Jump to content

Banner.jpg.b83b14cd4142fe10848741bb2a14c66b.jpg

Io's transit across Jupiter

callisto

By callisto
in Observing - Planetary

Recommended Posts

tony4563

tony4563

Posted
Posted

Feeling a bit under the weather today, but knowing that there was a transit of Io tonight between 10 and 11pm, I was determined to see it... weather permitting of course.

Anyway,It remained pretty clear here in West Yorkshire tonight, so I let the 10" Dob and 127 Mak cool down for a while. After an hour or so I turned them both towards the giant diamond in the sky, that being Jupiter. First the Dob. Seeing was not the best as the view was a little misty, (as if the eyepiece had starting to fog) I put it down to the high, fine hazy cloud, as the eyepiece and secondary were fine. On fine focussing, it was obvious this fine cloud was going to affect my views...and they did. Detail came and went on a regular basis. I found myself constantly trying to fine focus... Frustrating! On medium power, I saw the usual surface banding, and on closer inspection, the small black inky dot, being the transit. I had seen better views of Jupiter last week so with me not feeling 100% I decided to call it a night and get into the nice warm house! I thought I'd have a quick peek with the Mak, seeing as it was all set up and cooled.

On focussing the Mak, I got the same misty appearence around the planet, however on fine focussing I found the detail was just SO much better than the Dob! The mak was obviously not as affected as much by seeing tonight, as the Dob. The view of Jupiter, although a little dimmer, was still and clearer for longer periods. The black inky dot was sharp and defined in the lower left of the bottom equatorial belt. On closer examination, I also saw what appeared to be ANOTHER inky dot in the top right of the upper belt. This may have been a small barge but I'm just wondering if it could possibly have been Io passing in front of the planet AND the transit together?

Would Io also look like a black dot as it passes in front of the planet?

The Dob normally spanks the Mak on any other night, but the victor tonight was certainly the Mak. Its a really good scope for it's portability, aperture and price.

Glad it was to hand as I'd have gone in disappointed otherwise :)

Clear Skies

Tony

Link to comment
Share on other sites
Stu

Stu

Posted
Posted

Hi Tony

I was observing Jupiter at PSP last night, dodging cloud and not very good seeing. The black shadow transit was clear, and then there was also a barge on the other belt (top as viewed through my mak). They are dark storms, quite small and easy to mistake for a shadow.

I did see Io itself towards the second half of the transit. It appears bright white so is only really visible when it moves over the darker belt. Io and its shadow were close together, with Io following the shadow. Makes sense them being close as Io is relatively close to the surface.

Also managed some surprisingly nice detail on the GRS when that came along later. Was mainly using 22mm nagler in the mak giving x181. Did try x235 with a 17mm but it didn't really add anything

Cheers

Stu

Link to comment
Share on other sites
tony4563

tony4563

Posted
Posted

"Would Io also look like a black dot as it passes in front of the planet?"

After getting my thinking head on, I realised that Io, like Jupiter, would of course be illuminated directly by the sun as it passes in front of the planet.

Like Stu said, it would appear as a white/yellow disk over the darker belts of the planet. Not as an inky dot.

A barge in that upper belt seems to answer my query :)

Tony

Link to comment
Share on other sites
malc-c

malc-c

Posted
Posted

Last night was a mixed bag... looked promising around dusk, then the clouds rolled in. Thought about having an early night as there was naff all on TV and let the dog out at around 10.00pm , looked up and it was clear !

Rolled the roof off the observatory and managed to capture some footage before the clouds rolled back in again. Called it a night after that. But although focusing was a problem, and I over exposed the capture I did catch the transit

post-23388-133877682359_thumb.png

Link to comment
Share on other sites
Luke

Luke

Posted
Posted

We saw the transit plus barge, it was only clear for a bit that night but it was a real joy to see this and made it a special night for observing.

What I found strange as well is that when I looked half an hour or so earlier the visibility was a lot worse, I couldn't see any partial cloud in the way. I guess I should not give up if Jupiter looks poor earlier in the night, it can change pretty quickly, for whatever reason?!

Link to comment
Share on other sites
michael.h.f.wilkinson

michael.h.f.wilkinson

Posted
Posted
We saw the transit plus barge, it was only clear for a bit that night but it was a real joy to see this and made it a special night for observing.

What I found strange as well is that when I looked half an hour or so earlier the visibility was a lot worse, I couldn't see any partial cloud in the way. I guess I should not give up if Jupiter looks poor earlier in the night, it can change pretty quickly, for whatever reason?!

Turbulence in the air may change quite a bit. As temperature drops rapidly, a lot of turbulence may occur, ruining seeing. When the temperature stabilizes it may get a lot better. Another factor is the scope itself. Was it properly cooled down when you first looked? this may have a huge impact.

Link to comment
Share on other sites
Luke

Luke

Posted
Posted

Thanks for the ideas, the scope had been out for about 3 hours (12 inch dob). Weird how one eyepiece was too much then 30 mins later was very sweet. :)

Turbulence in the air may change quite a bit. As temperature drops rapidly, a lot of turbulence may occur, ruining seeing. When the temperature stabilizes it may get a lot better. Another factor is the scope itself. Was it properly cooled down when you first looked? this may have a huge impact.
Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.