tag:blogger.com,1999:blog-28989283.post7751376342276547039..comments2023-05-13T14:47:17.482+01:00Comments on Up: Neptune Completes First Orbit Since Discovery: 11th July 2011 (at 21:48 U.T.±15min)Bobhttp://www.blogger.com/profile/04484470826735770498noreply@blogger.comBlogger19125tag:blogger.com,1999:blog-28989283.post-23069499187470465772011-11-06T01:30:13.157+00:002011-11-06T01:30:13.157+00:00That looks like a great little film, Maarten - tha...That looks like a great little film, Maarten - thanks for posting it. <br />Good luck with your project.Bobhttps://www.blogger.com/profile/04484470826735770498noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-72763861445301364782011-11-05T21:52:41.681+00:002011-11-05T21:52:41.681+00:00I know it is a bit late, but in this period Neptun...I know it is a bit late, but in this period Neptune is still in the same spot in the sky as it was in 1846. I am making a documentary about the topic of the discovery and here is an edit I did for the anniversity in July, with a small part of the material: Searching for Neptune, to be found on http://vimeo.com/channels/planetaryscienceMaartenhttp://www.lightcurvefilms.comnoreply@blogger.comtag:blogger.com,1999:blog-28989283.post-19383556258290122552011-07-24T18:14:53.286+01:002011-07-24T18:14:53.286+01:00Of course, what I should have written is:
"....Of course, what I should have written is:<br /><br />"...Neptune will have completed one orbit on 2011 JULY 11 at 20:12 UT +/- 16m."<br /><br />Time for a break!<br /><br />John.jir1667noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-29524373641953896872011-07-24T14:07:04.083+01:002011-07-24T14:07:04.083+01:00Fabulous stuff, John!
I want to have a good look ...Fabulous stuff, John!<br /><br />I want to have a good look through the data you've presented before I say anything else, but it looks sound and it seems to be a step ahead of what I presented in the post. I'll add edits into the main post to draw attention to the updates or corrections that you've highlighted in your comments. <br /><br />Thanks for your input. I agree with you - we Bobhttps://www.blogger.com/profile/04484470826735770498noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-48456776384363932402011-07-24T13:25:12.172+01:002011-07-24T13:25:12.172+01:00Also, in all cases the angular separation is such ...Also, in all cases the angular separation is such that we could call the conjunction "overlapping", as shown for example in the image at the top of this post. In fact the view from the SUN is pretty much the same as seen from the SSB (though not exactly in the same part of the sky, relative to background stars). <br /><br />[A clarification about using words like "view" and &jir1667noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-81234611289471451322011-07-24T13:23:38.601+01:002011-07-24T13:23:38.601+01:00Further to my last observation about conjunctions,...Further to my last observation about conjunctions, I had the following scenario in mind.<br /><br />First determine the 3D inertial position of Neptune at the time of its discovery and mark it with an imaginary flag. Neptune then continues on its merry way around the solar system and we would like to know when it passes by the flag again. As one way of doing this we can find the time when the jir1667noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-35820818729253327722011-07-21T18:41:22.602+01:002011-07-21T18:41:22.602+01:00So we can see that the major issue is with the cho...So we can see that the major issue is with the choice between using the SSB or the SUN as the centre of motion. Like you I prefer the SSB because the motion of Neptune more closely follows a keplerian path than it does around the SUN. As you have shown the heliocentric orbit has false perihelia and aphelia, which are peculiar to Neptune and are a direct result of the intrinsic motion of the SUN. jir1667noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-15740502702869369172011-07-21T18:39:39.956+01:002011-07-21T18:39:39.956+01:00Bob,
I'm impressed with your detailed analysi...Bob,<br /><br />I'm impressed with your detailed analysis. Don't let the likes of Carolyn Porco put you off, these sorts of calculations are certainly worth doing, if only for educational purposes. It may be a matter of definition but once that has been agreed, precise calculations can be done and a lot can be learned from that process. It's the way I like to work, have been for many jir1667noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-28774616683494682442011-07-12T19:26:08.907+01:002011-07-12T19:26:08.907+01:00Thanks for your comment.
Re heliocentrism: yes, ...Thanks for your comment. <br /><br />Re heliocentrism: yes, that appears to be a common opinion. I don't understand why - I see it regularly thrown out as the orthodox view, rather than explained with any reasoning. I'd love to hear why you or anyone else chooses to take that view.<br /><br />In terms of the observed nature of the orbit, it is extremely clear from the two plots (<a href="Bobhttps://www.blogger.com/profile/04484470826735770498noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-48199129030850314282011-07-12T18:57:10.825+01:002011-07-12T18:57:10.825+01:00Hi Bob and everyone else who has posted.
I love th...Hi Bob and everyone else who has posted.<br />I love this topic. I respect your analysis using the SSB, but the consensus among my expert friends is that the heliocentric longitude is the more appropriate reference for a birthday. Nonetheless, I hope you had a good celebration today. In London, Ontario, the Royal Astronomical Society of Canada's local group celebrates with dinner at a local Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-28989283.post-65631527691729782362011-07-12T18:22:25.778+01:002011-07-12T18:22:25.778+01:00@Astrofloyd: even more intriguingly, Phil Plait ge...@Astrofloyd: even more intriguingly, <a href="http://blogs.discovermagazine.com/badastronomy/2011/07/12/happy-birthday-neptune/" rel="nofollow">Phil Plait</a> gets a result consistent with yours for the heliocentric return: he uses a discovery time 1 hr and ~8min later, and finds the same longitude is reached at ~18:38, 1hr ~8min later than the time you gave. So it looks like you're Bobhttps://www.blogger.com/profile/04484470826735770498noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-41534017554389694732011-07-11T17:58:46.675+01:002011-07-11T17:58:46.675+01:00Ah, that's useful to know - thanks.Ah, that's useful to know - thanks.Bobhttps://www.blogger.com/profile/04484470826735770498noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-54986787244719813092011-07-11T15:34:45.835+01:002011-07-11T15:34:45.835+01:00Hi Bob,
I used VSOP87 instead of DE405. The probl...Hi Bob,<br /><br />I used VSOP87 instead of DE405. The problem is that I don't have a routine for precession of heliocentric coordinates, so I used a simplified scheme. I'm not too surprised that my result is off by a few hours - without correction for precession is was off by ~1 year.<br /><br />BTW, you can use HORIZONS to compute data for a given set of date/times by selecting "AstroFloydhttps://www.blogger.com/profile/04994719632352493714noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-40238810179700478182011-07-10T02:39:10.476+01:002011-07-10T02:39:10.476+01:00On the subject of visibility, I am very happy to s...On the subject of visibility, I am very happy to say that I saw Neptune this evening, using only a small pair of 10 X 25 binoculars. <br /><br />A clear night, and a few miles from urban area (not brilliant location - some yellow glow), at 1.45am, and with Neptune at only 19º altitude. <br /><br />It took a few minutes after finding the right star field for fainter stars to reveal themselves; Bobhttps://www.blogger.com/profile/04484470826735770498noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-84704603773050968112011-07-10T01:30:51.878+01:002011-07-10T01:30:51.878+01:00Hi AstroFloyd,
Yes, it's definitely the night...Hi AstroFloyd,<br /><br />Yes, it's definitely the night of 23/24. It's not uncommon for "Sep 23" to mean the period from noon on 23rd to noon on the 24th. Noon on the 23rd is Sep 23.0, and midnight is Sep 23.5. If you look through some of the other pages of the MNRAS (e.g. <a href="http://articles.adsabs.harvard.edu/full/seri/MNRAS/0007//0000153.000.html" rel="nofollow">this Bobhttps://www.blogger.com/profile/04484470826735770498noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-73835649314963568402011-07-09T23:36:33.358+01:002011-07-09T23:36:33.358+01:00Looking at the discovery story, Galle received Le ...Looking at the discovery story, Galle received Le Verrier's letter on the 23rd and they discovered Neptune the same night, so that must have been the night of September 23/24, which means that the date in MNRAS is wrong and you used the correct UT date/time.<br /><br />Indeed, when I use the true heliocentric (rather than barycentric) longitude and your UT date/time of discovery, I find 2011/AstroFloydhttps://www.blogger.com/profile/04994719632352493714noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-58272560455133830022011-07-09T19:15:28.379+01:002011-07-09T19:15:28.379+01:00I have a silly question - perhaps I'm misunder...I have a silly question - perhaps I'm misunderstanding something: if Neptune was discovered early on the 23rd Berlin time (12:00:15 am = 0:00:15 hours), shouldn't that correspond to late (23:06:40 hours) of the *22nd* UT?AstroFloydhttps://www.blogger.com/profile/04994719632352493714noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-3524842850625466992011-07-05T13:18:52.099+01:002011-07-05T13:18:52.099+01:00Thanks Paul!
Spotting it through small-to-medium...Thanks Paul! <br /><br />Spotting it through small-to-medium-sized binoculars is exactly what I've been attempting to do. I'm getting the sense that it might not be feasible (especially after reading forum posts) but I haven't given up yet! <br /><br />It's passing very close by a little 5.4 mag star "e Aqr" according to Stellarium: 15' directly underneath. So now Bobhttps://www.blogger.com/profile/04484470826735770498noreply@blogger.comtag:blogger.com,1999:blog-28989283.post-75224014716220950532011-07-05T06:37:33.765+01:002011-07-05T06:37:33.765+01:00Thank you for this fascinating snippet.
What shou...Thank you for this fascinating snippet.<br /><br />What should we do. We should dust of our telescope's and get out there and observe the two distant ice giant's of the solar system.<br /><br />Remember you our part of an exclusive club, if you manage to spot Uranus, and Neptune through small to medium sized binoculars.PaulBhttps://www.blogger.com/profile/00110017697498431790noreply@blogger.com