Next Saturday's unprecedented lunar eclipse is no cause for alarm

[OzEclipse]

Just 7 or 8 sleeps to go until next Saturday morning's twilight lunar eclipse.

I've prepared a short mostly graphical summary on my website :
http://joe-cali.com/eclipses/PLANNING/TLE20180728/index.html

Joe

[skysurfer]

Mauritius or Reunion, there the totally eclipsed Moon (with Mars) is in the zenith !

[OzStarGazer]

How is it that I am not surprised?

[AstralTraveller]

I'm trying to work out whether to observe from my back yard or travel. The first is easier of course but the western horizon is partially obstructed. The question is: how low will the moon be when it disappears into the twilight? From Joe's diagram it appears it could be as low as 5 degrees. Anyone have any idea? [I have seen a rising eclipse but that was over the ocean and I have no memory of how high it was when we first spotted it.]

[OzStarGazer]

According to Starry Night Pro this is the situation for Wollongong at 5:15am, 18 degrees (first image), 5:45am, 13 degrees (second image) and 6:15am, 7 degrees (third image).
PS: My balcony faces east, so I will have to go downstairs and find a spot with my small telescope and my camera. Hopefully nobody will try to steal my scope.

[Icearcher]

Anyone planning anything in Adelaide?

Im thinking of going up to the Mt Lofty summit, it has a great view over the city and also east over the water.

Either that or there are some nice spots along the coast.

[OzEclipse]

David

It depends on local aerosols and other particulates in the air that might increase(by scatter) or decrease(by absorption) the brightness of the sky and contribute to extinction of the Moon. The moon will darken to midtotality then brighten to the end of totality at sunrise.

I'd suggest it isn't really possible to predict.

Once twilight arrives and sky brightness starts being comparable to the moon, all you need to do is switch your camera to Av mode and let it happen.
Even if the moon disappears, keep shooting, it might reappear as the Moon brightens.

Joe

[OzStarGazer]

I will watch the first part online and go down to find a spot short before 5...
There won't be another total eclipse so soon, so hopefully I will get a glimpse of it.

[DaveGee]

The moon's northern limb will graze by SAO 163510 during totality. The star is mag. 7.9 (7.3 Red). Map of the northern limit line attached below.

I'm not sure of the observability of the star against the Umbra but I'll find out...

[OzStarGazer]

Latest weather forecast around here:

[OzEclipse]

Dave,

I think the graze you are referring to in eastern AU occurs at about 6am -

30 mins into totality,
Moon altitude 12 degrees
1 hr until moonset
4 mins before the start of nautical twilight ACT, maybe about 10 mins after the start of nautical twilight on the coast.

Background sky brightness, atmospheric instability, low altitude extinction not to mention the rain that's predicted along the graze path, will further complicate observations. It passes 10k from my dark sky site but I don't think it's a goer. I'll probably stay in Canberra.

cheers

Joe

[Wavytone]

Forget the graze if you live in Sydney/Brisbane/Melbourne/Hobart.

In Sydney the moon is fully eclipsed (U2) at 5:30 am but sunrise is at 6:51 am. With the graze at 6 am that means the sky will be quite bright, so the moon will have vanished and be invisible. You can forget mag 7 stars even in a scope - I tried yesterday.

It might be feasible in Adelaide (and only maybe) but its reasonable for observers in Perth.

Its a pity because its a very very long wait for the good next total lunar eclipse over Australia - in 2031.

[MortonH]

What is unprecedented about this eclipse?

[Wavytone]

joe was having a jibe at a certain tv network whose collective memory is barely 3 weeks. Even rain was “unprecedented”...

Cripes Morton, you don’t watch much tv...

[OzStarGazer]

Originally Posted by MortonH http://www.iceinspace.com.au/vbiis/images/buttons/viewpost.gif (http://www.iceinspace.com.au/forum/showthread.php?p=1385894#post138589 4)
What is unprecedented about this eclipse?


Lunar eclipse of the century

A total lunar eclipse is always an awe-inspiring sight, but this one is special:


It's the longest lunar eclipse of the 21st century. The Moon will travel through the very center of Earth's shadow (https://www.timeanddate.com/eclipse/umbra-shadow.html), and the distance from Earth to the Moon (https://www.timeanddate.com/astronomy/moon/micro-moon.html) and to the Sun (https://www.timeanddate.com/astronomy/perihelion-aphelion-solstice.html) will be unusually large—making this eclipse the longest you will likely see in your lifetime!
It will coincide with the Perseids meteor shower (https://www.timeanddate.com/astronomy/meteor-shower/perseid.html), so you might see a few shooting stars during totality.
Mars will be at its brightest. The planet will appear as a reddish star, quite close to the Moon.

Source: https://www.timeanddate.com/live/



Then again, the tetrad was also supposed to be unique.


I do like the idea that it lasts longer than usual because clouds can be pretty nasty so the longer it lasts the better the chances to get a glimpse of it.
If the weather cooperates it would be the very first eclipse I can see since I got into astronomy.

[OzStarGazer]

... although unfortunately I won't see it all from where I am because it will be too bright towards the end and there are obstructions in the west (the escarpment).

[AstralTraveller]

Question: if a network is soooo 'bad' (insert fruity term here) that they cannot remember three weeks ago why would anyone who considers themselves educated, reasonable or possessed of good taste watch said station? Isn't knowing anything about that station a form of confession? "Forgive me Father for I know what the channel 10 weather girl wore last night." :P

[AstralTraveller]

From your place the elevation of the escarpment is <5 degrees. (It's about 5 from my place in Tarrawanna.) So I expect the dawn will get you before the escarpment.

[OzEclipse]

Just a bit of fun. It's a play on a line from an old 1980's song by Queen, "Flash"
Original line in the song was, "Today's unprecedented solar eclipse is no cause for alarm." :)

Joe

[Wavytone]

A CHALLENGE FOR VISUAL TYPES: Here is a technicality about this eclipse which might interest a visual observer:

It is possible to briefly see simultaneously both the rising sun in the east, AND the eclipsed moon setting in the west, thanks to atmospheric refraction.

However this is only possible if you happen to be standing on a decent site with really PERFECT low horizons east and west (and I do mean zero degrees altitude) AND very clear air. In other words: if you live in Sydney fuggedaboutit.

I saw this once with a similar lunar eclipse in the late 1970's at Mt Stromlo, where the sun rose in the east with the moon setting during the total phase (after second contact).

I've seen three similar lunar eclipses before - one in the early 1980's where at sunset the moon rose fully eclipsed, and two where the moon set soon after the total phase began. In all three cases it was a total waste of time setting up a scope and I won't be getting out of bed for this one.

Yes its the longest this century but in the eastern states disappointing. The time of second contact (5:30) is well into twilight so the moon will basically disappear and won't be much of a sight. To see it properly you have to be much further west - Perth, for example.

The unfortunate part - for the beginners here - is that it is going to be a very unusually long wait for another one over the eastern states - 2031 !

Aside: Something worthy of "Have You Been Paying Attention" (yes I do watch it) ... the ABC was guilty of calling the recent bushfire at Tathra "unprecedented" and was quickly chastised in letters to the editor of the SMH and Herald Sun for rather sloppy journalism - if the ABC had bothered to check the RFS website they would have found no less than 11 recent precedents dwarfing the Tathra fire. The ABC's sloppiness also rated a brief mention on 7 and 9.

[MortonH]

Thanks for explaining!

[DaveGee]

Hi Mr Wavytone,

According to Occult, we (Easterners) will see a Lunar Eclipse on 26th May 2021. See attached. Not so unprecedented as 'Next Saturday's' but :welcome: all the same.

Then another 7th September 2025.

[DaveGee]

You do know what a graze is... don't you? I don't think you do!

The graze I was referring to is of SAO 163510 - see previous map.

This star is occulted by the moon during totality, ONLY for observers south of the red line on the map - the northern limit. The graze occurs at sites along the northern limit. Sites South of the Northern Limit will see a Total lunar occultation (during totality).

As to the visibility or not. Most occultation observers use video nowadays and it's quite common to observe lunar occultations of mag. 7 stars will into twilight. I've been able to read my printed notes without a torch light, while the star is quite visible in the scope. Having said that, it is quite hard to predict visibility during eclipse because the of the colour of the umbra.

And notwithstanding clouds...:shrug:

[Wavytone]

Ah actually I do - When I lived in Canberra long ago I was one of Dave Herald’s lot timing grazing occultations in funny places in the countryside. But not since moving to Sydney.

[Wavytone]

Ah actually I do - When I lived in Canberra long ago I was one of Dave Herald’s lot and times many many grazing occultations in funny places in the countryside. But not since moving to Sydney.

The only significant thing that has changed since then is using a camera to record it...

Still think you’ll be struggling to see this.

Good luck !

[OzEclipse]

Hi Wavy,

No lunar eclipse visible eastern states in 2031. 7 total eclipses between Saturday and 2031 including this weeks eclipse. Another 4 visible in 2032/33.

Lunar eclipses of some description occur every year. However some of these are fleeting glimpses eg we might just catch the beginning/end of a penumbral as the moon is setting or rising. Total lunar eclipses occur pretty regularly with some years having only partial/penumbral eclipses(worldwide). For example, there is a total next yea but only visible from the other side of the Earth c Pacific, Americas, Europe, Africa but not here.

2020 is a no total year, 2021 there is a total visible here. 2022 there is a total but we only see the penumbral before moonset.

From any one location, we tend to see two or more sequential total eclipses clustered every 3-4 years. I'm making a broad generalisation here. I've attached a table extracted from Chris O'Byrne's eclipse explorer software showing total eclipses visible from Sydney 2001-2040. Where the text is grey, it means that event of the eclipse is below the horizon at the selected location.

Cheers

Joe

[skysurfer]

It is not the longest in the century: one saros ago (16/17 jul 2000, the very first year of the century) it was longer (1:46 and next Friday 1:43) and was closer to the center of the shadow (1.77 vs 1.72 now).


https://eclipse.gsfc.nasa.gov/LEplot/LEplot1951/LE2000Jul16T.pdf



And don't say "2000 is part of the 20th century as there is no year zero", because there *is* a year zero because there are also 'negative' years (BC). Simple basic arithmetics.

[Wavytone]

Interesting list - I was looking at the circumstances - including the maps - on Fred Espenaks site - yes there are some total lunar eclipses in the 2020’s but the circumstances for Australia are less favourable even than saturdays eclipse. And I have rather more faith in Fred’s website.

As I said, a very long wait for a decent one over the eastern states.

[skysurfer]

There are more total lunar eclipses visible from the East Coast in the 20s.


The most remarkable is New Years Eve 2029, at midnight the Moon is almost totally eclipsed.


Find the scheme here (times in UTC).

[Wavytone]

Take a closer look
http://www.eclipsewise.com/lunar/LEdisk/2001-2100/LE2029Dec20T.pdf

There's a huge issue with the date and time and visibility of your prediction. If there's a lunar eclipse on December 20 there can't be another 11 days later. Mr Eclipse is Fred Espenak, who has been running the NASA/JPL eclipse ephemerides for decades.

I know which one I'm inclined to believe.

[OzEclipse]

Hi Wavy,

Chris O'Byrne's calculator works off the 5MCE (Five Millennium Canon of Eclipses) which was produced by Fred Espenak. The eclipse you referred to is December 20, 2029, not 11 days earlier, but 12 synodic months after the new years eclipse on Jan 01, 2029.

The website you are looking at is expressed in UT, the calculator I used is EST, and the data Skysurfer posted December 31 is expressed in UT. The eclipse skysurfer and I listed is time consistent after converting time zones. He did refer to new year's eve 2029 which I can understand may have thrown you off but the circumstances in his post did clearly state Dec 31, 2028.

All circumstances published in this thread are correct and consistent. No huge problem exists with the predictions.

The list I published only lists total eclipses visible from Sydney. It lists the eclipse even if only a penumbral part is visible above the horizon using the grey text to show sub horizon events.

These lists can be confusing to read. It's easy to make mistakes with dates especially with the UT/EST confusion across midnight. When that change occurs across a year change, it's even easier to misread.

This eclipse and the July 16, 2000 are part of the same saros series 129, a series of very long eclipses.
1964 June 101 mins
1982 July 106 mins
2000 July 106 mins
2018 July 103 min
The 1982 & 2000 events were the longest/deepest of the saros and the eclipses of this series are now getting shorter.

So if you are waiting for a longer eclipse to call decent, you'll be waiting a long long time. :)

kind regards

Joe

[Wavytone]

To me that is 31 December not January 1.

Oh never mind let it pass.

[OzEclipse]

I do agree with you that it was a confusing way for him to express it. I would also have thought he meant Dec 31, 2029 had I not already seen the Jan1 2029 in my list. His attachment with circumstances did list it as Dec 31 2028.

I know that all the various people producing interactive maps, circumstances, predictions etc for solar and lunar eclipses have put a lot of effort into getting it all correct and consistent right down to moving from the old Watts lunar limb profile to the much more accurate Kaguya profile so that even limb corrections are consistent.

I trust anything by :
Espenak (mreclipse.com)
Ernest Wright (NASA)
Bill Kramer(eclipse-chasers.com)
Xavier Jubier(xjubier.free.fr)
Michael Zeiler (eclipse-maps.com)
Chris O'Byrne(eclipse explorer calculator)
Dave Herald(Occult software)
and probably quite a few others.

Cheers and clear skies

Joe