Starship Asterisk*

my attention when looking for the supernova, spotted something else?

Hello:

The difference you have noted with the other stellar object is due to variances in the atmosphere when each of the two images were taken and the methods used to process each picture. This, in addition to other less noticeable differences, is an artifact that becomes apparent when comparing astronomical images of the same object taken under different observing conditions.

Thank you very much for reviewing my project and commenting. I appreciate it (a lot!)

In [url=http://antwrp.gsfc.nasa.gov/apod/ap050719.html]APOD comment[/url] RJN wrote:... nearby supernova are rare and important because they frequently become bright enough to be studied by many telescopes and are near enough for their (former) host star and immediate surroundings to be spatially resolved.

So, where (or when) one can take a look at "spatially resolved" picture?

jgabany,
How does one weed out "variances in the atmosphere"? I'm curious that there haven't been more 'false alarms' as far as supernovae, etc.

The discussion points to the location on the right of the pictures, while the first forum post points to the one below galactic center. Which is the true supernova?

I was curious what the time span between "before" and "after"

So, how do I find info so I don't think something is something it's not?

Indigo_Sunrise wrote:jgabany,
How does one weed out "variances in the atmosphere"? I'm curious that there haven't been more 'false alarms' as far as supernovae, etc.

Hello:

Variances in the atmosphere is a reference "seeing" conditions that affects all astronomical images taken from here on the ground.

An excellent explanation of "seeing" is available at the following URL. Please be sure to also read the section, near the bottom of the page, titled "Overcoming Atmospheric Seeing":

http://en.wikipedia.org/wiki/Astronomical_seeing

The two side by side images used to create this photograph were taken seven months apart, from the same location, but under different seeing conditions. The image on the right taken at the beginning of the year, for example, had slightly better seeing conditions. This resulted in the stars appearing to be smaller.

Thad wrote:The discussion points to the location on the right of the pictures, while the first forum post points to the one below galactic center. Which is the true supernova?

Hi:

The supernova is the star that is visible near the center of the image on the right, immediately below the galaxy's center.

I also suspect that due to the size and brightness of the 'pseudo-nova' in the original image, that it is a foreground star (in our galaxy), and not something in M51. This make it much more susceptible to transient atmospheric effects, and rules it out as a supernova candidate.

kochevnik wrote:I was curious what the time span between "before" and "after"

Hi:

The image on the left (the before image) was taken at the beginning of this year over a period of several days. The image on the right (the after image) was taken over a period of several days between July 1-7, shortly after the supernova discovery was announced.

Both images were taken from the same location.

mwhidden wrote:I also suspect that due to the size and brightness of the 'pseudo-nova' in the original image, that it is a foreground star (in our galaxy), and not something in M51. This make it much more susceptible to transient atmospheric effects, and rules it out as a supernova candidate.

Hi:

Actually, the star to the right of the galaxy's center is located in the galaxy. I have an image, taken by the Hubble Telescope's keen eye, that shows this star with a much clearer view thanks to the absence of any seeing conditions.

This image was taken before the discovery of the supernova and was recently released to mark Hubble's 15th Anniversary.

http://www.cosmotography.com/images/m51 ... ubble.html

makc wrote:

In [url=http://antwrp.gsfc.nasa.gov/apod/ap050719.html]APOD comment[/url] RJN wrote:... nearby supernova are rare and important because they frequently become bright enough to be studied by many telescopes and are near enough for their (former) host star and immediate surroundings to be spatially resolved.

So, where (or when) one can take a look at "spatially resolved" picture?

Hi:

This is a great question- one that I asked myself shortly after acquiring my image of the supernova. Luckily, the Hubble Space Telescope team recently released a new anniversary image of M51, taken prior to the discovery of the supernova.

A version is available that displays the image at full resolution. The details are incredible! Here's a link to a portion of that larger image. This portion is centered on the area where the supernova is located. One of the stars in this closeup from Hubble was the progenitor of the supernova.

http://www.cosmotography.com/images/m51 ... ubble.html

jgabany,
Thanks for the link, it's very informative. Answered a lot of my Q's. Thanks again!

jgabany wrote:Hello:

The difference you have noted with the other stellar object is due to variances in the atmosphere when each of the two images were taken and the methods used to process each picture. This, in addition to other less noticeable differences, is an artifact that becomes apparent when comparing astronomical images of the same object taken under different observing conditions.

Thank you very much for reviewing my project and commenting. I appreciate it (a lot!)

I appreciate your response and everyone else who has added to such a exciting discussion, but i find that none of the other stars/objects in the surrounding area; appear to be showing the same variances, as evident by this one object.

So, i put forward the same question?, is this a new supernova or can we rule this out? also who would i contact to clarify this?.

A previous poster indicated what I also was led to initially believe - that the webpage indicated that the supernova was to the right of the galaxy center instead of below the galaxy center. Here is the sentence that led us astray:

"It is visible on the right of the above before and after images of the picturesque spiral."

Of course, what was meant was that the supernova is visible on the right image of the before and after images, not that the supernova is visible on the right side of each image. What added to the confusion is the aberation that could be mistaken for a supernova by the novice stsargazer, which aberation is indeed to the right of the galaxy center as noted at the beginning of this thread.

The english language is such a hairy thing.

Just for curiosity sake, I wanted to see what else stood out so I used a photoshop trick to digitally find the differences between the two pictures. It looks like this:

http://planthetrip.com/difference.jpg

The bubble looking things are caused by differences in aspect ratios between the two pictures (gets worse on the lower part of the picture). The supernova stands out quite well. The aberation caused by poor conditions is nearly as significant as the supernova using this method. Everything else disappears.

The_Agent wrote:

jgabany wrote:Hello:

The difference you have noted with the other stellar object is due to variances in the atmosphere when each of the two images were taken and the methods used to process each picture. This, in addition to other less noticeable differences, is an artifact that becomes apparent when comparing astronomical images of the same object taken under different observing conditions.

Thank you very much for reviewing my project and commenting. I appreciate it (a lot!)

I appreciate your response and everyone else who has added to such a exciting discussion, but i find that none of the other stars/objects in the surrounding area; appear to be showing the same variances, as evident by this one object.

So, i put forward the same question?, is this a new supernova or can we rule this out? also who would i contact to clarify this?.

Hi:

The pursuit of truth requires vigor and I respect your efforts to seek it out!

I have taken the time to re-inspect my images. First, let me explain how these photographs were created.

Because of the extreme faintness of astronomical objects, and this galaxy is extremely faint, a single snapshot is insufficient to capture enough light. Therefore, many exposures, each of several minutes duration with the camera shutter left open, are required. To produce both the left and right portions of this image, I had to take dozens of 15 minute images. Each image is called a sub-exposure. Most were to capture the light intensity, others added color.

So many exposures were required, that they could not be taken in a single night, so they were taken over a period of several days. During each sub-exposure, the conditions of the atmosphere through which the telescope viewed changed. Since several nights were required, that also introduced changes due to ongoing weather patterns.

Once all the sub's were acquired, they were combined using commercially available image processing programs specialized for astronomical photos and Photoshop, one of the most powerful image processing programs available on the market and widely used by photographers and the publishing industry. Combining sub exposures results in a single image, comprised of the sum of each sub-exposure. My combining method also applies an algorithm that attempts to weed out things that are unique to one or limited to a few of the sub-exposures so that the final single image is the mean of all the sub's.

If enough of the sub-exposures have a similar unique characteristic, then this will be reflected in the final master image.

This technique is not remarkable. It is used by both professional and amateur astronomical imagers. Similar techniques also are used to produce the wonderful images of the Hubble Space Telescope.

Therefore, late this morning, I reviewed the sub-exposures used to create the before and after sides of this image to see if there was anything that would indicate a change other than the presence of the supernova. I could not find anything. I did notice that several sub-exposures taken for the supernova image had stars that were a bit larger. This is due to poorer seeing conditions. There were enough sub-exposures in this set to affect the final master image and produce the appearance that the star to the right of the galaxy's center had grown (brighter).

I must also admit that the methods I use to process images continually evolves. Therefore, the right hand image showing the supernova was processed slightly differently than the earlier, left side image- taken at the beginning of this year. This is unavoidable.

Combined, both these differences result in the change you notice to the star right of the galaxy center in the right side image.

Dozens of professional astronomers have reviewed this image and commented by email. All have concurred with this explanation.

However, should this not convince you, the latest information regarding supernova discoveries can be found at the following URL. It is a clearing house to inform the astronomical community about these fascinating events:

http://www.supernovae.net/supernova.html


Additionally, all supernovas are reported through CBAT. Here's their web page:

http://cfa-www.harvard.edu/iau/cbat.html

Either of these web-sites can lead you to the leading experts on supernovas and this one in particular.

I hope this helps and I appreciate your interest in this project (a lot!)

ipaqgeek wrote:A previous poster indicated what I also was led to initially believe - that the webpage indicated that the supernova was to the right of the galaxy center instead of below the galaxy center. Here is the sentence that led us astray:

"It is visible on the right of the above before and after images of the picturesque spiral."

Of course, what was meant was that the supernova is visible on the right image of the before and after images, not that the supernova is visible on the right side of each image. What added to the confusion is the aberation that could be mistaken for a supernova by the novice stsargazer, which aberation is indeed to the right of the galaxy center as noted at the beginning of this thread.

The english language is such a hairy thing.

Hi:

I am very sorry for the confusion.

ipaqgeek wrote:Just for curiosity sake, I wanted to see what else stood out so I used a photoshop trick to digitally find the differences between the two pictures. It looks like this:

http://planthetrip.com/difference.jpg

The bubble looking things are caused by differences in aspect ratios between the two pictures (gets worse on the lower part of the picture). The supernova stands out quite well. The aberation caused by poor conditions is nearly as significant as the supernova using this method. Everything else disappears.

Hi:

That is cool! Thanks for posting it.

Fortunately, most of us have a natural built-in image comparison mechanism. Instead of reaching for Photoshop (or The Gimp), try this: fuse the two images by crossing or diverging your eyes, as you would to view a stereogram. Once fused, significant differences literally jump out of the page.
One of many advantages is that insignificant differences due to aspect ratios and systemmatic across-the-whole-frame effects are ignored automatically. (After all, your brain is able to cope with the different optical properties of each of your eyes effortlessly.)

thanks to everyone who has provided information regarding this matter, it has been most exciting.

The_Agent

You know, there were a lot of threads duplicating this one. Since there were more than one post in each, I will simply leave links here.

http://asterisk.apod.com/viewtopic.php?t=603
http://asterisk.apod.com/viewtopic.php?t=606
http://asterisk.apod.com/viewtopic.php?t=630 (new)

I think I will proceed this way from now on, becasue it takes time to quote everybody, and that time doesn't pay me back anything but censorship accusations

So let it be a lesson: take a minute to find proper thread, otherwise you might never receive a reply.