Pale Blue Dot Question

[Knight of Clear Skies]

I expect most of you are familiar with the Pale Blue Dot picture, taken from Voyager 1 in 1990. The moon is too small to show up, but what I was wondering is this: if it was visible, how far away from the Earth would it appear in that image? I tried to estimate it based on the fact that the Earth is 0.12 pixels across; the answer I got is 3-4 pixels away at apogee. However, I'm not confident this is correct, is the 0.12 pixel figure I used based on area or diameter? Is there another way of working this out please?

If my figure is correct, it gives an interesting perspective on the limits of manned exploration - a mere 4 pixels or so.

[cp255]

Using a bit of trig from a distance of 6 billion kilometers the angular separation between the earth and the moon is 0.0036 degrees. I don't know about the camera or optics on voyager but that is bigger than an arc sec so many armature telescopes could separate the two from that distance.

[Knight of Clear Skies]

That's for that. I found some sources describing the Voyager optics, the narrow angle camera used for the Pale Blue Dot has a field of view of less than 1/2°. The field of view of a single pixel is about 0.00053 degrees, which gives a maximum Earth-Moon distance of 6.7 pixels.

[Matt Scunthorpe]

That is an amazing photograph really. Everything to do with the voyager probes just amazes me.

[Knight of Clear Skies]

That is an amazing photograph really.

It's my favourite astronomical image, despite not being much to actually look at - the bands across it are artefacts caused by sunlight reflected from the camera lens.

[kirkster501]

Its quite beautiful in one way, but quite scary in another, I mean, that spacecraft is looking at our tiny *home* as a spec in the immensity of space. i think that's the sentiment that Carl Sagan tried - and succeeded brilliantly - in getting across.