Astronomy

M31 – Andromeda Galaxy

Astrophotography

This page is about my astrophotography images. You do not need a lot of kit to start taking astro photos: you can use the camera in your smart phone. To take lengthy exposures you do need some extra kit to overcome the effects of the Earth rotating on its axis. To photograph small objects, you will need either a lens with a longer focal length or a telescope.

From time-to-time I will put articles in the blog about astrophotography and how to go about it. So, keep an eye on the blog for astrophotography updates.

This page is about my astrophotography images. You do not need a lot of kit to start taking astro photos: you can use the camera in your smart phone. To take lengthy exposures you do need some extra kit to overcome the effects of the Earth rotating on its axis. To photograph small objects, you will need either a lens with a longer focal length or a telescope.

From time-to-time I will put articles in the blog about astrophotography and how to go about it. So, keep an eye on the blog for astrophotography updates.

Andromeda Galaxy

The above image was taken using a Nikon Z6 mirrorless camera. The camera was attached to a 100mm refracting telescope with a focal length of 550mm giving a focal ratio of f/5.5. It was mounted on a heavy duty equatorial mount, which is a tracking mount to allow for the Earth’s rotation.

Four exposures of 3 minutes each were stacked together to create the final image. Calibration images were also added to allow for electronic noise in the system and optical defects such as dust or vignetting.

Comet NEOWISE 2020

Comet NEOWISE 2020

Comets are not rare, however bright ones visible to the unaided eye are uncommon. This celestial visitor was discovered in early 2020 and it put on a good show when it became visible in northern skies in the summer of 2020. For me, it was the best comet since the late 1990s which saw comets Hale-Bopp and Hyakutake.

This is a single image captured using a 200mm lens, an ISO of 6400, and an exposure of 5 seconds.

The Moon

The Moon presents several challenges to photographers, the main ones are: it’s a small object (about half a degree across, or less than the width of your little finger at arm’s length); it moves across the sky due to the Earth’s rotation (about 1 degree every 4 minutes); it’s bright.

I will post items in the blog about how to get started photographing the Moon. This image was taken with a 20cm telescope with a focal length of 2,000mm, so f/10, it was taken using a tracking mount and the exposure was about 1/500s.

Milky Way

The brightest part of the Milky Way – the star clouds in Scutum and Sagittarius – are best placed in summer in June. Unfortunately, in the British Isles the skies are not really dark enough and we have to wait for August to start getting dark enough skies.

At that time of year, the Milky Way crosses overhead through the constellation of Cygnus. You need a wide-angle lens – full-frame 24mm or equivalent is good. Ideally you need a long exposure of 2 minutes or more. To avoid trailing, you will need a star tracker of some sort. Without that, you are limited to around 15s maximum exposure length.

The above image of the Milky Way through Cygnus used a 24mm lens and is a stack of several exposures of 120 seconds each. The camera was mounted on an iOptron star tracker. You can see the Andromeda Galaxy, M31, at the lower right.