Jupiter and Io Transit - 01/09/2021

[multiweb]

Slowly going through all the data I collected on those few nights.
This is Jupiter in RGB. Same rig. CN-212 - ASI462MC

90s streams. I should really go for 60s as Io seems to move quite fast at that FL which I did on the second segment.

I have a few animated GIFs below:

RGB

[10:29 - 10:36 UTC] (https://www.astropic.net/astro/Jupiter_RGB_1029_1036_20210901.gif)

[11:25 - 11:32UTC] (https://www.astropic.net/astro/Jupiter_RGB_1125_1132_20210901.gif)

[12:55 - 12:56UTC] (https://www.astropic.net/astro/Jupiter_RGB_1255_1256_20210901.gif)

IR

[11:11 - 11:21 UTC] (https://www.astropic.net/astro/Jupiter_IR_1111_1121_20210901.gif)

[12:35 - 12:51UTC] (https://www.astropic.net/astro/Jupiter_IR_1235_1251_20210901.gif)

UV

[12:24 - 12:31 UTC] (https://www.astropic.net/astro/Jupiter_UV_1224_1231_20210901.gif)

Here's a seamless animation with changing band passes of all the segments stitched together. The gap in the middle is a break I took imaging Saturn.

https://vimeo.com/598230939
https://vimeo.com/598230939

[Dennis]

Lovely work Marc, you're really cranking these out now.:):thumbsup:

Cheers

Dennis

[multiweb]

Thanks mate. :thumbsup: Lots to process. Perfect for a rainy week-end.

[Saturnine]

Excellent images Marc though I notice that you have blue and red fringes on Jupiter. I was imaging the same night and all my vids when processed have the same chromatic defects. Was using the 127mm apo at f 22 so have nowhere near the resolution that you have in your fine images.

[multiweb]

Thanks Jeoff :thumbsup: . Yeah I do. I'm at f/37 mate. :lol: I'm allowed ;)
When I get a bigger aperture I won't have to abuse my scope that way anymore. I think OSCs are also more prone to recording chromatic abberations. I noticed that with my FSQ106N and SONY NEX-5. I'm sure that any optics if you look close enough at something small and bright will show color fringing. Even "perfect" optics. Seeing will cause colours to shift. It's not something I'm bothered about or trying to chase. It's just a fact. I have an ADC on order and that supposedly should help with Venus and Mercury so I'll see if it also has any effect at higher elevation.

[Retrograde]

Really nice. Io stands out really well in your shot. :lol:

[multiweb]

Yes this time it did. :lol: A bit too much outside the planet disk. It was so bright. Might start looking into processing moons separately from the main planet. I wonder if that's what others do? :question:

[Retrograde]

I was talking about the image of Io transiting - should have made that clear. :lol:
An image I'm processing from later the same evening with Io just off Jupiter's limb also shows a lot of false colour (from dispersion I guess). The dark patches at the north & south of Io seem to disappear into the background making it look like an elongated smudge. Yeah it comes out very bright.

[multiweb]

You're right. It seems to have darker poles that the brighter equatorial band that make it look like an oblong dash line rather than a round shape. When it's brighter it shows a rainbow pattern but that's just chromatic. :lol: You'd need a larger aperture to start seeing a clearer picture. Having said that it's super bright in IR against the jovian disc so easy to spot there. It's still oblong in my IR shots so 90s is definitely too long. I've also noticed that Ganymede seems to have a darker spot closer to its north pole. I thought it was an aberration before but since saw some high end shots of it and it seems real.

[Sunfish]

Cool gifs. Great imaging on the planetary detail also.

[multiweb]

Thanks Ray. :thumbsup:

[Camelopardalis]

Nice one Marc! It’s great to see how it looks with the different absorption going on.

[multiweb]

Thanks Dunk. :thumbsup: Yeah got to play with the settings a little more but that was fun to do.

[Dave882]

Wow just saw the update with the video. Fantastic!! I’m really intrigued by the different wavelengths!

On the topic of atmospheric dispersion, I also noticed some in my images on this night too. Even when using the adc, the calibration point seemed to be different between Io and Jupiter, so had to isolate and do a manual align on Io in registax otherwise I still had issues in the final pic.

[multiweb]

Thanks David. :thumbsup: Yeah I think it comes down to processing too and aligning on the moon. I don't get any details on Io at 8.5" anyway. I'm already barlowed x3. I just don't have the aperture to get down to that angular resolution unfortunately. Will need a larger scope for that.

[Dave882]

Yep I hear ya! I’m pretty sure aperture fever needs to be an officially recognised disorder tho

[multiweb]

In my case it was always an underlying condition but dormant. That foray into planetary has started a serious itch again. :)

[multiweb]

Just an update about chromatic aberration and OSC capture. I wasn't sure if it was the barlow or something else. The FFC is an expensive piece of glass but you never know. At F/37 + variable seeing you're bound to get some color distortion. But on closer inspection I noticed that my color channels were offset after processing my color shots and I can only assume it is during the debayering process. I was surprised to see that it was quite a significant offset. So I realigned them. After all it seems that it wasn't caused by the glass. I have attached originals and corrected Jupiter discs.

The first is not so obvious but you see the blue tinge on the limb at 3 o'clock is not as pronounced in the corrected version.

The second is quite obvious with Io off field. There is no rainbow in the aligned corrected version, although the moon is still oblong because of its fast notion and the stream duration.

So that was an eye opener. Something I keep in mind now for future RGB shots.

[Saturnine]

Certainly an improvement with the re-processed images though barely noticed the blue fringe anyway, I'm used to them with my own efforts. Don't have an ADC and don't know if I could be bothered mucking around with one.
Most of the fringing I deal with in Registax, using the RGB Align function which does a good enough job of it for me.
They are very fine images by the way, well done.

[multiweb]

I have an ADC now that I'm going to use on Venus and Mercury see what I get. I'm not sure it's of any use at higher elevations although I'll give it a go. It has this weird feature which is a bubble level to align it with the horizon so I suspect it would go into a gimbal lock at the zenith. :lol: