Improving Photometry and Astrophotography by Eliminating Dark Frames and Flat Fields

I report on the efforts to improve the dark frames and flat fielding procedure for the charged-coupled device (CCD) camera for the Celestron C14 telescope at the UNH observatory. Dark frames are images taken while the shutter of the camera is closed so that only electronic and dark noise and other internal inconsistencies are recorded. These are important because they allow astronomers to subtract out interference from dark current. Additionally, flat fields are images of the entire field of the telescope so that the brightness in the pixels of the telescope’s field of view is uniform. Flat fields are vital since they provide a consistent illumination for all photos taken from the camera. With the combination of these two features, I was able to optimize the clarity of the telescope’s pictures and show through photometry how the new calibrated images appear in comparison to images prior to the calibration. Overall, these enhanced photographs will assist in achieving better results for future astronomy labs at UNH

Trust the Process: An Investigation into Astrophotography

When it comes to astrophotography, there is a lot more going on ‘under the hood’ than meets the eye. The images we have come to know and love, are not what is truly captured by telescopes – the data they collect must be post-processed to facilitate human interpretation. Filtering out aberrations, adjusting for Doppler shifting, contrast stretching, dark signal subtraction, multiple-image compositions, and utilizing general color correction are all examples of the post-processing work that go into creating the final-product photos the general population sees. On the other hand, numerical methods are also applied to reduce error and optimize images using regression methods, among others, allowing for systematic development of image profiles. Telescopes capture non-visual data as well, such as x-ray and infrared wavelengths, which can be adapted to color profiles perceivable by the human eye; each wavelength category has a characteristic appearance, the source of which is often overlooked. These images are able to tell us more about the history of the universe, as the light captured can be up to 100 million years old. The James Webb Space Telescope is an excellent example of an upcoming investigation, which will portray exoplanets and their characteristics in a ‘new light,’ as well as delve into the early development of stars. The chronology and processes from the data captured to the final image is akin to those used in all forms of photography. Images from telescopes have become the standard for how we visualize the world past the bounds of Earth, extending deep into the cosmos. Astronomers do the heavy lifting in processing raw data collected by telescopes using color correction, aberration elimination, compositions, and more in order to generate an image which portrays the data collected in a manner that speaks to all of the people who see it. Astrophotography is able to demystify the reality outside the planet we call home, and answer questions about our past – even those we may not have thought to ask – through the viewing lense of a telescope

TRANSFORMATION OF RUKYATUL HILAL METHOD (Postmodernism Analysis of Hilal Image Processing)

The usage of devices in performing of rukyat al-hilâl whose function is to make objects (hilāl) from outer space appear as bright, contrasty and large as possible isnot direcly give a solution. The view of fiqh on using devices in rukyat al-hilâl become an obstacle in the development of the rukyat  method with technology. The technology of rukyat al-hilâl is improving rapidly and developing significantly, in reverse with it’s legal developments. Therefore, there must be a transformation of the rukyat al-hilâl method as well as development of the times, without leaving it’s validity to fiqh. This study analyzes the views of postmodernism in hilal image processing. This research focuses on hilal images processing in the view of postmodernism. The research method used was library research with descriptive analysis. The results show that first, postmodernism considers that image processing is a development of method in rukyat al-hilâl that is needed. This is caused by limitations in the current method that has not been able to provide a solution, but the use of technology in rukyat should not leave its validity according to fiqh. Second, Restrictions on using devices in rukyat al-hilâl will obstruct it's main purpose which is to confirm the existence of the new moon and blocked the broadest development opportunities as a form of subjectivity and a plurality of knowledge

To catch a comet 2: Technical update on CAN-DO

Since the presentation of, To Catch a Comet, was given at the last G.A.S. Symposium, many events have impacted the CAN-DO Comet Halley program. This paper summarizes the changes to the payload and its mission, including improvements in camera control and CAN-DO's participation in the Halley Armada

Basic Astronomy Labs

Providing the tools and know-how to apply the principles of astronomy first-hand, these 43 laboratory exercises each contain an introduction that clearly shows budding astronomers why the particular topic of that lab is of interest and relevant to astronomy. About one-third of the exercises are devoted solely to observation, and no mathematics is required beyond simple high school algebra and trigonometry.Organizes exercises into six major topics—sky, optics and spectroscopy, celestial mechanics, solar system, stellar properties, and exploration and other topics—providing clear outlines of what is involved in the exercise, its purpose, and what procedures and apparatus are to be used. Offers variations on standard and popular exercises, and includes many that are new and innovative, such as The Messier List which helps users discover basic facts about the Milky Way Galaxy by plotting these objects on a star chart; Motions of Earth demonstrates just how fast the Earth is moving through space and in which direction it is going, and; Radioactivity and Time which measures the half-life of a short-lived isotope, and consider radioactive dating and heating of celestial bodies. Includes a guide to astronomical pronunciations, a guide to the constellations, spectral classifications, quotes on science, and more. For astronomers

Evaluating the summer night sky brightness at a research field site on Lake Stechlin in northeastern Germany

We report on luminance measurements of the summer night sky at a field site on a freshwater lake in northeastern Germany (Lake Stechlin) to evaluate the amount of artificial skyglow from nearby and distant towns in the context of a planned study on light pollution. The site is located about 70 km north of Berlin in a rural area possibly belonging to one of the darkest regions in Germany. Continuous monitoring of the zenith sky luminance between June and September 2015 was conducted utilizing a Sky Quality Meter. With this device, typical values for clear nights in the range of 21.5-21.7 mag$_{SQM}/$arcsec$^2$ were measured, which is on the order of the natural sky brightness during starry nights. On overcast nights, values down to 22.84 mag$_{SQM}/$arcsec$^2$ were obtained, which is about one third as bright as on clear nights. The luminance measured on clear nights as well as the darkening with the presence of clouds indicate that there is very little influence of artificial skyglow on the zenith sky brightness at this location. Furthermore, fish-eye lens sky imaging luminance photometry was performed with a digital single-lens reflex camera on a clear night in the absence of moonlight. The photographs unravel several distant towns as possible sources of light pollution on the horizon. However, the low level of artificial skyglow makes the field site at Lake Stechlin an excellent location to study the effects of skyglow on a lake ecosystem in a controlled fashion.Comment: 20 pages, 8 figures, Journal of Quantitative Spectroscopy and Radiative Transfer 201

Analysis of Image Processing Strategies Dedicated to Underwater Scenarios

Underwater images undergo quality degradation issues of an image, like blur image, poor contrast, non-uniform illumination etc. Therefore, to process these degraded images, image processing come into existence. In this paper, two important image processing methods namely Image restoration and Image enhancement are compared. This paper also discusses the quality measures parameters of image processing which will be helpful to see clear images

Astrofotografija

U završnom radu govori se o astronomskoj fotografiji. Objašnjava se proces izrade i faze procesiranja astrofotografije. U teoretskom dijelu obrađuje se povijest astrofotografije, važnost RAW formata fotografije te vremenu ekspozicije. Ukratko su objašnjene tri glavne postavke ekspozicije: otvor blende, vrijeme eksponiranja i osjetljivost. Također, navodi se važnost bijelog balansa te vrste objektiva koji se koriste za različite motive u astrofotografiji. Navode se metode snimanja i vrste astrofotografija koje se mogu fotografirati tim metodama. U praktičnom djelu rada snimaju se autorske fotografije mjeseca i zvjezdanog neba te se objašnjava način njihove obrade u Adobe Photoshopu. Pri obradi i procesiranju fotografija govori se o temperaturi boje, bijelim i crnim tonovima, sjenama, bijelom balansu, kontrastu i ispravljanju grešaka pri snimanju, kao i otklanjanju šuma. Cilj rada je objasniti i pokazati na koji način snimiti i obraditi amatersku astrofotografiju

A Deep Multicolor Survey I. Imaging Observations and Catalog of Stellar Objects

We have used the KPNO 4-meter Mayall telescope to image 0.83 square degrees of sky in six fields at high galactic latitude in six filters spanning 3000-10000\AA\ to magnitude limits ranging from 22.1 to 23.8. We have assembled a catalog of 21,375 stellar objects detected in the fields for use primarily in conducting a multicolor search for quasars. This paper describes the data reduction techniques used on the CCD data, the methods used to construct the stellar object catalog, and the simulations performed to understand its completeness and contamination.Comment: To Appear in ApJ Supplement, 1996. 168k uuencoded gunzipped tarred tex file (requires aas2pp4.sty and tighten.sty) and 4 PostScript figures. Also available at http://astro.as.arizona.edu/~pathall/astro.html#preprint