a different approach to amateur astronomy?

[Shiraz]

Hans' thread got me thinking about something that has been dwelling at the back of the brain for a while. There are some very nice large amateur setups out there all working in isolation. If those with good systems got together and coordinated some imaging time so that a large number of scopes was looking at the same bit of sky, they could combine the data to have a serious imaging capability. Modern cameras have low dark and read noise levels, the sky will limit the resolution of any scope in Australia without adaptive optics to maybe 2 arc secs, modern tracking mounts are capable of sub arc second tracking and we should be able to manage scattered light. So, with only a handful of say 12 inch scopes, it should be possible to pretty much match the photon gathering capability of a 1m. A few more and we could be looking at 2m, which could be a serious second tier imaging capability.

Now clearly, adding scopes together is not going to be a simple scaling exercise, and it will involve significant organisation - but it should be do-able. Can anyone suggest fundamental technical issues that would bring it undone? I would be happy to significantly upgrade my imaging system to participate in such a scheme if it seemed likely to work.

And does anyone have any ideas on what real science could be done with such a capability?

regards Ray

[bojan]

I think this will not work quite like you wanted..
Combining of scopes (like SKA for example) includes accurate phasing of wavefront from each aperture, impossible when telescopes are just scattered anywhere and not combined with appropriate networking.
Multiple telescopes (like ones on Mauna Kea for example) combine all images BEFORE sensor.
It the scenario you are proposing, what we would get is just summation of exposure time (and increased S/N) but not resolution.
Some deterioration will occur because of different scales of individual instruments..

So, yes, there will be some improvement of results when compared to images taken by individuals only.. and it is worth trying, but you must not expect too much.

[Shiraz]

Hi Bojan.
Yes I understand that there will not be any resolution increase from combining data post detection, but the atmosphere would limit even a 2m scope (without adaptive optics) to the same 1-2 arc sec as this scheme should provide. The main difference I can see between this and one big scope will be that the individual cameras will all contribute noise. We could end up with the equivalent of a large scope with atmosphere limited resolution - question then is what could be done with it.

[tlgerdes]

If you have a 2M scope, you will have AO ;)

[bojan]

I don't think so..
We would end up with multiple sets of frames for stacking - and corresponding Signal/Noise ratio improvement, and that's all.
The same thing you can obtain yourself, over couple of nights, collecting larger number of frames.
Yes, bigger telescopes will contribute more data, but data obtained with smaller ones will be rejected anyway in stacking process.

[Shiraz]

I'm not an expert - do we have any scopes in Australia with deformable optics? anybody know?



But this approach could enable us to compete with a fair size scope scope (without adaptive optics) in SNR and resolution (atmosphere limited) AND in ability to image a lot of different objects in a given timescale if required, which I cannot do by adding exposures with a single scope. If the atmosphere limits the resolution, which it will for larger scopes (eg about 12inch or above for 2 arcsec seeing), data quality for stacking will be determined only by the seeing. Agree that smaller scopes, where the resolution is not seeing limited, will be excluded.

I guess my basic question is - if we can get to the sensitivity and resolution equivalent of a 1-2m scope without adaptive optics, with a fairly wide field and no possibility of spectrometry, what can we do with it?

[silv]

Shiraz, networking would be great because then multiple scopes could ideally, weather permitting in all locations, capture the same part of the sky at the same time.

What would happen to the angle, though, if you control my PhD guided scope in NZ (via 3G internet and teamviewer, for example) and you operate yours in Australia?
The angle of the object captured in the sky would be different, wouldn't it?

If so, then an application of the captured data with the different angles would have to be found.

If not, then one could capture the data and during processing ideas for an application will pop up in the head, I'm sure.

Would you think combining data from different days would be a good idea if some scientific outcome is wanted?

[Shiraz]

Hi Silv, deep space objects are so far away that parallax would not be an issue - as long as the scopes point at the same bit of sky, the images can be combined (provided the scopes do not introduce distortion)

[silv]

Awesome!
I hope there'll be owners of guided 12" happy to chip in.
Looking forward to what you guys will be finding, processing-wise and scientific application-wise.

[Shiraz]

thanks Silv.

Huge distance to go before anything like this could become a reality. I am not yet too sure that it would be a useful capability in the end anyway - need feedback from those who have more knowledge of the professional side of astronomy.

Interesting to contemplate possibilities and a couple of additional benefits over a fixed scope come to mind:
- such a distributed capability could be relatively immune to clouds - clouds at one site would not stop imaging at others.
- final stacks could be based on seeing and poor seeing results from one location could be excluded or stacked appropriately - and would not ruin the result.

and then there is the problem of the voluntary acceptance of some form of external organisation by a group of people who really do this as an enjoyable hobby where they are able to express individual skills. effectively turning it into a part time unpaid job where they are just part of the crowd might not appeal to many, so that aspect would need to be worked around.

but I think it is still worth thinking about.