Do my eyes deceive me?

[Drychnath]

As a newcomer to both my scope and the views that it affords me, how much faith should I have in that what I am seeing is both accurate and correct.

On 13/03/2013 at approx 19:30 I had Jupiter and 3 gorgeous moons more or less centred in my scopes supplied 10mm eyepiece. All were wonderfully bright, Jupiter more so than I would have believed possible. I could also swear that I saw a black speck, clearly defined, on the surface of Jupiter.

Was this the shadow cast from the 4^th moon? Or is it more likely that this was an easy mistake to make due to inexperience.

Either way, I can’t wait for the skies to clear again.

Cheers,

Lee.

[ArmyAirForce]

On my 200PDS, with a 10mm plossl and x2 TAL barlow, I've easily seen shadow transits. I haven't checked the timings, but there's a good chance you did see the shadow.

[cantab]

Stellarium confirms that Io was transiting at that time, it doesn't show the shadow but I presume that would have been present also. (Just make sure you turn on "Simulate Light Speed" in the Stellarium settings when checking the positions of Jupiter's moons.)

[Stu]

Hi Lee

There was definitely a shadow transit at that time, so congrats, you saw it! :-)

See the two pictures to confirm. If you look closely at the second one, you'll see the shadow towards the right hand side, although it depends on the image orientation of your scope as to which way round everything appeared

Nice one

Stu

[Stu]

I think you have a Newtonian so the image would be upside down - the previous ones were set for a refractor with diagonal.

Io was transitting but it is usually pretty hard or impossible to see until it gets towards the edge of the planet where the contrast between the two increases

Cheers

Stu

[Stu]

http://stargazerslounge.com/index.php?/topic/180435-Jupiter-with-Io-and-transit-Shadow-13.03,13/page__view__findpost__p__1866414

Here's an image of what you saw, a bit later on when Io was just about to leave the surface of the disk

Stu

[Double Kick Drum]

Congratulations of managing to see a transit as a (relative) newcomer.

It's something I have not managed after observing for some years.

[rory]

yes , i saw this too. two transits over recent weeks actually ive managed,but the one the other night was really nice as one moon was just on the limb of jupiter and it looked great.

[Drychnath]

This is really exciting stuff. I am very aware that the conditions on that night were about as perfect as I could ask for, and will probably have to wait until years end to return.

Stu, is there a stellarium equivalent for the iPad, that you know of? Or is it just as useful to use on a desktop PC before a nights viewing?

[Stu]

Hi Lee

Have a look at SkySafari. There are three variants, I have the plus version, quite expensive but good.

I use Luminos too which is good, you can put your kit in here to get an idea of fields of view with different combinations

The app I used for the screen shots is called JupiterMoons and is very good for GRS, moon and shadow transits. There is an equivalent called SaturnMoons which is also good.

There are lots of other free ones out there too which you could try. I use an iPhone5 but they will work on iPad too. Just search the store for planetarium or star maps and you will find them to try.

Sure you won't have to wait too long to see another. Shadow transits are quite regular and are often easier to see than GRS these days because it has got so pale. I can see both in my 66mm refractor (tricky but do-able) so you should be fine.

Enjoy :-)

Stu

[andrew63]

Good spot Lee. I had just been out seeing comet Pansttars for the first time that night - was a lovely clear evening. Shorty after had a peek at Jupiter, and the shadow was a nice crisp feature in the 4" refractor 119x 6mm BGO. It was also a bright deep black in the 8mm BST 89x - the really good conditions would have helped. Have a try for the Great Red Spot - not that great or red though at present !

andrew

[ArmyAirForce]

Stellarium ....... it doesn't show the shadow ......

The latest version of Stellarium does show the shadows including a nice triple transit on October 12th 2013.

[Drychnath]

Good spot Lee. I had just been out seeing comet Pansttars for the first time that night - was a lovely clear evening. Shorty after had a peek at Jupiter, and the shadow was a nice crisp feature in the 4" refractor 119x 6mm BGO. It was also a bright deep black in the 8mm BST 89x - the really good conditions would have helped. Have a try for the Great Red Spot - not that great or red though at present !

andrew

Hi Andrew, must admit I'm a little jealous of those who have a view of Pansttars, no chance of seeing the western horizon from my home. The Great Red Spot is definitely high on my list for the next clear night.

[Drychnath]

Hi Lee

Have a look at SkySafari. There are three variants, I have the plus version, quite expensive but good.

Hi Stu, thanks for the info, bookmarked the app for buying next payday.

[colesmat]

Well done Lee. Not managed a look at anything since my scope arrived, what scope do you have there?

[Drychnath]

1363516160[/url'>' post='1870460']

Well done Lee. Not managed a look at anything since my scope arrived, what scope do you have there?

Hi Colesmat, it's the Skyliner 250PX Dobsonian. That first nights viewing was after a week of cloudy skies, and they have been cloudy ever since. Hopefully soon though.....crosses fingers...

[Torin]

Wow - well done, am so jealous!

[AndyWB]

I missed the transit itself by about 20 minutes, but I accidentally caught the shadow crossing the surface a little later. Io's shadow appeared to be a little pinprick of black that appeared when the seeing was good. Not back for my little 130p. I tracked it for about 20-25 minutes while the shadow moved the edge of the disc to be sure, and then checked on JupitersMoons. Really chuffed!

It's worth noting, JupitersMoons does have a tab that shows the events for a given day too:

[Drychnath]

1363557866[/url'>' post='1871366']

I tracked it for about 20-25 minutes while the shadow moved the edge of the disc to be sure,

Hi AndyWB, this is such a good piece of advice. Track it to be sure, I'll keep this in mind from now on.

[SkyGibbon]

First time I saw a shadow transit I kept trying to blow whatever was causing it off my eyepiece. That was until I realized the little black speck was moving. Now it is my main reason to view jupiter.

[Mattscar]

I thought I saw this but had no way of confirming it. From one newbie to another thanks for pointing it out!