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The Hubble scope had to spend many hours to find this target, basically taking "before" and "after" images to find changes: dots moving against the background s

by tabtab 8y ago

The Hubble scope had to spend many hours to find this target, basically taking "before" and "after" images to find changes: dots moving against the background stars seen via subtracting the pixels values of before and after. Once they find rough candidates, they take more pics to narrow down their orbits. Any new targets will be further away and thus probably dimmer to Hubble than Thule. Also, New Horizons only has so much fuel to change direction. Its room to operate is a very narrow cone, kind of like a long lopsided straw. It will be challenging finding new objects to visit. I wish they didn't have to depend on Hubble so much.

accnumnplus1 8y ago
Time to send a telescope into distant orbit?
- tabtab 8y ago
  You mean send a Telescope to the Kuiper Belt? I believe resources would be better spent sending a probe to one or few of the bigger Kuiper Belt objects, such as Eris and Sedna. New Horizon's "target problem" is rather specific to that probe. Pluto was its primary mission. Other bodies were considered a bonus, and the probe doesn't have enough fuel to target the bigger (known) objects. Perhaps that was a mistake; but many of these were discovered after the probe was budgeted.
- lmilcin 8y ago
  There would be no reason to do that. Putting telescope into distant orbit will not make it easier to observe anything except for the thing you are orbiting. The problem with kuiper belt objects is not that they are far away but that there is not much light reflected from them. The belt is huge, and if you put say Hubble in there you have no guarantee you would see anything. Putting space observatory is costly project, money are better spent by putting it in Earth orbit as it is much cheaper to put it there and possible to service while in orbit. If history teaches us anything it is that being able to service the telescope in orbit is very important for getting as much bang for the buck as possible.
  - tabtab 8y ago
    Re: There would be no reason to do that. In general, probably; BUT I'd qualify that to say it depends on the mission. As I mentioned nearby, visiting the bigger known Kuiper objects seems a bigger priority than finding new smaller ones (and finding them is better done near Earth). However, if something unusual were found at Thule such that a mission to study lots of smaller Kuiper objects were deemed warranted (like being made of gold or clear signs of life), then a probe with a relatively big telescope could be sent into the Kuiper Belt to hunt such objects in its approximate vicinity. That may still be cheaper than building larger-than-Hubble scopes near Earth to guide New-Horizons-like probes. But the math on that may depend how sparse smaller Kuiper objects are.
    - dogma1138 8y ago
      That probe would be worse than a Hubble like telescope at an earth or near SOL orbit. Firstly due to their relative small size their angular size wouldn’t make much difference at those distances. Secondly you essentially limiting your search envelope to a small section of the belt as most of it would be further away form the telescope in the belt than from earth. And lastly you can launch a much bigger telescope to a near earth orbit than to the belt and you can also get the data much more rapidly so you can actually search for candidates in hours not in months and readjust the telescope as you see fit.
      - peo939 8y ago
        Is there any reason to think of an array of telescopes, like the VLA? Like, multiple smaller telescopes scattered at large distances? Or is that too difficult to coordinate?
        lmilcin 8y ago
        This has a lot of sense and shouldn't be too difficult to coordinate. This has already been tested by LISA Pathfinder (https://en.wikipedia.org/wiki/LISA_Pathfinder https://en.wikipedia.org/wiki/LISA_Pathfinder) and proven to be feasible. Still, the reson here to get something far away from Earth as a general is not to have closer observation point but to have large distance between array nodes.
- dogma1138 8y ago
  Considering the size of the Kuiper belt it wouldn’t make much difference if you observe if form earth orbit or from within an orbit in the belt.
InclinedPlane 8y ago
Interestingly, we'll solve this problem just about when it won't matter anymore for New Horizons. In the 2020s the Large Synoptic Survey Telescope will come online, which will (among other things) catalog tens of thousands of KBOs/TNOs.
- jcims 8y ago
  Isn't TESS kind of built to do the same thing? Wide field analysis? Presumably it's looking for dimming rather than relative motion, but that seems more like a software issue than a hardware one?
  - InclinedPlane 8y ago
    Not exactly. TESS monitors bright objects. It uses actually quite small telescopes (only 10cm aperture or so), but the it has 4 such telescopes and uses very wide fields of view to monitor a large number of stars continuously. To see KBOs/TNOs requires more light gathering power.
    - jcims 8y ago
      Ah! OK, makes sense. Thank you!

by tabtab 8y ago

accnumnplus1 8y ago

Time to send a telescope into distant orbit?

tabtab 8y ago
You mean send a Telescope to the Kuiper Belt? I believe resources would be better spent sending a probe to one or few of the bigger Kuiper Belt objects, such as Eris and Sedna. New Horizon's "target problem" is rather specific to that probe. Pluto was its primary mission. Other bodies were considered a bonus, and the probe doesn't have enough fuel to target the bigger (known) objects. Perhaps that was a mistake; but many of these were discovered after the probe was budgeted.
lmilcin 8y ago
There would be no reason to do that. Putting telescope into distant orbit will not make it easier to observe anything except for the thing you are orbiting. The problem with kuiper belt objects is not that they are far away but that there is not much light reflected from them. The belt is huge, and if you put say Hubble in there you have no guarantee you would see anything. Putting space observatory is costly project, money are better spent by putting it in Earth orbit as it is much cheaper to put it there and possible to service while in orbit. If history teaches us anything it is that being able to service the telescope in orbit is very important for getting as much bang for the buck as possible.
- tabtab 8y ago
  Re: There would be no reason to do that. In general, probably; BUT I'd qualify that to say it depends on the mission. As I mentioned nearby, visiting the bigger known Kuiper objects seems a bigger priority than finding new smaller ones (and finding them is better done near Earth). However, if something unusual were found at Thule such that a mission to study lots of smaller Kuiper objects were deemed warranted (like being made of gold or clear signs of life), then a probe with a relatively big telescope could be sent into the Kuiper Belt to hunt such objects in its approximate vicinity. That may still be cheaper than building larger-than-Hubble scopes near Earth to guide New-Horizons-like probes. But the math on that may depend how sparse smaller Kuiper objects are.
  - dogma1138 8y ago
    That probe would be worse than a Hubble like telescope at an earth or near SOL orbit. Firstly due to their relative small size their angular size wouldn’t make much difference at those distances. Secondly you essentially limiting your search envelope to a small section of the belt as most of it would be further away form the telescope in the belt than from earth. And lastly you can launch a much bigger telescope to a near earth orbit than to the belt and you can also get the data much more rapidly so you can actually search for candidates in hours not in months and readjust the telescope as you see fit.
    - peo939 8y ago
      Is there any reason to think of an array of telescopes, like the VLA? Like, multiple smaller telescopes scattered at large distances? Or is that too difficult to coordinate?
      - lmilcin 8y ago
        This has a lot of sense and shouldn't be too difficult to coordinate. This has already been tested by LISA Pathfinder (https://en.wikipedia.org/wiki/LISA_Pathfinder https://en.wikipedia.org/wiki/LISA_Pathfinder) and proven to be feasible. Still, the reson here to get something far away from Earth as a general is not to have closer observation point but to have large distance between array nodes.
dogma1138 8y ago
Considering the size of the Kuiper belt it wouldn’t make much difference if you observe if form earth orbit or from within an orbit in the belt.

InclinedPlane 8y ago

Interestingly, we'll solve this problem just about when it won't matter anymore for New Horizons. In the 2020s the Large Synoptic Survey Telescope will come online, which will (among other things) catalog tens of thousands of KBOs/TNOs.

jcims 8y ago
Isn't TESS kind of built to do the same thing? Wide field analysis? Presumably it's looking for dimming rather than relative motion, but that seems more like a software issue than a hardware one?
- InclinedPlane 8y ago
  Not exactly. TESS monitors bright objects. It uses actually quite small telescopes (only 10cm aperture or so), but the it has 4 such telescopes and uses very wide fields of view to monitor a large number of stars continuously. To see KBOs/TNOs requires more light gathering power.
  - jcims 8y ago
    Ah! OK, makes sense. Thank you!