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Old 30-05-2020, 08:12 AM
Tropo-Bob (Bob)
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Chance encounter prompts question

I had a bit of luck last night. When I looked at the Moon, I saw Eta Leo about to be occulted. It disappeared at 6.42pm.

I spent a bit of time checking this morning, and I could not find any predictions of this in the literature (both print or web.) The best that I could find is that Regulus was 4 degrees south of the Moon.

I missed its reappearance because I did not know when it would happen. Anybody know where I can check for such events?
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Old 30-05-2020, 11:26 AM
Saturnine (Jeff)
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I know I would've read that Astronomy 2020 wasn't including printing lunar occultations tables this year, as they have done in all their previous editions but it is unfortunate that they decided not to . It is otherwise a fine yearbook of events in our night skies and I have every edition from 1997.
While observing lunar yesterday evening I did note that there was a bright star close to the limb and on checking found it to be Eta Leonis, after re-appearance. Also noted that it was between Regulus and Gamma, which gave a clue to which star it was. Have run a simulation on Stellarium and came up with a time, for the east coast, of 19:17pm for disappearance and 20:07pm for re-appearance .
Hope this info helps.
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Old 30-05-2020, 01:22 PM
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Tinderboxsky (Steve)
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Hi Bob,
It certainly is a shame the Australian Astronomy Guide seems to have ceased publishing tables of Lunar Occultations.
The Occultation Section of RASNZ is still active and does publish the list of predictions you are looking for. See here:
http://www.occultations.org.nz/total/totpreds.htm
The Occultation Section used to publish grazing occultation predictions that I used regularly. Has not been published for a while unfortunately.
I observed a Lunar occultation of 52 Geminorum last Tuesday. The Moon was a fine crescent and the disappearance occurred on the dark side bathed in brilliant Earth Shine. It was quite a sight with 52 Geminorum a distinct yellow against the Earth Shine. Reappearance was on the bright side of the fine crescent.
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Old 30-05-2020, 01:45 PM
Tropo-Bob (Bob)
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Thanks Steve,

That is excellent.

Jeff, thanks for your reply also.

Bob
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Old 30-05-2020, 01:55 PM
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Hi Bob,

You can use Stellarium. I just tried it starting as you suggested at 6:42PM last nightand then ran the time forward to about 7:30pm where it just grazes the edge of the moon. but doesn't appear to pass behind it. Maybe it's too close to call?

Here is a screen pic showing the path of Eta leo from 6:42pm (LHS) to 7:30pm (RHS)


Best
JA

Click image for larger version

Name:	Eta Leo Moon 1842.jpg
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Size:	197.8 KB
ID:	259896
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Old 30-05-2020, 02:41 PM
Tropo-Bob (Bob)
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Hi JA,

I think that the postion of the Moon looks about half a Moon diameter further north from down south than in does in Cairns. (or maybe even vice versa).

Years ago, I had a phone conversation with a friend of mine in Canbera and we were able to do a 'live' comparison of where the Moon was situated.
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Old 30-05-2020, 03:24 PM
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Quote:
Originally Posted by Tropo-Bob View Post
Hi JA,

I think that the postion of the Moon looks about half a Moon diameter further north from down south than in does in Cairns. (or maybe even vice versa).

Years ago, I had a phone conversation with a friend of mine in Canbera and we were able to do a 'live' comparison of where the Moon was situated.
Good point re your location. I didn't, but should have used your location for such a marginal thing. I used Melbourne.

Best
JA
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Old 30-05-2020, 03:53 PM
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Ok Bob,

Now using Cairns as the location from Stellarium

Eta Leo disappears behind the Moon at ~1842 29MAY2020 (1st Image below)

Click image for larger version

Name:	Eta Leo Moon 29MAY2020 1842.jpg
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and then
Eta Leo reappears from behind the Moon at ~ 2007 29MAY2020 (2nd Image Below)


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Name:	Eta Leo Moon 29MAY2020 2007.jpg
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Size:	169.9 KB
ID:	259901


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JA
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Old 30-05-2020, 03:55 PM
Saturnine (Jeff)
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From my observing spot last night at approx 34 deg Sth. Eta Leonis re-appeared just a little south along the limb from of Petavius.
The occultations.org.nz link will be very handy, thanks Steve.
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Old 30-05-2020, 04:34 PM
Tropo-Bob (Bob)
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Thanks Ja,

U have solved the mystery for me. I was expecting it to reappear after an hour and followed it closely for 20 mins before giving up. Gee, 18.42 to 20.07; that was a long occulation.
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