PEP at Ryde I.O.W.

from VSSC 102

PEP FROM THE BACKYARD OBSERVATORY AT RYDE

THE FIRST 5 YEARS (PART 2)

Kevin West

This series of articles sets out to show PEP light curves with some provisional analysis, and to compare these with any available visual light curves. The stars are all part of a programme of the long term monitoring of high declination, bright variables, conducted by the author. The data is readily available from the BAA database. It is intended that a more detailed compilation of the articles will be submitted for publication in the BAA Journal.
The programme comprises:
Psi 1 Aur, UU Aur, BR CVn, TU CVn, Y CVn, V465 Cas, Mu Cep, UX Dra, g Her, OP Her, Delta 2 Lyr, R Lyr, XY Lyr, X Per, ST UMa, VY UMa, RR UMi.

Four PEP lightcurves by the author are give below, together with visual lightcurves provided by Dave McAdam from the VSS database.

UX Dra

Very early observations were published in IBVS and the analysis showed a period of 168 days. With the benefit of a longer series, recent work by 2 independent analysts have given 178 and 179 days. A nicely pulsating longer period variable well suited to our limited UK observing opportunities.

608 visual observations by;- J M F Andujar, P Craven, B S Crawford, S Elliott, S J Evans, R B I Fraser, C Henshaw, T Markham, I A Middlemist, B R M Munden, G Pointer, G Ramsey, A Smeaton, M D Taylor.

ST UMa

A relatively poorly observed variable that was picked up at the suggestion of Melvyn Taylor, I believe after questions were raised about its variabililty. A healthy total range to date of almost 1 magnitude. I have only one analysis of this thin data which gives 111 days. The only listed information I have is 81 days(?) from a 1970 Binocular Sky Society chart. More data needed.

784 visual observations by;- S W Albrighton, A R Baransky, P Bibbings, N M Bone, J S Day, S J Evans, R B I Fraser, B H Granslo, C Henshaw, T Markham, I A Middlemist, Volodymir G Mormyl, I P Nartowicz, M J Nicholls, B O'Halloran, G Pointer, G Ramsey, D M Swain, M D Taylor, J Toone, Erol Yusuf.

Y CVn

Another longer period variable for which the weather windows and seasonal gaps don't have too detrimental an effect on the appearance of the light curve. As I understand it, Fourier analysis is almost unaffected by irregular gaps in the data. However, there is some disageement on the periods found within this particular data. One analyst found a period of 690 days and another found 240 and 310 days. Hopefully more data will eventually resolve this.

1184 visual observations by;- S W Albrighton, A R Baransky, R Billington, N M Bone, R C Dryden, S J Evans, R B I Fraser, D Gill, B H Granslo, C Henshaw, Steve Johnston, R Livingstone, T Markham, R A Marriott, I A Middlemist, Volodymir G Mormyl, I P Nartowicz, B O'Halloran, G Pointer, G Ramsey, D M Swain, M D Taylor, J Toone, Erol Yusuf.

Delta 2 Lyr

The first quarter of the data analysed for an IBVS gave a period around 79 days. The longer baseline of the complete dataset (to date) has provided a much cleaner power spectrum with possible periods evident at 1225, 88.2 and 65.6 days. Independent analysis gives some confimation with 68 and 89 day periods seen.

117 visual observations by;- T Markham, I P Nartowicz. (data entry incomplete)

For further information please contact: Kevin West at 5, Edward St., Ryde, Isle of Wight. England. PO33 2SH Tel: 01983 614591. E-mail