Halo Artifacts Around Bright Stars
Halo artifacts in the literature
Halo artifacts are almost always seen in bright star images. These are Fraunhofer diffraction patterns associated with circular apertures. In the case of Origin, the additional diffraction tail like this one in Betelgeuse (upper left), is caused by the camera cable at the front end of the instrument. I call this the "tadpole pattern". For many significantly bright stars, however, these tails are not always visible.
There are many good examples of halo artifacts in the three volumes of Burnham's Celestial Handbook (Dover Publications, Inc., New York, 1978).
- Altair in Aquila, V 0.76, Lowell 13-inch camera, Vol 1, p. 230
- Capella in Auriga, V 0.08, Lowell 13-inch telescope plate, Vol. 1, p. 262
- Arcturus in Bootes, V -0.05, Lowell 13-inch astrograph, Vol. 1, p. 305
- Sirius in Canis Major, V -1.46, Lowell 13-inch telescope, Vol. 1, p. 388
- Castor and Pollux in Gemini, V 1.9 and V 1.14, Lowell 13-inch camera, Vol. 2, p. 919
- Betelgeuse in Orion, V 0.42, Lowell 13-inch camera, Vol. 2, p. 1288
- Delta, Epsilon and Zeta Orionis, V 2.41, V 1.69, and V 1.90, Lowell Observatory, Vol. 2, p. 1304
- Mirfak in Perseus, V 1.79, Lowell 5-inch camera, Vol. 3, p. 1406
- Antares in Scorpius, V 0.91, Lowell 5-inch Cogshall camera, Vol. 3, p. 1662
- Aldebaran in Taurus, V 0.86, Lowell 13-inch camera, Vol. 3, p. 1811
- Pleiades in Taurus, Lowell 13-inch astrographic telescope, Vol. 3, p. 1870
- Polaris in Ursa Minor, V 2.02, Lowell 13-inch telescope, Vol. 3, p. 2013
Star images with halos published in Sky & Telescope articles from my home library include the following:
- Delta Geminorium with Pluto, V 3.53, Lowell 13-inch telescope (29 Jan 1930), S&T Feb 1976, p. 108
- Tau Canis Majoris, V 4.40, Boyden 60-inch reflector (1939), S&T Feb 1978, p. 189
- HD 112887 in Coma Berenices, V 7.17, 4-meter Kitt Peak telescope (1973), S&T Jan 1979, p. 13
- HD 226868 (Cygnus X-1), V 8.91, Hale Observatories, S&T Mar 1980, p. 235
- Zeta & Sigma Orionis, V 1.90 & V 3.79, 1.2-m Royal Observatory telescope, S&T Nov 1981, p. 416
- Regulus in Leo, V 1.40, 5.5-inch f/1.65 Schmidt camera, S&T Apr 1990, p. 459
- HD 164402 in Sagittarius, V 5.77, Anglo-Australian Observatory, S&T Dec 1996, pp. 20-21
- HD 198639 in Cygnus, V 5.07, 7-inch f/7 Astro-Physics refractor, S&T Dec 1996, p. 111
- Rigel in Orion, V 0.13, S&T Jul 1998, p. 127
- BD+46 3475 in Cygnus, V 9.69, 3.6-m Canada-France-Hawaii telescope, S&T Feb 2004, pp. 56-57
- Mizar & Alcor, V 2.22 & V 4.01, Digitized Sky Survey, S&T Jul 2004, p. 72
- HD 197912 in Cygnus, V 4.23, Kitt Peak WIYN 0.9-meter telescope, S&T Sep 2004, pp. 28-29
- HD 173582 and HD 173607 in Lyra, V 5.01 & V 5.21, Digitized Sky Survey, S&T May 2019, pp. 22-23
- HD 188947 in Cygnus, V 3.88, Digital Sky Survey, S&T Sep 2019, p. 57
- HD 41335 in Monoceros, V 5.21, S&T Jan 2023
Diffraction Effects Around Aldebaran
Discussion and References
Origin's diffraction pattern for Aldebaran in Taurus is shown here. There are several near-circular ridges that are caused by the circular aperture. I have highlighted them with dashed circles. The deviations from perfect circles, and the tail on the upper left, arise from the camera cable that connects the external sensor to the onboard computer. I added a black dashed circle at the centre of the bright Airy disk, named after mathematician and astronomer G. B. Airy, who first developed the normal irradiance equation for circular apertures in 1835 ( Radiation and Optics, John M. Stone, McGraw-Hill Book Company, New York, 1963, pp. 175-176).
Additional references
- Fundamental Astronomy, 6th Edition, Hannu Karttunen, Pekka Kröger, Heikki Oja, Markku Poutanen, and Karl Johan Donner, Springer-Verlag, Berlin, 2017, pp. 88-89.
- Stars, James B. Kaler, Scientific American Library, New York, 1992, pp. 41-43.
- "Star images in the presence of aberrations", Roger W. Sinnott, Sky & Telescope, Vol. 55(4), April 1978, pp. 347-354.
Logbook
- Date & Time: November 4, 2024, 0:38 am
- Location: Kempt Shore, Nova Scotia, Canada, 45°N
- Conditions: Clear, light winds, 2°C
- Moon: Waxing crescent (8%)
- Technical: 10-sec exposures, 10-min integration, battery power, no filter, no post-processing
Celestron Origin versus DSS2
Discussion
In this section I compare the Origin diffraction pattern for Mirfak (33 Persei) in Perseus to the pattern in the Second Generation Digital Sky Survey (DSS2). A link to Mirfak in the Simbad Database and DSS2 is made by selecting the action button "Link to Mirfak in Simbad".
Origin captured the 1.27° x 0.85° field centred on Mirfak on the evening of January 25, 2025. Because the outside temperature was -7°C at the time, a hot pixel appeared in the image as shown with the red label and arrow. Several reference stars, ordered by decreasing visual magnitude, have been labeled in white with Simbad links provided in the next section.
The Origin Airy disk is much smaller than the DSS Airy disk, the latter extending out to the yellow dashed circle labeled DSS Inner Disk. All of the stars revealed by Origin within the yellow circle, such as GAIA DR2 441700484037998720, are hidden behind the DSS Mirfak Airy disk, originally created with the 48-inch Oschin Schmidt Telescope at the Palomar Observatory. Many stars between the DSS inner disk (yellow) and DSS outer halo limit (blue) such as BD+49 913, can be seen in both Origin and DSS.
Logbook
- Date & Time: January 25, 2025, 6:04 pm
- Location: Kempt Shore, Nova Scotia, Canada, 45°N
- Conditions: Clear, -7°C
- Moon: Waning crescent (16%)
- Technical: 10-sec exposures, 10-min integration, no filter, no post-processing