Earlier Adventures in Astrophotography

This is the Celestron 130 SLT telescope Dee bought me for Christmas 2006.
It's a 130mm diameter Newtonian reflector with a focal length of 650mm. It has an alt-azimuth mount and computerised "Goto" functionality.

Click on image for a larger version

This telescope is certainly not ideal for astrophotography but I've been pleasantly surprised by what it is possible to achieve.
This page shows some of my successes and failures.

1 Jan 2007

This is my first ever astronomy picture, it was taken using a small digital camera held up to the eyepiece of the telescope.

Location: My back garden in suburban London Camera: Canon Ixus 40 looking through eyepiece Shutter speed: 1/200 sec Lens aperture (of camera): F2.8 Click on image for larger version

For the next image it was impossible to hold the camera still enough so I used sticky tape to hold it in place against the eyepiece and then put it in self timer mode so the telescope vibrations had a chance to die down before the image was taken.

Location: My back garden in suburban London Camera: Canon Ixus 40 looking through eyepiece Shutter speed: 1/50 sec Lens aperture (of camera): F4.9 Click on image for larger version

Saturn required an even longer exposure. This a crop of the whole image. This was the best of a very bad bunch. I think the camera self-timer did not give the telescope vibrations time to die down after pressing the shutter release.

Location: My back garden in suburban London Camera: Canon Ixus 40 looking through eyepiece Shutter speed: 1 sec Lens aperture (of camera): F4.9

Shortly after this I bought a T-adapter with integrated 2x Barlow, Nikon T-ring so I could use a digital SLR camera.

11 Jan 2007

The Orion Nebula was my next target.
This was rather disappointing to look at through the telescope - all I could see was a fuzzy patch that looked nothing like the photographs in books or on the Internet.
However, a long exposure photograph began to bring out detail invisible to the naked eye.

Location: My back garden in suburban London Camera: Nikon D70 + 2X Barlow at prime focus of telescope Exposure: 4*15 sec = 1 min at ISO 400 Processing: 4 images de-rotated and stacked. Click on image for larger version

The weather was windy - which shook the telescope so much that only 4 frames out of 24 were worth processing.
Also, it took ages to get the focus spot on because the image in the camera viewfinder is simply not bright enough.

14 Jan 2007

Second attempt at photographing the Orion Nebula.
This uses 110 images which had to be de-rotated (to remove the field rotation induced by the alt-azimuth mount) and then stacked. The uniform orange light pollution was then subtracted. The brighter stars have an obvious "sparkly" shape due to telecope movement.

Location: My light polluted back garden in suburban London Camera: Nikon D70 + 2X Barlow at prime focus of telescope Exposure: 110*30 sec = 55 min at ISO 1000 Processing: 110 images de-rotated and stacked. Background light pollution (partially) subtracted. Logarithmic intensity scaling applied. Click on image for larger version

I later realised the following:
1) The 2 bright patches near the top left of the frame are typical Nikon D70 long exposure CCD bright patches. Apparently there are some hot electronics next to the CCD that cause this thermal noise footprint.
2) The huge bright circular area in the centre of the image is more light pollution that needs to be subtracted.

At some point I'll try subtracting the remaining light pollution at the centre of the image. But separating it from the faint detail in the nebula will be difficult.

Later note: See 29 April 2007 for a second attempt at removing the light pollution from the same data.

25 Jan 2007

Taking a picture of the moon was surprisingly difficult. It needed an exposure time of 1/60 sec but at this speed the mirror slap of the SLR shook the telescope enough to seriously blur the image (in fact any shutter speed slower than 1/1000sec showed vibration blur). I therefore set the camera to take a 10 sec exposure whilst hand holding a piece of cardboard in front the telescope tube. The cardboard was waved away for a fraction of a second to expose the image. But hand waving a piece of carboard at 1/60sec is impossible so the telescope was stopped down to 1/4 aperture.

Location: My back garden in suburban London Camera: Nikon D70 + 2X Barlow at prime focus of telescope Exposure: approx 1/4 sec (using sheet of cardboard) at ISO 200 Click on image for larger version

I later realised the following:
1) Stopping down the telescope aperture has a serious effect on resolution - making the image very soft.

6 Feb 2007

An attempt to image the Andromeda Galaxy with a fast camera lens.

The images below are both de-rotated and stacked. But one of them has the background light pollution subtracted.

Location: My light polluted back garden in suburban London Camera: Canon EOS 300D with 50mm f1.8 lens piggybacked on telescope Exposure: 72*30sec = 36 min at ISO 100 Processing: 72 images de-rotated and stacked. Right-hand image has background light pollution subtracted. Click on image for larger version

The disk of the galaxy is only just becoming visible above the noise of the light pollution.
I'll have another go at this next Winter with a longer exposure.

23 Feb 2007

By taking a picture of Orion with a fast camera lens I could tell if it was possible to image the nebulae in Orion from my back garden under the light polluted skies of suburban London.

Click on this link for the story behind this photo.

Location: My light polluted back garden in suburban London Camera: Canon EOS 300D with 50mm f1.8 lens piggybacked on telescope Exposure: 230*30sec = 115 min at ISO 400 Processing: 230 images de-rotated and stacked. Background light pollution subtracted. Click on image for larger version

3 March 2007

On safari in Kenya I took these photos of the total lunar eclipse.
The camera sat on a monopod tied to a fence post!

Location: Samburu, Kenya Camera: Nikon D70 + 70-200mm telephoto lens Exposure1: ISO 400 1/1000 sec at F5.6, 200mm Exposure2: ISO 400 1/320 sec at F8, 200mm Exposure3: ISO 400 5 sec at F8, 200mm Click on any image for larger version

1 Apr 2007

Having failed to get a good image of Saturn on numerous occasions, I finally managed to get this. The "wave a piece of cardboard in front of telescope" method was used to get a vibration-free exposure.

Location: My back garden in suburban London Camera: Canon EOS300D + 2X Barlow at prime focus of telescope Exposure: 1/2 sec (to expose Saturn) and 15 sec (to expose moons) at ISO 400 Processing: Composite of 2 images using Photoshop. Click on image for larger version

There are 4 moons near Saturn and (in the large image) you can just make out another two: one in the top left and one in the bottom right of the picture.

12 Apr 2007

The atmosphere was sufficiently turbulent-free to show the Cassini division in Saturn's rings.
14 images were taken using the "wave piece of cardboard in front of telescope" approach.
But only 1 of those images clearly showed the Cassinin division:

Location: My back garden in suburban London Camera: Canon EOS300D + two 2X Barlow lenses at prime focus of telescope Exposure: Approx 1 sec (using sheet of cardboard) at ISO 400 Processing: Slight sharpening in Photoshop.

Two 2x Barlow lenses were used in succession to give sufficient magnification. This also gave a larger target for focusing the camera.

15 Apr 2007

To get greater magnification I rigged up a wire harness to hold the camera in place to perform eyepiece projection.

Click on either image for larger version

Rotating, stacking and deconvolving the best 8 images out of 70 gave the following result:

Location: My back garden in suburban London Camera: Canon EOS300D using eyepiece projection from 9mm eyepiece Exposure: 8 images of approx 1 sec each (using sheet of cardboard) at ISO 400 Processing: De-rotation, stacking and slight deconvolution (using blur from one of Saturn's moons)

21 Apr 2007

Here I tried the above eyepiece projection method, but on the moon. As always, the "wave a piece of cardboard in front of telescope" method was used to get a vibration-free exposure.

Location: My back garden in suburban London Camera: Canon EOS300D using eyepiece projection from 9mm eyepiece Exposure: 3 images of approx 1/2 sec each (using sheet of cardboard) at ISO 400 Processing: Stacking and slight Gaussian deconvolution applied. Click on image for larger version

The same night I tried to image the famous M13 globular cluster in Hercules.

Location: My back garden in suburban London Camera: Canon EOS300D + 2X Barlow at prime focus of telescope Exposure: 65 images of 30sec each at ISO 400 Processing: 65 images de-rotated and stacked. Light pollution subtractd then slight deconvolution using blur from a small star. Click on either image for larger version

29 Apr 2007

I found some time to re-process the Orion Nebula image from 14 Jan. The old image is on the left; the re-processed one is on the right.
A lot more of the nebula structure is now visible - just emerging from the background noise.

Location: My light polluted back garden in suburban London Camera: Nikon D70 + 2X Barlow at prime focus of telescope Exposure: 110*30 sec = 55 min at ISO 1000 Processing: 110 images de-rotated and stacked. Background light pollution (partially) subtracted. Scaling:Logarithmic scaling for left hand image but Gamma=2.5 applied to right hand image. Click on image for larger version

1 May 2007

A 99.7% full moon. This time using a very fast shutter speed to overcome vibration.
32 images were stacked to reduce the image noise from ISO 1600.

Location: My back garden in suburban London Camera: Canon EOS300D + 2X Barlow at prime focus of telescope Exposure: 32 images at 1/1000 sec ISO 1600 Processing: Stacking and slight Gaussian deconvolution applied. Click on image for larger version

6 May 2007

Star trails taken on a long weekend in Spain.

Location: Sierra Lujar Mountains, Costa Tropical, Spain Camera: Nikon D70 + 18-70mm telephoto lens on fixed tripod. Exposure: 120 images at 30 sec, ISO 200, F3.5, 18mm Processing: Stacking. Click on image for larger version

19 May 2007

Moon and venus in the sky together, shortly after sunset.
Note that the "dark" part of the moon is being gently illuminated by the relected light from the earth' surface and cloud cover - this is called earthshine.

Location: My back garden in suburban London Camera: Nikon D70 with 55-200mm telephoto at 145mm on static tripod. Exposure: 5 seconds at f5.6, ISO 200 Click on image for larger version

Later in the evening I made my first attempt at photographing Jupiter. Unfortunately here in the U.K. Jupiter only climbs to 15 degrees above the horizon. This leads to a phenomenon known as atmospheric prismatic dispersion where blue wavelengths are seen on the top fringe of a bright object and red wavelengths on the bottom. In the image below this is noticeable on Jupiter and its moons. The low elevation also means that the image is not as sharp as it otherwise would be, because the light has travelled through much more atmosphere, therefore hitting more turbulence.

Location: My back garden in suburban London. Jupiter was visible between rooftops for 1 hour! Camera: Canon EOS300D using eyepiece projection from 9mm eyepiece Exposure: 8 images of approx 3 sec each (using sheet of cardboard) at ISO 100 Processing: Stacking and slight Gaussian deconvolution applied. Click on image for larger version (4 moons can be seen).

5 June 2007

Venus - just before sunset.

Location: My back garden in suburban London Camera: Canon EOS300D using eyepiece projection from 9mm eyepiece with moon filter Exposure: 1 sec at ISO 100 Click on image for larger version

12 June 2007

Mercury - 30 minutes after sunset.
Mercury was 6 degrees above the horizon, hence a huge amount of dispersion and scatter appears in this image. But this fuzzy blob really is Mercury! It was only slightly brighter than the surrounding sky.

Location: My back garden in suburban London Camera: Canon EOS300D using eyepiece projection from 9mm eyepiece. Exposure: 5 sec at ISO 100

18 June 2007

Another attempt at Jupiter - this time the red spot was in view. Again Jupiter was only 15 degrees above the horizon and some atmospheric prismatic dispersion is apparent.

Location: My back garden in suburban London. Camera: Canon EOS300D using eyepiece projection from 9mm eyepiece Exposure: ISO 100, 3 sec Processing: Slight Gaussian deconvolution applied. Click on image for larger version.

20 June 2007

This was a great night for photos!

Firstly Venus taken before sunset:

Location: My back garden in suburban London Camera: Canon EOS300D using eyepiece projection from 9mm eyepiece Exposure: ISO 100, 1/10 sec Click on image for larger version

Then the moon:

		Location: My back garden in suburban London Camera: Canon EOS300D + 2X Barlow at prime focus of telescope Exposure1: ISO 100, 2 sec Exposure2: ISO 100, 1/10 sec Processing: Slight Gaussian deconvolution applied.
		Camera: Canon EOS300D using eyepiece projection from 9mm eyepiece Exposures: ISO 100, 2 sec Processing: Slight Gaussian deconvolution applied. Click on any image for larger version

Then the moon, Venus and Saturn together in one picture:

Location: My back garden in suburban London Camera: Nikon D70 + 70-200mm telephoto lens at 75mm Exposure: ISO 200, 3 sec, f8 Click on image for larger version

Later it became a bit misty:

Location: My back garden in suburban London Camera: Nikon D70 + 70-200mm telephoto lens at 200mm Exposure: ISO 200, 3 sec, f8 Click on image for larger version

18 July 2007

Another look at Venus - one and a half hours before sunset. It is now a thin crescent and the apparent size is much larger than the 2 images taken in June because it is closer to the Earth.

Location: My back garden in suburban London. Camera: Canon EOS300D using eyepiece projection from 9mm eyepiece Exposure: ISO 100, 1/8 sec Click on image for larger version.

4 August 2007

Whirlpool Galaxy from rural France. It is very faint and is only just appearing in the image.

Location: Riberac, Dordogne, France. Camera: Canon EOS300D + 2X Barlow at prime focus of telescope Exposure: 64 images at 30 sec ISO 400 Processing: Stacking and background subtraction. Click on image for larger version.

7 August 2007

Milky Way from rural France.

Location: Riberac, Dordogne, France. Camera: Canon EOS300D + 18-55mm lens at 18mm on fixed tripod Exposure: 40images at 30 sec ISO 800, F3.5 Processing: Stacking. Click on image for larger version.

11 August 2007

Dumbbell Nebula from rural France.

Location: Riberac, Dordogne, France. Camera: Canon EOS300D + 2X Barlow at prime focus of telescope Exposure: 36 images at 30 sec ISO 800 Processing: Stacking and background subtraction. Click on image for larger version.

11 September 2007

Milky Way from rural England showing the constellation Aquila. The bright star up and left of centre is Altair.

Location: Appledore, Kent. Camera: Canon EOS300D + 50mm lens at 18mm on fixed tripod Exposure: 66 images at 8 sec ISO 1600, F1.8 Processing: Stacking. Click on image for larger version.

04 October 2007

Another attempt at the Andromeda Galaxy (M31) - this time from a reasonably dark location. The galaxy M110 can be seen directly above it as a smaller "fuzzy" object.

Location: Lydd, Kent Camera: Canon EOS 300D with 50mm f1.8 lens piggybacked on telescope. Exposure: 43*30sec = 21 min at ISO 400 Processing: 43 images de-rotated and stacked. "Curves" processing used in Photoshop Click on image for larger version

19 October 2007

I've bought a new telescope - a Celestron C11. My first target was M27 the Dumbbell Nebula.

Location: My back garden in suburban London. Telescope: Celestron C11 with F6.3 focal reducer on standard CG5 goto mount. Camera: Canon EOS 300D body. Exposure: 40*30sec = 20 min at ISO 800 Processing: Stacked in IRIS, 2x2 binning, "Curves" processing in Photoshop Click on image for larger version

Compare it with the image taken with the same camera and same exposure using the Celestron 130 SLT in rural France.

Location: Riberac, Dordogne, France. Telescope: Celestron C130 SLT Camera: Canon EOS300D + 2X Barlow at prime focus of telescope Exposure: 36 images at 30 sec ISO 800 Processing: Stacking and background subtraction. Click on image for larger version.

20 October 2007

M57, the Ring Nebula.

Location: My back garden in suburban London. Telescope: Celestron C11 with F6.3 focal reducer on standard CG5 goto mount. Camera: Canon EOS 300D body. Exposure: 50*30sec = 25 min at ISO 800 Processing: Stacked in IRIS Click on image for larger version

29 October 2007

The previous week, the comet 17P/Holmes burst into life. This was my first opportunity to photograph it.

Location: My back garden in suburban London. Telescope: Celestron C11 with F6.3 focal reducer on standard CG5 goto mount. Camera: Canon EOS 300D body. Exposure: 8*30sec at ISO 400 Processing: Stacked in IRIS, 2x2 binning, followed by Photoshop curves Click on image for larger version

31 October 2007

These two images show the comet before and after processing to reveal jets within the coma. The processing consisted of creating a rotational smear around the comet centre and then subtracting this from the original image.

Location: My back garden in suburban London. Telescope: Celestron C11 with F6.3 focal reducer on standard CG5 goto mount. Camera: Canon EOS 300D body. Exposure: 50*30sec at ISO 400 taken over a period of 90 minutes. Processing: Stacked in IRIS Click on image for larger version

14 November 2007

This animation consists of images I took on the evenings of: 28,29,31 Oct, 4,8,14 Nov. It shows how quickly the coma is enlarging.

Location: My back garden in suburban London. Telescope: Celestron C11 with F6.3 focal reducer on standard CG5 goto mount. Camera: Canon EOS 300D body. Click on image for larger version

7 December 2007

M1 - the Crab Nebula. This would be much improved if the subs were longer. For that I would need to guide the mount.

Location: Tuesnoad, Kent. Telescope: Celestron C11 with F6.3 focal reducer on EQ6 mount. Camera: Canon EOS 300D body. Exposure: 120*30sec at ISO 400 (unguided). Processing: Stacked in IRIS and cropped. Click on image for larger version

8 December 2007

The Horsehead Nebula. This would also be much improved if the subs were longer. For that I would need to guide the mount.

Location: Tuesnoad, Kent. Telescope: Celestron C11 with F6.3 focal reducer on EQ6 mount. Camera: Canon EOS 300D body. Exposure: 180*30sec at ISO 400 (unguided). Processing: Stacked in IRIS and cropped then 4x4 binned to improve signal to noise ratio. Click on image for larger version

16 December 2007

International Space Station

I took this at 5:20pm in the afternoon. It's my first ever attempt at the ISS. I can't believe my luck - it actually worked!
I manually swung the C11 on the EQ6 mount and had the Nikon D70 attached. It's a montage of the best 7 shots.

According to http://www.heavens-above.com/ it was magnitude -2.4 over Sidcup

Location: My back garden in suburban London. Telescope: Celestron C11 with F6.3 focal reducer on EQ6 mount. Camera: Nikon D70 body. Exposure: 1/1000sec at ISO 1000

19 December 2007

The moon showing many favourite features.

Location: My back garden in suburban London. Telescope: Celestron C11 with F6.3 focal reducer on EQ6 mount. Camera: Canon EOS 300D body. Exposure: 1/4sec at ISO 100 Click on image for larger version