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First Jovian opportunity this apparition...


Kokatha man

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Hi SGL folk - South Australia has been in the grip of very unusual Summer weather for quite a long time now...since Christmas we've had almost 4" of rain at our place just South of Adelaide when the average would be no more than 1/2"...

This week just gone the temperature hovered above 40°C for several days & the humidity has been extreme & much more like the tropical North instead of the dryer heat we usually experience down this way...but the biggest problem for the last couple of months has been the amount of cloud covering the state even when other conditions have been favourable - large in-feeds of cyclonic cloud coming down through the centre from the NW coast of Western Australia that has dumped 12" or more of rain in our state's normally very dry  Northern regions...

Anyway, enough "weather-whinging" :lol: - this particular morning was good & bad...the "good' being reasonable seeing but the "bad" being extreme focus shifts from one channel capture to the next, making it very difficult to accurately focus or keep the image focused even during a 3 minute span where we opted for running longer avi's to WinJupos together, banking on having a bit more time to focus between each channel interval this way - the down side being that in a 3 minute capture the focus changed considerably between start & stop! :(

You can see the focus shifts in Pat's graph that I include in the main image...on the Moonlite Digital ReadOut display 4 units of step-shift in focus equates to 1uM focuser movement...you can see from the graph that the red channel focus moved over 500 steps in 26 minutes - this equates to 125uM which is a huge amount!

Despite all this still reasonably happy with the results as there is a lot of time (8 weeks) till opposition still so plenty of time to get the really nice images one always hopes for... ;)

Here is an rgb image with the individual channels cobbled together from WJ...an iR610nm image...& an animated sequence put together from a number of red channels that morning... :) j2017-02-07_19-35_rgb_dpm.pngj2017-02-07_20-12_ir_dpm.png2017-02-07-1907_1_R-Wjd-Lge85%CapScale.gif

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Thanks Michael - as I said to someone else, if you use your pc screen magnifier to increase (say double) the red channel animation it not only better displays that there are white storm spots right up towards both poles of Jove...but also that you can see that the movement of details is much more curvilinear in those areas as one would expect as the lines of latitude become more curved as they approach the poles. ;)

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Fantastic shots as usual :). Only eight weeks to opposition and I still haven't seen Jupiter this apparition :( need to get my skates on.

Lovely white ovals storms as you point out. I see the curvature more clearly in the South than North, is that simply because of how Jupiter is presenting to us currently?

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Hello, Darryl!
As always a good job, amazing how you get a good result at such low elevation even without using ADC.
I never achieved anything acceptable here with the planet less than 50º.
I do not know if it is due to local particularities or some of my deficiencies.
I like the overall color of your photos and the non-exaggerated processing, they are smooth and take a more realistic look.
Are you using 1.5X barlow? If so, do you consider it more appropriate than 2X?

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Thanks for the comments fellas! :)

Avani - this isn't at "low elevation" - even if we have achieved some outstanding results at elevations down to 29° without an ADC.

These images were taken around 60° but no ADC, using an ADC with the small-pixelled sensor of the ASI290MM would demand very low barlow amplification.

That would not be a problem using my invention below...despite wanting to "refine" this device I invented 5 or 6 years ago (by machining a slimmer component for the part where I modified a cheap GSO 2" E.T.) it has served us extremely well & really does not weigh very much at all & is rock solid - I can get down to about 1.2X with it or right up to 3.5X. :)

I am still using it to set the barlow magnification/amplification to whatever amount we need...still important with or without an ADC because of the increasingly smaller pixel-sizing used in cmos camera development! ;)#1.jpg#2.jpg#3.jpg#4.jpg

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Wow, very interesting! A great idea to copy.
Yes, the 290 has a smaller pixel than the 224 that I currently use and has been married very well with the PM 2X.
Soon I must buy the 174 but I think I will have to modify the set and maybe use the PM 2.5 due to the larger pixel.
I here, it is very rare to get something acceptable below the 50º. My site always has very high relative humidity (around 80%) which greatly deteriorates the image.
Jet Stream always constant, this always makes me try at higher altitudes but since I'm at -30º South it is not always easy.Wow

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9 hours ago, astroavani said:

Wow, very interesting! A great idea to copy.
 

Be my guest! :)

 

For SCT owners looking for an easy ADC set-up people might also be interested in this very inexpensive unit made from a small piece of copper water-pipe fitting using the swaged end of it (or a fitting itself) a long setscrew & a couple of nuts plus a cheap bubble-level phial. :)

The larger nut fixes (jams) the setscrew in the thinner section of the copper pipe & the other nut is a locknut to lock it in place...the bubble phial fits snugly in the swaged end of the copper pipe.

Set this into where the white screw goes for the ZWO ADC & orientate the slip-ring with this level unit at the midpoint of the 2 slots, tighten it lightly to lock it there & rotate the ADC until the bubble shows the setscrew is level. (you do need to ascertain if your ADC is left or right-handed first to know which side of it is positioned on.

Once this bubble shows "level" with the adjustment levers closed together, you then move said levers apart until the distortion is corrected. (using FC tuner for example)

This setting will last for quite some time as the planet's position shifts during the night but once the bubble has moved well beyond the "level" position (as it will as the mount moves the scope) then it is time to readjust. ;) 

IMG_0487.JPGIMG_0468.JPG

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Hi Darryl,

Lovely images and an interesting thread. I have always found that I needed to refocus for every image/filter. Looking at your graph illustrates why that was necessary. I have to use an ADC for all planets now that they are lower in the sky from the UK.

Best regards

Peter

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Thanks Peter...these sites being predominantly Northern Hemisphere-populated was the reason I thought re-posting my simple ADC device for SCT's worthwhile - if I have posted it on SGL before, that is. :lol:

That morning was one of the particularly "bad" sessions for radical focus shifts, but they can be quite frequent at times...always a pita! :(

Has a stroll through your image gallery/website just now which I don't think I've done for quite some time & had forgotten about...some nice images there brother! :) 

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Super images Darryl (as always!) and what a way to tee off the 2017 season. Things are literally on the up for you folk down under ( not least a lovely Mars opposition for next year ) and I think we can expect some humdingers in the coming weeks - weather permitting of course!!

                                                       Best regards,

                                                                           Ralph

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