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Notes from CCD Session 26 (S00026) Magnitude reach - GSC 1075:909 Area Identification of Uranian Moons (Oberon, Titania & ? Umbriel) Double-Double in Lyra M92 Globular Cluster > Images from CCD Session 26
Images of an area around GSC 1075:909 (less than 2 deg from Altair), where taken at 2 sec, 5 sec, 10 sec and 30 sec exposure. Magnitude limit increased from +13.0 for 2 sec exposure to +15.0 for the 30 sec exposure.
2 sec exposure, mag limit +13.0 |
2002-09-20 22:06h UT CCD Image, 2 sec exposure (2x2 binning) 11.4 x 7.6 arc min (#26003) |
10 sec exposure, mag limit +14.5 |
2002-09-20 22:07h UT CCD Image, 10 sec exposure (2x2 binning) 11.4 x 7.6 arc min (#26005) |
30 sec exposure, mag limit +15.0 |
2002-09-20 22:08h UT CCD Image, 30 sec exposure (2x2 binning) 11.4 x 7.6 arc min (#26006) |
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Based on earlier analysis of CCD Images of Uranus taken on 2002-09-01 and 2002-09-13 it was suspected that new CCD Images of Uranus taken on 2002-09-20 showed the two uranian moon Oberon and Titania. This was confirmed using the "UranianSats" Visual Ephemeris program by Dennis W. Tracey (http://www.winnipeg.rasc.ca/ftp/dtracy/ ).
Uranus, Oberon and Titania |
The empheris program predicted that Umbriel would lie at sufficient distance from Uranus that it might just be visible at the edge of the light glare from Uranus (Mag +5.8)
Umbriel ? |
2002-09-20 22:39: to 22:42h UT 5 CCD Images, 30 sec exposure (2x2 binning) |
Catalog magnitudes of offset stars |
2002-09-20 22:39: to 22:42h UT CCD Image, 5 x 30 sec exposure (2x2 binning) 11.4 x 7.6 arc min (#26018-22) |
See also :
Uranian
moon identification in images taken on 2002-09-01
Uranian
moon identification in images taken on 2002-09-13
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Images of Double-Double in Lyra were examined (1x1 binning/0.5s exposure and 2x2 binning/5s exposure). As found previously (Notes from CCD Session 2, 2001-09-25) it was very difficult to split the two 4.5 magnitude 'stars' into their component double, due to their brightness and very close separation.
Double-Double (Lyra) |
2002-09-20 23:23h UT CCD Image, 2 x 5 sec exposure (2x2 binning) 11.4 x 7.6 arc min (#26039-40) |
Repeating the FWHM method the two 'stars' can be identified as non-single point source objects as they have anomalously large FWHM values of 7-8.5 arc secs, compared to expected FWHM of 3.4-4.5 for a single point source object. A FWHM diagram of Image #26039 is shown below
It was noted that whilst individual Images #26039 and #26040 obtained astrometric solutions with 21 and 19 stars respectively using CCDSoft's Insert WCS/Auto Astrometry function, the averaged Image with higher signal to noise ratio achieved an astrometric solution with 23 stars.
An annotaed image showing the Double-Double stars together with offset stars (with their catalog magnitudes) is shown below
Double-Double Catalog magnitudes of offset stars |
2002-09-20 23:23h UT CCD Image, 2 x 5 sec exposure (2x2 binning) 11.4 x 7.6 arc min (#26039-40) |
The Double-Double was in fact the first astronomical object I ever imaged with my CCD Camera on almost one year ago (First Images)
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Images of M92 were processed
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This Web Page: | Notes - CCD Session 26 (2002-09-20) |
Last Updated : | 2015-05-16 |
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