その他惑星 ALPO-Japan Latest

Hunting the lower orbit H2A rockets Image 2008/06/25(UT)

Ralf Vandebergh
R.Vandebergh

Ralf Vandebergh(250mm Newton)
From most for the observers visible rocket stages,I pointed out that
the Japanese H-2A rockets may be the most interesting,as their dimensions 
are a good 13.5m x 2.5m.General problem with rocket bodies is that
the lower orbit bodies are often small and not very interesting with
dimensions of around 2.5m x 2.5m,making them appear as just disks,even
with hightest possible resolution.There are some rocket stages with
around 8 meter in length(Titan upper stages)and some with 10 meter,but
these are in relatively high orbit(mostly round 800-900km)Most H-2A bodies
are in high orbit as well,but 2 interesting exceptions are the rockets
which carried the IGS-3A and IGS-4 spy-satellites.These move in orbits
considerably below 500km,making them more interesting to hunt.(the spinning 
fairings E and F of the IGS-4 rocket can be seen often as flashing satellites).

Attached is the final observation,I managed on June 25,after several nights of
overcomming problems.An important problem for such lower orbit objects is
there relative fast dimming when they depart in the Earths shadow.
Most passes of either IGS-3R or-4R couldn't that way be tracked until culmination
when the distance is closest.Exactly what I expected though,the elongated
shape is clearly visible in all frames,even when we see the body probably
slant side-on.

For observers interested in the difficulty of imaging these objects,
I have created the following simulation.It shows different stages of
unsharpness,caused by effects of either bad seeing or limited resolution
of the optical system.The file on top shows a rocket body with dimensions
of a H-2A as seen from an optimal angle,showing full length.The lower file
presents a situation as we see it slant side-on,showing not the full
length in proportion to its width.the simulation at left shows the dimensions
of the body like we would see it in perfect resolution,without any optical
or atmospheric limits.Only a slight blurring caused by atmospheric or optical
effects is necessary to see the situation presented in the mid.This can be
compared to what a good telescope approximately shows in good seeing.
In the worst case,you will only see a narrow elliptical or even round image
as presented in the righter example.Note that this most rocket bodies are even
shorter in proportion.


Simulation:


 From most for the observers visible rocket stages,I pointed out that
  the Japanese H-2A rockets may be the most interesting,as their dimensions 
  are a good 13.5m x 2.5m.General problem with rocket bodies is that
  the lower orbit bodies are often small and not very interesting with
  dimensions of around 2.5m x 2.5m,making them appear as just disks,even
  with highest possible resolution.There are some rocket stages with
  around 8 meter in length(Titan upper stages)and some with 10 meter,but
  these are in relatively high orbit(mostly round 800-900km)Most H-2A bodies
  are in high orbit as well,but 2 interesting exceptions are the rockets
  which carried the IGS-3A and IGS-4 spy-satellites.These move in orbits
  considerably below 500km,making them more interesting to hunt.(the spinning 
  fairings E and F of the IGS-4 rocket can be seen often as flashing satellites).

  Attached is the final observation,I managed on June 25,after several nights of
  overcomming problems.An important problem for such lower orbit objects is
  their relative fast dimming when they depart in the Earths shadow.
  Most passes of either IGS-3R or-4R couldn't that way be tracked until culmination
  when the distance is closest.Exactly what I expected though,the elongated
  shape is clearly visible in all frames,even when we see the body probably
  slant side-on.

  For observers interested in the difficulty of imaging these objects,
  I have created the following simulation.It shows different stages of
  unsharpness,caused by effects of either bad seeing or limited resolution
  of the optical system.The file on top shows a rocket body with dimensions
  of a H-2A as seen from an optimal angle,showing full length.The lower file
  presents a situation as we see it slant side-on,showing not the full
  length in proportion to its width.the simulation at left shows the dimensions
  of the body like we would see it in perfect resolution,without any optical
  or atmospheric limits.Only a slight blurring caused by atmospheric or optical
  effects is necessary to see the situation presented in the mid.This can be
  compared to what a good telescope approximately shows in good seeing.
  In the worst case,you will only see a narrow elliptical or even round image
  as presented in the righter example.Note that most rocket bodies are even
  shorter in proportion.


    From most for the observers visible rocket stages,I pointed out that
    the Japanese H-2A rockets may be the most interesting,as their dimensions 
    are a good 13.5m x 2.5m.General problem with rocket bodies is that
    the lower orbit bodies are often small and not very interesting with
    dimensions of around 2.5m x 2.5m,making them appear as just disks,even
    with highest possible resolution.There are some rocket stages with
    around 8 meter in length(Titan upper stages)and some with 10 meter,but
    these are in relatively high orbit(mostly round 800-900km)Most H-2A bodies
    are in high orbit as well,but 2 interesting exceptions are the rockets
    which carried the IGS-3A and IGS-4 spy-satellites.These move in orbits
    considerably below 500km,making them more interesting to hunt.(the spinning 
    fairings E and F of the IGS-4 rocket can be seen often as flashing satellites).

    Attached is the final observation,I managed on June 25,after several nights of
    overcomming problems.An important problem for such lower orbit objects is
    their relative fast dimming when they depart in the Earths shadow.
    Most passes of either IGS-3R or-4R couldn't that way be tracked until culmination
    when the distance is closest.Exactly what I expected though,the elongated
    shape is clearly visible in all frames,even when we see the body probably
    slant side-on.

    For observers interested in the difficulty of imaging these objects,
    I have created the following simulation.It shows different stages of
    unsharpness,caused by effects of either bad seeing or limited resolution
    of the optical system.The file on top shows a rocket body with dimensions
    of a H-2A as seen from an optimal angle,showing full length.The lower file
    presents a situation as we see it slant side-on,showing not the full
    length in proportion to its width.the simulation at left shows the dimensions
    of the body like we would see it in perfect resolution,without any optical
    or atmospheric limits.Only a slight blurring caused by atmospheric or optical
    effects is necessary to see the situation presented in the mid.This can be
    compared to what a good telescope approximately shows in good seeing.
    In the worst case,you will only see a narrow elliptical or even round image
    as presented in the righter example.Note that most rocket bodies are even
    shorter in proportion.


In July I hope to take a good shot of the new Japanese laboratory at ISS.

[バンディバ:オランダ]
[Ralf Vandebergh:Neighbourhood of Maastricht Netherlands]

ALPO-Japan Latest Oplanets Section
2008/06/29 [Ganymede]
2008/06/21 [SeaSat]