Astroblog

Sunday, June 17, 2012

Still More NEO 2012 LZ1


NEO 2012 LZ1 at 7:53 UT, nearly 9 hours after closest approach. 5x120 second Images taken with iTelescope T5. The images were stretched in FITSliberator, then stacked in ImageJ and a Max intensity Z project made, then despeckeled.	NEO 2012 LZ1 two hours later, zipping through star clouds. Processing as for the earlier image.

These look to be my final images of the NEO 2012 LZ1, taken with the New Mexico T5 instrument nearly 9 and 11 hours after the asteroids closest approach.This is a much narrower FOV instrument that T14 and T16. A big thank you to Jeff Woods of iTelescope who adjusted the travel of T5 so we could take earlier images.

I'll now do some astrometry on these images to help refine the asteroids orbit.

There is a nice article at Universe Today which features one of my images, and here's a nice animation by Peter Lake using iTelescope T11. My other shots and animations of this asteroid are here, here and here.

My animation here

Labels: animation, asteroids, FITSLiberator, imageJ, iTelescope

# posted by Ian Musgrave @ 7:28 pm 0 comments

Saturday, June 16, 2012

Near Earth Asteroid 2012 LZ1 10:10 UT, 15 June 2012

2012 LZ1 imaged with iTelescope T14 on June 15, 2012 10:10 UT. The image is a stack of 7x120 second exposures, stretched in FITS Liberator and stacked with ImageJ. Click to embiggen (it's not as big as my previous image, but worth it)

NEO 2012 LZ1 was imaged here at 10:10 UT, nearly 11 hours after its closest approach of 13-14 lunar-distances (that's the distance between the Earth and the Moon, 0.036 AU) on June 14 23:10 UT. The asteroid is just zipping past the faint globular cluster PAL 11 when this series of images were taken.

I was trying for a longer series of images to make a really cool animation, but the oncoming twilight put paid to that.

Here's my animation.

Labels: animation, asteroids, FITSLiberator, imageJ, iTelescope, NEO

# posted by Ian Musgrave @ 9:26 am 0 comments

Friday, June 15, 2012

Near Earth Asteroid 2012 LZ1 1:45 UT, 15 June 2012

2012 LZ1 imaged with iTelescope T16 on June 15, 2012. The image is a stack of 5x120 second exposures, stretched in FITS Liberator and stacked with ImageJ. Click to embiggen (it's big but worth it)

2012 LZ1 was imaged at 1:45 UT after its closest approach of 13-14 lunar-distances (that's the distance between the Earth and the Moon, 0.036 AU) on June 14 23:10 UT. The asteroid had just zipped past Barnard's Galaxy and the Little Gem Nebula when this series of images were taken.

Here's my animation.

Labels: asteroids, astrophotography, FITSLiberator, imageJ, iTelescope, NEO

# posted by Ian Musgrave @ 1:50 pm 0 comments

Monday, June 11, 2012

Farewell Beautiful Comet C/2009 P1 Garradd

Comet C/2009 P1 Garradd imaged with iTelescope T14 on June 9. The image is a stack of 5x120 second exposures, stretched in FITS Liberator and stacked with ImageJ then despeckled.Click to embiggen

Comet Garradd, after delighting us for months with it's beautiful double tails, is now sinking towards the horizon and is below the range of the iTelescopes travel. This image was taken before astronomical twilight, but soon it will be too low even for that.

While never getting brighter than magnitude 6, Comet C/2009 P1 Garradd went through some beautiful regions, and its ever changing aspect was really delightful.

The comet will return in October at magnitude 12.4, but if you wish to remember this delightful little comet, you can browse the images I have here.

Labels: astrophotography, C/2009 P1 Garradd, comet, comets, FITSLiberator, imageJ, iTelescope

# posted by Ian Musgrave @ 2:15 pm 0 comments

Saturday, February 19, 2011

The Tarantula Nebula (and FITS Liberator)

Left Image: Tarantula Nebula imaged using GRAS 14 instrument at Global Rent a Scope with 3 x 120 sec Red filter FITS images, 3 x 120 sec Green filter FITS images and 3 x 120 sec Blue filter FITS images. Each series of individual filter runs stacked using in Image J using Z projection of maximum intensity, then stacked and assembled into a RGB composite using ImageJ. Right Image: Single 120 sec RGB filter FITS images stretched using FITS liberator and ArcSinh(x) stretch. Stretched files stacked and assembled into a RGB composite using ImageJ. These are smaller frames of the nebula cropped form the whole image. You really, really need to click on these images and embiggen them (and compare to this APOD image which is 31 hours of exposure).

As people know, I'm a fan of low cost astroimaging. For GRAS remote telescope images, my workhorse is the freeware ImageJ. This works pretty well, especially for stacking and aligning images. However, astronomical images can have a large dynamic range from the very faint to the almost overexposed. How to bring out faint structure without turning the bright sections into glaring blobs.

This is where FITSLiberator comes in, it's a freeware app (also there are photoshop plugins), which makes it very easy to adjust the dynamic range of your images for later assembly in other image processing programs (You can do something similar in ImageJ but it's not as easy). As you can see above, with FITS liberator I was able to adjust the dynamic range of my Tarantula Nebula images to almost match the brightness of the multi-stacked images, without the central regions getting overexposed or the background being over-coloured.

Obviously my Tarantula Nebula won't win the astrophotography contest, and I still have a lot to learn, but I'm going to get a lot more out of my images now.

The FITS Liberator website comes with links to a whole range of Hubble raw images, and step by step instructions so you can create your own version of classic Hubble pictures. The PDF user manual is here.