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Very nice seeing at last -from Yongala..! More images added!

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#1 Kokatha man

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Posted 25 September 2021 - 03:56 AM

EDIT: despite the tendency for most folks to only look at the "pretty pictures"  at the start of any thread, I've decided to "advertise" grin.gif  additional images I have or intend adding to the thread from this night (including maps) of very good seeing. (relatively-speaking!)

 

I'll start by inserting a larger scaled image of one of those below in Post #17 further down the page, & additional images further along as I process them: I'm not a fan of the plethora of over-blown images (imho) that populate the internet, but I think this one scrapes by as a balance of larger-scaling & still maintaining most of what I aspire to in detail, clarity & aesthetic refinement...& I'll also use it for a polar projection map basis later in the thread.

 

Hi all...well, the title of this thread says it all from me, the first really decent night's seeing for a long time notwithstanding anything we've captured in the interim. smile.gif

 

We used the ASI462MC colour camera after we had the experience of clouds scuttling any imaging on the first night we were up there (Tuesday) - on that particular night the sky started out magnificently clear but by the time we were ready to capture the clouds were almost covering the complete sky - something we've experienced regularly this year unfortunately! frown.gif

 

Through the thickening & thinning clouds we could see that the onscreen image was pretty nice - but to no avail as the clouds were too thick to attempt to image...only catching very fleeting glimpses of a really nice Jove in the manner I alluded to earlier today in Ray's thread...

 

With the prospect of the late appearance of the GRS (which has eluded us of late) & the GFS still suggesting that clouds & mist might encroach on the Yongala region we opted for safety-first & employed the colour camera again.

 

I really would have like to use the mono & if we had imaged the next night would surely have used it...as it was we had disassembled the scope & mount on Thursday morning intent on heading for the coast for some fishing r&r but after checking the weather forecast decided to head home Friday due to the gusty winds along the coast for the next few days - so no fishing! wink.gif

 

Being at Yongala was great...no-one else around and just the faint light from a couple of house windows shaded through the trees from the nearby hamlet...& Wednesday night the clouds stayed away on the distant S-W horizon. 

 

Here are 4 images from about 38 minutes prior to culmination through until 70 minutes after.....the seeing was somewhat variable but nothing really to complain about (Con! rofl2.gif ) even if I am a perpetual "Oliver Twist." rofl2.gif

 

But wait - later in the session Pattie thought it looked a bit strange onscreen when I shone the light onto the corrector plate for the constant de-fogging using the hair-dryer...I didn't get too worried as it didn't look too bad but in the morning I discovered that the primary was quite fogged: during the session we were using the hair-dryer after almost every capture & by the finish of the imaging session water was literally dripping off the scope everywhere!

 

I'll present these images in time order - very pleased to capture some extremely fine detail in the images as the GRS marches towards the CM - I've included a feed snippet from one of the captures (just randomly, probably not the best at all) & 3 small examples of the collimating procedure: de-focused star then moving closer to focus with a final feed very close to focus.

 

Observers will note that on first glance the star-feeds might look a bit shoddy but several factors need to be taken into account. (these were simply using the "L" filter (ir/uv cut) with the 462MC - I rarely bother with the red filter or ir610 filter with it btw)

 

With experience your eyes become adept at deducing what is actually happening with the Poisson Point & Diffraction Rings in these onscreen displays so although there appears to be a lot of distortion/aberration etc this does not represent poor collimation...as evidenced by the degree of resolution that the images reveal! wink.gif

 

It should also have the consideration that the primary mirror is still "relaxing" at this stage after having the temperature of it dramatically reduced by the application of a 5kgm bag of heavily-salted ice applied to the C14's rear casing for about an hour before we start the scope up, find the planet & adjust the finder etc before targeting the collimating star...this to lower the scope's temperature to about 2°C below air ambient for the imaging start...which was about 6°C when we commenced imaging - ie, getting the primary down to about 3.5° to 4°C by then.

 

j2021-09-22_12-07_rgb_dpm.png

 

j2021-09-22_12-43_rgb_dpm.png


Edited by Kokatha man, 26 September 2021 - 02:52 AM.

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#2 Kokatha man

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Posted 25 September 2021 - 03:57 AM

The next 2 images with the last of these 2 with the GRS well onto the disk & nearing the C.M.

 

j2021-09-22_13-11_rgb_dpm.png

 

j2021-09-22_13-20_rgb_dpm.png


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#3 Kokatha man

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Posted 25 September 2021 - 04:00 AM

Here's where we start the collimating procedure with a reasonable amount of defocus - the feeds where we move closer to focus will be in the next post due to the limitations of file-size. wink.gif

 

Note the comments I make about this & the next feeds in my first post above. wink.gif

 

DeFocusStarFeed.gif


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#4 Kokatha man

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Posted 25 September 2021 - 04:02 AM

The next 2 feeds as we move closer to focus...

 

SmallDeFocusStarFeed.gif

 

CloseFocusStarFeed.gif


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#5 Kokatha man

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Posted 25 September 2021 - 04:03 AM

Finally a short feed snippet from one of the captures chosen at random - note this is only 47% of the actual capture scale due to CN file limits. smile.gif

 

Jupiter1251_6-Feed@47%.gif


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#6 Foc

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Posted 25 September 2021 - 04:32 AM

Lovely fine features and great interest in every sector.  Shows what can be done with a 462mc if you have the talent.  I wonnder, if you are looking at the new Zwo cameras as well? One of the nicest feeds I have seen from you in a long time as well.  I always like to see the collimation images...it is always the steps and judgements between the initial and end images that give the trouble though!         Yes more please sir....as Oliver would say.


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#7 phileefan

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Posted 25 September 2021 - 06:28 AM

Darryl,

 

Great images as always my friend! waytogo.gif  The collimation star pics should definitely help others here as well. Thanks for posting.



#8 John Boudreau

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Posted 25 September 2021 - 06:47 AM

Great to see that you two finally got to enjoy very fine conditions. Nice work! bow.gif



#9 kevinbreen

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Posted 25 September 2021 - 07:05 AM

Here we go!!

#10 Ittaku

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Posted 25 September 2021 - 08:34 AM

Shows what can be done with a 462mc if you have the talent. 

And aperture.

 

Great images as always Darryl. Very natural looking.



#11 BKBrown

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Posted 25 September 2021 - 08:58 AM

Beautiful work by your team Darryl, and instructive too...waytogo.gif

 

Clear Skies,

Brian snoopy2.gif


Edited by BKBrown, 25 September 2021 - 09:03 AM.


#12 JMP

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Posted 25 September 2021 - 11:37 AM

Beautiful work here, thanks for sharing the collimation images as well.

#13 Kiwi Paul

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Posted 25 September 2021 - 03:52 PM

A very interesting post Daryl with superb images. Your description of checking collimation or collimating with the out of focus Star progressively to focus confirms my thinking on this topic. Many thanks for posting that section (and all the other images).
Cheers Paul

#14 Kiwi Paul

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Posted 25 September 2021 - 04:01 PM

One other point Daryl, does salting the ice lower than melting point of the ice?

Paul


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#15 Tulloch

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Posted 25 September 2021 - 05:13 PM

Spectacular as usual, I've never seen anything like that raw feed, it was a long chase to finally catch that seeing, well done :)



#16 Quopaz

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Posted 25 September 2021 - 07:43 PM

Very nice, some great fine details there. The seeing was no good here that night, so you picked the right spot to go to.
I'll have to look up where Yongala is, never heard of it. Up North somewhere?

#17 Kokatha man

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Posted 25 September 2021 - 08:05 PM

EDIT - I'm slipping that larger scaled image from UT 1320 in here as referred to in the edited first post of this thread. wink.gif

 

Many thanks for the posts Ross, Mick, John, Kevin, Con, Brian, Jeff, Paul & Andrew - & all the "Likes" also from Pattie & me! smile.gif

 

These results were very satisfying in that I could process & end up with images from the data that displayed that are (from here on Earth with an AA scope anyway! lol.gif ) very fine details that don't succumb to the inevitable heavy results that seem to be the most common (us included!) this year...the STrZ, STB & Z & SSTB & Z...as well as the turbulence before & after the GRS in the SEB & elsewhere displaying delicate details/features that really "float our boat"..! lol.gif

 

Enough trumpeting grin.gif lol.gif - Paul, the effects of common salt on ice are well known & can be googled & in practise makes a really dramatic difference to the cooling process...it would be no exaggeration to say it reduces the time enormously & is able to drive the primary mirror temperature down much colder, as well as faster - & we have done the comparisons on numerous occasions btw. wink.gif  The old film fixer (hypo, sodium thiosulphate) is even more effective but common salt is cheaper & more readily available mainly...

 

We'd rate the seeing at between 7.5/10 to just below 8/10 at most tbh - I know this might sound ridiculous when you see people touting 5/5, 4/5 or 8-9/10 but we think those figures are silly also...8/10 is fantastic seeing in our books & I'd venture to say that most people have never experienced that...if they really have, let us know - we'll be there in a flash! lol.gif

 

We would've liked to have stayed at Yongala longer but cloudy skies were coming in (which makes me regret not imaging on the Thursday night) but after over 8 years & an enormous amount of work the battery bank in our van is truly stuffed & needs replacing, which is on my "to do" list this week. As well the 3kw Honda generator needs an oil change that I must do also, but we'll hopefully get back up there or else into the Murray Mallee asap...time is starting to run down for Jovian imaging possibilities now with perhaps around 7 weeks of reliable possibilities still left.

 

Due to the CN limits remember when looking at the onscreen feed snippet it is only 47% scale & can make things look better than actual - use your screen-browser (see image below if I'm using a weird term) to pump the scale up to what you'd really see the feed at if you wish...

 

I'll probably post a compendium of all the captures later if I can fit it in with all the other jobs I have now that we're back home again..! wink.gif

 

The additional image I've just inserted here will probably need clicking on the thumbnail to get to full-scaling.

 

j2021-09-22_13-20_rgb_dpm-Large.png

 

UsingBrowserZoom.jpg


Edited by Kokatha man, 26 September 2021 - 02:47 AM.

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#18 Kokatha man

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Posted 25 September 2021 - 08:06 PM

Sorry, missed your post Q - Yongala has the record for the lowest temperatures in South Oz :lol: & is situated between Jamestown & Peterborough...about 10km before Peterborough. :)



#19 KiwiRay

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Posted 26 September 2021 - 12:38 AM

Beautiful images, Darryl. Really glad you got a night of such good seeing on your trip. A single frame of that clip in post #5 is better than most of my recent images!



#20 Lacaille

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Posted 26 September 2021 - 02:03 AM

Superb, and, as ever, very helpful and irreplaceable technical advice along the way!

 

Mark



#21 R Botero

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Posted 26 September 2021 - 02:56 AM

Glad you got the seeing at last! Your images are superb waytogo.gif

 

Roberto



#22 Kokatha man

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Posted 26 September 2021 - 02:59 AM

Thanks Ray & Mark - we were lucky as good seeing is such a haphazard commodity! Thanks also Roberto! smile.gif

 

Ray, your comment had me do something silly & is not meant to be cheeky...in fact, a single frame of that feed in Post #5 was better (almost!) than several outcomes we obtained from home in the last 2 or 3 weeks - which pride would not allow us to post of course..!!! shocked.gif blush.gif lol.gif

 

But here's a single frame grabbed from that little snippet & "dolled" up slightly...with noise et al! 

 

SingleFeedFrame.png


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#23 Wildetelescope

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Posted 26 September 2021 - 08:07 AM

Finally a short feed snippet from one of the captures chosen at random - note this is only 47% of the actual capture scale due to CN file limits. smile.gif

 

attachicon.gifJupiter1251_6-Feed@47%.gif

lol, you have more detail in your raw feed than I am able to get in many of my processed images.   Such is life under the jet stream!

Wonderful images.

 

JMD


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#24 tboss70

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Posted 26 September 2021 - 08:49 AM

Excellent work Darryl, congrats!

I am curious about the 462mc and how many frames per second were you capturing at?

"USB 3.0 Port: Providing 5Gb bandwidth to let ASI462 run at 136.1fps (10bit, high speed mode) or 63.9fps (12bit, normal mode) at full resolution(2.1Mega)."

 

Have you ever noticed a difference between the 10bit and 12bit images, and, is it worth it to capture more frames with the 462 in 10bit high speed mode (less color and shades) rather than 12bit normal (more color and shades)?



#25 Kokatha man

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Posted 26 September 2021 - 07:17 PM

Thanks again for comments & "Likes" - appreciated! smile.gif

 

JMD, am about to email you the tute...Todd, the dynamic range in planetary imaging is so constrained that anything more than 8bit captures are a waste...here's the card from one of the captures of this night: we could have achieved the same fps (frame rate) with a 4 millisecond exposure but I forgot to note in the first post that although the seeing was "very nice" there was a high-frequency influence from the seeing that had us decide to lower the exposure value somewhat in the hope that it would assist...could well have, but there's as much experiential logic as there is hard evidence in some of our decisions! wink.gif

 

I'll post the polar projection maps I've put together later today...& a very late response to Ross's much earlier question about camera-types: atm I don't believe there is anything to surpass the ASI290MM & ASI462MC & we're not interested in larger sensors btw...when one does arrive, hopefully Sam will send me one to trial..! fingerscrossed.gif

 

ScreenHunter_182 Sep. 26 23.23.jpg

 

 


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