Search found 87 matches

by Dan Cordell
Tue Jul 12, 2005 5:42 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Slightly Off-Topic: the 25" telescope
Replies: 1
Views: 5308

Slightly Off-Topic: the 25" telescope

Lenses, pasted from the email I got: TELE VUE EYEPIECES & LASER COLLIMATORS We are often asked "What eyepieces should I use"? Tele Vue Nagler and Panoptic eyepieces are simply the best for fast reflecting telescopes like the Obsession. As an OEM (Original Equipment Manufacturer) we off...
by Dan Cordell
Mon Jun 06, 2005 1:33 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: CMBR Dipole
Replies: 30
Views: 18038

Sorry, I don't have anything on what you asked for nor am I too familiar with it. However I thought it best to at least explain how it's possible.
by Dan Cordell
Fri Jun 03, 2005 7:29 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: CMBR Dipole
Replies: 30
Views: 18038

Ok this is taken directly from the excellent An Introduction to Modern Cosmology by Andrew Liddle: "...inflation is defined as a period in the evolution of the Universe during which the scale factor was accelerating: INFLATION <==> ä(t) > 0 Typically this corresponds to a very rapid expansion o...
by Dan Cordell
Thu Jun 02, 2005 3:58 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Stranger streak - straight lines on satellites of Saturn
Replies: 11
Views: 7565

Looks like big, long scars on the surface of the moons to me. Other than that I'm not really sure. I'll point RJN toward this thread tomorrow at lunch, perhaps he can shed some light on this.
by Dan Cordell
Thu Jun 02, 2005 3:55 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: CMBR Dipole
Replies: 30
Views: 18038

Re: Another Question

Does that mean that everything including the earth is moving away from one point in space or everything is moving at an equal rate away from eachother? Sorta your second idea but not quite. On a macroscopic level, everything in the universe is moving away from everything else. However on a galactic...
by Dan Cordell
Thu Jun 02, 2005 3:53 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: CMBR Dipole
Replies: 30
Views: 18038

I'll dig up my cosmology textbook and make a more detailed post.

But, in short, yes due to expansion objects can move faster than light. However this only happened during the inflationary period of our universe.
by Dan Cordell
Tue May 17, 2005 1:21 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: CMBR Dipole
Replies: 30
Views: 18038

It would be a mistake to think there is a "center" or a place where there is no dipole, as there most likely is not. Keep in mind that there is "stuff" beyond the CMB, which is at the limit of how far we can see due to the age of the universe (~12-15gigalightyears). Thus differen...
by Dan Cordell
Thu May 12, 2005 5:27 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Siding Spring (SD) CONCAM status
Replies: 22
Views: 16850

Re: Sat 7 May---cam still shows march 13

The Siding Spring camera has been displaying the "temporarily down for maintainence" message for ages now.... and it shows the last capture of the 13 march... any idea on what is going on and how long it will take to fix? Right now all the CONCAM 3's are down to fix some software problems...
by Dan Cordell
Thu May 12, 2005 5:25 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: CMBR Dipole
Replies: 30
Views: 18038

We're moving so fast due to large-scale cosmic expansion. As groups of galaxies collapse, the groups themselves are still moving rather quickly in reference to the rest of the universe.
by Dan Cordell
Thu May 05, 2005 6:27 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Poll on APOD?
Replies: 7
Views: 5545

I had trouble deciding between the top three, but I chose solar system objects simply because I love picture of Mars.
by Dan Cordell
Thu May 05, 2005 6:26 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Saturn's cloud bands
Replies: 4
Views: 5232

It's an enhanced-color image, so probably not, although it's possible. I'd have take a look at the non-enhanced version to draw any sort of conclusion.
by Dan Cordell
Thu May 05, 2005 6:23 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Saturn's cloud bands
Replies: 4
Views: 5232

BMAONE23 wrote:It may be just an optical illusion caused by the ring shadow.
Correct.
by Dan Cordell
Thu Apr 21, 2005 12:16 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Flash at MK
Replies: 7
Views: 7891

We've done just that... there's not much chance it's a cosmic ray hit, the point-spread function is just too star-like. Cosmic ray hits have much sharper edges.
by Dan Cordell
Tue Apr 19, 2005 2:32 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Flash at MK
Replies: 7
Views: 7891

Personally I think it's a head-on meteor, but it's still under investigation.
by Dan Cordell
Mon Apr 18, 2005 4:22 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Flash at MK
Replies: 7
Views: 7891

We're looking into it.

Not sure what it is yet, it might be a burst star or something but we're really not sure yet.
by Dan Cordell
Sun Apr 03, 2005 7:12 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: What makes nebulae red?
Replies: 6
Views: 9016

Note there is also a third group, absorption.

In the image posted above:
Image
The dark areas are masses of dust absorbing light.
by Dan Cordell
Sun Apr 03, 2005 7:11 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Siding Spring Black Blob
Replies: 4
Views: 6000

I'm inclined to agree with the moth theory.
by Dan Cordell
Sun Mar 13, 2005 7:23 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Dew Control on Transparent Dome
Replies: 1
Views: 3815

We usually recommend that domes are not used with the CONCAMs, because we have as of yet (that I am aware of) been unable to prevent dew forming on the domes.
by Dan Cordell
Sun Mar 13, 2005 7:21 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Sporadic meteors
Replies: 8
Views: 7406

Re: CI Sporadic Meteor

Noctuas_Universe wrote:This looks like it may be a sporadic meteor....
[img-]http://nightskylive.net/ci/ci050312/ci0 ... 12120a.jpg[/img]
That very well might be.

Kinda hard to tell since it's not a great image but it looks like a meteor.
by Dan Cordell
Sun Mar 13, 2005 7:20 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Unidentified streak on NSL image
Replies: 1
Views: 3961

Probably a satellite or possibly an airplane.

Not all satellites are listed on Heavens Above, and that streak looks very much like a satellite.

However it is a rather long streak so it might just be an airplane.
by Dan Cordell
Tue Mar 01, 2005 3:53 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Mauna Kea (MK) CONCAM status
Replies: 38
Views: 28583

Re: CONCAM Status

khagol wrote:Moon at 73.8% fades away most of the stars limiting the visible magnitude to 3.0. The screen seems to be oval in shape. Don't know why.
Looks like a combination of the moon and possibly dew on the lens.

It should clear up when the moon goes away.
by Dan Cordell
Tue Mar 01, 2005 3:52 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: star leaving galaxy
Replies: 5
Views: 5417

Stars are routinely ejected from our galaxy (and all other galaxies) due to gravitational slingshot effects.

The more times a star orbits its host galaxy, the more erratic its orbit becomes, and some stars end up being ejected.
by Dan Cordell
Tue Mar 01, 2005 3:51 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Sun Spectrum (27/02/2005) - RJN ?
Replies: 2
Views: 3992

I'll figure it out later today. I should be able to calculate an approximate number.
by Dan Cordell
Wed Feb 09, 2005 5:50 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Which satellite is this?
Replies: 193
Views: 195713

Re: A question for Mr. Cordell...

My main question is: What constitutes a conspiracy theory? It is difficult to define. While this is not the place to discuss such a thing, I will say that, for the purposes of how I moderate things, a "conspiracy theory" is going to generally be any wild claim that presents either no proo...
by Dan Cordell
Wed Feb 09, 2005 3:22 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Voynich manuscript discussion: 2005 January 22 - NEW TOPIC
Replies: 35
Views: 31859

Voynich manuscript discussion: 2005 January 22 - NEW TOPIC

In this thread discussion on the Voynich manuscript may continue. Please observe the forum rules while posting. What is the strange astronomical Voynich manuscript? This manuscript was discussed on the 2002 August 26 APOD and the 2005 January 22 APOD respectively found here: http://antwrp.gsfc.nasa....