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Category Archives: Photometry
Galactic Nova ASASSN-17gk
Nova ASASSN-17gk (ATel #10387) was confirmed at Shenton Park Observatory using the ALPY 600 at R~530. This very bright nova in Centaurus is near maximum and was easily identified with a 600s exposure. Further detail kindly provided by Prof. Steve … Continue reading
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Deriving new colour and magnitude transforms using ‘Transform Generator’
Changes in the optical train at Shenton Park Observatory together with a renewed 2017 AAVSO transform campaign have prompted revisiting photometric B and V band transformation coefficients. The addition of an AAVSO sequence for the southern hemisphere cluster NGC 3532, … Continue reading
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Nova Sgr 2016d
A second nova this week, confirmed in a spectrum taken with the target setting in the western sky on October 27. The ATel (also kindly prepared by Steve Shore) can be found here: (ATel #9678). A follow up ATel hinting to … Continue reading
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Determining photometric transform coefficients
The following summarises attempts to determine magnitude and colour transform coefficients for photometric projects (using the “UBVRI” colour system) undertaken at D21. The first attempts use Landolt equatorial fields near transit, which have since been found to contain some errors in published values, … Continue reading
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Southern RR Lyrae period analysis
Seven RR Lyrae variable stars were imaged over 4 nights spanning 12 June to 19 June. Targets were chosen with ‘all night’ viewing potential, to maximise data collection over a single night.
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Differential photometry analysis using MaxIM DL
The following analysis investigates the accuracy of magnitude measurements using MaxIM DL’s information tool in aperture mode, by plotting instrument magnitude against published magnitude for a Landolt field.
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An aperture photometry test using MaxIM DL and UCAC3
Non photometric catalogues are notoriously unreliable, but are increasingly used by novices amateur astronomers using commercial software such as TheSky and MaxIM DL. The following basic magnitude ‘measurement’ test shows results using MaxIM DL’s photometry tool, unfiltered images of a random field of stars, … Continue reading
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Testing the linearity of the KAF-16803 CCD sensor
Testing the linearity of the KAF-16803 sensor (the anti-blooming version of Kodak’s KAF-16801) seems to reveal a workable photometric range of up to 50% of the sensor’s full well capacity and a ‘comfortable’ upper limit of 40,000 ADU.
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