Astrophotography after a full moon has set.

[StuartJPP]

We all know that the moon has a detrimental affect on imaging when it is full (besides narrowband), but how much does it affect it once it has dropped below the horizon? I can't seem to find topics regarding this as the search terms are too generic.

I suppose the seeing/clarity of the air will make a huge difference.

I was imaging last night/this morning (with a ~70% disc) and when the moon was at about 17 degrees, I couldn't even make out the MW. However after restarting at about 2am and it was about 5 degrees below the horizon, it was obviously much, much darker. The MW was easily visible, even in the SW where the moon set.

So although it isn't ideal imaging during full moon, obviously waiting for the moon to set is best, but how far below the horizon would it have to go before being on par with say a ~30% disc? Of course there won't be as much imaging time left after it has set, but some of us have to take all we can get.

What are your thoughts/experiences?

[Big Jim Slade]

I found a link here that asks this same question: http://physics.stackexchange.com/questions/1968/lunar-twilight-and-sixth-magnitude-stars

But my own thought would be the effect of the moon once below the horizon would be minimal. We have about 2 hours of twilight in the UK at this time of year, but the Sun is typically 400,000 times brighter than the full moon. I think the effect you observed would have had more to do with changes in atmospheric transparency, to be honest.

[Luke]

Amazing that the sun is 400,000 times brighter than a full moon. You wouldn't think so when you walk out into the garden at night and it dazzles you!

[Big Jim Slade]

True. Or when you're standing outside at 2am looking at your shadow on the lawn!

[tdmodels]

Amazing that the sun is 400,000 times brighter than a full moon. You wouldn't think so when you walk out into the garden at night and it dazzles you!

Wierd! I knew that the size difference between the moon and sun was around 400,000 times and the difference in distance was 400,000 times, but I never knew the difference in magnitude was also 400,000 times.

You learn something new every day!

Cheers Luke.

Sent from my iPad using Tapatalk HD

[Pat mcevoy]

I found that the moon doesn't affect your photos as much as I thought it would

This is a pic from the same night taken about 10oclock

Canon 550d unmod

Ascention 105 mm trip ref

3min exp at iso 800

11 pics stacked in dss

[Gib007]

For me it's the detail picked up in the exposures that I notice the most. It's akin to doing an exposure down near the horizon with a city in the distance and doing it near the zenith where it's really dark. The object brightness captured is very different. For example, the first time I captured Andromeda Galaxy was with 5 minute exposures and the detail captured was tremendous (it's a large, bright target after all). Last night though, I captured a 7 minute exposure with the near-full Moon up high in the sky and yes, you can see dust lanes after stretching but it's nowhere near as detailed as my dark sky 5 minute exposures. It makes sense though, to think that the fine, darker details are "washed out". 

[Gib007]

Also, the background of images is a lot easier to smoothly clean up of noise when the sky is dark!

[themos]

When the full moon sets, the sun comes up!

[ollypenrice]

There is a formally defined 'astronomical darkness' which you can find from a number of sources. I use SkyMap Pro. It is unambiguous.

As a full timer I tend to see the arrival of the moon as a time to start going to bed while it is still dark and, later, enjoying breakfast with my wife. (Sausage, egg, black pudding, bacon, beans and tomato with fried bread, cornflakes and tea. It's a meal in itself, really...  ) 

Olly

[skybadger]

As a full timer I tend to see the arrival of the moon as a time to start going to bed while it is still dark and, later, enjoying breakfast with my wife. (Sausage, egg, black pudding, bacon, beans and tomato with fried bread, cornflakes and tea. It's a meal in itself, really... 

I really like that idea. And your idea of breakfast. Time for a trip to Les Granges then  . Can I have wine with brekky ?

Mike

[ian_bird]

There is a formally defined 'astronomical darkness' which you can find from a number of sources. I use SkyMap Pro. It is unambiguous.

As a full timer I tend to see the arrival of the moon as a time to start going to bed while it is still dark and, later, enjoying breakfast with my wife. (Sausage, egg, black pudding, bacon, beans and tomato with fried bread, cornflakes and tea. It's a meal in itself, really...  ) 

Olly

All I got was an egg and a piece of bacon! What gives! :grin:

[LukeSkywatcher]

There is a formally defined 'astronomical darkness' which you can find from a number of sources. I use SkyMap Pro. It is unambiguous.

As a full timer I tend to see the arrival of the moon as a time to start going to bed while it is still dark and, later, enjoying breakfast with my wife. (Sausage, egg, black pudding, bacon, beans and tomato with fried bread, cornflakes and tea. It's a meal in itself, really...  ) 

Olly

No white pudding?. You can keep your fried slice. That stuff will clog your arteries.