14 replies to this topic

[Quopaz]

Well it was tough conditions here with constant wind all night, mostly clear sky with the odd cloud going through,
and although not a heavy dew it was still dewy enough that my primary mirror kept fogging up but I am quite used to
that now. I just had to plan when to defog a bit more carefully than other nights.
Despite the wind I felt I got some OK videos early on of Callisto with the red spot, but I was disappointed when the
seeing turned very bad just before the actual triple transit however there was nothing I could do about it.
To describe the seeing, it was horrible at times but then there would be patches of OK in amongst it, so I was hoping
I could still get something out of it. I also had trouble with the wind buffeting the telescope, and a few times resorted
to holding a cardboard shield to block the wind a bit as I was having trouble keeping the planet on screen.
This one is of the triple transit with all 4 moons present, from left: Europa, Europa's shadow, Ganymede, Ganymede's shadow, Callisto, Io.
Taken with SW 10 inch dob and ASI 462mc camera. More to come as I haven't had time to process much yet.

[HarveyDeckAstro]

Nice moment!

[matt_astro_tx]

Good job!

[Quopaz]

Thanks, I still have a lot of data to go through, but here's one from earlier in the night when
the seeing was a bit better of Callisto and it's shadow along with the GRS.
I was a bit surprised to see there is quite a bright spot right in the middle of Callisto,
I have no idea what that is. Does anyone know?

[Foc]

Good sharp focus on those moons and nice exposure on those just off Jupiter.  You have a well tuned reflector!

[Quopaz]

Thanks Foc. In addition to the triple moon transit this night there were also 2 separate double shadow transits.
The Europa/Ganymede one above, and also an earlier Ganymede/Callisto one.
I went with a wider view to fit all 4 moons in.
Also by chance the string of storms is quite central.
Seeing was still good at this stage, so you can see how close I came to having good conditions hold up
for the triple transit. If only it would have held up a bit longer.
L to R: Europa, Ganymede, Ganymede's shadow, Callisto, Callisto's shadow, Io.

[KiwiRay]

If I were you, I'd consider finishing the processing and then start a new topic leading with your best image - each image here is better than the last! The third is a little dark, but the seeing looks to have been much better, and your processing is otherwise nicer (it's lost the pink tint of the previous images).

 

As for that dot in Callisto, that seems to be a sharpening and/or diffraction artifact - I've seen it in my own images and in those from others, and I usually try to blur it away.

[Quopaz]

Could do that but I thought I'd just put them all together. Seeing varied throughout the night, and some earlier
ones were also affected by low altitude.
Yeah I wondered if that dot on Callisto was an artifact or not, could be.
Also sorry if there is a pink tint- I'm colourblind and cannot see the pink tint.

[Tulloch]

I agree with Ray here, that 3rd image is certainly the best of the lot, worthy of its own thread. A real shame that the clouds came through when they did at your location, in Melbourne we hardly had any view of the sky at all. Don't forget to colour balance every image Nick, you may not be able to see the difference, but we can .

 

I'm unsure about blurring out the "dot" on Io, it appears so often on everyone's images that it may well be real. It doesn't appear on any other moon, and I noticed that when I made my animation of Io being eclipsed, it disappeared behind Jupiter's shadow in exactly the way I would have expected a real feature would.

 

Andrew

[KiwiRay]

Yeah, not Io, just the dot in Callisto and the transiting shadows. I believe the darker area on Io corresponds to a darker part of the moon's surface (although we see it when Io is in front of and behind the planet, even though the moon is tidally locked, so presents opposing faces in each direction of movement when near the planet).

 

The advantage of starting a new topic is that most people don't read past the first couple of posts, and don't revisit topics they've already looked at a day or two before - they're going to miss your best images.

Edited by KiwiRay, 17 August 2021 - 04:59 PM.

[Tulloch]

Yeah, not Io, just the dot in Callisto and the transiting shadows.

Doh! 

 

I'll try to read people's posts more fully before I blunder in

[Kokatha man]

That thin thread of detail on Io is real, a "connecting" feature between the 2 dark poles which themselves make Io look egg-shaped. (ie, the tend to be slightly invisible & "flatten" Io's appearance into an oval...)

 

That "spot" on Callisto is from over-sharpening...along with that is the tell-tale "halo" that is another hallmark of over-sharpened images: like Saturn's rings the processing for the Galilean Moons requires something slightly separate from the disk itself if you want to present your images at their best - the disk benefits from more sharpening than the moons & whilst it is really simple to process moons separately that are not transiting Jove, it takes slightly more effort to process those appearing on Jove's disk...but not much!

 

I'll address that processing in the next day or so...

[Quopaz]

Just on the colour Andrew, I'm pretty sure I did the same for each one. I did an autobalance in Registax then increased the blue
by one click. However I think the RGB number values came up differently for each one. Maybe I would be better off just going by
the numbers and setting them all to that? If I could find RGB numbers that work for Jupiter.
Not the first time I've made pink images and I wish I could avoid it if possible.

[Mikehuerto]

Hi guys

 

A  beginner on planetary imaging  jumping in here. Needless to say great shots!  Don't want to get too far off topic, but its interesting and comforting  to see how much seeing can vary in a single session/night. It seems the lesson for a beginner here is sampling as many images for as long as possible during the night (and morning) .. and plenty of space on your hard drive1 Any comments?

Also what was the FPS for these shots. 

 

Best

 

Mike

Edited by Mikehuerto, 18 August 2021 - 08:07 AM.

[Quopaz]

Hi, yes some nights like this one you need a lot of space. It pays to look at the forecasts but you don't really
know what the seeing will be like till you try. If there wasn't all the moon action going on I wouldn't have been
out there in those conditions, but even so there was still some good seeing. FPS was 100 for the first one, 196 for
the second and 100 for the last. Another thing that has an effect is how high the planet is, normally I try to get it
when it's around the highest point for the night, but sometimes that's not possible if you're trying to capture moon
shadows or the red spot- you have to get it when it's there.
Here's one of the first captures for the night, I was trying to get it when Callisto's shadow was on the red spot,
but it was low in the sky and seeing wasn't good. It wasn't real successful but I thought it was worth a try, if the
seeing had been better it would have looked good. But it was that sort of night.