Category Archives: Astronomy

Jupiter's Moons '08

After what I think was 2 months of cloud, last night gave me a welcome view of the night sky. Conditions did not look as if they would last, so whilst setting up for a deep sky shot of IC1396 (post to follow) I took a quick snapshot of Jupiter & her Galilean moons. This is what Stellarium predicted that I should see:

image   Click stellarium image for a bigger view…

And below is the quickie 15 second exposure that I took:

Jupiter & moons  Click image for a larger view …

Its always good when predictions are accurate 🙂

Needless to say tonight is back to gloomy cloud but at least I had a planetary view, saw several late meteors from the recent shower & took some deep sky exposures. Hopefully it won’t be 2 months before the next clear night.

 

 

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The Milky Way

When thinking about imaging galaxies it is easy to over look our own galaxy, the Milky Way. Most of the nebulae & star clusters that we image, are part of the Milky Way. Last night offered a brief respite in the summer clouds, which allowed me to take a quick widefield image of our galaxy. Naturally, being within one arm of the galaxy we cannot image the full beauty of its spiral structure; instead what we see is an awe inspiring myriad of stars, banded with dust and peppered by nebulae. This is a sight that all should stand and enjoy, a simple pair of binoculars or a spotting scope will help bring the billions of stars a little closer.

 

Here’s my image from last night, it is centred on Cygnus and shows, amongst others; the N. American, Pelican & Elephant Trunk nebulae:

Milky Way  

Image Details:

Canon 300D modified
Canon 15mm fisheye
ISO800 f3.2
12×1.5mins exposure
UHC Filter
CG5 mount unguided

 

click image for a larger view …

 

The Milky Way is thought to be a barred spiral galaxy (SBbc), containing over 200 billion stars of which our sun is a fairly average individual. The galaxy is 100,000 light years in diameter (1 light year equals 5,878,499,812,499 miles!). To put this in perspective the distance across our solar system from Earth to Pluto is about 0.08 light years; the furthest travelled man made probes are the Voyager spacecraft, they are currently crossing the boundaries between our solar system & interstellar space. When observing from Earth our galactic centre is in the direction of Sagittarius; a clear dark rural sky is best for viewing our galaxy. The galaxy is over 10 billion years old and most likely contains a super massive black hole at its centre. Our solar system is located on the inner edge of the Orion arm of our galaxy.

 

To view a map of the Milky Way & our position click here.

 

If you have Worldwide Telescope, click here for a view similar to part of my image.

 

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Cygnus Loop '08 – Part 1

As part of my summer project (an exploration of Cygnus), I am aiming to create a detailed mosaic of the Cygnus Loop (Veil Nebula). The clouds have not been helpful so far and the forecast for the next few weeks is no better 🙁 However I have had chance to take a test widefield image of the loop region.

This image is intended as the rough outline for my mosaic, the lid of the jigsaw puzzle box, if you like. It consists of 5 x 5 minute sub exposures at ISO 800 & f3.2; so not much integration time but hopefully deep enough.

veil-130608-b1f od2-AL2b   Click image for a larger view …

Anyway, with the lack of available imaging time, I thought I’d share the above image with you. Hopefully something is better than nothing!

Image Data:

Camera
Optics
Focal Length
Focal Ratio
Filtering
ISO
Mount
Autoguiding
Sub-exposures
Total Exposure
Canon 300D (modified)
Canon 70 – 200 L
200mm
f3.2
Astronomik UHC filter
800
CG5 German equatorial
SX Lodestar @ 300mm & PHD
5 x 300s
25mins

 

The whole nebulous area is a remnant of an ancient Supernova that took place some 15 to 20 thousand years ago. It is located only about 2,600 light years away from Earth.

It is catalogued as several separate entries including NGC6960 (the Witch’s Broom or Western Veil) to the right & NGC6992 (the Eastern Veil) to the left. Also included are NGC6995 (below 6992), NGC6974 & 6979 (top middle-left) and Fleming’s Triangular Wisp (top middle-right).

To view this region in Worldwide Telescope follow this link.

Watch this space over the coming months for a more detailed image (oh & please wish me clear skies!).

 

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NGC7000 & the Pelican in H alpha

The North American Nebula (NGC7000) & the neighbouring Pelican Nebula (IC5070) are just 2 of the beautiful cosmic sights to be seen in the constellation of Cygnus, "The Swan". Having undertaken a brief tour of Cygnus last summer, I am encouraged to do so in more depth this year – providing time & weather cooperate for me! To start it off I wanted some Hydrogen alpha (Ha) data for these two beautiful nebulae.

Last week I had the only reasonably clear night for some time and so set out to capture the data in widefield. After waiting for clouds to clear and then sorting out a few initial problems I had little time left for imaging before dawn. I did however manage to capture 7 x 5minute exposures @ f3.2 that I was happy with.

ngc7000-Ha-07062008-a3-2  Click image for a larger view …

Image Data:

Camera
Optics
Focal Length
Focal Ratio
Filtering
ISO
Mount
Autoguiding
Sub-exposures
Total Exposure
Canon 300D (modified)
Canon 70 – 200 L
200mm
f3.2
Astronomik 13nm Ha
800
CG5 German equatorial
SX Lodestar @ 300mm and PHD
7 x 300s
35mins

After processing the Ha data in Iris, I looked out some of my archive RGB data (20D & 100-400 L f5.6 1.5hrs) of the region and set about combining it. The combine process involved adding some of the Ha to the red channel (thus reinforcing the nebula saturation) and then using the Ha as a luminosity layer. Layer opacity was adjusted by eye before a high pass filtering and final output. {This is based on a method by Don Goldman}. A small version of the completed HaRGB image is shown below.

ngc7000-07062008Ha 240807RGB-b2-Edit   Click image for a larger view …

For those of you with Microsoft’s Worldwide Telescope, click here to load and view the region.

About this region:

Cygnus lies right across the Milky Way, it contains both large clouds of ionised hydrogen & dark regions of interstellar dust. These two phenomena combine to give us the beautiful shapes and patterns seen above. The nebulae are thought to be about 1900 light years distant. To read more about these nebulae try the articles on the Wiki or on Britannica.

 

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A more colourful Whirlpool Galaxy photograph

Whilst my previous image of M51 was an improvement upon my original attempt from last summer, I felt that it lacked colour & character; so I’ve had another go at it!

Background Info

As mentioned previously, Messier 51 is located in Canes Venatici and is pictured here with its companion galaxy NGC 5195. The pair are in strong gravitational interaction, hence the disturbances effecting the beautiful ‘whirlpool’ shape. NGC5195 is actually orbiting around M51 in a decaying manner and it is thought that they will collide & merge in another 1 or 2 billion years time.

For the record here again are the galaxy’s vital statistics:

  • Visual Brightness: 8.4
  • Distance: 37 million light years
  • App. Size: 11 x 7 arc mins
  • Constellation: Canes Venatici
  • Discovered by Lord Rosse in 1845

Below is a cropped and downsized view of my latest image:

 M51-WhirlpoolGalaxy-2cameramerge Click image for a larger view …

Imaging Info

As mentioned above I wanted to capture some of the colours, to do so I decided to combine data collection from 2 different cameras & optical setups. The seeing was only moderate during both sets of exposures. Imaging details below:

Session 1

Camera
Optics
Focal Length
Focal Ratio
ISO
Mount
Autoguiding
Sub-exposures
Total Exposure
Canon 40D
6" Schmidt Cassegrain
1500mm
f10
1250
CG5 German equatorial
SX Lodestar @ 300mm
45 x 300s
3hrs 45mins

Session 2

Camera
Optics
Focal Length
Focal Ratio
ISO
Mount
Autoguiding
Sub-exposures
Total Exposure
Canon 300D (astro modified)
Canon 500mm f4 L + x2 ext
1000mm
f8
800
CG5 German equatorial
SX Lodestar @ 300mm
28 x 300s
2hrs 20mins

Each session’s data was stacked and preliminarily processed in Iris before being exported to Photoshop. Iris processing included drizzling, wavelet noise reduction & a Richardson Lucy deconvolution for the luminance channel, as well as my standard processing routine. The resulting images were then adjusted for image scale, aligned & combined within Photoshop to produce the  image you see above. Note the feint distant galaxy in the top right corner.

I am not convinced that this two setup method was necessarily the best use of my imaging time but it was an enjoyable experiment. As for the final image, well I’m fairly pleased with it considering the less than brilliant sky conditions. At some point in the future I’d like to image M51 in more close detail but that will definitely require excellent seeing and maybe a bigger scope too.

Further Resources

This pair of galaxies give us an insight into the awesome forces at work in the cosmos, for further information about interacting galaxies take a look at Britannica’s article.

Can’t wait? Would you like that close up view of Messier 51 right now? Then follow this link to Hubble’s view of the Whirlpool.

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