nikonians

Even though we ARE Nikon lovers,we are NOT affiliated with Nikon Corp. in any way.


Sign up Login
Home Forums Articles Galleries News Workshops Shop Recommended
members
All members Wiki Contests Vouchers Apps Newsletter THE NIKONIAN™ Magazines Podcasts Fundraising

Chasing New and Old Moons

nrothschild

US
10916 posts

Click to send email to this author Click to send private message to this author
nrothschild Neil is an expert in several areas, including camera support Registered since 25th Jul 2004
Tue 11-Sep-12 08:29 PM | edited Mon 06-May-13 09:35 AM by nrothschild

Any members reading this have surely shot the moon. Most start with the full moon, doubtless because there is some intrinsic romanticism associated with the full moon. Then we graduate to the first quarter moon when it is pointed out that full moons have poor contrast and bad light, similar to noon-time light on Earth.

At some point you might feel like you have had your fill of the basic moon shots… then you may want a new challenge. That challenge is the chasing of both new and old moons. This is arguably best done with a pair of binoculars and any moderately long lens, such as a 70-200 or 70-300. No motorized mounts are needed and very long focal lengths are not necessarily optimum or even desirable.

Best of all, very new and old moons are by definition very close to the horizon at dawn or dusk and therefore make great landscape shots.
Most people have seen a 2 day old moon, just after sunset to mid-dusk. It appears as a slender crescent. That is an easy shot. We are going to concentrate on moons near 24 hours from new, and the closer to new the better. The challenge is to shoot the oldest and newest moon possible.

Very few people have seen a 24 hour old moon and fewer have seen an old moon 24 hours or less from new. A visual sighting might require binoculars to pick the dim moon out from the bright dawn or dusk sky and you have to know when and where to look.

Like the romanticism that has grown up around the full moon, the new moon seems to generate far more interest than old moons. Sky & Telescope magazine will occasionally run an article about chasing new moons but I don’t ever recall an article promoting old moons.

My Lunar Phase Pro software provides me with a chart of all upcoming new moons, but not old moons. That I have to research myself . I always try to march to the beat of a different drummer so I am giving old moons equal time here. Plus, it gives us something to chase in the new moon “off season”.

Some Celestial Mechanics

More so than “normal” moons some knowledge of the orbits of the earth and sun are required.

The sun follows a path through the celestial background called the ecliptic. It makes one full revolution roughly once every 365 days. The fact that it is actually 365.25-something days results in leap years and occasional leap seconds.

The ecliptic is tilted such that it is highest in the sky at the summer solstice and lowest at the winter solstice, giving us our seasons.

The planets orbit around the sun, more or less following the same path but all are slightly tilted relative to the ecliptic, presumably due to catastrophic events in distant epocs. As a result, planets will generally appear some number of degrees above and below the ecliptic.

The moon orbits the Earth, of course, and its orbit is tilted about 5 degrees from the ecliptic, such that at any time it may appear as much as 5 degrees North or South of the line of the ecliptic and this is a critical aspect of chasing these moons.

All phases of the moon have seasons. These seasons are fixed to the calendar. In the Northern Hemisphere, December is the optimum month to view a full moon and June is the poorest. That is because the full moon is opposite the sun and when the sun is lowest in the sky in December the full moon is on the “high side” of the ecliptic, opposite of the sun, where the sun will be in June.

The first quarter is best viewed around March and the last quarter best viewed around September.

Picking the right time of year to view any “normal” phase of the moon is a simple matter. In the Northern hemisphere, simply view the moon when it is furthest north along the ecliptic. That furthest north point of the ecliptic is always in the area of the constellations Taurus and Gemini.

Very new and old moons are quite different and more complicated.

Because the moon’s orbit is tilted relative to the ecliptic, there can be better than average optimum seasons for the moon. But if the moon is 70 degrees above the horizon at optimum, what’s another 5 degrees, plus or minus? There are more or less favorable seasons for any phase of the moon in any given year but we are generally unaware of it unless we carefully study astronomical ephemera.

When chasing new and old moons, though, every degree counts! And for that reason we must obsess over more or less favorable positions of those moons. Some years are just not good years, where other years are more favorable. This makes the challenge frustrating at times, but all the more satisfying when accomplished. It also means that these opportunities are fleeting and far between.

Edit: The US Naval Observatory has a very interesting web page here, concerning earliest possible visible crescent moons, and is well worth reading. The short story perhaps is that you just need to go out and look . The subject of the newest possible visible moon is an extremely complex matter.

The September 15, 2012 Old Moon

Below is a map drawn from SkyMap Pro V10. The lines are altitude and azimuth (not astronomical right ascension and declination). The upper blue area ends at the physical true horizon. I have added a few annotations in red.

Old moons are rather complex because, for example, in this case the moon is 28 days 18.72 hours old, but is 15.53 hours from new. I’ve never seen astronomical software that provides the old moon’s “age” counting back from the new moon (another example of that bias toward new moons).

The length of a single lunar orbit around the Earth (a “lunation varies. For that reason the age is not terribly useful. We care about the length of time until the upcoming new moon.

The map was drawn as of 6:38am EDST, positioned on the Maryland coast where I would go if I wanted to view this. The new moon occurs at the same time all over the world. In this case, at 10:10pm EDST on Sept 15.

Members in London, GB will experience the same sunrise 5 hours earlier so their old moon will be about 20.5 hours from new. Members on the West Coast USA will see a 12 hour moon- a very daunting task.

From the above you can conclude that somewhere in the world we see whatever age moon we want, but in any given place we have to take what is handed to us. The age of any given old or new moon, only visible for an hour or less, is purely dependent on the exact time of the new moon, which varies without much obvious pattern from month to month.

A moon less than 24 hours from new is tough. The record is somewhere around 10 hours, as I recall, and that would be done at a certain place on Earth for a very favorable moon (specific to that event), and usually from a high altitude. To see something like that you would likely have to chase it like a solar eclipse, with all the attendant time and expense involved in those pursuits.

For us mere mortals, I suspect that 16 hours may be a practical limit and I think quite an accomplishment. At this point in time that happens to be my own personal “reasonably achievable" goal - a 16 hour moon- new or old. If I lived at altitude I might have a more ambitious goal.

On the map below we see the sun just rising, with the moon to upper right. The moon is just about 5 degrees above the horizon and would definitely not be visible as the sun rises. It is too dim, too delicate an image.

Here is the big question: will the moon rise out of the typical murk on the horizon and be visible before its very delicate light is washed out by the brightening dawn? On any given day and conditions that answer may vary. It's a closely contested horse race!

The moon lies about 4 degrees south of the ecliptic, and that is the problem here, and everywhere in the world on that morning. I have drawn a line perpendicular to the ecliptic, and about centered on it. That line roughly represents the approximately +/-5 degree possible placement of the moon relative to the ecliptic. Here it is well south and South is always unfavorable.

As mentioned, this unfavorable old moon is only 5 degrees above the horizon. If it were 5 degrees North of the ecliptic it would be about 8 degrees above the horizon and that is a HUGE 3 degrees! That might double or triple the odds, or even just make it possible.

I won’t say this moon is impossible but we have about the worst possible placement on the ecliptic during what is otherwise a very favorable time to view old moons. Members in Europe or even east of Western Europe would have a progressively easier time of this but then again, they would be viewing a 20-24 hour moon, which is not nearly as difficult, all else equal.

In the Northern Hemisphere the new old moon season spans approximately late summer to early fall. The new moon season spans roughly January to May.

You will note that the ecliptic rises steeply, and if the moon were well placed it would be directly above the sun or could even be slightly North of the sun. That is what you ideally want.

A shallow ecliptic, rising not as steeply, is unfavorable for reasons that should be obvious and shortly will become more obvious. In the spring, the old moon sits on a very shallow ecliptic.

Click on image to view larger version



The September 16, 2012 New Moon

To recap, on the morning of Sept 15th we have a less than 24 hour old moon. At 10:10pm that evening (East Coast USA, EDST) we have the new moon, where if the moon were placed precisely on the ecliptic we would have a solar eclipse. As we have seen, the moon is far from the ecliptic so no joy there.

On the evening of the 16th the sun will set at about 7:01pm EDST on the East Coast USA and by then the now new moon has passed the sun and is 20 hours and 49 minutes old. In principle this is easier to see because it is 5 hours further from the sun than the old moon but it isn’t that simple .

And we can see below, the ecliptic is very shallowly inclined and the moon is still about 4 degrees south of the ecliptic. That is a doubly unfavorable new moon. As you can see, it will set only a few minutes after the sun, making it impossible to view.

A similar situation can occur with the old moon in the spring when the angle of the ecliptic relative to the horizon is similarly shallow around the location of the old moon.

I have, again, drawn a line perpendicular to the ecliptic to illustrate where, with some luck, the moon might be well placed. If this new moon were sitting at its maximum 5 degree travel north of the ecliptic then it would be at about 10 degrees altitude at sunset and would be very viewable in good weather.

From that I have concluded that in truth the position of the moon relative to the ecliptic is more important than the season. And that is counter to what I have always read in the past, where the seasons (with the ecliptic sharply angled into the horizon) are emphasized.

In terms of seasons, it is important to understand that while the new moon is in the furthest north ecliptic region (Taurus-Gemini) around mid-May to early June, the tilt of the ecliptic is most favorable around March (with the straddling months also very good). That assumes a similar positioning of the moon perpendicular to the ecliptic, as previously stressed.


Click on image to view larger version


Below is my favorite new/old moon image. This was shot March 16, 2010 at 7:31 EDST when the new moon was 26 hours old. I include this image not just to illustrate how the new moon can be incorporated into a landscape but also to illustrate that, amazingly enough, it can be visible right down to the horizon.

And it is obvious that I did not even have a “clean” horizon although it did add greatly to the image. Twenty minutes before I shot this I would not have wagered 10 cents that this image would happen. I was amazed.

The point I am making is that if the circumstances present themselves always try to shoot the new and old moons. Don’t let anyone (or yourself, or me!) talk you out of it .


Click on image to view larger version


This next image is an old moon, about 29.5 hours from new, shot on March 25, 2009 in the “worst season” for the old moon. The moon was about 2 degrees north of the ecliptic (not ideal, but a 7 out of 10 if you think about it). The moon was probably within a degree or two of the horizon, at least according to my camera EXIF and I do try to keep my camera clocks very accurately set just for this purpose. It was slightly under 7 degrees altitude at the moment of sunrise, long after it would have disappeared into the glare of the increasingly bright dawn sky.

Interestingly, this is the oldest moon I’ve shot, based on age from the prior full moon, but I have two old moons closer to the new moon and therefore, by my way of thinking, more desirable. That was due to the March 2009 lunation being on the long side. I previously mentioned that the periodicity of the moon’s orbit varies a bit.


Click on image to view larger version


And I have to add my crowning achievement so far in this venture, 20 hours 40 minutes from new .

This image was shot April 25, 2009, at 8:14pm EDST, with a very favorable steep ecliptic (remember – new moon in spring!).

I was also blessed with a moon 4 degrees north of the ecliptic, so this was about as good as it gets. I only regret that it wasn’t a couple hours earlier because these are the conditions needed to get a truly new moon- something approaching 16 hours.

Here the moon is about 5 degrees above the horizon, with the sun about 5 degrees below the horizon. The moon was directly above the sun- it just doesn’t get any better than that.

I found the moon with binoculars and as I recall I got my first shot at 8:03:54pm, within a minute or two after my visual sighting. I recall that when I got that first shot the moon was not yet visible naked eye but it was very dimly visible in the viewfinder (a very important observation!).

My last shot was at 8:18pm and I suspect it went into the murk at the horizon. I typically try to get my first and last possible shots just for documentation and future research. There are many questions about how close to the horizon, how close to the sun, and etc. Good records are helpful when planning future conquests!

Click on image to view larger version

Attachment #1, (jpg file)
Attachment #2, (jpg file)
Attachment #3, (jpg file)
Attachment #4, (jpg file)
Attachment #5, (jpg file)

_________________________________
Neil


my Nikonians gallery.

Subject
ID
Reply message RE: Chasing New and Old Moons
1
Reply message RE: Chasing New and Old Moons
2
Reply message Where to shoot these moons...
3
Reply message Exposure...
4
Reply message The cycle of favorable new moons
5
Reply message RE: Chasing New and Old Moons
6
Reply message RE: Chasing New and Old Moons
7
Reply message RE: Chasing New and Old Moons
8

G