Spots on Jupiter

[shane.mcneil]

Hi all

I have just been looking at Jupiter. I can see a moon shadow on it, near the edge, at about 4 o'clock. But I also thought that I could see a dark smudge at about 7 o'clock, halfway between the centre and the edge of the planet.

Am I seeing things? I am a bit new to this.

Many thanks

Shane

[Rob_K]

Hi Shane. I checked Jupiter2 - there was no shadow transit but what you saw was probably the last bit of Callisto's transit across the face of Jupiter. As far as the dark smudge goes, I don't know, but the Great Red Spot was close to the limb at the same time, not far from Callisto. Hope that helps!

Jupiter2 software is available free at:
http://www.astrosurf.com/rondi/jupiter/

Cheers

[shane.mcneil]

Thanks Rob.

I downloaded Jupiter2 and that explains it. But I can't quite match the times. I have the UTC set to zero. Is that correct?

Then I need to set the time to 10:00 pm to get it to look like what I saw, but it would have only been 9:00pm.

Am I doing something wrong?

Thanks again.

Shane

[orestis]

Hi shane,
Yes you are doing something wrong . You have to set the utc to your timezone.depending where you live the timezone changes for me it is +10 hours and i'm about 100km out of sydney.Yours should be +10 hours too.

orestis

[orestis]

hi shane,
checked jupiter 2. what you saw was Callisto transiting jupiter.(Not the shadow,as it started at 6 O'clock in the morning which would of been imposible to see).As for the dark smudge i'm pretty sure you must of been looking at the GRS. Was it on one of the major bands? :question:

orestis:thumbsup:

[shane.mcneil]

OK. I manged to make sense of Jupiter2 and all is well.

So the black "spot" was Calisto. I guess it shows up as black against Jupiter.

As for the dark smudge, I thought it may have been the GRS but it was on the Eastern side. Jupiter2 says it should have been on the western. So I don't know what I saw. It was just below the lower major band, I think.

Thanks again for your help.

Shane

[rider]

Depending on your scope, the view may be showing as mirror imaged and therefore it swaps east & west. If you havent taken this in to consideration, this may be the difference.

regards Rider

[shane.mcneil]

Thanks rider. I thought of that too. But Callisto and the other mark were on opposite sides of Jupiter in the eyepiece. J2 says they should have been on the same side. It may have just been a feature in the bands that I haven't seen before.

Regards

Shane

[Davekyn]

What an amazing little program! Thanks for the link! Just a couple of newbie questions. I have not yet had a successful view of any Jupiter transits.
I take it a 12”f/5 Dobsonian is enough to view these events? If so What eye piece or Mag do you recommend with such a telescope? Should I use a planet filter, if so what color suits Jupiter?
With the UTC I am just outside of Brisbane and usually just use +10:00 that my computer uses, but I was wondering how do you account to set the minutes more accurately? & if it’s worth doing.
Oh yea…what should I set the Display (Inversion setting) to if I am using a Newtonian or Refractor?

According to the program (from how I have it set-up)-Ganymede will just be transiting right on 11:38 tonight. What should I be looking for in terms of image/brightness/contrast/shape/size & color? Does a shadow always accompany such events?


I really have no idea & would appreciate if anyone could assist with “any” of the above questions.
Thanks you
David

[shane.mcneil]

Well I'm no expert David but I'll tell you what I know.

I take it a 12”f/5 Dobsonian is enough to view these events?

Yes. I have a 10" F5 and can see it.

If so What eye piece or Mag do you recommend with such a telescope?

I magnify it as far as I can. But balance it with ease of tracking too. I usually barlow a 15mm at the most.

Should I use a planet filter, if so what color suits Jupiter?

Never tried. I have used my polarising filter which can help.

With the UTC I am just outside of Brisbane and usually just use +10:00 that my computer uses, but I was wondering how do you account to set the minutes more accurately? & if it’s worth doing.

Don't know & probably not.

Oh yea…what should I set the Display (Inversion setting) to if I am using a Newtonian or Refractor?

The default settings were right for me.

According to the program (from how I have it set-up)-Ganymede will just be transiting right on 11:38 tonight. What should I be looking for in terms of image/brightness/contrast/shape/size & color?

All you will see is a tiny black dot on Jupiter the size of the moon with space as its background.

Does a shadow always accompany such events?

No

Don't worry. It is not too hard to see. Just make sure you are collimated first and you'll be fine. Let me know how you go.

Regards

Shane

[Davekyn]

Many thanks Shane,
rain has set in here (Which is well needed) maybe by Monday night things will be clear. I will be sure to let you know.
Cheers
Dave.

[shane.mcneil]

No worries. The rain is here too. :(

BTW, do you have Stellarium yet? It is a good free program. Just Google it to get it.

May I ask what brand telescope you have and what you think of it? I can't quite make it out in the picture.

Shane

[Davekyn]

The avatar is to just represent the Dobsonian in general is all. I bought my From Andrews Communication –Guan Sheng GS-980 12" ASDX 300mm x 1500mm-NEW Adjustable Super Deluxe (ASDX) heavy-duty 12" Dob!
It arrived with a dent in it courtesy of TNT- I’ve bought a few items from there. Be careful when buying CHEAP large app Bino’s like 90mm ett…I learnt the hard way with collimation on those…whilst it’s only permitted to only talk highly of such distributers I really have nothing to say. OK…moving on:

The performance of that scope…Very Good. I’ve got no uni degree or MIT certifications, but as someone new to the hobby I was blown away, with things like Omega Centuri/Orion/eta carina…One night at a dark spot I even got a good look at the Crab neb…as far as that one goes…it was not lit up like Orion or Carina…but it was AWESOME to make out the shock wave filaments’ or whatever the pros here want to call them…Fantastic stuff!!!! I enjoyed a few Galaxies…the leo triplet and one shaped like half a hamburger and others elsewhere…Can’t remember them all as it’s been like 8 months since I’ve really played with it. Since I got it and did spend time with it, I was able to appreciate the subtle differences in contrast and was absolutely blown away with the UTC filter (I think that’s what it is called…lol…out of the loop too long) I bought…have not had a chance to try the OIII on the crab or other planetary nebs. I like looking at certain stars as well and this is where I appreciate the practices of collimation…I was terrified of collimation before I got the scope…but after ripping it apart a few times already (can’t help but play with things like that) I got a good grounding or at least understanding in that too now. I’ve washed down the mirror which was a good experience and I have learnt heaps from that too. Bit early to wash some may say, but I’ve been out in some windy conditions with it, & you would be surprised just how much crap can build up if you don’t take precautions. I’ve scratched the mirror by first using a “lens pen” to clean the damn thing OMG!!!!!! BUT…oh well, you live and learn…I managed to clean it up like new since then, with those little resulting swirl marks hardly effecting it at ALL!...Therefore now, I simply take precautions such as a dust cloth below, watch the wind, how I transport and move it since cleaning, & it’s like new every time I bring it back inside. It’s been a good introductory to the hobby for me. I am not working at the moment, however my marathon training leaves my need my sleep at night…I think I am going to change my training times so that I can get enough sleep and camp out. Before I packed it all away last year, I was getting into sketching…I really enjoyed scanning them and doing the negative thing then making a slide show presentation. After I finish running my marathon, I will get some more work, & plan on getting a 16” truss version + a trailer to go with it. The moon is fantastic!!!!!!! I have a book specifically to teach me how to view that…another time…but the Mountains (build up/whatever)look awesome…love chasing the shadows and all that…unfortunately I don’t really have any friends that truly understand what it is that I see. After they move away from the eye piece, it’s like what else is there? Honestly I cannot compare this scope in performance to others of it’s type…But since getting it & also the help I have received here, the views just keep getting better.

LOL…just downloaded stellerium for my Windows7…it’s good to have the new build…thanks for the tip…I love the program and sometimes take it out with me…I also use star map on iPhone and printout negative prints on my Utamantria 2.000 atlases (excuse spelling)…Nice meeting you Shane…I need my sleep now, as I have a big run in the morning.

How do you find your scope…you been gazing long?
Cheers
Dave.
PS...Love your avatar!!!

[shane.mcneil]

Thanks David. I haven't been game to pull it apart yet but I will. I've had it for about 6 weeks. I am happy with it so far but I have nothing to compare it with. So I'm still learning the sky and how to find things. I nearly bought one with goto but I find that you are better off learning the sky and there is a great satisfaction with finding something difficult.

I am enjoying the hobby though. The only thing is the telescope is a bit bulkier that I thought and it is a bit difficult to get it outside. But I'll work on that. When I get round to cleaning out my garage it might fit there on a trolley.

I hope the run went well. Thanks again for your comments.

Regards

Shane

[Davekyn]

I injured myself…but that happens & I’ll soldier on…;) Just be careful & put some kind of elastic dust cover on the bottom of your scope to help keep the shed dust off your mirror. To move my 12” scope, I stand directly in front of it like a sumo wrestler with the red dot & other finders facing opisite. I then push my gut up against the tubular section whilst reaching either side to unscrew the tension controllers with my head to one side. Once loosened, I lift with my legs and balance the scope against my stomach as I stand. When done correctly you will be surprised just how effective this method can be. Takes a little practice, but once mastered you’ll simply walk the scope gut first out the door & into the yard…simply balance appropriately and head back to bring out the mount separately and simply follow the same procedure to plop it back in…You should always collimate regardless of using a trolley or not…its easy after you’ve done it several times and you’ll get good view each time because of it. Anyways that’s how I get around with my 12” DOB…I even leave my foam camping mattress (dew shield) wrapped around the top when doing all that above. I can even fit my Dob in my 4cyclinder sedan…I found using a trolley to move it around just as time consuming, if not more. Also Top Heavy where steps are concerned…Perhaps you will find a better way, but I can’t imagine a 10” being that hard to move around…let me know what the secret is to keeping the mount securely on the trolley, less of course you don’t have to worry about steps.
Tried the seeing tonight, but clouds kept coming in…I think the Jupiter 2 says Sunday night will have a transition about 10:10pm…that sound right…I seemed to get the mirror look the right way round by selecting “east west inversion”
Later
Dave

[Davekyn]

Clouds are in...doh! I was looking forward to tonights transit...never know..still have a few hours to go...I guess even if I get a patch in the sky, it will most likely be to moist...oh well, off to check the software for the next available one.

[shane.mcneil]

Lousy weather. Thanks for the tips on moving and storing the telescope. My J2 shows moons moving left to right by default. I think that is what I saw in my eyepiece? Can't remember, I'll have to check again. Hope the sky clears up.

Shane

[Davekyn]

No probs...I know that method of moving my dob is not for everyone & I may even have to change it in the years to come, but at the moment I find it’s best for me and my scope. Bummer Last night hey…It did not clear up on my end…oh well…Europa transits at about 1am “after” tonight…I’m that keen, even if I am only lucky enough to see a miniscule spec crossing over. (Question…does the image of moon get washed out buy the brightness of Jupiter making it all the more harder to see-like are the shadows easier to see than the moons themselves? (When shadow is present))???
About the inversion options…my brain is back to front most of the time, so I’ll double check that one for you, but having said that, because the moons were all lined up on one side…it was easier for my brain to think…mmmmmmmmm…”when I viewed those moons they were on the other side…but not sure about the upside down issue. I really need to get my head around both my Newtonian & Refractor with regards to this…as it can get really messed up with star hopping on DSO and so forth…OH YEA! …glad you are also finding objects yourself as I am in the same boat. Honestly, I think were much better off learning that way as each season comes around you will start to simply point here and there knowing exactly where everything is…who knows, we may end up wizards with a laser pointer, like some kind of walking projector rattling off information looking up in one direction then the other, with a small crowed murmuring along with the occasional WOW…lol…I better go, you have a good day Shane. Hoping the weather clears, but my Veggies are looking awesome with this beautiful rain. ;)
Later
Dave