Southern Star Trails – Barton – ACT – Australia – 20170205 @ 02:14:38 to 02:48:46
Image by MomentsForZen
"Lord, you can take me now, I’ve seen it all." (Dan Dierdorf, TV commentator, 19941017).
This was the first long exposure star trail photograph that I took using a recently acquired Zeiss (Hasselblad) 30mm fisheye lens. The lens that I used was manufactured in 1996 but it was in perfect condition. I acquired this lens to serve as a wide-angle lens for my Hasselblad 501CM camera.
The geometry of the scenes that are photographed with a fisheye glens is unusual – I think of it as being midway between the geometry obtained using a conventional rectilinear lens and the geometry of a 360 degree lens. It is quite disarming the way that it captures so much of the horizon – and this is the case even when using the CFV-50c digital back where the recorded photograph is a cropped portion of the image circle. (** I shall have to take some photographs using a film that includes a larger portion of the image circle, just to see the full fisheye geometry of this lens!).
When considering the use of a fisheye lens, it must also be remembered that a fisheye lens geometry is actually quite appropriate for astrophotography as the visible hemisphere is best mapped as a curved space, not a rectilinear space.
As for the photograph itself … When looking at the LCD screen at the time of capture, it had a pleasing composition, and the light trails, though short, curved nicely around the South Celestial Pole.
Several days later, when I had organized some time to process the image, I sat back to evaluate my feelings about it and …
… I couldn’t be more pleased.
The maximum exposure length for my Hasselblad CFV-50c Digital Back is just over 34 minutes (34:08), which is barely sufficient for capturing star trails. What this exposure length does allow, however, is for various "ghost" features of a short exposure to be drawn out but to remain recognizable. The curve of the star clouds that define the Milky Way are evident, as is a smudge near the right hand edge of the image, just above the building facade, that relates to the Large Magellanic Cloud (LMC). Within the confines of the Milky Way, close to the middle of the image, is a dark region that is the expression of the Coalsack Dark Nebula. The final feature that I shall mention is the dramatically elevated exposure in the lower left corner of the image. This is a product of the street lights along Bowen Drive and beyond that, to the "lavish" (extravagant, excessive) street/building lights in Kingston.
I would imagine that an exposure time of 16 minutes or so might result in an even "balanced" blend of star trails and point star features.
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This is one of a pair of photographs that I took of the stars around the South Celestial Pole on this morning. The web links (URL’s) for the pair are given below. One was a "point star" photograph with an 8 second exposure, whilst this image was a "star trail" photograph with a 34 minute 8 second exposure.
The post-processing applied to this star trail photograph was largely based on Lightroom preset 20170206-108. This preset captured the sequence of processes applied to the complementary point star image.
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URL’s for the pair of point star and star trail photographs …
Point star image on Flickr …
www.flickr.com/photos/momentsforzen/32671217101/
Star trail image on Flickr …
www.flickr.com/photos/momentsforzen/32788031332/
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[ Location – Barton, Australian Capital Territory, Australia ]
Photography notes …
The photograph was taken using the following hardware configuration …
(Year of manufacture indicated in braces where known.)
– Hasselblad 501CM Body (Chrome) – S/N 10SH26953 (2002).
– Hasselblad CFV-50c Digital Back for Hasselblad V mount camera (2016).
– Hasselblad Focusing Screen for the CFV-50c digital back, with focusing prism and crop markings.
– Hasselblad 45 Degree Viewfinder PME-45 42297 (2001).
– Hasselblad Carl Zeiss fisheye lens – F-Distagon 3.5/30 CF T* (1996).
– Really Right Stuff (RRS) TFC-14 Series 1 Carbon Fiber Tripod – MFR # 13996.
– Really Right Stuff (RRS) BH-30 Ball Head with Mini Screw-Knob Clamp – MFR # BH-30 PRO.
– Hasselblad HATQCH (3043326) Tripod Quick Coupling.
– Arca-Swiss ARUCP38 Universal Camera Plate 3/8".
– Nikon AR-3 Shutter Release Cable.
– Artisan & Artist ACAM-302 Silk Cord for Hassleblad Cameras (Black).
I acquired this photograph (8272 x 6200 pixels) with an ISO of 100, exposure time of 34:08 seconds (20170205 @ 02:14:38 to 02:48:46), and aperture of f/11.0
Post-processing …
Finder – Removed the CF card from the camera digital back and placed it in a Lexar 25-in-1 USB card reader. Then used Finder on my MacBook Air to download the raw image file (3FR extension) from the card.
Lightroom – Imported the 3FR image.
Lightroom – Used the Map module to add the location details to the EXIF header.
Lightroom – Applied Lightroom preset 20170206-108.
Lightroom – Used the Spot Removal tool to attenuate a number of the characteristic small, dark circular artifacts that are related to dust spots on the digital sensor.
Lightroom – Decreased the saturation and increased the exposure for the blue fraction of the image (see HSL panel).
Lightroom – Added a small radial filter to the bottom left corner to reduce the exposure in this region.
Lightroom – Saved the complete processing sequence as Lightroom preset 20170212-004.
Lightroom – Output the image as a JPEG image using the "Maximum" quality option (8272 x 6200 pixels).
PhotoSync – Copied the JPEG file to my iPad Mini for any final processing, review, enjoyment, and posting to social media.
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