Talk:Hubble Deep Field

Image

There is now a new Hubble ULTRA Deep Field image available (TODAY 3/9/04). I would love to see that entered into wikipedia, but I do not have the technical expertise to do the edit myself. Any volunteers? - FrankH 3/9/2004

Contradiction?

The Hubble Deep Field page says that the HDF image is the deepest image of space taken in visible wave lengths, but the Hubble Ultra Deep Field page says the HUDF page is the deepest image taken in visible wave lenghts... Wouldn't it be logical to conclude the the Hubble Ultra-Deep Field image is the deeper image of the two? --5ptcalvinist 17:18, 14 October 2006 (UTC)

It says that the HUDF is 11.2 square arcminutes and the HDF is 144 arcseconds across, which equates to a maximum of 5.76 square arc minutes. I doubt we did a tinier slice of sky in the 90's than the 2000's and some change is needed to clear it up. I'll look around for a scholarly citation of the actual arc lengths of sky each respective deep field surveyed and give some citation. --150.216.128.186 17:47, 14 November 2007 (UTC)

http://hubblesite.org/newscenter/archive/releases/2004/07/ So hubble says HUDF is 12.7 millionth of the sky. The sky contains 466560000 square arcminutes (360 degrees*60minutes longitude * 360degrees*60minutes) so one 12700000 of that would be 36 square arc minutes.

http://www.cosmiclight.com/imagegalleries/deepfield.htm this site says deep field is 15 arcminutes across, 225 square arc minutes at most... but a little less from not being a perfect square.

http://hubblesite.org/newscenter/archive/releases/1998/41/image/c/ This is hubble's site saying 15 arc minutes across as well. So I think it's safe for me to go ahead and change the data of both --150.216.128.186 18:15, 14 November 2007 (UTC)

I think this is a misunderstanding. The hubblesite.org page cited explains:

"The carefully selected HDF-S target field in the constellation Tucana, as imaged by the 4-meter Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile. The field of view is 15 arc minutes, approximately half the angular diameter of the full moon. The respective fields of Hubble's three instruments are outlined."

so the Cerro Tololo image shows the targeted field, which has a FOV of 15 arc minutes, and as shown in the image the FOV of HDF-S is only a fraction of that, most probably 144 arc seconds (2.4 arc minutes) as stated in the article earlier. Please note also, that the specs of the WFPC2^[1] used for the imaging of HDF-S state a FOV of 2.7 arc minutes. Please check and consider reentering the original value for the FOV. --Sir48 (talk) 19:32, 16 December 2007 (UTC)

There has been no response to this, so let me add, that the source: [2] states the size of the field as 5.7 arcminutes² for both the HDF and the HDF-S. Please note, that this corresponds to 2.4 arcminutes across.--Sir48 (talk) 18:16, 20 January 2008 (UTC)

Some queries

'A special Institute Advisory Committee'—can 'special' be removed or qualified?

It was described as such in Williams et al (1996) - I'm guessing they mean an advisory committee which was specially convened rather than a standing committee, although I couldn't say for sure - will try to find out. Worldtraveller 11:42, 30 August 2005 (UTC)

Please check my change: 'the areas of sky towards the poles of Hubble's orbit that are not occulted by the orbit of the Earth or its Moon'—the role of 'orbit' was unclear.

Tried to clarify this in the text, and Image:Hubble Deep Field observing geometry.png in the Observations section also illustrates how the CVZs come about. Worldtraveller 11:42, 30 August 2005 (UTC)

congrats!

Well done indeed. Tony 05:11, 4 September 2005 (UTC)

Data processing, some queries

How many pixels does the HDF contain ? The statement "final pixel sizes of 0.03985 arcseconds" and an image size of 144 arcseconds implies that it is 3613.5 pixels wide. 0.03985 arcseconds is a very odd number; there is almost certainly some rounding or uncertainty which makes this inappropriately precise, especially in contrast to the ".09 arcseconds" for the unprocessed pixels. What is the bit depth of the image ? It seems odd that an article about a digital image doesn't say how big it is. Great article though. PeterGrecian 12:57, 13 October 2005 (UTC)

The original science frames each contain four blocks of 800x800 pixels = 2.56×10⁶, but the drizzling resampling does give that very exact pixel size, smaller than the original pixel size due to the image reconstruction from sub-pixel pointing changes. Don't know about bit depth, each monochrome image has an 8 bit greyscale, but I don't know enough about the terminology to know whether that means the total bit depth is 256⁴. Will do some reading and add what I find out to the article. Worldtraveller 08:57, 14 October 2005 (UTC)

The HDFN images I have are all in FITS format, and measure in COUNTS. That is, there is no bit depth per se, but each pixel is assigned an integer corresponding to the number of photons detected. On top of that, there are considerable blank areas around the perimeter of the image, which is an artifact of the optics. The normally quoted figure for WFPC2 images is 2 megapixels, although the drizzeling probably increased this. Incidentally, should we link to the actual data files themselves, or is that something only of interest to us astronomers? Modest Genius 17:07, 18 February 2006 (UTC)

Scott Wyffels???

I find it unlikely that any one astronomer could single-handedly repair a satellite in orbit without any mention appearing online about his acheivements. Accordingly I've removed the daft reference to "Scott Wyffel" repairing the hubble optics. If this is in error, please provide a reference here. Mat-C 22:08, 13 October 2005 (UTC)

Even if that could be referenced, that information would belong in the Hubble space telescope article and not this one Majts 22:40, 13 October 2005 (UTC)

To the Stars Manifest Destiny

The United States needs the technology to get to the stars in a reasonable time. Reasonable is any star in the Milky Way galaxy (our galaxy) within an hour. The technology for space travel for life support systems is not mature enough and needs a new technology advance for deep space travel lasting years making it very difficult for any person to currently travel beyond the Earth's Moon.

The United States needs a ways and means to get to the stars. However it may be, a new and better understanding of the Universe, new and better understanding of life support systems for space travel, new and better ways of travel (airpower, by example, was a unexpected and very successful), new and better power sources including power sources for space travel, and new and better propulsion for space travel needs to be made. We need something better than chemical, nuclear, or ion rockets (all three have been examined) to get us past the light barrier problem to first take the Milky Way galaxy for humanity and the United States, and second take the Universe as it is ours. The galaxy called the Milky Way galaxy belongs to the United States and then humanity, so it is ours to take and use to our prosperity with full authority over the galaxy given to the United States and humanity. The rest of the Universe is ours for the taking for the United States and then humanity to use for our prosperity with full authority over the Universe given to the United States and humanity. Manifest destiny is there, all the people of the United States and the rest of humanity shall take advantage of any ways and means to improve technology; all of the people of the United States and the rest of humanity shall take advantage of any opportunity go out into our galaxy initially starting from our solar system the United States has called the Sol system, and then go to the rest of the Universe and take it, since it is ours and ours by authority. Every day in science fiction entertainment the capability for people to travel and prosper across the galaxy and the Universe is imagined. We have the ability to imagine it, now we must do it and go to the stars for our purposes and claim what belongs to us as the United States and rest of humanity.

Even though your ideas are intriguing, this page is just for talking about the article. Majts 23:08, 15 October 2005 (UTC)

What has the United States got to do with anything? 203.218.87.40 12:37, 16 December 2005 (UTC)

Very unclear

"galaxies, some of which are among the youngest and most distant known." If they are the most distant, they must be the oldest, not the youngest, that's very basic cosmology. If the intended meaning is "observed as they were at a very early stage of development" or "observed as the were at a very young age of the universe", please say so. Thanks. 84.141.103.132 11:34, 19 August 2007 (UTC)

External links

Should we have the following two external links in the article? (They were in it until I removed them a few minutes ago)

• ESA information page about the HDF
• The most important image ever taken (short educational film on the Hubble Deep Field)

The first links to an ESA page summarizing all of the deep fields, but they're now covered in more depth here. The second is to a video by an amateur astronomer. Personally I don't think either are needed. Mike Peel (talk) 13:39, 27 December 2008 (UTC)

It seems reasonable to remove them. Check around 1:30 into the video. — Twas Now ( talk • contribs • e-mail ) 00:43, 28 December 2008 (UTC)