Deep Impact / Tempel 1 Observation

57 views
Skip to first unread message

Jeff R. Schroeder

unread,
Jul 4, 2005, 4:59:37 AM7/4/05
to
From Ford observatory in Wrightwood, California. We had a successful view of
the aftermath of the collision with our 18.5" f/7 newtonian under 5.0
magnitude skies. The comet was NOT seen before the collision by two
observers using magnifications from 70x to 350x. The sky was perfectly
clear, but we had considerable interference from L.A. cityglow to the
southwest. Two minutes after the predicted impact time, I saw a faint
unstructured spot appear that was about 10 to 15 arc/sec wide. Ten minutes
later, a starlike nucleus could be seen with averted vision at the spot's
center. After another ten minutes, several of us could see the central point
easily with direct vision. The debris cloud brightened a little more by the
end of one hour post impact. Except for the central point, no structure was
seen in the cloud and it appeared symmetric. Assuming that the comet was
just below detection before the impact, I would (roughly) estimate that it
brightened by 2 magnitudes in the first hour that we observed it. After
that, we didn't see any further brightness increase, but it was getting
lower and extinction and brighter light pollution were taking their toll. We
stopped observing just after midnight.

Even though this was about as faint & fuzzy as you can get, seeing it appear
from nowhere as predicted was a real thrill! There was a lot of excitment in
the dome, and a night to be remembered by all.

Jeff Schroeder


Davoud

unread,
Jul 4, 2005, 9:11:45 AM7/4/05
to
Jeff R. Schroeder:

No doubt! This is a very nice report, appreciated (not to say envied)
all the more, I would think, by those of us under the East Coast Haze
and Light Dome. Thanks.

Davoud

--
usenet *at* davidillig dawt com

nytecam

unread,
Jul 4, 2005, 11:02:34 AM7/4/05
to

Well done - nic e report.

Nytecam


--
nytecam

Robert Sheaffer

unread,
Jul 4, 2005, 4:13:36 PM7/4/05
to

I was with the San Diego Astronomy Association, observing from
reasonably dark skies in Tierra Del Sol, CA, about 75 miles east of San
Diego, elevation 3700 ft.

Before impact, I could see Tempel 1 in my 11" Celestron. It looked like
a small fuzzy region, like a galaxy, no detail. You needed averted
vision. Some observers couldn't even see it when it was pointed out to
them. In a 24" Dob, the comet was easy but featureless. The previous
night, it seemed a little brighter. We supposed it was that
"outgassing."

Several minutes after impact, what I observed was similar to what Jeff
describes. At first I seemed to see a small region of turbulence in the
coma (that might or might not have been due to atmospheric effects).
Soon afterward, a small starlike point of light appeared, we all agreed
it hadn't been there before. We then looked in a 22" scope, and the
little "star" was even clearer, inside the comet's thin coma. We agreed
that we were probably seeing the comet's tiny nucleus, that had
brightened.

We strolled up to Catfish Observatory to see comet images that were
being projected on the wall, from a laptop computer. The brightening was
clearly seen in the images, although it was not dramatic. A TV news crew
was there, filming it. Coming back, by then it was about midnight, and I
couldn't see the little "star" any more in the 11". Whether that's
because it has faded, or because it was setting into the haze in the
west, I don't know.

Robert


Jeff R. Schroeder wrote:

> From Ford observatory in Wrightwood, California. We had a successful view of
> the aftermath of the collision with our 18.5" f/7 newtonian under 5.0
> magnitude skies. The comet was NOT seen before the collision by two
> observers using magnifications from 70x to 350x. The sky was perfectly
> clear, but we had considerable interference from L.A. cityglow to the
> southwest. Two minutes after the predicted impact time, I saw a faint
> unstructured spot appear that was about 10 to 15 arc/sec wide. Ten minutes
> later, a starlike nucleus could be seen with averted vision at the spot's
> center. After another ten minutes, several of us could see the central point
> easily with direct vision. The debris cloud brightened a little more by the
> end of one hour post impact. Except for the central point, no structure was
> seen in the cloud and it appeared symmetric. Assuming that the comet was
> just below detection before the impact, I would (roughly) estimate that it
> brightened by 2 magnitudes in the first hour that we observed it. After
> that, we didn't see any further brightness increase, but it was getting
> lower and extinction and brighter light pollution were taking their toll.

--
Robert Sheaffer - User name "Roberto" at debunker-dot-com
Skeptical to the Max!
Visit the Debunker's Domain - http://www.debunker.com
Resources Debunking All Manner of Bogus Claims
Also: Skepticism / Astronomy / Opera / more

fredf...@spamcop.net

unread,
Jul 4, 2005, 7:19:29 PM7/4/05
to

Robert Sheaffer wrote:
> ...


> At first I seemed to see a small region of turbulence in the
> coma (that might or might not have been due to atmospheric effects).
> Soon afterward, a small starlike point of light appeared, we all agreed
> it hadn't been there before. We then looked in a 22" scope, and the
> little "star" was even clearer, inside the comet's thin coma. We agreed
> that we were probably seeing the comet's tiny nucleus, that had
> brightened.
>

Isn't the term nucleus still used to refer to the solid part of the
comet? It seems unlikely that the nucleus would brighten (how could
it?) rather one would suppose that the innermost part of the coma,
surrounding the nucleus had brightened.

--

FF

Greg Crinklaw

unread,
Jul 4, 2005, 7:38:48 PM7/4/05
to

There is some historical confusion regarding the term "nucleus." It
definitely refers to the actual comet body, but it has also been used in
the past to describe the bright inner coma. Today, many people use the
term "pseudo-nucleus" to refer to the latter, but context usually tells
which is which anyhow.

Clear skies,
Greg


--
Greg Crinklaw
Astronomical Software Developer
Cloudcroft, New Mexico, USA (33N, 106W, 2700m)

SkyTools: http://www.skyhound.com/cs.html
Observing: http://www.skyhound.com/sh/skyhound.html
Comets: http://www.skyhound.com/sh/comets.html

To reply have a physician remove your spleen

David Nakamoto

unread,
Jul 5, 2005, 4:38:23 AM7/5/05
to
Ahem ! I don't mind if people mention my name on the Internet Jeff, and as we
both know, I was one of the two observers, you being the other one, in the dome
that night monitoring the show's progress.

I personally thought there was a faint smudge at the comet's indicated position,
but I couldn't hold the image even with averted vision, but got about three
detections in the same spot and nothing else anywhere else across a few minutes
observing. No way was this an easy object in an 18-inch Newtonian. This made
the direct sighting a half-hour after the impact special. I agree with
everything else Jeff reported.

We thought of imaging the comet before and after, but since it took a lot of
effort to location the right position visually, and the uncertainty about how
much brightening there actually was going to be, we thought it better to go
visual all the way. I don't regret the decision, which I made and recommended
to Jeff Had we tried to switch back and forth between eye and camera, we might
not have seen the show.

--- Dave
--
----------------------------------------------------------------------
Pinprick holes in a colorless sky
Let inspired figures of light pass by
The Mighty Light of ten thousand suns
Challenges infinity, and is soon gone

david.n...@verizon.net


"Jeff R. Schroeder" <1...@earthlink.net> wrote in message
news:ZT6ye.3563$8f7...@newsread1.news.pas.earthlink.net...

shneor

unread,
Jul 5, 2005, 10:20:16 AM7/5/05
to
observed Tempel1 from about 10:40 p,m. PDT in the Sierra foothillls
at an altitude of slightly over 5,000 feet, using my 22" f/4 on an
equatorial platform. Conditions were excellent with very clear dark
skies, and with good seing.


At about 10:54 I began to notice what appeared to be tiny flashes of
light near or in the core of the comet. I was unsure that I was really
seeing these, but another observer confirmed that he saw the flashes
thourgh his telescope as well. A few minutes later, the core brightened

a bit and acquired a persistent "stellar" point.


Clear skies,
Shneor Sherman

niiic...@yahoo.com

unread,
Jul 5, 2005, 1:04:49 PM7/5/05
to
Hi sci.astro.amateur folks:

Here is a question for you: is there any chance at all that the "flash"
from the Deep Impact blast could have been seen with the naked eye? I
was in the central Oregon desert on July 3 with about 20 other people
camping. It was very dark with no artificial lights. As 10:52 pm PST
approached, I pointed everyone towards where Tempel1 was supposed to be
based on web printouts (just above Spica), although I said that at best
we might be able to see a fuzzy spot through high powered binocs after
the impact.

At what we thought was about 10:47 pm, but the relevant watch could
have been inexact, about 10 people saw a brief flash, decaying rapidly
(1 sec) in exactly that region. I were looking at Jupiter with the
binocs at the time, so I didn't see anything. They said it didn't
streak like a shooting star or cruise like a satellite.

I've looked on the web and I haven't seen any reports of naked eye
observation of the flash, or even amateur telescope observation of the
flash. So, was this a mass hallucination, or what? Can anyone think
of an alternative explanation?

Comments appreciated,
Nick

David Nakamoto

unread,
Jul 5, 2005, 3:59:38 PM7/5/05
to
No way. Probably was a meteor heading straight at the observers that burned up
rapidly. Happens more often than a lot of people think, but most don't observe
it since it happens so rapidly. That bright image recorded by spacecraft you
saw on the news and Internet sight was 70 million miles away. No way it could
be seen. NO other reports cite this type of flash, and a lot of people were
looking from various locations. My friend Jeff Schroeder was looking at the
comet with an 18-inch telescope, and saw nothing except a very gradual
brightening, no flash. I would have known if he had; I was in the dome of the
observatory with him and Jeff is not one to be quiet if something like that had
happened.

--- Dave
--
----------------------------------------------------------------------
Pinprick holes in a colorless sky
Let inspired figures of light pass by
The Mighty Light of ten thousand suns
Challenges infinity, and is soon gone

david.n...@verizon.net


<niiic...@yahoo.com> wrote in message
news:1120583089.1...@g44g2000cwa.googlegroups.com...

Michael McCulloch

unread,
Jul 5, 2005, 4:12:40 PM7/5/05
to
On 5 Jul 2005 10:04:49 -0700, niiic...@yahoo.com wrote:

>I've looked on the web and I haven't seen any reports of naked eye
>observation of the flash, or even amateur telescope observation of the
>flash. So, was this a mass hallucination, or what? Can anyone think
>of an alternative explanation?

You probably saw a satellite's or aircraft's Sun glint. Such happen
all the time with the Iridium satellites and probably many others,
especially around sunset and sunrise.

There is no possibility you saw a naked eye flash from the comet.

---
Michael McCulloch

Morris Jones

unread,
Jul 5, 2005, 3:58:04 PM7/5/05
to
niiic...@yahoo.com wrote:
> Here is a question for you: is there any chance at all that the "flash"
> from the Deep Impact blast could have been seen with the naked eye?

It was a struggle to detect with a very large telescope from a dark sky.

> I've looked on the web and I haven't seen any reports of naked eye
> observation of the flash, or even amateur telescope observation of the
> flash.

There are a few dozen reports in this newsgroup that you might have
scanned first.

Mojo
--
Morris Jones
Monrovia, CA
http://www.whiteoaks.com
Old Town Astronomers: http://www.otastro.org

niiic...@yahoo.com

unread,
Jul 5, 2005, 5:09:41 PM7/5/05
to
Thanks for the reply!

Looks like I'll have to go disillusion the troops...

shneor

unread,
Jul 6, 2005, 10:24:13 AM7/6/05
to
Three observers at IHOP saw faint "scintillations" or flashes near the
comet's core mear impact itme time, in three different teleasopes
ranging from 9.25" to 22". We did have near ideal conditions with
excellent transparency, good seeing and dark, moisture-free skies at
5,000 feet. Tempel 1 was faint, but was visible even in 8" SCTs (there
were two of those present).

Did no one else see the flashes?

Clear skies,
Shneor Sherman

Reply all
Reply to author
Forward
0 new messages