<p>You could google "Maccone focal" for the most ardent proponent of this project (and I love it too, the most furthest meaningful mission possible within a life time, and what a view!) But others may have variations of his idea. One should be a bit wary about enthusiasts.</p>

<p>Here's a link to some article where Maccone is cited to explain that planets need 6-17 greater distance to become gravitaional lenses than the Sun needs. Neptune surprisingly happens to be next best after Jupiter: <a href="http://www.centauri-dreams.org/?p=15290" rel="nofollow">http://www.centauri-dreams.org/?p=15290</a></p>

<p>Paper (might not be available for free):
Maccone, “A New Belt Beyond Kuiper’s: A Belt of Focal Spheres Between 550 and 17,000 AU for SETI and Science.”</p>

<p>Here are slides from one of his presentations where he explains his calculations more generally, but I think only for the Sun:
<a href="http://www.spaceroutes.com/astrocon/AstroconVTalks/Maccone-AstroconV.pdf" rel="nofollow">http://www.spaceroutes.com/astrocon/AstroconVTalks/Maccone-AstroconV.pdf</a></p>

<p><strong>And then there's micro gravity lenses! A very different thing in terms of our observation.</strong> I now think my answer above misunderstood what you were looking for.</p>

CC BY-SA 3.0
2017-11-13T07:06:24.587Z
Is this an answer to another question?
J. Chomel
CC BY-SA 3.0
2014-07-21T22:23:36.943Z
2014-07-21T22:23:36.943Z
LocalFluff
<p>Is it ever possible for starlight to be distorted in a noticeable way from something as small as a planet? </p>

<p>I'm guessing that the chances of this working are better on a dense terrestrial planet than a gas giant.</p>

<p>How do you calculate this?</p>

<p>Edit: I was unclear, sorry. I'm specifically thinking about lensing that would distort the shape of a star, not just move its position.</p>

<gravity><light><gravitational-lensing>
How massive does a planet need to be to create gravitational lensing?
brentonstrine
# How massive does a planet need to be to create gravitational lensing?

(Asked by: username_0 on 2014-07-21)

Is it ever possible for starlight to be distorted in a noticeable way from something as small as a planet?

I'm guessing that the chances of this working are better on a dense terrestrial planet than a gas giant.

How do you calculate this?

Edit: I was unclear, sorry. I'm specifically thinking about lensing that would distort the shape of a star, not just move its position.

**Tags:** gravity, light, gravitational-lensing

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## 1 answers

### Answer by username_1 on 2014-07-21. Score: 3

You could google "Maccone focal" for the most ardent proponent of this project (and I love it too, the most furthest meaningful mission possible within a life time, and what a view!) But others may have variations of his idea. One should be a bit wary about enthusiasts.

Here's a link to some article where Maccone is cited to explain that planets need 6-17 greater distance to become gravitaional lenses than the Sun needs. Neptune surprisingly happens to be next best after Jupiter: <http://www.centauri-dreams.org/?p=15290>

Paper (might not be available for free):
Maccone, “A New Belt Beyond Kuiper’s: A Belt of Focal Spheres Between 550 and 17,000 AU for SETI and Science.”

Here are slides from one of his presentations where he explains his calculations more generally, but I think only for the Sun:
<http://www.spaceroutes.com/astrocon/AstroconVTalks/Maccone-AstroconV.pdf>

**And then there's micro gravity lenses! A very different thing in terms of our observation.** I now think my answer above misunderstood what you were looking for.

> **Comments:**
> **username_2**: Is this an answer to another question?  

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