Frozen & Jupiter

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Frozen & Jupiter

Postby Aratus » Tue Mar 08, 2016 11:56 am

On Monday night the clouds eventually cleared revealling a sparkling sky. Unfortunately it also caused the temperature to drop to freezing pretty quickly. Chocky the Cat decided that the rubber floor of the observatory was far preferable to the frozen ground outside and happily muffed herself in her usual place. It is a little daunting listening to the sound of crunching frost as the aperture lid is raised! I spent a little time observing Jupiter noting that both Europa and Io were lining themselves up ready to dash across the face of Jupiter. Jupiter is almost at opposition and is at its biggest and brightest. It also means the shadows of the satellites will be pretty close to the bodies responsible for them. I set up the Canon, and was able see from the live view on the computer that the seeing was a little better than average, Jupiter was now about 40 degrees high, so I was hoping for some decent images. It was fascinating to watch Europa getting closer and closer to the limb of the planet. I lost sight of it at 2310 as it merged into the planet. However by 2315 it had appeared again as a bright dot slightly to the east of its own small, black shadow. In fact it seemed unusually bright. Chocky the Cat jumped on my lap to take a look. (Or was it just to warm her paws?) It merged once more into the brightness of the planet by 2340. I continued observing until 0010 UT. I was tempted to stay out another hour and watch Io and her shadow do a repeat performance, but I was getting rather chilly. Then a bit of drama as I discovered that the observatory door was frozen and wouldn’t open. Reluctant to start banging about and possibly disturbing the neighbours, I pushed hard on the bottom of the door until it eventually popped open again.

I include a couple of images showing Europa just before and after it started to pass in front of Jupiter. You can clearly see in the second image, Europa shining brightly against the disk of Jupiter with its shadow just below it. They are both 250 images stacked of 1000

Image
I use an 11" reflector (Celestron CPC 1100) and a 3" refractor, (Sky-Watcher ST80) mounted on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI 120MM, ZWO ASI1600MC and Canon 1300D for imaging.
Aratus
 
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Re: Frozen & Jupiter

Postby Supercooper » Tue Mar 08, 2016 4:28 pm

Great stuff buddy. :o)
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Re: Frozen & Jupiter

Postby Aratus » Tue Mar 08, 2016 9:17 pm

Thank you Barry. For the last 20 minutes of the session I tried out a 2x Barlow. Theoretically it should give twice the detail, but most often it means harder to focus, harder to keep the image centred, and a dimmer image more sensitive to atmospheric turbulance. Well, on this occasion things seem to have come together. With Jupiter high in the sky, at its brightest and largest, and over an area with only distant houses, I stood the best chance. ISO 3200 250/1000 images, 1/60th sec. It is the best Jupiter image I've managed to produce.
Image

All the basic belts and zones you normally see on a chart are there. All kinds of interesting festoons and swirls just about visible.
I use an 11" reflector (Celestron CPC 1100) and a 3" refractor, (Sky-Watcher ST80) mounted on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI 120MM, ZWO ASI1600MC and Canon 1300D for imaging.
Aratus
 
Posts: 950
Joined: Tue Jan 12, 2016 2:17 pm
Location: East Lincolnshire

Re: Frozen & Jupiter

Postby Supercooper » Wed Mar 09, 2016 9:10 pm

Hi,

That's a lovely image. Great detail.

Colcour on the satellite too... :o)
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For My FREE Telescope Help Website: http://supercooper.jimdo.com/

Using fab Helios f8 150mm Achromatic Refractor on SkyWatcher EQ5 - enjoing the views!
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Re: Frozen & Jupiter

Postby Aratus » Wed Mar 09, 2016 11:06 pm

I admire your eyesight! I hadn't noticed it before, but there is an overall orangy tinge to it. Normally it is hard to get any sharpness to these satellites let alone any colour. Certainly now is the time to view Jupiter and its satellites at its best.
I use an 11" reflector (Celestron CPC 1100) and a 3" refractor, (Sky-Watcher ST80) mounted on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI 120MM, ZWO ASI1600MC and Canon 1300D for imaging.
Aratus
 
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Joined: Tue Jan 12, 2016 2:17 pm
Location: East Lincolnshire

Re: Frozen & Jupiter

Postby dave.b » Wed Mar 09, 2016 11:58 pm

Good work! Making me wish I'd overcome my "inertia" to go outside last Monday myself. :-[

The Barlowed image works very well and I'm now inspired to have a go with a Barlow on my new camera to see what the improved image scale does to the final image quality.
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Re: Frozen & Jupiter

Postby Aratus » Fri Mar 11, 2016 12:23 am

These cold, often freezing evenings are not conducive to observing. It does take a lot of effort to leave the warmth of the house. Don't feel too bad about it. Jupiter is looking good this evening, but the freezing mist at low levels is keeping me inside tonight! I normally image Jupiter without a barlow first then try a few with it. That way I don't go away empty handed if the barlow shots don't work. Focus on the satellites if you can. It is easier to see if they are focused than the planet itself. Take as many images as you can, but don't let the run go over about 3 minutes because of the rotation of the planet. Taking a video of the planet takes frames more quickly. I risk about 1000 frames. The percentage I keep is based on the amount of time the image appears to keep focused when watching it. However, I keep a little more that how it appears. On this occasion it appeared to have sharp focus for about 1/5th of the time, so I kept the top 1/4 of the frames. I'm not sure of the mechanics behind that but it does work for me. In this case using the top 250 frames gave a better image than the top 200. Using 300 or 400 frames degraded the image as it lets in more bad frames. There is room for experimentation. I used Registax and I turn all the wavelets to full, and then lower the upper ones to reduce the grain, and the lower ones to get rid of any ghosting of the edge of the planet. I increase the colour saturation until blue artifacts appear in the white areas, and then pull it down until those disappear. I tend to increase the mid-range contrast which darkens the belts but being careful not to dim the limb of the planet, which is very easy to do with Jupiter.

Any other advice? Clean the barlow because dust specks on it show up very strongly. You need good alignment to keep the planet in the frame. It is very frustrating to see it swimming out of view before you have all the frames you want. If the image only sharpens for an 1/8th of the time or less, you will either get grainy images (too few good frames) or blurred ones (too many bad ones in the mix) Give up with the barlow and try again another night! Take mulitiple sets of images. The seeing might be better in one than the others. Inexplicably the seeing can sometimes settle down for a few minutes before getting worse again. You increase the chance of getting a good set by taking more of them.

Good luck!
I use an 11" reflector (Celestron CPC 1100) and a 3" refractor, (Sky-Watcher ST80) mounted on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI 120MM, ZWO ASI1600MC and Canon 1300D for imaging.
Aratus
 
Posts: 950
Joined: Tue Jan 12, 2016 2:17 pm
Location: East Lincolnshire


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