright to catch the planet on camera. Better luck next time, maybe?

Anyway, here are the results:

 

Saturn with storm

 Venus

Observing Report 29th-30th January 2010 (Mars just after Opposition)

Posted by on January 31st 2010 in Astrostuff, Observing Reports
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The original plan was to observe Mars on the 27th, the night of its closest approach to Earth (the closest approach distance was 0.664 AU (99.33 million km), giving Mars an apparent diameter of 14.105") but the skies were cloudy so the deal was off. Instead, I had to be content with observing just after opposition on the 29th when the skies were nice and clear, the reflected light-pollution was minimal and the seeing was good. The only downside was that the Moon was almost full and visually quite close to Mars, so the sky wasn't as dark as usual. It was damned cold here, but I wasn't about to let the falling temperatures get in the way of seeing Mars at such close quarters.

Before opening the obsy roof I had to put the fan-heater on for a few minutes to warm up the mount as it had been iced-up for a couple of days and it doesn't like starting in the cold (ice in the gears isn't a good thing). After that it was a doddle, except for the frost that formed on everything unheated. The scope was soon pointing at Mars and I cranked-up the new camera.

This time I was trying something different - using RGB filters and a mono camera. This meant grabbing filtered avi data-runs for each of the three colour-channels and another for the luminance-channel... all within a four(ish)-minute period so as to minimise any image-blurring due to Mars' rotation. After a few failed attempts I managed to get the suss on it, and after that the data-sets were quite easy to get, if a tad rushed.

Soon it was time to move on. I had a good look at the Moon but didn't think it merited any camera-work, as the surface-contrast was low due to the face-on illumination. Still, it was fun trying to find the Apollo landing areas. Next time out I might try for some images of them, just for the hell of it.

After an hour indoors to warm up, I went back out and slewed the scope around to Saturn. This time the rings were more open so I grabbed some filtered avi data, but yet again it didn't turn out well due to the planet being so low above the horizon. I'll probably process the data anyway, but if they're crap I'll just bin 'em.

After another hour or so of watching Saturn the temperature had fallen to -7C. The mount was struggling, no doubt due to the cold thickening the grease inside, so I ended the session, closed the obsy roof and put the fan-heater back on to get rid of the ice.

Anyway, this is the result:

Not bad for my first attempt at this method, eh?

Again, you'll have to wait for me to find time to process the Saturn data.

Observing Report 10th-11th December 2009 (Frosty Mars)

Posted by on December 13th 2009 in Astrostuff, My vids, Observing Reports
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The weather here on Thursday evening was a bit odd - periods of thick fog alternating with cold clear spells. I got the scope set up early and while waiting for the longer clear bits I used the odd short bits of good visibility to get good focus and tracking. Oh, and to fight the battle against condensation on the kit.

Some time after midnight the fog lifted and everything was clear and still, not a breath of wind and the seeing was brilliant. All of the condensation froze within minutes. Undeterred by the layer of ice on the kit, I had a good look at Mars before nabbing some webcam footage of it. Visually, I'd never seen it so good - the polar cap was really bright and the planet was almost motionless, unlike the previous Mars session when the thing was moving around like a demented Morris Dancer. I spent a good hour or so just studying the surface detail, something I've never been able to do before. Here's some of that webcam footage after selecting a 256x256px region of interest around the planet:

Soon it was time to move on. I changed the eyepiece setup and this caused some melting of the ice on the kit. Figuring that it would be best to let the temperature settle down a bit I nipped in for a cuppa and then sat outside for twenty minutes watching a fair few meteors blazing across from East to West - they were mostly Geminids but there were a few others up there. I did contemplate setting up the D50 with the 35mm prime in order to get some images, but the camera was by now well-frozen and I wasn't going to risk trashing the mechanics inside the lens.

When all was settled I slewed the scope around to Saturn, which had risen to a reasonable height above the horizon. It looked a bit dimmer than I've seen it before but I could still see the rings, not far past being edge-on. A couple of dim moons were visible but not much else. I grabbed a fair few avis with the webcam but they didn't look much good.

After another half-hour of visual, watching Saturn and some more meteors, the fog returned. This time it was thick, freezing, and obviously here to stay. I ended the session and closed the obsy roof. The next hour was spent mopping up meltwater from the kit and from the underside of the roof. I returned to the house at 06:00 vowing to get a cheap dehumidifier in the post-Christmas sales.

Anyway, I did some preliminary processing of the Mars data and sent the pics to a learned friend. He's confident that he's identified the surface features correctly, and pointed out the tiny clouds in the vicinity of Olympus Mons. He also reckons that the colours are fine, but I'm not so sure:

 

 

Again, you'll have to wait for me to find time to process the Saturn data.

I'll finish with a reminder - don't forget that Geminid meteor shower.

Observing Report 21st-22nd November 2009 (Mars at short notice)

Posted by on November 24th 2009 in Astrostuff, Observing Reports
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Saturday evening was forecast to be cloudy and wet, and I was resigned to an evening of avoiding Strictly, Casualty and the rest of the Beeb's prime-time twaddle, but the forecasters got it wrong - just for a change there was more gap than cloud. I grabbed my chance and cranked-up the obsy.

At such short notice I'd not had much time to think ahead, so, as the Newt's cooling-fan purred away, I sat back and looked up for inspiration. Rising in the East was Mars, and just for once it looked fairly bright. Target acquired!

After the scope had been cooled and the collimation checked I slewed it around to Mars and set about trying to get a decent focus - not easy, as the scope was dancing around in the wind, sending the image dancing all over the webcam chip. After a quarter of an hour of this malarkey I was happy with the focus and set about grabbing some .avi data. While this was going on I was on the lookout for Alpha-Monocerotid meteors - a minor shower that peaked on the 21st. I managed to spot a couple of them and a few sporadics as well, but didn't have the dSLR set up so there are no pics. 

Most of the webcam runs had some blurring and fading due to clouds and hence got consigned to the Recycle Bin, but some were OK. By about 03:00 a full cover of cloud had rolled in and spoiled the show so I closed the roof, had a cuppa and started processing the data. I figured that the night had finished so I parked the scope and packed away.

Leaving the obsy at 04:00 I looked up again and all was clear, so I did a smart about-face and went back in. Half an hour later I was set up again and looking at Saturn for the first time in ages. I grabbed a few .avis before the clouds spoiled things again, and this time there was some drizzle so the session was definitely finished.

After a couple of hours of kip I finished processing the Mars data, ending up with some rubbish and a few decent images. From these I've made a composite image just to see if there are any noticeable differences due to processing or planetary rotation. For an explanation of what's what, see the text below the pic:

 

Upper images from a 7200-frame avi taken at 02:08 - left: best 10% of frames stacked, right: best 90% of frames stacked.
Lower images from a 7200-frame avi taken at 02:20 - left: best 10% of frames stacked, right: best 90% of frames stacked.

Damned if I can tell any difference between them!


I'm quite pleased with this - it's by far the best Mars image-set that I've done to date, not bad for a cheapo webcam. I'm inspired to get some better data later this month when Mars is a lot higher in the sky.

As for the Saturn data, I've not yet found time to process it properly. First impressions are that the data's not worth the effort, but I might be tempted to have a whack at it. If I get anything worthwhile, I'll let you know.

 

And now for the rest of the astronews...

Followers of this blog will know that I'm a keen meteor observer, and they may be wondering why there are no observing reports here about the recent showers. Well, the weather's the main culprit...

The Orionid shower  peaked on the 21st of October. I managed a short visual session during the preceding evening when all was clear for an hour or so, and managed to spot four Orionids, but the main night was clouded out. Typically it was much clearer the night after too, but I was too busy to get out. It was a similar story with the Leonid shower on the 17th of November - clear the night before when I spotted about ten Leonids, and then cloudy and rainy for the main night and for the rest of the week.

Let's hope for a break in the weather around the 14th of December for the Geminid shower, which is always a good display.
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