Jupiter GRS

[foffof]

What is the minimum aperture and magnification which I can use to see the great red spot and other details of Jupiter? Is it possible to see great red spot through 4 inch refractor? Which type of telescope is more suitable to see the great red spot- newtonian, mak or refractor? Thank you!

[Josh Wilson]

The type of telescope doesn't really matter, but I have noticed that the GRS is hard to pick out against the bright white background of Jupiter itself. It is for this reason that I have trouble picking out the GRS with any telescope. I've owned a refractor, Mak-Cass and reflector, but I have only seen it once and it was after about 5 mins of continuous moving and viewing. It is alot easier with some color filters. I find 80A is the best for bringing out the red colors of Jupiter's cloud belts and the GRS. High power is preferable to see it easier and bigger. The highest power you could use with a 4 inch frac is about 200x under the best conditions. I don't know what the focal length of your telescope is but you can find the eyepiece focal length you'll need to get 200x by dividing the focal length by the desired magnification.

[Stu]

As stated, there is not necessarily a best type of scope for seeing the GRS, so long as it is reasonable quality and collimated well and of sufficient aperture to have enough resolution. Cooling is also very important to make sure the scope is giving nice stable and sharp images.

Alot also depends on seeing conditions and transparency, aswell as observer experience.

I can see GRS and other details through a 66mm refractor at around x120. They are not easy necessarily but they are visible, along with shadow transits.

Through a reasonable 4" refractor they should definitely be visible, GRS is nice to observe through my 106mm apo.

I believe a 130mm newtonian or similar sized mak will do the job. Maks tend to have longer focal lengths so will give a higher magnification for a similar focal length eye piece so in some ways they are regarded as more suited to higher power, planetary viewing. They do tend to take longer to cool though. In general, the bigger the scope, the better the resolution although if seeing conditions are not great, often a smaller scope can suffer less than the larger ones.

Knowing when the GRS is visible helps too, so check out various apps which will tell you when is the best time to observe.

Stu

[cotterless45]

If you get Jupiter up on Stellarium and press the close up slash key , it'll not only show you the GRS position, but also the alignment of the moons.

It does move pdq and in one night's viewing the rotation can be seen. Really depends on viewing conditions, in a 102 , from terrible to pin sharp shapes and barges on the edge of the belts. Try different filters, even a Moon filter will do the trick,

Nick.

[Stu]

Stellarium is not always foolproof for GRS in that you have to make sure the setting is correct for the current position of GRS relative too the meridian (I believe). This is because it moves over time but once set correctly it will be fine.

Stu

[andrew63]

I think it is worth pointing out that although it called the great red spot - and it looks impressive in images - the colour is not always that apparent! For my in a 4" refractor it is apparent from about 100x plus but the 'colour' is quite washed out and will not stand out as a high contrast feature. Look carefully though and as jupiter is getting better placed you'll have more of a chance of observing the great pale spot!

andrew

[Stu]

That's very true. I never see colour on Jupiter anyway, but even so there are other, higher contrast features such as barges which stand out better. As Andrew says, GRS is large and can be quite pale.

It is a dynamic storm which changes frequently. In fact, the latest images on SGL show that there is another system close by. I'm looking forward to seeing it visually this year.

Stu

[John]

The best tip for seeing planetary details is to observe the planet as much as possible. Your eye seems to get "tuned in" after a while and then, gradually, you start to pick out the more subtle features that are not initially apparent. These skills take time to develop though - the initial view can be discouraging but you need to keep at it.

[michael.h.f.wilkinson]

All of t he above tips are very good. I have spotted the GRS with my 80mm apo, and even with my schools 70mm achro. It mainly requires good seeing, and patience.

[Josh Wilson]

Try this site for finding if Jupiter's GRS is visible or not: http://www.skyandtelescope.com/observing/objects/javascript/Transit_Times_of_Jupiters_Red_Spot.html

[saiph]

Here's a little something i got from my Apex102, for example (first two and last picture, on my Photobucket album)

http://s120.photobucket.com/albums/o167/saiph_ro/outer_space/Planets/Jupiter/GRS%20transit/

Clear skies!

[JimFR]

Hokay.

GRS transit times ? CHECK (table on p52 of October AN )

big magnification ? CHECK (although the eyepiece* and barlow combo is rather heavy for my poor focuser)

clear skies ? CHECK (it was fabulously clear (but blimmin cowd!) last night)

cooled gear ? CHECK (scope had been out for an hour before I went out - I catnapped in front of Horizon on catchup )

GRS ? Ummmm...no. couldnt categorically say I'd seen it - but I did see equatorial bands and was looking at the right time.

I did find that my Baader Neo improved things somewhat, but still no confirmed GRS sighting.

Question to the company here assembled: will an 80A or 82A help me more than the Neo ? I've had a look at some of these on eg: FLO and scopesnskies etc,

and they look close in colour to it.

I think practice is helping - I've been looking at Jupe on and off for about 25 years now, and I tend to ignore everything else (pretty much) when the big fella's around - think I saw some shape in the bands, and the northern one almost looked like two...but that could've been me...

speffics: the eyepiece was the ED 12mm, in the Deluxe 2x Skywatcher barlow - so I got 83x.

[Stu]

Have you seen it before Jim? Presumably you have if you've been looking for many years? I would try more magnification, if the skies are ok the x150 to x180 works very well on Jupiter.

GRS is large and pale these days, can almost just look like the equatorial belt has a break in it as, it comes round the corner on to the surface facing us.

I don't normally use filters on Jupiter, though I believe they can give benefits pulling out certain features.

What time were you looking? I would just say give it a go at higher mag. I'm assuming collimation was good?

Cheers

Stu

[cotterless45]

It was so good and clear last night that I kept shining a red light in my eye to close seeing down.I have used a standard Vixen Moon filter , although have used;

no.8 ; light yellow :belts.

no.12 ; yellow; red/orange on Jupiter.

no.21; orange; belts and poles.

no.23A , light red;belts and poles.#

no.25A,red;belts and moons.

no.38A, Dark blue;belts, grs.

no.82A, light blue, low contrast features.

It's really a matter of finding what works for you.Filters will enhance a view, but it must be good to start with.

The GRS is huge, lightly coloured and did a full transit ( from l to r in a Newt). That was at x120, then bunged in a Barlow end and still good at x192. The southern belt is getting pretty ragged at the edges, neat,

Nick.

[John]

I've seen the GRS a few times with my 4" ED refractor but it's a darned sight easier with my 120mm ED

Actually the 120ED has shown me the best views of Jupiter I've had in my 30+ years in the hobby. On a good night the details that can be glimpsed in the moments of good seeing are amazing both in and around the GRS and barges, festoons and other spots at various latitudes on the planet.

It's in these moments of great seeing we see what our scopes can really deliver - the rest of the time they are effectively hobbled by our atmosphere

By spending time at the eyepiece studying the planets at least you are on hand to capture those magic moments and your eye becomes attuned to the brightness and contrast so makes the best of what the optics are delivering too.

I believe that planetary observing is something that takes time and patience to master.

[JimFR]

Have you seen it before Jim? Presumably you have if you've been looking for many years? I would try more magnification, if the skies are ok the x150 to x180 works very well on Jupiter.

Jupiter ? yeah, I've seen jupiter before - many times ;-)

never really tried for the GRS as I always assumed my equipment was below par (certainly the dodgy 60mm Dixons special I had when I was a teen !).

If I get organised, I may well have to do it by webcam instead.

GRS is large and pale these days, can almost just look like the equatorial belt has a break in it as, it comes round the corner on to the surface facing us.

Aha ! In which case I may well've seen it by a gap in the belt !

I'll try again in a few nights (terrestrial cloud features permitting )

I don't normally use filters on Jupiter, though I believe they can give benefits pulling out certain features.

What time were you looking? I would just say give it a go at higher mag. I'm assuming collimation was good?

Cheers

Stu

The skies are pants here, usually, but it was quite high - I'd started looking at Jupiter around 10, and was watching at regular intervals (time for coffee in between !)

but was out for the advertised time of 1:21am this morning.

Collimation was probably a leetle bit off - not done that job for months ! Loaned mine out so thats not really been a goer.

[John]

With an F/4 newtonian, accurate collimation would be critical. The things that get lost if the collimation is out is contrast and resolution - both of which are exactly what you need to see planetary details.

[JimFR]

I agree, it does make a difference, but not that great, cos of the local air quality

[earth titan]

I heard it refered to recently as the great biege spot, which is more like it.

[cotterless45]

Definately, it's got so much lighter than last year,there's a perimeter line to the edge, there's also a mini spot to it's trailing side.You really need super seeing conditions to start picking these out,

Nick.

[eli71]

Another good program to know when to look for the GRS, is the Solar System Imaging Simulator http://kyleedwards1.webs.com/astronomysoftware.htm, and also valid for the Jupiter,s moon positions and the rest of the planets of the solar system.

[earth titan]

Another good program to know when to look for the GRS, is the Solar System Imaging Simulator http://kyleedwards1.webs.com/astronomysoftware.htm, and also valid for the Jupiter,s moon positions and the rest of the planets of the solar system.

Thanks.

Will try that one as I've not seen it before.

Typed by me on my fone, using fumms... Excuse eny speling errurs.

[chiltonstar]

What is the minimum aperture and magnification which I can use to see the great red spot and other details of Jupiter? Is it possible to see great red spot through 4 inch refractor? Which type of telescope is more suitable to see the great red spot- newtonian, mak or refractor? Thank you!

Coming back to the original post, as others have said any scope will do, but you do need as much contrast as possible (ie good seeing, no dewing on diagonals etc). Don't over-magnify as this will blur the detail and make the GRS more difficult to see. Unfortunately, the colour is much faded now compared with when some of us first started observing in the '70s, so using eg pale blue filters won't help an awful lot. A useful tip is to look up transit times for the GRS for the month ahead (I used AN, but the websites quoted will serve the same function) and put them into your web or phone calendar so you get an email alert before you start an observing session.

Chris