Comet Lulin video

Comet Lulin graced North American skies in the winter of 2009. Fortunately, the closest approach was during the Winter Star Party in February. Comet Lulin proved to be much more interesting than I had previously been inclined to believe. The comet brightened dramatically over the week of February 24 and sported a beautiful ion blue tail. I slewed to the comet with the scope and began my initial exposures and was surprised by the views on the LCD screen. The blue ion tail was crumpled and extending away from the comet nucleus in a beautiful fashion. So this object became the main target object during the 2-4 a.m. imaging window on most nights.

This video is a time-lapse sequence of 9 3.5 minute exposures taken on February 21, 2009 from the Winter Star Party in the Florida Keys. Each image was optimized in Adobe Light Room and the video was compiled with Windows Movie Maker. The video loops several times so that the viewer can pick up the subtle changes in the blue ion tail. Geostationary satellites are common in this area of sky and pass through the field as through they were moving airplanes, but in fact it is the telescope and camera moving to compensate for the Earth's rotation.

You can download a wmv file from my Vimeo site which is a much larger and higher quality presentation.

Comet Lulin

Comet Lulin graced North American skies in the winter of 2009. Fortunately, the closest approach was during the Winter Star Party in February. Comet Lulin proved to be much more interesting than I had previously been inclined to believe. The comet brightened dramatically over the week of February 24 and sported a beautiful ion blue tail. I slewed to the comet with the scope and began my initial exposures and was surprised by the views on the LCD screen. The blue ion tail was crumpled and extending away from the comet nucleus in a beautiful fashion. So this object became the main target object during the 2-4 a.m. imaging window on most nights. More information on the comet can be found by clicking on the title of the blog at NASA's website. You may also click on the image for a larger presentation.

This particular image was taken during the 2 a.m. hour of February 21, 2009. It is a composite of 9 exposures of 3.5 minutes each at ISO 1600 on the Canon 450D through the TMB 92SS refractor. Comet imaging poses additional challenges when the comet is fast moving such as Comet Lulin. The imager must combine several short exposures for the background sky as well as for the comet. So two iterations of stacking are needed since the comet is moving relative to the fixed star field. This is quite challenging in processing, but we do have techniques that allow us to accomplish this with nice results.

All of the processing was accomplished with Adobe Light Room 2.0 and PS3 with some Noise Ninja for noise reduction. Images were aligned and stacked with Images Plus. A Sigma median combine was used on the comet nucleus to achieve a reduction in star trails and isolate the comet nucleus and tail in the combination. The total exposure time is approximately 30 minutes. I am also going to present a movie which depicts the comet moving relative to the star field. I hope you enjoy the image and please check out the NASA link for more information on the comet.

What size should web image be?

With the introduction of the "netbooks" and smart phones, I was curious to revisit the most common screen resolutions currently being recorded by web browsers and those data mining groups that do such things. One report I found lists 36% of surfers are using 1024x768 in January 2009, down a bit from 2008. Where is the move? To higher resolutions. The report only lists resolutions higher than 1024x768 and that percentage is 57%. But are we possibly seeing a move back to smaller screens? Do the data mining groups account for web browsing on smart phones? I know that I look at images on an iPhone, Macbook Pro, and a 24" Apple Cinema display. I have looked at the netbooks and can't say that they catch my fancy at the present time. A quick look at one of the HP netbooks (N270) shows it sporting a 1024x576 screen resolution. Will netbooks find a strong foothold in the marketplace? Another consideration for how large of an image to post to the web is how much of an image do you want your audience to view. I personally always want the entire image showing with no zoom effect. Why? I take great care on the entire composition of the image and want the image always viewed in its entirety. To me, posting a larger than 1024 image on the web would be like Ansel Adams only allowing you to view one of his prints from a distance of 6" away. There is a proper viewing distance for all images and one should consider that even for web presentations. Now I do understand that some browsers can re-size the image to fit the window, but I really don't want to rely on that effect 100% of the time. So at the present time I have chosen to post images with a long side of 1000 pixels with some modifications for portrait orientation. To me that hits the sweet spot of fitting nearly every screen resolution out there (93%)and presenting the image in its entirety to the viewer. So that is my take on proper image size in June 2009. I hope to revisit the issue as time passes to see where screen resolutions may go into the future.

An Orion experiment

Now this is simply crazy. I had some Orion Nebula data from WSP that I basically captured on a whim. So in reviewing the data in Light Room I wanted to see just what the new techniques could bring out of this data. Let me state up front that this is simply not enough data to get what I eventually want out of this image. But, it is a great exercise in seeing exactly what the technique can do with very limited amounts of data. I selected 11 of the best frames captured on the Canon 450D and TMB 92SS combination. I optimized each image in LR 2.2 and exported to tiff. I used Images Plus and Sigma clip for the alignment and combination and then processed as normal in PS3. Now one other major error on my part, not that the clouds at WSP had anything to do with it, was that I failed to capture shorter exposures to compensate for the over-exposed core of M42. So I did plug in some old data from other instruments for the core of M42 in this image. There is a fair amount of noise reduction via Noise Ninja applied to the shadow areas. So for only 40 minutes of data with a lowly DSLR, I am very happy with the potential to really capture the Orion Nebula area as I hope next year. My expectations are that two hours of data at ISO 800 will be wonderful data to work with and accomplish my imaging goals. Please drop me a line if you have any questions or comments and I hope you enjoy the image.

Rosette Nebula from Winter Star Party

The Rosette Nebula (please click on image for larger presentation) is approximately 5500 light years from Earth and spans over 1 degree in the sky which is more than 5 full moons. The nebula itself has different NGC designations including 2223, 2238, 2239, and 2246. The open star cluster in the middle of the nebula is designated as NGC 2244. The nebula is located in the constellation Monoceros.

This image is another in my continuing experimentation with using Adobe Light Room and Photoshop exclusively in post-processing. I actually selected only 11 of the best images I had for this object taken during the Winter Star Party in February 2009. The 11 images were each 3.5 minutes in exposure at ISO 1600 for a total exposure time of 40 minutes. ISO 1600 was used as a compromise to maximize exposure time due to the sporadic cloudiness that was present. The telescope used was a Tom Back 92mm signature series refractor at approximately f4 and a focal length of about 400mm. The camera used was a modified Canon 450D. So far, I am very happy with the results of the Adobe processing work flow. The only question that I have is how well with this process work on hydrogen alpha images. I hope to do some experimentation with this in the coming weeks. I hope you enjoy the image and please drop me a line if you get a chance.