"Strange" lights on Ceres

[rseferino]

What is the exposure time in the photographs that sends Dawn? With long exposure time with higher albedo are very bright, even brilliant.

 

[statickid]

sure, but exposure time doesn't really matter without knowing the sensitivity of the ccd, f-ratio, aperture...ect/probe instrument equivalents.

in general, probes tend to use fairly long exposure times compared to hand-held photography.

I think we can all rest assured that when they want a clear picture of the bright spots, they will adjust the equipment accordingly

 

[dman]

Ice volcano would require some heat source to create the liquid water to be forced upward toward the surface where it flash freeze into ice.

Question is what is heat source....??

Sulfur volcano on IO and the ice volcano on Saturn moons are powered by the tidal
forces from Jupiter/Saturn.

Ceres is too far from Jupiter for the tidal forces

Radioactive minerals (Uranium/Thorium/Potassium) perhaps........

 

[SolarLiner]

solar?

Yes? :lol:

That does look strange. Surely it will be studied when the probe start orbiting it.

 

[martins]

That's no moon ... even if it has gathered quite a bit of dust by now.

 

[fsci123]

This image gives a little more perspective on the great white dots of Ceres.

 

[Unstung]

What is the exposure time in the photographs that sends Dawn? With long exposure time with higher albedo are very bright, even brilliant.

At Vesta, the camera typically had exposure times of 1/100 second through the clear filter. Fun fact, Dawn's Framing Camera can achieve exposure times of 1/1000 second to 3.5 hours and the lens is a 150mm telephoto with an aperture of f/7.9. The albedo of the white spots is at least 40% compared to about 10% for Ceres.

Vesta has an albedo of 42%, it's brighter than Ceres. Vesta is also closer to the sun with a semimajor axis of 2.4 AU compared to 2.8 AU for Ceres. With this information, it should be possible to calculate Dawn's exposure time at Ceres.

The solar intensity is about 75% at Ceres compared to Vesta. Vesta is also 4x more reflective. So exposure times should be about 5.5x longer at Ceres. If my logic is correct, 1/100 * 5.5 means that Dawn would need an exposure time of 1/20 to 1/10 second at Ceres through the clear filter.

If Dawn was shooting through the color filters, the exposures would need to be about 10 to 100x longer. So around 1 to 10 seconds.

 

[Andy44]

If Dawn was shooting through the color filters, the exposures would need to be about 10 to 100x longer. So around 1 to 10 seconds.

With exposure times that long, I wonder what kind of motion blur you're going to get, depending on the distance and relative motion between the vehicle and Ceres.

 

[steph]

Thinking maybe some sort of momentum wheels and a good image stabilizer on the cam?
Even by how a normal camera reacts to the slightest movement in long exposure photos, I guess it's a big problem, especially if using very long exposures. But maybe as it closes in on the planet, exposure times drop a bit.