Observing space curvature.

xelasnave · #1 07-01-2016, 08:43 PM

I have been thinking about Eddington's observation of space curvature as predicted by GR.
Could we make such observations using a disk to replicate the Moon.
Using filters whatever we set the mount running and measure to test GR.
I just think it would be a great project. OK why wont it work?

Somnium (Aidan) · #2 07-01-2016, 08:50 PM

Quote:

Originally Posted by xelasnave

I have been thinking about Eddington's observation of space curvature as predicted by GR.
Could we make such observations using a disk to replicate the Moon.
Using filters whatever we set the mount running and measure to test GR.
I just think it would be a great project. OK why wont it work?

you mean a coronagraph? if i am understanding you correctly, you want to simulate a solar eclipse with a coronagraph and image a background star's position to test GR? you would still need a generally dark sky, an eclipse make the whole atmosphere dark, you would still be imaging through light and unlikely to see any stars ...

xelasnave · #3 07-01-2016, 08:50 PM

I think we need an eclipse.

xelasnave · #4 07-01-2016, 08:56 PM

Well here is the chalenge.
Can we photograph stars in day time near the Sun.
Seems impossible but is it.
Could you somehow use a filter and a light frame style subtract to remove atmospheric dust... any idea is worthy to do the seemingly impossible.

xelasnave · #5 07-01-2016, 08:59 PM

Maybe really dark glass... Must be a way.

Somnium (Aidan) · #6 07-01-2016, 09:12 PM

i have thought about this a bit. the stars are still providing the same flux during the day, the only issue is that the background noise has become a serious issue and completely drowns out any signal from the star. surely if the sun is blocked out and you take a stack of images of the surrounding sky, you may just be able to tease out the signal in the noise with stacking

xelasnave · #7 07-01-2016, 09:59 PM

I take that as highly encouraging.
I set up to capture a Earth eclipse of the Moon.
Had shutter speeds set close to what I needed.
Took some shots the Moon was faint as, so extended the shutter speed again and again.
I think it went to a minute.
Later I found only half the shutter was openning.
Thats where all the light went.
However the Moon photos were excellent with stars in the back ground so maybe a dark filter for the Sun.
I have unrealistic visions of a decent wide field shot with the Sun cruising through.
I think we have to do it from space really.

xelasnave · #8 07-01-2016, 10:05 PM

Mayby the radio scope guys are doing this already

Somnium (Aidan) · #9 07-01-2016, 10:11 PM

Quote:

Originally Posted by xelasnave

Mayby the radio scope guys are doing this already

i am sure they are, we also have the soho scope which can do it

xelasnave · #10 07-01-2016, 11:06 PM

Thanks

xelasnave · #11 07-01-2016, 11:15 PM

a few of their ideas maybe.
if you were high in a desert maybe you could get stars but not near the Sun.

pmrid (Peter) · #12 08-01-2016, 06:51 AM

Quote:

Originally Posted by xelasnave

a few of their ideas maybe.
if you were high in a desert maybe you could get stars but not near the Sun.

What about the old " down the mine " trick. Never tried it but it may serve to limit the background flux. Finding a hole deep enough and pointing in the right direction could be problematic.
peter🌞🌙✨

bojan · #13 08-01-2016, 08:13 AM

Quote:

Originally Posted by pmrid

What about the old " down the mine " trick. Never tried it but it may serve to limit the background flux. Finding a hole deep enough and pointing in the right direction could be problematic.
peter��✨

This "trick" will not remove the bacground noise we are talking about here.

KenGee · #14 11-01-2016, 07:01 PM

Alex if you want a direct measurement of space curvature, why not measure the position of Mercury?

Eratosthenes (Peter) · #15 11-01-2016, 09:17 PM

I would have thought that it would be a lot more difficult to observe a perfectly FLAT region of space.

Even a Neutrino, with its tiny tiny mass, technically imparts a curvature in space (time)

xelasnave · #16 11-01-2016, 11:12 PM

Quote:

Originally Posted by KenGee

Alex if you want a direct measurement of space curvature, why not measure the position of Mercury?

Yes that would work. Thanks Ken.

xelasnave · #17 11-01-2016, 11:17 PM

Quote:

Originally Posted by Eratosthenes

I would have thought that it would be a lot more difficult to observe a perfectly FLAT region of space.

Even a Neutrino, with its tiny tiny mass, technically imparts a curvature in space (time)

It would be tiny tiny about one third a pofteenth I recon.
The Sun does no bend it much and the Moon much much less so.
Sorry I cant be specific but its out there somewhere if you want the amount.

Eratosthenes (Peter) · #18 12-01-2016, 12:01 AM

Quote:

Originally Posted by xelasnave

It would be tiny tiny about one third a pofteenth I recon.
The Sun does no bend it much and the Moon much much less so.
Sorry I cant be specific but its out there somewhere if you want the amount.

isn't micro-lensing an form of space bending that can be observed?

xelasnave · #19 12-01-2016, 11:26 AM

Quote:

Originally Posted by Eratosthenes

isn't micro-lensing an form of space bending that can be observed?

I dont know what can you tell me about it?

Somnium (Aidan) · #20 12-01-2016, 12:22 PM

Quote:

Originally Posted by Eratosthenes

isn't micro-lensing an form of space bending that can be observed?

good point, one project i am looking to do down the track is to try and image gravitational lensing in galaxy clusters. fascinating stuff. micro lensing might be difficult to observe for an amateur ... my understanding on the topic is that generally these are one off detection events so it is difficult to monitor known stars with micro lensing. also i am sure the signal would be really difficult to tease out of the noise, especially in the conditions that most amateurs are in and the gear that we have ...