Members' Observations: Duncan Waldron
Evening crescent Moon
5th July 2011
Taken with Zeiss 6-inch refractor at approx. 35x, using afocal method and 5 megapixel camera at moderate zoom. 7 frames stacked to reduce noise.
Taken with Zeiss 6-inch refractor at approx. 35x, using afocal method and 5 megapixel camera at moderate zoom. 7 frames stacked to reduce noise.
Saturn
18th June 2011
Taken with Zeiss 6-inch refractor at approx. 250x, using afocal method and 5 megapixel camera at full zoom. Stacked frames from 30 second video exposure at 20:16 AEST (10:16 UT). Stacked using Registax; post-processed with unsharp masking.
Taken with Zeiss 6-inch refractor at approx. 250x, using afocal method and 5 megapixel camera at full zoom. Stacked frames from 30 second video exposure at 20:16 AEST (10:16 UT). Stacked using Registax; post-processed with unsharp masking.
Morning planets: 2
12th May 2011
One day later, at the same time, and the movement of individual planets is apparent. 8 merged exposures.
At this time, Venus is around 3 months from superior conjunction, and is presenting a small, almost full, disk image. At around -3.81, it is within 0.02 magnitudes of its minimum brightness, as increasing phase angle is accompanied by a slightly decreasing angular size.
One day later, at the same time, and the movement of individual planets is apparent. 8 merged exposures.
At this time, Venus is around 3 months from superior conjunction, and is presenting a small, almost full, disk image. At around -3.81, it is within 0.02 magnitudes of its minimum brightness, as increasing phase angle is accompanied by a slightly decreasing angular size.
Morning planets: 1
11th May 2011
4 naked-eye planets in the twilight, at 5:40 am. 5 images taken with 5 megapixel camera; images merged to reduce noise.
4 naked-eye planets in the twilight, at 5:40 am. 5 images taken with 5 megapixel camera; images merged to reduce noise.
Jupiter and transit of Io
6th Nov 2010
Single image of Jupiter, taken with Zeiss 6-inch refractor, using afocal method and 10 megapixel camera. Exposure at 19:02 AEST (09:02 UT).
Single image of Jupiter, taken with Zeiss 6-inch refractor, using afocal method and 10 megapixel camera. Exposure at 19:02 AEST (09:02 UT).
Venus - just before conjunction
28th Oct 2010
This image is the best of a selection of frames from a video of Venus near conjunction. In the animated image (around 12 seconds long) there are hints of the thin, brilliant crescent, but with pretty poor seeing, they are just hints.
The video was taken around 26 hours before conjunction, at 09:18 AEST on 28th October (23:18 UT, 27th October). 9.7 mm eyepiece; other details as for the image below.
Note: The full GIF file is nearly 2MB and will take some time to load fully; click the image for the animation (opens in a new window).
This image is the best of a selection of frames from a video of Venus near conjunction. In the animated image (around 12 seconds long) there are hints of the thin, brilliant crescent, but with pretty poor seeing, they are just hints.
The video was taken around 26 hours before conjunction, at 09:18 AEST on 28th October (23:18 UT, 27th October). 9.7 mm eyepiece; other details as for the image below.
Note: The full GIF file is nearly 2MB and will take some time to load fully; click the image for the animation (opens in a new window).
Venus - waning crescent, 7 days from inferior conjunction
22nd Oct 2010
This image shows Venus presenting a thin crescent as it approaches the Sun on its way to inferior conjunction, when it will be between the Earth and the Sun. Conjunction occurs on the 29th of October, when it will be about 5 degrees away from the Sun. Taken during daylight, at 15:53 AEST, the warm atmosphere was causing very poor seeing, resulting in a fairly blurred image; this was the best of a couple of dozen exposures with the 5 megapixel camera, this time held against the highest power eyepiece (6mm) on a 200mm Meade SCT.
NB Anyone planning to observe Venus when it is close to the Sun should make sure that the Sun is hidden from view; position yourself so that the Sun is behind a wall, or some similar arrangement, so that the Sun's light cannot enter your field of view while searching for Venus.
This image shows Venus presenting a thin crescent as it approaches the Sun on its way to inferior conjunction, when it will be between the Earth and the Sun. Conjunction occurs on the 29th of October, when it will be about 5 degrees away from the Sun. Taken during daylight, at 15:53 AEST, the warm atmosphere was causing very poor seeing, resulting in a fairly blurred image; this was the best of a couple of dozen exposures with the 5 megapixel camera, this time held against the highest power eyepiece (6mm) on a 200mm Meade SCT.
NB Anyone planning to observe Venus when it is close to the Sun should make sure that the Sun is hidden from view; position yourself so that the Sun is behind a wall, or some similar arrangement, so that the Sun's light cannot enter your field of view while searching for Venus.
First quarter Moon
15th Sept 2010, 16:57 AEST
This image was taken through the 6-inch Zeiss refractor at the Sir Thomas Brisbane Planetarium. It's a fairly low-tech attempt, using a 5 megapixel point & shoot camera, held against the low-power Huyghenian eyepiece. I did shoot a lot of frames, and this is a combination of about a dozen of the best ones, so that the JPEG image artefacts have been suppressed. In doing so, the seeing has been 'averaged' - there was quite a bit of wobble in the telescope image - so in the final composite, seeing is no better than about 2 arcseconds. Click the preview for a larger image.
This image was taken through the 6-inch Zeiss refractor at the Sir Thomas Brisbane Planetarium. It's a fairly low-tech attempt, using a 5 megapixel point & shoot camera, held against the low-power Huyghenian eyepiece. I did shoot a lot of frames, and this is a combination of about a dozen of the best ones, so that the JPEG image artefacts have been suppressed. In doing so, the seeing has been 'averaged' - there was quite a bit of wobble in the telescope image - so in the final composite, seeing is no better than about 2 arcseconds. Click the preview for a larger image.
Lunar eclipse
26th June 2010
Also taken using the Zeiss telescope, but this time using film at prime focus. Unfortunately, it was 400 speed film - not ideal, but all I had at the time. Taken early in the eclipse.
Also taken using the Zeiss telescope, but this time using film at prime focus. Unfortunately, it was 400 speed film - not ideal, but all I had at the time. Taken early in the eclipse.
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The following observations are mainly photographs taken with fairly simple equipment - either using normal camera lenses or through a telescope.
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International Space Station — 3rd March, 2009
Thanks to Terry Gill's enthusiasm for the event, those present at the March observing session were able to see the ISS moving up from the horizon. It was a bright object, at around mag 2.5 - as bright as Jupiter. As luck would have it, I had my 6-inch reflector there, and with a low power eyepiece (around 48x), was just able to follow the ISS as it moved higher. My estimate was that it moved at around 1 degree every 1-2 seconds, so following it wasn't easy, and at best I could see a shaky image, but even so, was able to make out that it wasn't a normal-looking satellite, that it had a complex structure. To make up for not being able to share the viewing with other members, here's an image of the ISS in front of the Moon.
Comet 2006P1 McNaught — 21st January 2007
January 2007 brought a rare spectacle - a beautiful, bright comet. Discovered last August by Siding Spring astronomer Rob McNaught, it provided a few good nights of easy viewing at dusk. Now fading, it can still be seen with binoculars as it retreats from the vicinity of the Sun, on its long journey back to the dim depths of the outer solar system.
Hailed as the best comet in 40 years - if not longer - McNaught was best seen from the southern hemisphere as it swung round from perihelion (the closest approach to the Sun), brightening and growing a spectacular tail as it went. As a comet approaches the Sun, the frozen material of the comet's nucleus is melted by the Sun's warmth, releasing gas and solid matter as it goes. This material is blown away from the nucleus by the solar wind, forming the familiar tail. Comets may have 2 types of tail: the dust tail, and the gas tail; in 1997, comet Hale-Bopp showed both types in spectacular fashion. The gas tail is usually blue in colour, while the dust tail is yellowish. Typically, the gas (or ion) tail points directly away from the Sun, as the powerful solar wind easily pushes the lightweight molecules of gas rapidly away. In the process, the solar energy causes the comet's gas to emit blue light. The dust tail, on the other hand, tends to lag somewhat, as the comet follows its curved path away from the Sun; this is because the heavier particles are not accelerated away from the nucleus as fast as the gas is, and so are "left behind". Imagine sweeping a hose around: the water coming out of the nozzle will be sprayed out in a curve as the end of the hose moves sideways; this is similar to the effect seen in a comet's dust tail. The dust tail emits no light of its own, merely reflecting the Sun's light, hence the yellowish colour.
For the most part, Comet McNaught seemed to be all dust tail, and these photos give a good impression of its dramatic appearance, sweeping away to the right. They are combinations of 3 and 4 images, to improve the quality; even so, using fast film, and digitally enhanced to reveal faint details, they show significant grain. Striations within the dust tail can easily be made out though, and the extent of tail visible here is similar to that seen visually. Enhancement has been used to improve faint details; the brighter portion of the tail may be over-enhanced in comparison. Compare these images to those taken by Rob McNaught himself.
Thanks to Terry Gill's enthusiasm for the event, those present at the March observing session were able to see the ISS moving up from the horizon. It was a bright object, at around mag 2.5 - as bright as Jupiter. As luck would have it, I had my 6-inch reflector there, and with a low power eyepiece (around 48x), was just able to follow the ISS as it moved higher. My estimate was that it moved at around 1 degree every 1-2 seconds, so following it wasn't easy, and at best I could see a shaky image, but even so, was able to make out that it wasn't a normal-looking satellite, that it had a complex structure. To make up for not being able to share the viewing with other members, here's an image of the ISS in front of the Moon.
Comet 2006P1 McNaught — 21st January 2007
January 2007 brought a rare spectacle - a beautiful, bright comet. Discovered last August by Siding Spring astronomer Rob McNaught, it provided a few good nights of easy viewing at dusk. Now fading, it can still be seen with binoculars as it retreats from the vicinity of the Sun, on its long journey back to the dim depths of the outer solar system.
Hailed as the best comet in 40 years - if not longer - McNaught was best seen from the southern hemisphere as it swung round from perihelion (the closest approach to the Sun), brightening and growing a spectacular tail as it went. As a comet approaches the Sun, the frozen material of the comet's nucleus is melted by the Sun's warmth, releasing gas and solid matter as it goes. This material is blown away from the nucleus by the solar wind, forming the familiar tail. Comets may have 2 types of tail: the dust tail, and the gas tail; in 1997, comet Hale-Bopp showed both types in spectacular fashion. The gas tail is usually blue in colour, while the dust tail is yellowish. Typically, the gas (or ion) tail points directly away from the Sun, as the powerful solar wind easily pushes the lightweight molecules of gas rapidly away. In the process, the solar energy causes the comet's gas to emit blue light. The dust tail, on the other hand, tends to lag somewhat, as the comet follows its curved path away from the Sun; this is because the heavier particles are not accelerated away from the nucleus as fast as the gas is, and so are "left behind". Imagine sweeping a hose around: the water coming out of the nozzle will be sprayed out in a curve as the end of the hose moves sideways; this is similar to the effect seen in a comet's dust tail. The dust tail emits no light of its own, merely reflecting the Sun's light, hence the yellowish colour.
For the most part, Comet McNaught seemed to be all dust tail, and these photos give a good impression of its dramatic appearance, sweeping away to the right. They are combinations of 3 and 4 images, to improve the quality; even so, using fast film, and digitally enhanced to reveal faint details, they show significant grain. Striations within the dust tail can easily be made out though, and the extent of tail visible here is similar to that seen visually. Enhancement has been used to improve faint details; the brighter portion of the tail may be over-enhanced in comparison. Compare these images to those taken by Rob McNaught himself.
The Moon (& distant friends)
With the exception of image 6, these are photos taken through the eyepiece of the telescope. This is not the ideal method of taking astronomical photos, but it shows what can be achieved with a very casual snap. Photos 1-3 are quite successful, partly because the camera could automatically measure the light for a good exposure. The 4th image shows camera movement, which has blurred the image because of a longer exposure. The camera allowed only for automatic exposure, and measured the subject as mostly dark, so increased the exposure time. As a result, the faint earthshine can just be seen, while the sunlit portion of the moon is very over-exposed. With a manual-exposure camera, the exposure time could be set for the best result - or a variety of results if desired. The thing to remember with the moon is that it is a sunlit landscape, and so needs a similar exposure to that required in any normal terrestrial daylight landscape photo: about 1/60th of a second, with ISO100 speed film, with an f/16 telescope.
With the exception of image 6, these are photos taken through the eyepiece of the telescope. This is not the ideal method of taking astronomical photos, but it shows what can be achieved with a very casual snap. Photos 1-3 are quite successful, partly because the camera could automatically measure the light for a good exposure. The 4th image shows camera movement, which has blurred the image because of a longer exposure. The camera allowed only for automatic exposure, and measured the subject as mostly dark, so increased the exposure time. As a result, the faint earthshine can just be seen, while the sunlit portion of the moon is very over-exposed. With a manual-exposure camera, the exposure time could be set for the best result - or a variety of results if desired. The thing to remember with the moon is that it is a sunlit landscape, and so needs a similar exposure to that required in any normal terrestrial daylight landscape photo: about 1/60th of a second, with ISO100 speed film, with an f/16 telescope.