Re: Starlink-2 color

From: George Roberts via Seesat-l <seesat-l_at_satobs.org>
Date: Sat, 18 Jan 2020 08:24:52 -0500
Air scatters blue light and lets red light through thus causing 
sunsets.  If the satellites are low in the sky they can be red just like 
the sun, moon, etc. when approaching the horizon.  This may be less 
noticable on stars as they may be too dim for our eyes to register this 
(our color perception gets worse as things are less bright).

This can also happen when there are a lot of particulates in the air, 
for example from volcanic eruptions, smoke from australia, or air pollution.

But also if satellites are "skirting the shadow" there is a similar 
effect where from their perspective they see the sun setting.  They can 
be high in the night sky but close to the earth's shadow.  This happens 
just before they wink out into the earth's shadow, just after they 
appear out of the earth's shadow, or even as Brad says, they may pass 
along close to the earth's shadow.

- George


On 1/17/20 11:13 PM, Brad Young via Seesat-l wrote:
> I have noticed that on several of them when they are "skirting the shadow", similar to the ISS. Normally they seem to appear white; i.e. it is phase angle effect.
>
> Brad Young PE

> On Friday, January 17, 2020, 08:45:04 PM CST, Bob King via Seesat-l <seesat-l_at_satobs.org> wrote:
>
> I saw a pass of about 40 Starlink-2 satellites on the evening of Jan. 16
> from Duluth, Minn. Through binoculars they appeared orangish, not white.
> Were my eyes playing tricks or is this their true color.

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Received on Sat Jan 18 2020 - 07:25:42 UTC

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