Will we be able to see Asteroid 2019 EA2 when it passes earth on March 22nd.

[SamsarandaParticipant @samsaranda]

Asteroid 2019 EA 2, which is estimated at 128 feet across, will pass between earth and the Moon on March 22nd. Does anyone know will it be visible and if so what we will we need to be able to see it, will binoculars see it or will we need a telescope?

Dave W

[SamsarandaParticipant @samsaranda]

[martin perman 1Participant @martinperman1]

I would assume it would need a serious telescope to see it, if it passed half way that will be 119,000 miles away from earth travelling at 25 kilometers a second, 90000 kilometers an hour56250 miles an hour.

Martin P

[Mick B1Participant @mickb1]

Posted by martin perman on 16/03/2019 16:45:54:

I would assume it would need a serious telescope to see it, if it passed half way that will be 119,000 miles away from earth travelling at 25 kilometers a second, 90000 kilometers an hour56250 miles an hour.

Martin P

That's about 625 times its own length every second.

Blink and you'll miss it, I should think.

[Enough!Participant @enough]

Martin, I would guess that what matters is angular speed relative to the observer ….. and If my ageing brain were up to it I could probably estimate it from the numbers you give. As it is, I think I'd need to leave that to someone else.

Edited By Bandersnatch on 16/03/2019 17:32:40

[SamsarandaParticipant @samsaranda]

I was led to believe it’s true speed would only be 5 km/second, still I take your point a serious telescope will probably be necessary, unless it passes during the hours of darkness when perhaps it might be illuminated by reflected sunlight.

Dave W

[martin perman 1Participant @martinperman1]

Posted by Samsaranda on 16/03/2019 17:47:15:

I was led to believe it’s true speed would only be 5 km/second, still I take your point a serious telescope will probably be necessary, unless it passes during the hours of darkness when perhaps it might be illuminated by reflected sunlight.

Dave W

My speed is a googled average for said objects, 5 km/second is still 18000 mile an hour so its still not hanging around.

Martin P

[Mick B1Participant @mickb1]

Posted by Bandersnatch on 16/03/2019 17:31:53:

Martin, I would guess that what matters is angular speed relative to the observer ….. and If my ageing brain were up to it I could probably estimate it from the numbers you give. As it is, I think I'd need to leave that to someone else.

Edited By Bandersnatch on 16/03/2019 17:32:40

Hmmm.. looks like my 'blink and you'll miss it' is wide of the mark. Doing a rough angular velocity calc. it looks like it'll take about 133 sec. to travel 1 degree at that distance (which is a guess as halfway, isn't it?), so in binos with a 7 degree field, it'll cross it in about 15 1/2 minutes.

I read somewhen in my distant youth that the 200 inch Palomar scope could just about see St.Paul's if it was on the Moon. That's very roughly in the size range of this space rock, so unless an isolated rock in space is a lot more conspicuous (will it be in sunlight in a night sky?), it doesn't look as if the binos have much chance.

Neil knows about this stuff – whass 'e fink?

[martin perman 1Participant @martinperman1]

We are still looking for a tiny object thousands of miles away going like the bat out of hell across a very dark sky, looking for St Pauls on a stationary, relative, object would be a very lot easier.

Martin P

[Chris TriceParticipant @christrice43267]

Nearest approach in the UK will be 3 in the morning. It'll pass at roughly 200,000 miles which is not much nearer than the moon. It's approximately house size so if you have a telescope that could resolve a house on the Moon while tracking the object, you stand a chance. Otherwise, it's unlikely you'll see even a pin prick of light without knowing where to look.

[Neil WyattModerator @neilwyatt]

It is only down to how bright it is. The angular size of stars is much smaller, but you can still see them naked eye.

Angular size is really only important when doing things like resolving details or splitting double stars.

This asteroid is expected to reach magnitude 16.4, the bigger the number the fainter. I found a table of limiting magnitudes for scopes of different sizes and it says 14" by one method and 24" by the other.

So to see it with your own eyes you will need a big scope, certainly bigger than my 10" dob.

On the other hand I have regularly imaged stars fainter than magnitude 17, so with a bit of luck it could photograph it.

I've managed to image some larger asteroids, this is Pallas at mag 9.7, EA2 would be as faint as the faintest stars in this image:

<edit> note how there are many more faint stars in the top, stacked, image made up of 40 minutes of photos. The animation appears to show stars down to about 15.5, so would not show EA2 in these single exposures.

 

Edited By Neil Wyatt on 16/03/2019 23:26:03

[Mick B1Participant @mickb1]

Thanks, Neil,

Don't think I'll be getting out my Celestron 6 then – not for that one, anyway.

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