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Showing results for tags 'hads'.
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Another HADS star from last night, V467 Dra - this one has a period of 4.74hrs, so I let the scope chug away. Guiding was working really well as well. This is from 369 separate 30sec exposures over almost 5hrs, through 350mm f4.6 newt, V filter, ST2000XM. Transparency not so great and the y-axis is quite expanded compared to some other HADS plots as there's only 0.35 mags variation for this one.
This was another HADS run taken on the 10th Apr - only really chance to do one star and then quickly reduce/plot. I'm going to struggle with suitable reference stars for this one - there's nothing really within a magnitude in the same field that I have (26'x18') - the nearest star in terms of magnitude in the east of the field below is saturated on some frames which is unhelpful - I may be able to trim those out before a submission. For timing purposes, this should be fine though. PT Com, HADS, Period 1.97hrs, Mag quotes as 12.03- 12.31, but my figures come out a little brighter using nearby stars in the APASS catalogue. A very straight rise for this star, almost like a sawtooth this profile. 124 X 40sec, Johnson V filter, 350mm f4.53 newt, ST2000XM.
Preliminary results from a 3h40m run on V799 Aur last night - this is a HADS star with period 1.83 hrs. Autofocus had a slight blip in the middle where there's an 8 min gap or so, but got the period, and the slightly odd shape nicely. AIJ complained about the red ref star - need to check saturation levels on that. These were all 7sec exposures - unflitered exposures need to be so short, even at mag 10.something to stop saturating the stars!
Another HADS star from the study Dave has introduced to me - new V filter in place now as well. GSC 03004-00870 in UMa. Quite a non-descript field, and had to again go hunting for reference stars using the APASS v9 photometric catalogue - everything here is over magnitude 12... Curve looks OK - instrumental flux steadily dropped throughout the evening - suspect I might have had a little misting of mirrors, but good enough for the result. I must connect up my secondary dew heater...
A run at capturing V416 UMa this evening, which is a short period HADS (~1.52hrs) - it's a faint one (mag 13.9-14.5 from my results) and I wanted to have a go at using the G filter and see what kind of exposure is required for this kind of magnitude star. (I have a Johnson V but haven't had chance to take the FW apart to install as yet and to refocus the OAG as a result) I ended up using 120sec exposures - it'll be interesting to see if this is fine enough to use for timing studies (will await feedback...). Using the APASS DR9 figures for the check stars (from VizieR), I get reasonably close figures, so think that the exposures are about right given the lack of brightness for this one - just whether the timing is good enough. (For some reason I can't get the absolute magnitudes out of AIJ to plot - not sure why?) Shame the clouds rolled in at the end and prevented me from getting the rise back to maximum to complete the whole cycle - I wasn't that far off...! (the points at the end of the run go completely haywire as a result of the decreased and variable flux).