The Four Ages Of Sand

M81, Bode's Galaxy

Remember my photo of M82, the so called "star-burst" galaxy? (previous post)

The clearly disrupted centre was caused by its close encounter with another galaxy, M81.  This is a fairly easy galaxy to spot with binoculars from a dark sky, though I must admit I struggled to find it at all with the 10" scope. It's also supposed to be one of the easiest galaxies to photograph but as you can see, my first attempt is nothing special. Better to come in the near future I hope, and it shouldn't be too hard to image the spiral arms.

More info:

http://en.wikipedia.org/wiki/Messier_82

M42 The Orion Nebula (again)

As I climb the Astrophotgraphy learning curve, I'll able to do a better job on M42, the showpiece nebula of the Northern skies.

This is my previous "prettiest" version:

And this one showed the most detail but was rather ugly, with lots of noise:

The latest shot is a marked improvement and shows quite a lot of delicate cloud detail, especially on the left side.

This is a composite of images taken at 1600 ISO. Total exposure time 2 minutes 17 seconds

 

 

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M65 and M66 in Leo

Leo (the Lion) is one of the few constellations which looks anything like the object it's supposed to represent. You have to stay up very late to see it at the moment but by spring time it will be higher in the sky. The main attraction for astronomers is that it has 5 bright galaxies in it.  

 http://en.wikipedia.org/wiki/Wolf_359

 

Bright is a relative concept of course, at magnitude 9.3 and 8.9, M65 and M66 respectively are not easy to spot, even with a decent telescope:

They can be seen, along with a third galaxy, NGC 3628, just to the north, with a pair of 8x40 or 10x50 binoculars - providing that the sky is very dark and transparent. Sadly in our light polluted skies such conditions do not occur often. The 9th magnitude brightness given for these galaxies seems quite bright, but this is the integrated magnitude over the whole galaxy and each part only shines with the equivalent brightness of a 12th magnitude star. These "faint fuzzies", as they are often called, are quite a challenge!

http://www.jodrellbank.manchester.ac.uk/astronomy/nightsky/AList/Leo.html 

Integrated Brightness means the brightness of the galaxy if it was condensed down to a single star-like point. Since galaxies are "spread out" over a large area, they are much dimmer than the magnitude would suggest. 

Here's my first attempt at capturing M65 and M66. Pretty rubbish I know but it was 2.00 am, the telescope was literally freezing up, and I still haven't got the scope accurately aligned enough to allow exposures of more than 20-25 seconds.  

This is a stack of 5 exposures, totalling 1 minute 57 seconds at 3200 ISO, equivalent to over an hour exposure at 100 ISO. The grain is very bad because there are only 5 frames (with increased number of exposures, the grain cancels out) and I've had to boost the levels to reveal the faint details.

On a positive note, you can see the elongated structure of M66 and the hint of 2 spiral arms around the tight central core of M65. And best for all, M66 is 41 million light years away, making it the most distant structure I've imaged so far.

The light that landed on the CCD of my Nikon sensor had been travelling for 41 million years, that's around the same time that New Word Monkeys become the first simians (higher primates) to diverge from the rest of the group, colonising South America. (http://www.newscientist.com/article/dn17453-timeline-the-evolution-of-life.html?full=true) Unless of course those pesky Creationists are right, in which case both galaxies are 6000 years old ;-)

The Joy of Piggybacking

When I approached The Wife on Saturday night with elastic cables in my hand and told her I wanted to experiment with a little piggybacking she ran from the room. Once she'd calmed down  - and unlocked the bathroom door - I was able to explain that piggybacking just means attaching a camera on top of a telescope to take astro photos.

Why would you want to use a camera lens and not make use of the huge and powerful lens sitting right underneath it? Some astronomical objects are too large to fit into a single telescopic field of view. The Andromeda galaxy (M31) is a perfect example of this, as I found out to my cost (you may remember my embarrassing first attempt at imaging it)

At 6X the size of the full Moon, no telescope can capture M31 in one go, but according to my calculations, my 500mm telephoto lens should be able to get it all in, as well as its 2 satellite galaxies, M32 and M110. 

The telescope's job is simply to hold the camera in the correct position as the motorised equatorial drive keeps the camera fixed on the same spot in the sky. Without this, even an exposure of a few seconds would be "smeared" because of the Earth's rotation.

And the bag hanging from underneath the scope?

The lens and camera weigh in at well over 2kg, which can seriously unbalance the delicate motordrive of the telescope so you need a couple of heavy books to act as a counterbalance. I recommend the hardback edition of Beyond Seven Years in Tibet and Being and Nothingness, but I suppose this is a matter of personal choice. 

For my own part, I was very glad to find a use for Sartre's tome as it is surely one of the most badly written books of all time. The ideas in it are wonderful and ground-breaking, but they are expressed by somebody trying to show how clever they are, rather than seeking to communicate those ideas clearly. That's French Existentialists for you I suppose.

Where was I? Ah yes, the Andromeda Galaxy. I ended up taking 11 exposures at 800 ISO, totalling 5 minutes 24 seconds exposure time, and the result isn't half bad. The 2 dust lanes are clearly visible, and a bonus is that NGC 206, a star cloud in one of the outer parts of M31 is just visible as a faint triangle.

 

Can you spot the 2 satellite galaxies?

 

Here they are: 

 

 

 

The Joy of the Whirlpool Galaxy M51 and NGC 5195, and a supportive wife

Ah this may well be the photo I'm most proud of so far. It represents a huge amount of effort, and I wouldn't have been able to tackle something like this just a couple of months ago. 

The Whirlpool Galaxy is the most photographed galaxy in the heavens and it's easy to see why. It is "face on" to us so the spiral shape is clear. Also it is connected by a "bridge" of stars to a smaller galaxy, NGC 5195, which makes a beautiful sight.  You can just make out the bridge in my image. 

Visually, you can't make out the spiral arms without a large telescope, and I've never seen them through my 10" though you can just spot the galaxy as a small buzzy blob through binoculars. It's near the Plough if you fancy giving it a go:

Finder chart for M 51 and NGC 5195. Limiting magnitude 7.5. 
Credit and copyright SkyTools 2 by Capellasoft

http://www.backyard-astro.com/deepsky/top100/08.html

This is a combined image of the best 18 images picked from dozens of attempts,   20 - 25 second exposures. They were taken at 3200 ISO which is equivalent to a single 100 ISO exposure of 3 hours!  I also took 3 Dark Frames, which means you take photos with the lens cap on. This reveals all the "noise" produced by the sensor, eg, red and blue dots, and these frames are subtracted from the Light Frames in software to produce a clearer final image. 

I spent 2 hours imaging and a further 2 hours post processing. In the Spring, M51 will be much higher in the sky but in January you have to wait until 1 in the morning for it to be sufficiently high for serious imaging.  

As well as a decent telescope and camera, you need a very understanding wife to take produce an image like this. It  turns out that she didn't mind me coming in and out of the house looking for cables, lenses and filters at 2 in the morning. It was the sound of her hairdryer waking her up every 10 minutes that really tested her patience (you need to give the main lens of the scope a regular blast of warm air to keep the dew off it)

It's 37 MILLION light years away, by the way. That's 3X further than the most distance object I've managed to image before. 

 

 

 

Answer to "What is it? 188"

4AoS has decided to award the prize to Alan.

Is it the Fat Blob nebula?

Posted by: Alan | January 10, 2011 at 03:35 PM

 

It's M82, which is a galaxy in the constellation The Plough,

(Credit and copyright SkyTools 2 by Capellasoft).

 

but when it was first recorded by Messier, it was thought to be a nebula, so that's close enough.

Alan, the chocs are even now on their way to you, but given all the recent weather disruption, I can't say when they will arrive, if at all.

Imaging galaxies is many times more difficult than planetary imaging. I spent 7 hours in the garden on Saturday night, and ended up with 6 or 7 galaxy photos.  

The first problem is finding the darn things. With a dark sky you can use an atlas to  "star hop" from bright stars to the faint ones, leading to the target, but on Saturday, the light pollution was pretty bad and only the main stars of the constellations were visible and it took me an hour just to find M82. This is one of the brighter galaxies but apart from Andromeda, even the bright ones are pretty dim.

M82, also known as the Cigar Galaxy, is Magnitude 8.4 so it would be 15 or 20x too dim to be seen by the naked eye even under a very dark sky, and given the state of the sky at the time, I suspect it was perhaps 40 or 60X too dim. 

Also, because I don't yet have accurate guiding systems for the telescope, I can only manage exposures of 20-30 seconds. Any longer than that and objects appear "smeared" as they move across the sky due to the rotation of the Earth. The solution is to take lots of short exposures then combine them using Astro software. This image is a composite of 12 photos selected from a total of around 25. In total, I took 472 long exposures over the night. 

As mentioned before I'm shooting at 3200 ISO. This means light is recorded 32 times faster than the slowest "normal" camera setting of 100 ISO. 

Total exposure time for this image was around 6 minutes, which is equivalent to a single 100 ISO exposure of over 3 hours!

The Cigar Galaxy is perhaps the most intensely studied galaxy of them all. Due to a close encounter with another galaxy, M81, has been "ripped apart" causing huge disruption and also large scale star formation. (For more, see here: http://en.wikipedia.org/wiki/Messier_82)

Here's the final result, after post-processing in Photoshop.  I'm so pleased with it for so many reasons, not least that it's the most distant object I've imaged so far. The Andromeda Galaxy (See here for my oh so dodgy first imaging attempts) is  mere 2.2 million light years away, whereas M82 is 12 million light years away. Yes, the light that produced this image set off across space 12 million years ago, long before the existence of humans.

 You can see even see the main star forming regions:

Compare this diagram from http://www.inaoep.mx/~ydm/m82/index.html

with my image. 

 

 The reddish colour in the A region is just showing here.

As you'll see in the NASA photo at the end of the post, there are jets of material flying out from the dark area at the centre.  It looks like one is just visible as a dark line against the background noise in my image. This is odd because as I understand it, this shouldn't be showing up in the visible spectrum.

 http://apod.nasa.gov/apod/ap060425.html

 

And these are just a few links to the many research papers on M82:

http://cseligman.com/text/galaxies/m81m82.htm

 

http://zuserver2.star.ucl.ac.uk/~msw/thesis/chap2.pdf 

 

http://arxiv.org/PS_cache/arxiv/pdf/0708/0708.0814v1.pdf

 

 

 

The joy of 3200 ISO and The Running Man NGC 1977

The clouds parted very briefly last night so I ran outside and set up the telescope. By the time I was ready, it was already turning misty and cloudy again, and the sky was orange with light pollution. Only the brightest stars were vaguely visible, and  I should have just packed up but thought I'd give it go. 

I was particularly keen to try imaging at 3200 ISO. For non-photographers: In the old days you used film which was 100 ISO or 200 ISO. This number tells you how "fast" the film is, in other words, how sensitive it is to light. You might even use 400 ISO film but that would be very grainy. 200 ISO film is twice as sensitive as 100, and 400 is 4X more sensitive than 100 etc. With digital SLRs the same principle applies; you set the speed of the digital "film" depending on the light conditions. You can easily get away with 400 ISO and even 800, though noise becomes apparent at this level and the image is degraded. 

For deep sky astrophotography you need to collect as much light as possible. Most Astro sites say you should use a setting of 400 ISO or 800 if you really need to, but I fancied pushing it even further and tried shooting at 3200. At this speed, a 1 minute exposure  is equivalent to 32 minutes of 100 ISO exposure. This is fantastic for faint objects especially when you don't have very accurate guiding systems to keep the object tracked ("fixed" in one place when viewed through the eyepiece) but the grain is awful.

Orion was visible so I had a go at a nebula called The Running Man, NGC 1977, so called because it looks like ...er... a running man.

Everyone knows the constellation of Orion, it's the one with 3 stars in a row, making the belt of Orion. Underneath are 3 much fainter "stars" making up his sword. The middle star is M42, the biggest, brightest nebula in the sky (see here for my efforts at imaging The Orion Nebula)

And here's what's possible. Just to spell it out; NOT my image!!! 

Image source: http://www.celestronimages.com/details.php?image_id=3633&sessionid=3rqad8b84b5fqglldpaar093t1

In the centre is M42 and in the bottom right you can see the Running Man nebula, NGC 1977. This image shows the 3 "stars" of the sword, which would normally be vertical with the NGC 1977 at the top.I've looked for it on many occasions but never been able to make it out. It's magnitude 7, compared with M42 which is mag 4. Regulars will know (see previous post) that a difference of 1 magnitude = 2.5 times brighter or dimmer, so NGC 1977 is  - give me a moment... - over 15 times dimmer than M42.

What were the chances of picking it up on such a terrible night?

Here's a 20 second exposure, straight out of the camera:

 

It's a RAW image so it's easy to remove the grain and stretch the levels to bring out any subtle detail:

 

Can you see it yet?

Ok, here's 4 images stacked, giving a total of  92 seconds exposure.  That's not much, but is the equivalent to a 45 minute exposure at 100 ISO

Tah nah!

Yes, it's a bit rubbish, but it's amazing that there is anything at all. Can't wait for some decent weather to do this again properly.

What do you mean you can't see the running man?!

Ok, I'll outline it for you.

And here's NASA's version:

 

The Janssen Rille, Rheita Valley and the Lunar 100

I've managed one observing session in the past 3 weeks! The rubbish weather in this country is one of the main reasons I gave up astronomy 3 years ago.  Thankfully, astrophotography provided hours of fun for cloudy days, in fact you NEED hours to sift through all the data and to post process what you've captured.  And that's exactly what I've been doing this morning. 

As you know, the best way to image planets and the Moon is with a webcam set up. I use the Meade LPI and associated software. You stack multiple images in real time, and this produces a much sharper image than any individual frames. Here's one produced exactly 1 month ago. I didn't record the number of individual frames that went into producing this composite but my average is around 50:

It's good, but not very good. Here's another composite, moving down the Moon a bit:

This one is clearly better, but with post processing there is always room for improvement. 

I'd taken 6 separate composites of the area at the top, so I picked the best 4 and then stacked those using RegiStax V5.1, which produced a composite of the composites. With the lower image I only had 2 good ones so I did the same with those. Then I stitched the 2 composite composites together in Photoshop and did some minor adjustments in Levels and Sharpening. Here's the er stitched composite of the composites... around 600 individual images.

 This is the southern mountainous highlands area of the Moon, and it shows 2 special features; Vallis Rheita, the second largest valley on the Moon, almost 500km long, and the Janssen Rille, a rare example of a highland Rille, believed to be a collapsed lava tube.  Both of these are in the Lunar 100, a list of the 100 most interesting lunar features. Click on the image for a higher quality view.

 

 

Answer to "What is it(for)? 185"

So, why would you want to take photos using a telescope as a huge lens, with the lens covered up?

It's all about the Hot and Dead Pixels. The CCD chip in a digital camera gets hot when you take long exposures. It's not a problem with sub-one second exposures but in astrophotography you are looking at half a minute minimum, and up to 5 minutes. This produces all kinds of nasties, in particular some pixels light up as bright red or blue, and others remain dark, and the effect changes depending on the exposure and the heat of the CCD at any one time.

The solution is to take regular photos with the lens cap on, matching the exact conditions and exposure of the original image (the Light Frame) and then this image (the dark frame) will be subtracted using software. 

There's more about this here: dark frame subtraction

Gosh I miss The Wife...

...but the hermit-like isolation and lack of domestic duties does give me ACRES of time to sort through all my astro stuff. "Another drink Iain?" "What a good idea" "Time for the washing up?" "Leave it for another day. Just do the one glass." 

This is special. Remember my very dim, very dodgy planetary nebula NGC 2022? 

As a rule, planetaries are pretty small and dim. NGC 2022 is 28" in diameter and 12th magnitude (what does this mean? see previous post) but some are much brighter and bigger. One of the biggest and best is the Eskimo Nebula NGC 2392, visible in binoculars in the constellation of Gemini on winter evenings.

Wikipedia describes it as a bipolar double-shell Planetary Nebula, which I think means it gets depressed a lot. 

How bright is it? Different sites give different answers. This one says it is Magnitude 9.1 which means it is about 15 too dim to see with the naked eye but 15 times brighter than NGC 2022.

 http://www.suite101.com/content/the-eskimo-nebula-in-the-constellation-gemini-a211491

This site also says it is 5000 light years away, and others say less than 3000. 

It appears to us as 0.8' x 0.7' in diameter. How big is this compared with NGC 2022? About twice the size. 

In large scopes it looks like a face with a "furry" hood around it, hence the name. 

Ok, enough of all this, you want to see my photo. As usual, I couldn't even be sure I was pointing the scope in the right direction so I took multiple images and hoped for the best. After a lot of searching through dozens of images, looking at star charts, etc I found it:

Dah Dah! Impressive isn't it?

What do you mean "Where?!" 

Bottom centre of course.

Zooming in:

The central bright area is visible but not the furry shell. Let's boost the levels in Photoshop:

Oh, that's rubbish isn't it? :-(

But wait, why am I working with the JPG file? This isn't the Stone Age! Let's use the RAW file.

Ah, now THAT's better ;-) 

There are 26 PNs visible from the Northern Hemisphere, and I'd like to bag as many as possible:

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