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Tue, 07 Nov 2017 - Important News about Neptune.

SPA member Martin Lewis has, in the past few days, sent me some outstanding photographic observations of the outer ‘gas-giant’ planet Neptune. Using his large Dobsonian telescope mounted on a tilting equatorial platform and a monochrome planetary camera looking at near infra red wavelengths he has captured the motion of a massive pale storm feature in the upper atmosphere of the planet. Today he was also kind enough to forward to me an email sent from noted amateur Ricardo Hueso which I think deserves wider dissemination; I hope Ricardo does not mind me repeating the main points of it here. It includes ephemeris data calculated by Marc Del Croix showing the date and time the main feature is calculated to cross the central meridian of the planet, along with the longitude of the CM at that time in degrees. I would encourage any person with a larger telescope (perhaps 10” or 250mm aperture is the minimum required) and an astronomical planetary camera plus infra red pass filter, as described in the text below, to attempt imaging Neptune if they can. This may be your best opportunity to add important scientific data-points for those studying the atmosphere of this distant world. Please note these images from Martin are animated gifs so should show the rotation of the storm features over time.

 

 

 

 

 

 

 

 

 

Here is the text of Ricardo’s e-mail:-

The current activity in Neptune is now more and more exciting. Amateur observations of an equatorial bright large cloud have confirmed the persistence of this cloud over October and early november. About 10 amateurs (most notably Phil Miles, Darryl Milika and Pat Nicholas) have observed this cloud system repeatedly providing very useful data to study this unusual equatorial cloud. A second equatorial bright cloud has been observed since late October in images by different people (Clyde Foster, Darryl Milika and Pat Nicholas, Martin Lewis and Phil Miles). Tracking of both cloud systems show that they are converging tonight and in the next few days. Their merger (or at least their coincident position over Neptune's disk) may produce the brightest and easiest cloud to image with amateur equipment in Neptune's recent history. The merger is not well constrained and could happen anytime from today to November 10th. The latest observation of Neptune by Phil Miles on November 3 shows the system of both clouds as an elongated bright band with a head and a tail that correspond to the previous well separated spots. Previous observations by Darryl Milika and Pat Nicholas show an already noticeable increase of brightness in the system.

Although this list corresponds to highly advanced amateurs I include here a short note for people with less experience in case you want to share with brave observers trying Neptune for the first time: Although Neptune is very demanding target it may be easiest these few nights than before. The highest contrast is found using IR long-pass filters like the IR610 and IR685nm. Seeing has to be from good to excellent and the telescope collimation has to be excellent too. Also note that for the observations to have a scientific value we need Triton to appear in the frame to allow a precise navigation of the images.

Attached at the end of this e-mail you can find ephemeris of the bright cloud from observations in early and mid October calculated by Marc Delcroix. The ephemeris have been precise over October but they may change now depending on the outcome of the two structures encounter. We don't know if both will merge or not as the two features are slightly separated in latitude: one almost in the equator and the other may be 1-4 degrees to the north but the outcome of this event will nevertheless be of great interest.

Happy Neptune hunting.

Ricardo Hueso.

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WinJUPOS 10.3.5 (Neptune), C.M. transit times, 2017/10/16  23:13
Object longitude: L = 275,6° + 47,2820°/d * (T - 2017 Oct 08,5)
Time interval: 2017 Jun 01,0 ... 2017 Dec 01,0
Output format: Date UT (C.M. of System 1)
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2017 Nov 01   04:24 ( 315°)   22:04 ( 350°)
2017 Nov 02   15:44 (  25°)
2017 Nov 03   09:24 (  60°)   09:25 (  60°)
2017 Nov 04   03:05 (  95°)   20:45 ( 130°)
2017 Nov 05   14:25 ( 164°)
2017 Nov 06   08:05 ( 199°)
2017 Nov 07   01:45 ( 234°)   19:25 ( 269°)
2017 Nov 08   13:05 ( 303°)   13:06 ( 304°)
2017 Nov 09   06:46 ( 338°)
2017 Nov 10   00:26 (  13°)   18:06 (  48°)
2017 Nov 11   11:46 (  83°)
2017 Nov 12   05:26 ( 117°)   23:06 ( 152°)
2017 Nov 13   16:46 ( 187°)   16:47 ( 187°)
2017 Nov 14   10:27 ( 222°)
2017 Nov 15   04:07 ( 257°)   21:47 ( 292°)
2017 Nov 16   15:27 ( 326°)
2017 Nov 17   09:07 (   1°)
2017 Nov 18   02:47 (  36°)   02:48 (  36°)   20:28 (  71°)
2017 Nov 19   14:08 ( 106°)
2017 Nov 20   07:48 ( 140°)
2017 Nov 21   01:28 ( 175°)   19:08 ( 210°)
2017 Nov 22   12:48 ( 245°)   12:49 ( 245°)
2017 Nov 23   06:29 ( 280°)
2017 Nov 24   00:09 ( 315°)   17:49 ( 349°)
2017 Nov 25   11:29 (  24°)
2017 Nov 26   05:09 (  59°)   22:49 (  94°)   22:50 (  94°)
2017 Nov 27   16:30 ( 129°)
2017 Nov 28   10:10 ( 163°)
2017 Nov 29   03:50 ( 198°)   21:30 ( 233°)
2017 Nov 30   15:10 ( 268°)
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Added by: Alan Clitherow