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Objects Session Notes
RR Lyrae - Variable Star Gamma Draconis - Star Delta Cepheid - Variable Star T Tauri - Variable Star Mars
- 7.9 hour session, clear sky all night, 83% phase moon (but set at 01:30h UT ). - Ambient temperature 4 degC dropping to 1 deg C. Heavy Dew. Light air frost on end of dew shield by end of session. Generally calm. - Aims of session were to record an extended image sequence on RR Lyrae (to confirm the variation seen during previous session on 2005-10-05), additional magnitude information on Delta Cepheid, baseline image sets for T Tauri and baseline astrometric position data for Gamma Draconis.. - Mars was a brilliant object all night long and opportunity was taken to acquire a low resolution picture with BVR filters. - Image numbers from S99 session (#99001 through to #99952) unfortunately these overlap with image numbers used during the previous session, S98 (#98001 through to #99248).
The images #99001 to #99248 from S98 will be referred as #99001 {S98} to #99248 {S98} wherever feasible]- More Notes
An alternating sequence of V Filter (10s exposure) and B Filter (20s exposure) images were recorded over a 5.7 hour interval. Image capture was via automated scripts, however occasional manual intervention was required to keep both RR Lryae and the reference star within field of view and on 4 occasions to remove dew which had formed on the front lens of the LX200 scope. Two breaks were also made in order to acquire image sets of Delta Cepheid and T Tauri.
The dataset records the rapid brightening of RR
Lyrae over a 1.5 - 2 hour interval, followed by a gradual dimming as the star
proceeded through its regular period. The timing of the rise recorded in this
session and during the previous session (S98) seem to be consistent with the
standard period of 0.56686776 days.
[More on RR Lyrae Photometric
Analysis]
RR Lyrae (Lyra) [RR Lyrae (bottom left), reference star SAO 48408 (top right), control star SAO 48415 ] |
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CCD Image (at ~ Minimum) 10s exposure, V filter 2005-10-13 22:48h UT (#99409) |
CCD Image (at ~ Maximum) 10s exposure, V filter 2005-10-14 01:02h UT (#99693) |
Magnitude Data (B & V Filters) | |
Goto RR Lyrae Photometric Analysis Notes | |
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Gamma Draconis was the star that the English physicist Robert Hooke made the first 'modern' attempt to detect annual parallax in 1669. His attempt was unsuccessful, and it was not the 1830's/1840 that Friedrich Wilhelm Bessel and other astronomers first correctly detected parallax using slightly closer stars (eg 61 Cygni). The star is probably too far away for it to show a parallax that can be measured using amateur equipment. However to check this a baseline astrometric measurement of Gamma Draconis' position was made. This task was made difficult as the number of catalog stars directly around the star is limited. To achieve an adequate plate solution the star was moved to one corner of CCD field of view.
Astrometric solution of Gamma Draconis (Draco) at
2005-10-13 based on 8 USNOB stars, image scale 1.31 arc sec/pixel |
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CCD Image 15s exposure, V filter 2005-10-13 19:29h UT (#99029) |
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Astrometry measurement of Gamma Draconis based on 4 images (#99029-32), 1x1 binning, 15s exposure |
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Errors bars at +/-1 SD |
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Image sets of Delta Cepheid & reference star SAO 34542 were recorded at around 20:15h UT, 23:05h UT (2005-10-13) and 02:25h UT (2005-10-14). Image sets comprised 7 sequences of 3 x 0.2s V & 3 x 0.6s B (alternated between Delta Cepheid & reference star) These were analyzed using the methodology described under 2005-10-05 Notes, and combined with previous estimates
B Band Magnitude estimates for Delta
Cepheid |
Further observations will be made during
future sessions in order to further refine the light curve |
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Image sets of T Tauri were recorded at around 23:40h UT (2005-10-13) and 02:45h UT (2005-10-14). Image sets comprised 3 x 15s V and 3 x 60s B.
T Tauri & adjacent nebula NGC 1555 (Taurus) [ NGC 1555 also known as Hind's variable nebula) |
CCD Image 1 20 sec exposure, C Filter 2005-10-14 02:40 h UT (#99920) |
T Tauri Photometry Baseline |
CCD Image 30 sec exposure, V Filter 2005-10-13 23:39 h UT (#99519) |
Photometry V & B Bands |
Further observations will be made during
future sessions in order to further refine the light / colour variation. |
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Mars |
CCD Colour Image (Approximate Colour) Red : 0.11s (R Filter), Green : 0.11s (V Filter) Blue : 0.3s (B Filter) 2005-10-14 02:47 h UT (#99926, 29 & 35) |
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This Web Page: | CCD Images - Session 99 (2005-10-13) |
Last Updated : | 2015-05-16 |
Site Owner : | David Richards |
Home Page : | David's Astronomy Web Site |