File:Comet Neowise over Hamilton, Canada - Flickr - SyamAstro (750,000 views - thank you^).jpg
Original file (5,344 × 3,563 pixels, file size: 9.09 MB, MIME type: image/jpeg)
Captions
Summary edit
DescriptionComet Neowise over Hamilton, Canada - Flickr - SyamAstro (750,000 views - thank you^).jpg |
Finally caught a glimpse of the comet after a week of cloudy weather. Shot from the escarpment, with some of the downtown Hamilton in the foreground. HSS! Here is my technique for subtracting the foreground (sky glow) from sky photos near horizon (works for normal to telephoto lens range; doesn't work for wide angle lenses): 1) Take the photo as RAW, process it as 16 bit color per channel, to preserve all the information 2) Open the photo in your image editor (GIMP, Photoshop etc), straighten the horizon, and erase to transparency all objects which are not sky glow - bright stars, comets, landscape. You end up with a "Swiss cheese" photo. Save it as a TIFF file with transparency enabled, say bg.tif . 3) Use a command line tool ImageMagick (Q16 version) to process bg.tif. Execute the following command: $ magick convert bg.tif -resize 1xH\! -resize WxH\! bg2.tif Substitute W with the width, and H with the height of the image bg.tif in pixels. The above command will effectively average out all the rows of pixels in bg.tif (but only for non-transparent pixels), creating a sky glow model for your photo. 4) Load bg2.tif back to your photo editor (where you still have your original photo, with the horizon straightened). Apply a bit of vertical motion blur (~20 pixels) to make the model smoother. 5) Make it as the second layer, with the first layer being your original photo with the horizon straightened. Choose Difference as the first layer option (so the second layer is subtracted from the first one). 6) Voila - the sky glow is gone! You can now merge the two layers, and adjust the levels as needed, to bring out all the faint details. |
Date | Taken on 17 July 2020, 22:52 |
Source | Comet Neowise over Hamilton, Canada |
Author | SyamAstro (750,000 views - thank you!) |
Flickr tags InfoField | hss |
Licensing edit
Public domainPublic domainfalsefalse |
This work has been released into the public domain by the author on Flickr, where the author has declared it as a "Public Domain Work" and tagged it with the Creative Commons Public Domain Mark.
|
||
The Public Domain Mark (PDM) is not a copyright license, but a symbol used to indicate that a work is in the public domain. When it is applied by the author or the copyright holder, community consensus has decided such works as being public domain in the US and countries where it is legally possible to release own work to the public domain. In the countries where this is not possible, the copyright status of the work remains undetermined.
| ||
If a file is tagged with Public Domain Mark by someone other than the author or the copyright holder, a more specific copyright tag such as one found at Commons:Copyright tags/General public domain must be applied. If this is your own work, please use {{Cc-zero}} instead.
Public domain Public domain false false |
This image was originally posted to Flickr by SyamAstro (850,000 views - thank you!) at https://flickr.com/photos/30041560@N03/50128485178. It was reviewed on 21 April 2024 by FlickreviewR 2 and was confirmed to be licensed under the terms of the Public Domain Mark. |
21 April 2024
File history
Click on a date/time to view the file as it appeared at that time.
Date/Time | Thumbnail | Dimensions | User | Comment | |
---|---|---|---|---|---|
current | 08:20, 21 August 2020 | 5,344 × 3,563 (9.09 MB) | Red panda bot (talk | contribs) | In Flickr Explore: 2020-07-20 |
You cannot overwrite this file.
File usage on Commons
The following page uses this file:
Metadata
This file contains additional information such as Exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file. The timestamp is only as accurate as the clock in the camera, and it may be completely wrong.
Camera manufacturer | Canon |
---|---|
Camera model | Canon EOS 6D |
Exposure time | 4/1 sec (4) |
F-number | f/2.8 |
ISO speed rating | 800 |
Date and time of data generation | 22:52, 17 July 2020 |
Lens focal length | 50 mm |
Orientation | Normal |
Horizontal resolution | 300 dpi |
Vertical resolution | 300 dpi |
Software used | Adobe Photoshop CC 2015 (Windows) |
File change date and time | 10:33, 18 July 2020 |
Exposure Program | Manual |
Exif version | 2.3 |
Date and time of digitizing | 22:52, 17 July 2020 |
APEX shutter speed | −2 |
APEX aperture | 2.970854 |
APEX exposure bias | 0 |
Maximum land aperture | 1.75 APEX (f/1.83) |
Metering mode | Center weighted average |
Flash | Flash did not fire, compulsory flash suppression |
DateTime subseconds | 16 |
DateTimeOriginal subseconds | 16 |
DateTimeDigitized subseconds | 16 |
Color space | Uncalibrated |
Focal plane X resolution | 1,520 |
Focal plane Y resolution | 1,520 |
Focal plane resolution unit | 3 |
Custom image processing | Normal process |
Exposure mode | Manual exposure |
White balance | Manual white balance |
Scene capture type | Standard |
Serial number of camera | 101026002679 |
Lens used | EF50mm f/1.8 STM |
Rating (out of 5) | 0 |
Date metadata was last modified | 06:33, 18 July 2020 |
Unique ID of original document | CB4653268CC08D859BCBC6C76FCE973D |
IIM version | 24,832 |