Variable Stars – Crayford Manor House Astronomical Society Dartford

CMHASD Trustee John Howarth has been thanked for his help in a paper called SAO28567: One that got away published in a recent edition of the BAAVSS, written by Chris Lloyd of the RAL.

John said ''Chris originally suggested to Roger Pickard and Malcolm Gough that this would be a good object for the APT, as there had been a conflicting observation and they passed their data to me for analysis. Subsequently the star was shown to be a double and was being pulled out of shape by the gravity of its companion, hence the variability. I still had the data, so was able to send it to Chris Lloyd for his analysis, and the paper shows this.

I was pleased to be mentioned but it is also a great tribute to the Jack Ells APT and its operators. Timely too, because we are currently trying to find a permanent home for the APT, or at least for its photometer.''

To view the paper click on the link below to download the edition of the BAAVSS circular that has the paper in it.

VSSC201

First Light with a new CCD on RS Boo

3rd June 2019

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A phase curve from Martin Crow's first four sets of test observations using the pulsating star RS Boo as a target. Period 0.37733days. Acquired with 235mm SCT @ f6.3 and SX694 camera and sxcon software . Processed with AIJ and VSS spreadsheet.

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HD209458

22nd July 2018

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HD 209458

HD 209458 is an 8th magnitude star in the constellation Pegasus. It is very similar to our Sun, and it is classified as a yellow dwarf (spectral class G0 V). The star is easily visible With good binoculars or small telescope.

Essential Details

Star Designation(s)

TYC 3198-1634-1 (TYC is also known as the Guide Star Catalog GSC)

Position

J2000 RA:22h 03m 10.7723s DEC:+18° 53' 03.548"

Magnitude (Vmag)

7.65

Expected variation

Period

3.524748595 days

Results

The observations below were obtained on 2009 Aug 31 by carrying out time series photometry using a C9.25 SCT @ f10 with a MX916 camera, 'V' filter and 10 sec exposures. The 'V' filter in this instance was only used because the target star is so bright for CCD work. The conditions (typically) were less than ideal with intermittent cloud and a long stretch of cloud cover interfering with the observations. The top plot shows all of the data obtained. The next set is the same data but with all of the scatter removed. The bottom plot is this data average every five data points. The dip due to the transit can be seen in this plot.