Astrophotography with a digital SLR camera


Images taken with Nikon D7500




The image on the right shows Antares
(the brightest star in the constellation
of Scorpius) and the Rho Ophiuchi
molecular cloud complex.

This star-forming region is one of
the closest to us at a distance of
about 400 light-years.

It was taken with a Nikon
D7500 DSLR and a 135mm f/2 lens
mounted on an iOptron SkyTracker.

Antares and Rho Ophiuchi
60 x 120s



The image is the result of
stacking (adding together)
60 individual exposures
each of which was 120s long.

Click here for a labelled image.


Images taken with Nikon D7100




The image on the right is the
centre of the Milky Way from
Scutum (top) to Sagittarius (bottom).

It was taken with a Nikon
D7100 DSLR and a 85mm lens
set at f/2 and mounted
on an iOptron SkyTracker.

Milky Way through Scutum and Sagittarius
4 x 10 x 120s



The image is a mosaic of
4 images, where each
image was created by
stacking (adding together)
10 individual exposures,
each of which was 120s long.

Click here for a labelled image.




The image on the right is the
Milky Way from Cygnus (top left)
to Scorpius (bottom right).

It was taken with a Nikon
D7100 DSLR and a 10-20mm lens
set at 10mm and f/5.6 and
mounted on an iOptron SkyTracker.

Milky Way from Cygnus to Scorpius
6 x 240s



The image was created by
stacking (adding together)
6 individual exposures,
each of which was 60s long.

Click here for a labelled image.


Images taken with Nikon D200 + 35 mm f/1.8 wide-angle lens




The image on the right was taken
with the K2 star tracker that I
designed and built to allow long
exposure images to be taken
without the stars trailing due
to the rotation of the Earth.

Milky Way through Scutum and Scorpius
20 x 60s



The image was created by
stacking (adding together)
20 individual exposures,
each of which was 120s long.

Stacking reduces the noise levels
in the images and so allows
fainter detail to be captured.


Images taken with Nikon D70/D200 + Sigma 100-300 mm f/4 telephoto lens

M31 Andromeda Galaxy
2 x 600s

M45 Pleiades star cluster
3 x 300s
M8 Lagoon + M20 Trifid Nebulae
300s

C63 Helix Nebula
20 x 120s
NGC7000 North America Nebula
20 x 120s

Total Eclipse of the Sun
5 images of various exposures
( more images here )

Comparison of Raw/Stacked/Processed images


Images taken with Nikon D200 + Sigma 100-300 mm f/4 telephoto lens

Markarian's Chain and other galaxies
Virgo and Coma Berenices
10 x 120s

Markarian's Chain and other galaxies
Negative image makes it easier to differentiate
galaxies (fuzzy edges) from stars (sharper)

Markarian's Chain and other galaxies
Negative image with galaxies labelled
with Messier (M) numbers or NGC numbers


Images taken with Nikon D70 through Meade LX200 telescope

M42 Orion Nebula
LX200 prime focus mosaic of 4 x 300s

Moon (11 day)
LX200 prime focus mosaic 1/250s

Five moons of Saturn
LX200 prime focus 8s
( click here for labelled image )

Other images taken through Meade LX200 telescope

M1 Crab Nebula
LX200 with DSI imager
45 x 15s
M51 Whirlpool Galaxy
LX200 with DSI imager
60 x 15s
C23 Spiral Galaxy
LX200 with DSI imager
66 x 30s
Saturn
LX200 with 26mm eyepiece
Canon XM2 camcorder
Subset of 8075 x 1/25s exposures f/38



Specification of Meade LX200 telescope
  • Mirror diameter = 250 mm
  • Focal length = 2500 mm
  • Focal ratio = f/10
See www.meadeuk.com for more details

Specification of Nikon D70 digital camera
  • CCD chip resolution = 3000 x 2000
  • Pixel size = 8 x 8 microns
  • Chip size = 24 x 16 mm
See imaging.nikon.com for more details


Image processing

The images were processed using the freeware Macintosh image analysis software Image SXM, a program that I wrote for use with scanning microscopy images (but which can also be used with astrophotography images).

If a caption indicates '6 x 120s' this means that 6 images (each of 120 seconds exposure) were added together in software. The object(s) of interest will add up but random noise that is inherent in all images will tend to cancel out, giving a 'cleaner' resultant image compared to the original images.

Mosaic images were created using Image SXM which automatically overlaps images and then removes any visible artefacts at the joins.



Click here for my first attempts at astrophotography with a Meade LX50 telescope


Steve Barrett   June 2018

S.D.Barrett@liv.ac.uk

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