Jupiter - 30 Sept 2011

[asteria]

Hi there - spent last night looking at Jupiter with the MakCass. The conditions weren't very good, and it was difficult to get a settled image. Best ep was a 14mm Plossl (giving around 128x), which gave a sharp image and some details in the equatorial bands. Some subtle details towards the poles from time to time. A 26mm Plossl gave a fine overall view (giving around 70x) of the moons and planet.

Further magnification with a 9mm Plossl (giving 200x) didn't really help the image, except at moments of good seeing, which were very rare.

All in all, pretty typical for this planet!

Thanks. Ed

[red dwalf]

i observed Jupiter last night from Nootingham area, 1130pm-0100 am,

conditions here where the best i`ve had looking at Jupiter, could make out 7 Moons which is something i`ve never been able to acheive before, got some webcam images some trying out my new neoyridium sky and Moon filter, processed one late last night which is one of the best i` ve had so far, spent time on the focus which made image better i`m sure,

all in all a fantastic night would have loved to have stayed out all night as weather was superb.

[Stu]

Only 4 moons I'm afraid red dwalf, the rest are background stars which just happen to be in the same field at the moment.

Similar experiences for me at the moment, not much to be gained from using more than x150 magnification. Let's hope the seeing improves over the winter.

Stu

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[asteria]

Hi Stu - I'm hoping for better images later in the year, and hopefully in subsequent years as the planet gets some northern declination. I've got all the bits and bobs now to take advantage of those good nights when they come along.

Good luck!

Ed

[stringbean]

I'm not an experienced back yard astronomer. I saw Jupiter for the first time tonight using my six inch refractor. I was a bit disappointed. Although I could certainly see the four moons, I just couldn't get a sharp enough definition on the planet. Magnification seemed useless as it just seemed to make the planet look kind of smeary. My best views were when I used a 32mm eye piece and although I could make out two dark bands, the planet seemed small. Is this normal for Jupiter using a six inch refractor or was I experiencing poor seeing? I didn't get the wow factor like I did when I first saw Saturn. Maybe my expectations were too high.

[Stu]

stringbean, what scope do you have? What is the focal length etc? As you can see from other comments, the seeing has not been very good lately and jupiter can be difficult at higher powers. It can tend to look soft around the edges and the features are not very high contrast. Best magnification to use changes depending on the sering and as you've found, it's better to have a smaller, sharper image. In good seeing it can be amazing though.

If your scope is an achro then it, may be showing chromatic abberation (colour fringing) more than normal because jupiter is very bright. A 'fringe killer' filter may help.

Watch out for transits, especially shadows as they are quite easy to spot.

Cheers

Stu

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[stringbean]

stringbean, what scope do you have? What is the focal length etc? As you can see from other comments, the seeing has not been very good lately and jupiter can be difficult at higher powers.

Hi,.

I have a Celestron C6-R 1200mm focal length achromatic refractor. Yes, I did notice that the planet was so bright that I was experiencing reflection when using higher power and just couldn't achieve a decent contrast. Using low power 32mm 1 1/4 eyepiece gave a clearer view but the planet was small.

Ann.

[todd8137]

been out every night over the last couple a days and they have ben ok not great seeing here at the min Jupiter was not great here last night,20mm ep was about the limit for me ,but as already said the cooler winter nights will soon be with us the neo filters are great for planets

[asteria]

Stringbean - your mag. with the 32mm ep was 1200mm/32mm=37.5 times which would give a small image. Your scope should be well suited to planetary observation due to long focal length (1200mm/150mm=8 - i.e. giving a focal ratio of 8 or f8).

Long focal lengths suit planetary viewing - for example my Maksutov is f12.

I think your difficulties with magnification were probably due to poor sky conditions more than anything else. You may be more impressed when you can view Jupiter when it is higher in the sky, and has gained more declination. You should be able to achieve around 150x magnification with very good seeing conditions.

It is difficult to achieve anything more than this magnification wise unless the sky conditions are exceptional, when you may get around 200x.

Hopefully I've got the maths right!

Ed

[Stu]

Maths is spot on asteria, and I think with that scope the problem is most likely to be seeing. It has a reasonably long focal length so CA shouldn't be too bad and should be good on planets.

Main thing will be to view late at night/early morning when the seeing has stabilised a bit, and get out as much as possible to catch the nights that are good. The hot weather is not helping so when it finally does cool down, it should be better.

Good luck

Stu

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[asteria]

Hi there - the nights down here have been very warm. For example, observing in shorts and t-shirt on Friday night at 11:30PM! In late September....! There has also been a huge amount of moisture in the air, which has made transparency poor. Agreed - cooler nights and drier air will help a lot. Should make viewing Jupiter a more rewarding experience.

Early morning viewing can be a treat - just before dawn in mid-winter can often be the best seeing of all. Great for the early risers amongst us.

Ed

[stringbean]

@Asteria (Ed)

Thanks for your reply. Looked at Jupiter again last night and the best I could get was using the 20mm ep and as far as Jupiter itself was concerned, I could just make out the two dark belts, nothing else. Maybe it's the sky conditions and poor seeing that's lowering my spirits a bit on this one at the moment. Having said all that, it was great seeing all four moons in the positions they were from the previous night. I stared at them for ages.

[asteria]

Hi stringbean - doing astronomy is a real learning process, and often the subtlety of it takes a while to appreciate. Hang in there and it will grow on you.

Good luck with the hobby.

Ed