Download Bölcsföldi József

1
The principle of the solar telescope
The Italian Claudio Maccone has already planned a telescope which is based on the
Sun as a gravitational lens (Figure 1: FOCAL). The present essay contains the principle of a
solar telescope (SOLIS) which is geocentric and focusable.
The SOLIS solar telescope consists of a terrestrial microwave transceiver with a
preparatory-processing computer subsystem, the aerials of the microwave transceiver on the
South and North Pole, a microwave transceiver on a satellite revolving synchronously with
the Earth, a relay subsystem on the orbiting satellites and the Sun as a gravitational lens
(Figures 2 and 3).
Relay subsystem (ring-aerial) on satellites
Let us set up relays as satellites revolving on the same orbit and equidistant from each
other in a plane which is perpendicular to the Sun-Earth axis (Figure 3). The minimal radius
of the relays’ common orbit is rmin=R(d-1)/d, where R is the radius of the Sun, d=KF1
minimum 550 AU. In the case of R=696000 km and d=550 AU, rmin=694735 km. The radius
of the relays’ common orbit is „r” and rmin<r<R. It must be studied in details and distincly
what value the ’r’ common orbit radius should take within this interval and what size a relay
should be physically. The relays are not connected with each other, so every relay is a
satellite. Every relay rotates around its own axis, which is perpendicular to its orbital plane,
and the time of rotation is equal to the time of orbiting around the Earth, so they can form an
integral ring-aerial. There can be another solution with several relays on a semicircularshaped satellite. The more relays the system consists of, the more effective it is, so the number
of the relays has to be increased to the upper limit of the possibilities. The relay subsystem
can easily be repaired. If, for example, a meteor „knocks out” a relay, the system can still
work with the rest n-1 relays and the lost relay is relatively easy to replace. As the satellites in
a certain relay subsystem hold their orbital plane, two objects can be observed during a
calendar year. If the objects are situated behind each other on the optical axis, we can observe
two or more of them. We have to choose the orbital plane of the relay subsystem, that the
telescope could watch as many objects as possible in the two points of time of the year.
Objects in other directions can be observed with the relay subsystem which faces there. In
order to avoid collisions a minimal difference must be left in the orbital radiuses of the
different relay subsystems. We can expose with every relay subsystem twice a calendar year.
Relay subsystem on a single ring in the Sun-Earth librational point
The relays can be installed on a connected chain-ring which can practically be situated
in L1 librational point, perpendicular to the eclipse so that the ring could always face the Sun
and B satellite,namely, its rotation axis must coincide with the Sun-Earth axis. The
disadvantage of this solution is that, for example, a meteor-shower can do a lot of harm in this
hard ring-aerial and this damage is more difficult to repair than it is if we have stand-alone
satellites. On the other hand, the great advantage of a hard ring-aerial in the L1 librational
point is that this system can be operated continually, not only twice a year, because the ringaerial heads for the Sun at every moment of time. In the simplest version of the system the
relays of the ring-aerial can be replaced with rotatable planes which can reflect microwave
rays.
The operation of the solar telescope
During transmission the aerial on the currant terrestrial pole transmits the microwave
signal to B satellite revolving synchronously with the Earth,which forwards it to all the relays
of the ring-aerial simultaneously (Figure 2). The „s” rays go along the generating lines of a
cone’s surface (envelope) between the B transceiver and Ai relays. The relays of the ring-
2
aerial transmit the signal in the direction of the Sun’s edge. The b rays go along the generating
lines of a truncated cone’s, the b’ rays go along those of a cylinder’s surface and the a’ rays
go along those of a cone’s surface. In the upper position of the nodding relay-aerial the rays
are transmitted a bit farther from the edge of the Sun and they are made parallel with the
optical axis by the solar lens (Figure 2: p-s-b-b’ ray-courses). In the lower position of the
nodding relay-aerial the rays are transmitted to the edge of the Sun and they are focused on F 1
point by the solar lens (Figure 2: p-s-a-a’ ray-courses). (As the relay orbits around the Earth,
there is a different solar edge-point opposite the relay at every moment of time.) The Sun
focuses the rays coming from the ring-aerial, so it magnifies the signal significantly. The gain
is great, the intensity of the signal increases remarkably because of the focusing. If we operate
the aerials of the relays between their two extreme positions (we „open them out”)
continuously and simultaneously, the F focal point will cover the focal line from F1 to the
infinite distant point, so we can focus on an optional target (farther than F1). As the Earth
orbits around the Sun, the focal line will scan the ecliptic plane during a year. The exceptions
are the inner points of the circle with KF1 radius, however, there is nothing to observe here,
because the nearest star is 4 ligh-years from the Sun.
The SOLIS-system can be used as a transmitter and a receiver alike. While receiving,
it focuses the rays starting from F point on B point (Figure 2: a’-a-s-p or b’-b-s-p ray courses,
etc.). In the case of the satellite-version, the aerials of the relay subsystem have to be able to
nod between the upper and lower positions on both side of the orbital plane, because they
have to nod in the opposite direction in half a year.
Figure 1: Maccone’s FOCAL telescope
K:
Rn :
KF1:
F1:
t:
a-a’:
F:
p:
the centre of the Sun
the radius of the Sun
minimum 550 AU
the nearest focal point of the solar lens
the optical axis
rays arriving at the Sun’s edge, photosphere in parallel with the optical axis, focused
on F1 by the solar lens
the current focus with the microwave transceiver as an artificial satellit revolving
around the Sun at an orbit with KF radius
the F satellite’s orbit around the Sun
3
Figure 2: the SOLIS solar telescope
T:
K:
R:
B:
the centre of the Earth
the centre of the Sun
the radius of the Sun
the microwave transceiver (satellite around the Sun) revolving synchronously with the
Earth
É:
the current terrestrial pole (North or South) with the aerial of the terrestrial microwave
transceiver on it. The northern aerial works in summer, the southern one in winter. The
changing of the aerials is at the vernal and autumnal equinox.
A:
the ring-aerial (relay subsystem)
Ai:
an element of the A relay subsystem (i=1,2,…n)
a-a’: the rays grazing the edge of the Sun, which are focused on F1 by the solar lens.
b-b’: the rays passing a bit farther from the edge of the Sun, which are made parallel with
the optical axis by the solar lens.
F1:
the nearest focus of the solar lens (KF1 minimum 550 AU)
F:
the current focus
F1-F…:the focal line
p:
microwave rays between the current pole of the Earth and the B microwave transceiver
s:
microwave rays between the B transceiver and the relay aerials
4
Figure 3: the ring-aerial (relay subsystem)
a/ from the direction
which is perpendicular to its orbital plane
b/ from the direction of its orbital plane
with the B satellite
T: the centre of the Earth
A: the orbit of the ring-aerial (relay-subsystem)
Ai: an element of the A ring-aerial, i.e. a „nodding” relay aerial
Fi: the rotation axis of the Ai nodding relay aerial
Af: the „upper” position of the Ai rodding relay aerial
Aa: the „lower” position of the Ai nodding relay aerial
s: microwave rays between the B microwave transceiver and the relay aerials
5
Figure 4:
The FOCAL system and the SOLIS system
As the Earth orbits around the Sun, the focal line scans the ecliptic plane during a year.When
the focal line approaches an object we want to observe and we know its distance, we focus the
system on the object by the turning of the relay aerials. If we do not know the distance of the
object, we have to search for it in the whole angle-domain (between the „upper”and „lower”
positions).
The relay subsystem can be set up with fixed aerials instead of the nodding ones. In
this case , the fixed aerials are practical to direct on p-s-b-b’ ray courses (Figure 2).
The SOLIS-system can be operated in the visible light domain if we use plane-mirrors
instead of the microwave relays and a light-source or a photon-detector instead of the
microwave transciever.
18th January, 2003
Bölcsföldi József
physicist
Gábor Dénes College
Hungary
Claudio Maccone:
Almár Iván:
THE SUN AS A GRAVITATIONAL LENS:
PROPOSED SPACE MISSIONS
(IPI Press, Colorado Springs, Colorado, 1999)
A SETI SZÉPSÉGE.
Kutatás Földön kívüli civilizációk után.
(Vince Kiadó, 1999)