A Starburst Cigar

 Deep Sky  Comments Off on A Starburst Cigar
Feb 242013
 

I have been using my trusty old C11 that I normally use for the Moon and planets to take some deep sky objects. The C11 gets used more this time of the year because it is ‘Galaxy Season’. This means that the Milky Way is not dominating the sky to us here at this time of the year as it is during the Summer months when it stretches across the sky, and that means that we can more easily see out of our galaxy to other distant galaxies without the plane of the Milky Way getting in the way.

This galaxy is often referred to a the Cigar Galaxy. It is Messier 82 and it is often shown together with M81, Bode’s Galaxy, but the field of view with the C11 and my ATIK 383L CCD will not fit them both in the FOV at the same time. This means we can zoom in on M82 which is only about 11 arc minutes across.

M82 is a bit of a strange galaxy to look at. It is a ‘starburst’ galaxy, seen edge-on and is also the closest starburst galaxy to the Milky Way. As a starburst galaxy M82 has a rate of star formation 10 times greater than our galaxy. Conditions for the starburst activity were believed triggered by a past close encounter with M81 between 300 and 600 million years ago which must caused gas and dust to be compressed into conditions favourable for star formation.

 Posted by at 1:51 pm

First Light Horse-Head

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Jan 312013
 

I recently bought a new 130mm f/7 APO Refractor and have already posted one or two images from this new bit of kit. However, one of the reasons I wanted it was because it comes with a nice focal-reducer/field-flattener that brings the f-ratio down to about f/5. This gives a slightly wider field of view and is optically ‘faster’. In fact it is nearly twice as fast because the speed is related to the squares of the f-numbers being considered. So (7×7) / (5×5) = 49/25 = 1.96.

I’ve had the kit since November 2012, but, I was unable to achieve focus with the reducer in place! To cut a long story short, the reducer went back and it was discovered that the lenses had been assembled wrongly!

Anyway, here is my ‘First-light’ image of the Horse-Head Nebula in Orion. It is an H-alpha image (because the Moon was about) and consists of 11 exposures each of 20 minutes.

 

 Posted by at 4:55 pm

Cosmic Tadpoles

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Jan 022013
 

A Happy New Year to all!

This is my first astro image of 2013, taken on New Years Day evening. It shows a nice emission nebula IC 410 in the constellation of Auriga. Maybe ’emission’ is an appropriate word here, as these two bright streamers in the stellar winds look like two sperm (or sperms – both seem to be correct) trying to enter an ovum!

 

This image is taken through a 130mm F/7 APO refractor, using a 7nm H-alpha filter. Recorded with an ATIK 383L CCD camera, this is the result of stacking 15, 20 minute exposures. Not as sharp as I had hoped – I think the seeing was a bit poor last night, as precise focusing was very difficult!

 Posted by at 1:53 pm

A Heart (but no Soul)

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Dec 272012
 

As the weather here in the UK is still terrible, I’m still messing about with older data. Here is a re-processed image of IC 1805 – The Heart Nebula which lies in the constellation of Cassiopeia. This image, taken through a 7nm Hydrogen-Alpha narrowband filter, is composed of about 8 hours of exposures, each of 20 minutes. To help appreciate the apparent scale of this image, the full moon would fit about 4 times across it, but the field is not wide enough to include the nearby Soul Nebula – hence the title for this blog entry.

This large emission nebula is a region about 200 light-years across and lies in the Perseus arm of our Milky Way galaxy. Our Solar Syatem is located on the Orion-Cygnus arm which is just ‘inside’ and next to the Perseus arm. The IC 1805 region is about 7,500 light years away (compared to the overall diameter of the Milky Way which is roughly 100,000 light-years across).

 

This emissions from this lovely nebula are powered by a cluster of hot, young stars, collectively known as Melotte 15. ‘Young’ at only 1.5 million years old, really means just that, when you consider our Sun is over 5 billion years old. However, some of these youngsters weigh in at about 50 times the mass of our Sun, and will burn bright and fast. Here is the center of the Heart in more detail.

 Posted by at 1:18 pm

A Christmas Rose

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Dec 242012
 

Happy Winter Solstice to everyone!

Here’s a Winter Rose. It’s the Rosette Nebula (Caldwell 49) taken in H-alpha. Also, click the thumbnail below to see the center region in more detail.

 

 

 Posted by at 2:00 pm

A Busy Winter Night!

 Deep Sky, Jupiter  Comments Off on A Busy Winter Night!
Dec 112012
 

It’s been clear and frosty for a few nights here on the South Coast of England, and when it’s dark by 16:30 it’s a long night! So, it’s possible to do a lot in one night.

I am still fascinated with those classic, well known deep-sky targets, so I decided to use the early part of the evening to image M33, the lovely galaxy in Triangulum. I haven’t used this combination of equipment on it before and my Pentax 75 with the ATIK-383L CCD gives a great field of view for this object, and as there was no moon to get in the way I used a clear Luminance filter on this occasion, with the intention of grabbing colour data another night. Here is the result of combining 14, 15 minute exposures:

 

So, by about 22:30, Jupiter beckoned! It had risen nice and high, so I switched telescopes and cameras to image it. I have my Celestron C11 OTA riding alongside the little Pentax refractor, so no need to move any kit in the dark. It turned out that the seeing conditions at very high resolution were not a good as I had hoped (the seeing does not affect wide-field astrophotography as much). So Jupiter came out a bit ‘soft’ as you can see below. This image is a combination of 9, 1 minute video captures with my mono Flea3 CCD. Frames were captured at about 60 frames per second and I took 3 runs in each colour (RGB). WinJUPOS was used to compensate for the rotation of the planet over the 9 minute capture period.

 

Onwards to my next target – The wonderful Horse Head Nebula in Orion. This was sitting nicely in the sky about an hour before culmination, so I switched back to the deep sky kit again and managed to grab 2 hours of data before deciding to quit for the night. How I’d love to try this target from a more Southerly latitude as it doesn’t get above about 36 degrees from here.

 

 

So, all in all a good night. Plenty more to do to turn these two deep sky shots into the finished colour images I want. I’ll probably shot some H-alpha on these as well to sharpen the up!

 

 Posted by at 4:09 pm

The Pleiades – My last word!

 Deep Sky, Patrick Moore  Comments Off on The Pleiades – My last word!
Dec 112012
 

In my last post, I presented a re-processed version of an image of M45 – The Pleiades that I took last year with a one-shot colour CCD. This made me think I should have a go using my more sensitive mono CCD and separate filters. So here is the result!

The image consists of 4 hours of luminance data (a white-light filter) and 1.5 hours each through red, green and blue filters (all exposures were 10 minutes). Taken over the two nights of 8/9 December 2012.

I shot the colour data on the sad day that the great British Astronomer Sir Patrick Moore passed away. I was lucky enough to have known him for the last 42 years (since I was a lad of 10). I know he would have liked this image – he was a fan of the work of amateurs and was fascinated on how we can produce better images now than even the largest telescopes in the world could produce not too many years ago.

 Posted by at 12:17 am

An Old Favourite Reprocessed – The Pleiades

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Dec 072012
 

From time to time it becomes apparent that your image processing skills have improved to the point where you become convinced that it would be possible to reprocess old data and stun the world with the results!

I often find, however, that the improvements are minimal, and that is probably the case here, but I still find this target fascinating. Here is a re-processed image of M45 – The Pleiades, which is currently well placed in Northern Hemisphere skies. Jupiter is not too far away too.

I captured this data in September 2011 using a QHY-8 one-shot colour CCD camera (which I have since sold!). The telescope was my little 75mm Pentax APO refractor. I took 20 exposures each of 10 minutes and combined them to produce this.

 Posted by at 3:35 pm

The Gamma Cas Nebula

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Dec 062012
 

What to do before taking images of Jupiter at about 10pm? It gets dark here at about 5pm so there’s plenty of time! I currently have my little Pentax 75mm APO mounted side-by-side with my C11 so that I can switch easily from Deep-Sky imaging to Jupiter and back again.

So, last night I decided to use a H-alpha filter on a target I’ve never tried before – The Gamma Cas Nebula (IC 59/63). Gamma Cas is the middle star of the ‘W’ shape of the constellation of  Cassiopeia. The star itself is an ‘eruptive’ variable and its brightess varies from about +1.6 to around +3.0. The nebula nearby the star is quite faint and I used 30 minute exposures; 8 in all making 4 hours of total exposure. The scale of this image (using an ATIK 383L CCD camera) is about 124′ x 92′ (for scale, the Moon is about 30′ (arc-minutes) across. I guess I need to grab some RGB colour soon! Click the image to see the full size version (actually it’s 50% of the original).

 Posted by at 1:10 pm

Adding a Splash of Colour

 Deep Sky, Image Processing  Comments Off on Adding a Splash of Colour
Nov 302012
 

Yesterday, I posted the monochrome H-Alpha image of M42, taken in full moon-light. To get the RGB colour data, I will have to wait for the Moon to go away, or will I?

In the image below, I took the RGB (Red, Green and Blue) data from a colour image of M42 I took last year with a one-shot colour CCD camera. The colour image was taken at a much smaller scale with a much smaller refracting telescope, and I had to scale it up in size to align, rotate and fit the new H-Alpha image which I used as the luminosity channel in this image. The colours look a bit washed out here, which happens if you just simply use Ha as luminance, but I think it does look pretty!

It just shows that the colour data does not have to have the full resolution (detail) of the luminance data. This is why astronomers often shoot the RGB data for their images with their cameras in ‘binned’ mode. If you bin by 2×2, it means that you have 4 pixels adding up to make one. The camera becomes twice as sensitive and you can expose for less time to get the same ‘depth’ of image. The downside is that the image has half the number of pixels across and down, so you pay by losing resolution. But we’ve just discovered that doesn’t matter too much!

 Posted by at 9:50 am