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Kokatha man

Neptune's large EQ spot...

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Hi all, apart from a few comments in other folks' threads I have been lazy & not posted any of our efforts of late... ;) 

That doesn't mean we haven't been busy, on June 10th we were the first to pick up a very large bright spot (storm/atmospheric feature etc) in Neptune's equatorial region https://britastro.org/node/10860  ...this being an unusual place for these features to be present, especially when considering that winds in that region reach 1000km/hr! :eek:

PVOL's Calar Alto PlanetCam scope also picked this spot up soon after...with the Keck in Hawaii also picking it up on June 26th & July 2nd, releasing the following article: http://www.keckobservatory.org/recent/entry/new_storm_makes_surprise_appearance_on_neptune

As the article points out this feature was unusual & possibly anchored deeper into Neptune's atmosphere for it to survive at all in the ferocious winds present at those latitudes constantly...:eek:

On both the dates mentioned for our images, this spot was so bright & large that Pat & I both thought we could see it in FireCapture's live feed & it was certainly easy to see in the unsharpened & un-processed RAW stacks.....we even picked it up in a red light (filter) image such that an rgb we made also clearly displayed the spot - visible light images showing atmospheric phenomena are pretty rare for Neptune from amateurs & I "think" we are actually the only AA'ers to have achieved this, a couple of times actually...this as opposed to "false colour" images that are prevalent.

Now that burst of immodesty is over, :lol: here are some of those images: everyone (especially the professionals, but Pat & I also! ;) ) wanted to see if this EQ spot was longer-lasting.....& after waiting 6 weeks for the weather to clear (yes, it has been - & generally still is - rotten weather here in South Oz :( ) we went out & spent 4 nights imaging last week. (23rd, 24th, 25th & 29th August)

Before I post the following information apropos our most recent search to determine whether the EQ spot is still present, the first lot of images below will show some of the iR610nm images both as RAW stacks & mildly sharpened ones revealing it...& the aforementioned rgb image of Neptune also displaying it.....ie, the EQ spot in our images from June 10th & July 14th.

In our most recent search unfortunately, even though we picked up a bright spot on the 23rd (possibly a twin system but only the 1st frame shows the 2nd spot before it disappears around the P limb for the other frames in the animation) this feature was at a much more Southerly (approx. -40° S) & another, less bright & somewhat distended feature right on the Northern (uppermost) limb on the 25th (approx. +20° N) - the other 2 nights only revealed faint dark & light features moving with the rotation of the planet. :( 

These 4 nights gave coverage of Neptune's entire globe making us think that unless the EQ spot was playing a form of "hide & seek" it likely had dissipated in the interim...

By that I refer to the fact that the estimated drift rate of this feature (3.5°/hr due to those very strong winds) could possibly mean it had effectively remained hidden by its' longitudinal movement despite us surveying the whole globe over those 4 nights spanning 7 nights...

We have been in constant contact with Prof. Hueso of PVOL who is also studying this phenomenon (they imaged it at Calar Alto on July 11th) & Imke de Pater from one of the Keck teams where they imaged it on June 26th 7 July 2nd as previously mentioned...the Keck team imaged again on August 25th & 26th with no sign of the EQ spot as well as Chris Baranec from another group at Keck on August 10th - no sign of it in those images either.

This makes Pat & my images from June 10th & July 14th the first & last times it has been imaged, proving it lasted at least those 34 days - probably amazing in itself considering the winds there..!

Keck will image again tonight & 2 later & the OPAL program will start a survey of Neptune around opposition also. (5th September)

We will be imaging again if the weather lets up & it will be very interesting to find out for certain whether it is still around...although the aforementioned professionals also believe it is highly likely it has dissipated also... :( 

As an interesting aside to all this, the image posted here & the 2-frame animated gif from 25th August showing a distended, not-so-bright feature started out fairly promising as far as seeing was concerned before clouds swarmed in & stopped us just after the 2nd capture: Triton could be easily seen in the live feed during capture & this little looping snippet at the end of the images is a sample from that feed: Triton can be seen dancing around about 5-10mm in from the right hand margin at exactly 3 o'clock wrt Neptune.











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Great stuff - love the animation, those are pretty much the same thing I saw through my 15x70 binocs last weekend :wink:

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Thanks for taking the time for such an in-depth explanation of the images presented. It is amazing such detail can be captured by "amateur" telescopes. Very interesting to see the animation of the capture view as well showing Triton.

6 weeks without imaging makes the UK sound like paradise! :icon_biggrin:

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Amazing work Darryl, must be incredible to be linking into the pros the way you are, and getting there first too!

Loved the way you've presented and described it, really nice.

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That is phenomenal.... to get that sort of detail that far away is truly a great achievement.... well done.

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Thanks for the replies folks - we hope to be able to put some more light on the EQ spot's situation as soon as a weather opportunity presents itself, but the professional images should put its' presence or not to bed one way or the other in the near future regardless!

For us as AA'ers Neptune is on the cutting edge as far as planetary imaging & what it might show - & is an area where AA'ers can make worthwhile contributions to pro studies...& why we spend as much time as we can focusing on that little grainy spot (pardon the pun) that dances around on the FireCapture preview screen as displayed in that little looping animation I've posted above where you can also make out Triton...as Nick (Happylimpet) recently commented on CN, it can be pretty challenging in the wee small hours - but the results can be very rewarding in our opinions! :) 

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Outstanding work on this distant world Darryl, pushing the limits of amateur astronomy to a new level, Thanks for sharing!

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