||Last revised: 07/24/06
6/03/01: Created. 2/28/02: Minor
Asked Questions for the Pluto Imaging Challenge
Why is this
a "Challenge"? Pluto should be easily imaged with a modern amateur CCD
camera, in every type of light pollution, with amateur scopes down to 3" or
The impetus for the Challenge is the
lack of small-scope Pluto images on the web. With all the deep magnitude
claims made by modern amateur imagers, I thought that strange.
"Challenge" as used here can be taken as "contest" or "experiment".
Before the Pluto Challenge, my search of the
web turned up Pluto images made with 8"-10" (200-250-mm) telescopes
-- nothing smaller. So the 3" (80-mm) refractor CCD image submitted
during the year 2000 Challenge experimentally proves the viability of CCDs and 3" telescopes. Now, let's find out how much smaller a scope and CCD will image the planet.
Now, consider the contest element of the
Challenge. Would we ever cancel the Olympic Marathon under the pretext that
"it has been done before." Like the marathon, the point here is to
see who can do it the "best" within the rules. The "best"
for this Challenge is to capture Pluto in the smallest aperture
Finally, the sole purpose of all amateur
activity is the reward of accomplishing a goal. Think about it: any decent
observatory can best anything an amateur can do! Amateurs are rethreading the
same ground when they image the moon and planets, before moving onto deep sky
imaging -- yet it doesn't stop them. To quote a Pluto Challenge imager:
"The experience of imaging Pluto was one of the most rewarding events
I've had in astronomy." From that imager's location, there is a constant
artificial twilight caused by New York City and the sprawling suburbs. This
was the last place I'd expect an entry from. Now, that entry will inspire those
in like locations to make images they thought were not available to them.
This particular Challenge will not end until
the days comes when Pluto can be imaged with a "pinhole" camera in a
single short exposure; at that point, I would agree, that there is no real
Challenge. Note that this Challenge is also for film-based images -- I
couldn't find one amateur image of Pluto made on film -- I'd like to see what
film could do.
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the true challenge be to see who could visually detect Pluto in the smallest
I don't see the conceptual difference between a
visual challenge and an imaging challenge. If it is a valid contest to "find
the smallest telescope that a particular person can visually spot Pluto
given the viewing condition, then why can't we continue down the aperture
scale using an imaging instrument other than the eye? At least the imaging
offers proof. If someone posts "I see Pluto in a 50-mm" what can we
One of the points of the Pluto Imaging
Challenge is to demonstrate how far astro imaging has come in a century. I've
been reading these past few years that, with the advent of cheap CCD and
computer processing, amateur equipment can do "real" astronomy in
specific areas. A small aperture challenge will serve to see how small the
equipment "envelope" can be pushed. For instance, I get the asteroid
and lunar occultation alerts by e-mail. The sponsoring organizations desire observers spread out across designated zones to record the event. But, the
predicted occultation path often shifts, as orbital refinements are made up to
the time of the event. As a result, the organizers don't always get the
coverage they'd like. I think the ability for the observers to travel to
observing zones is inversely proportional to the bulk and weight of their
equipment. So, these small scope "Challenges" will give observers
some insight into imaging situations where a small scope will do fine for the
Rebuttal: Sky and Telescope
magazine held a real challenge where an amateur imaged down to 22-23
magnitudes in light pollution.
It's great that some amateur, somewhere with
the right equipment can image down to "pro" magnitudes, but what
makes this Pluto Challenges interesting is the constraint (small aperture) and
being pleasantly surprised at how the participants overcome them. I can't see
how the "Magnitude Challenge" is any more real than the "Pluto
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If I have a
big telescope, why should I stop it down to enter the Challenge? This is like
having a deep sky photo contest with the worst performing film!
While watching the Olympic swim races, I
noticed they gave the medal to the competitor that finished in the smallest
amount of time. "Shortest time" is the "Challenge" the
athletes must meet in most of those competitions. My Pluto Imaging Challenge
is analogous to this, in requiring that Pluto be imaged with the
"smallest aperture" telescope. Of course, there are challenges that
go the other way time-wise: for the "longest time" one can sit in a
tree, ride a roller coaster, or stay awake, etc. Setting up the Pluto
Challenge to image the planet in the "largest aperture" scope would
not entice many amateurs to enter.
The nature of the Challenge would point toward
using the finest films/CCD and lens possible, due to the small aperture
constraint. Only those with the luxury of large aperture can overcome the
deficit of employ the "worst" film.
Rebuttal: The shortest
swimming times means maximum, and the swimmers did not have to swim with an
arm tied behind their backs.
The swimmers are constrained by the type
of swimming style for that event -- that is the challenge of the various
races. The "freestyle" is the fastest form of swimming but is only
employed in a few races. Auto racing and sailing are also competitions where
the rules limit equipment size for various classes of events. It is not
unusual at all to have constraints of this sort in competition.
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highest quality CCD coupled to the weakest telescope? Larger telescopes cost
more money but so do high-end CCD cameras. So what is the difference? The fact
is that aperture is paramount and should be fully utilized.
I'm not challenging scopes here,
but modern CCD/film cameras and post-processing equipment/techniques. Large
scopes and film imaged Pluto 7-decades ago, and we know they still can. As CCDs
have become cheaper, they have moved from large scopes to smaller scopes. The
Pluto Challenge's sample image section has Pluto images from 8"-10"
scopes, to demonstrate what that class of scope is capable of. I'm interested
in the next step: when CCDs become more common on sub-8" scopes.
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fair to stop-down a big telescope in order to enter the Challenge?
There may be one advantage of stopping down a big
scope to smaller aperture -- as opposed to just using a small scope of that
aperture: resolving power.
Say you wanted to stop down a 14"
telescope to 4". Starting with a 14" diameter mask: you could cutout
4-circles, with 2" diameters, at 90-deg intervals, along the extreme edges of the mask. Voila!
You now have the light grasp of a full 4", with the resolving power of a
14"! This would make Pluto easier to resolve if it were near another
star. Anyone stopping down this way should note that down when submitting
entries to the Challenge. I'd like to know if it makes a difference.
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