Jack Ells APT 1996

from VSSC92

The Jack Ells Automatic Photoelectric Telescope - Report for 1996

Roger Pickard & Malcolm Gough

The telescope performed without incident during 1996, but of course, the weather, oh the weather! Indeed, until the Autumn, we recorded the fewest number of observations ever. Apart from a short spell of fine weather in February, only one worthwhile observation was made until the onset of Autumn, when a more normal weather pattern developed.

A summary of the observations is reported in Table 1 below.

It must be emphasised that the results summary presented here, as in previous years, does not list all the occasions when the APT was set up, but for some reason, such as cloud (usually) or mechanical breakdown, etc., no results were obtained.

In Table 1, under "Comments", any reference to "no result" means that, although a number of observations were obtained, apparently the ephemeris is in error, and no eclipse was seen. Although our prediction programme is constantly updated, some of the stars have not been observed for a number of years, or at least, no observations have been reported that we are aware of, and so we are relying on an old ephemeris. With some stars this is just not adequate, as in the case of V1898 Cyg, where we have been trying to catch at another minimum for some years now! (The minimum recorded on 2449332 was not a particularly good one).

This might also be a good moment to explain a little of the procedure that must be adopted in order to report APT observations.

It must be explained immediately that all the telescope software was written for use on a BBC computer which means that it is not immediately readable on a modern PC. Therefore, after the initial reduction and analysis of the observations on the trusty Beeb, the results must be converted into a plain text format for transporting to the PC. In this respect it was necessary for fellow Crayford member, John Howarth, to write a programme and supply a suitable cable so that the Beeb and the PC could be connected together and the data transmitted across. Once that has been done, the data can be manipulated using one of the standard software packages available.

In some instances, for example the data for Chris Lloyd, it is has become necessary to supply more than just the reduced data and John Howarth again came to the rescue by writing a suitable programme to transfer all the Beeb output onto a PC.

In addition, sometimes it is useful to play around with the data analyis programme on the Beeb to extract the last bit of useful information, especially where EBs are concerned.

All this represents quite a time consuming exercise, especially if there are many results to analyse.

Notes on the Table and Graphs

X Per

Observations continue of this star, although it is high time we secured some more before Paul Roche is after us!

NSV 1663

Chris Lloyd suggested this star would be a good target for the APT, and so after a stuttering start in February, a better run of observations were made in November/December. At the moment we are awaiting a full analysis of these observations from Chris, although apparently the early diagnosis is not too good.

AR Aur

The telescope didn't record the passage of any nocturnal visitor on the night of December 24th, only the eclipse of yet another EB! This eclipsing binary has a period of over 4.1 days. Despite a lot of scatter in the observations a primary minimum was observed with an "O-C" of only 0.004 days (around 6 minutes), showing that this is a system which is well behaved.

VW Cep

Once again our old favourite VW Cep has been observed to make sure it is behaving properly. The graph doesn't look that brilliant until it realised that the total range is only 0.4 mag!

AR Lac

A good result, probably the best of the year as far as scatter in the observations is concerned. It shows interesting variations at the bottom of the curve, assuming they are real and not due to local atmospheric conditions, which is a possibility - an area which would repay greater research. This was a secondary minimum, and the range of magnitude covered is only 0.4. The O-C was 0.0049 days, about 7 minutes.

CM Lac

One of the nicer curves, even though the range is relatively large with an amplitude of one magnitude. The system is well behaved with an O-C of only 0.004 day.

THE JACK ELLS APT AT TROTTISCLIFFE

(Operated by Crayford Manor House Astronomical Society)

RESULTS SUMMARY 1996 - TABLE 1

No	Double Date 1996	JD 2450..	Star Name	Star Type	No. of Obs.	Filter	Comments
1	Feb 8/9	122	NSV 1663	Delta Scuti	72	V	For Chris Lloyd
2	Feb 16/17	130	"	"	38	V	"
3	Feb 27/28	141	"	"	56	V	"
4	Apr 17/18	191	AW UMa	EW	50	V	No result
5	May 14/15	218	VW Cep	EW	71	V	Mins I & II
6	Jun 4/5	239	V1898 Cyg	?	67	V	No result
7	Sep 13/14	340	SW Lac	EW	95	V	Min I
8	Sep 15/16	342	CM Lac	EA	90	V	Min I
9	Sep 16/17	343	V836 Cyg	EB	119	V	Min I
10	Sep 17/18	344	AR Lac	EA	94	V	Min II
11	Oct 2/3	359	V477 Cyg	EA	47	V	No result
12	Oct 5/6	362	XZ Cep	EB	48	V	No result
13	Oct 15/16	372	DM Per	EA	80	V	No result
14	Oct 16/17	373	GH Peg	EA	21	V	No result
15	Oct 22/23	379	AO Cas	EB	54	V	No result
16	Nov 14/15	402	X Per	Be	6	V	For Paul Roche
17	Nov 14/15	402	X Per	Be	3	B	"
18	Nov 18/19	406	AH Cep	EB	45	V	No result
19	Nov 23/24	411	NSV 1663	Delta Scuti	52	V	For Chris Lloyd
20	Nov 29/30	417	"	"	61	V	"
21	Dec 4/5	422	"	"	136	V	"
22	Dec 5/6	423	"	"	93	V	"
23	Dec 24/25	442	AR Aur	EA	130	V	Min I

Notes:-
Chris Lloyd is a professional astronomer at Rutherford Appleton Laboratory.
Paul Roche is a professional astronomer at Sussex University.
No result means an eclipse was not seen indicating the ephemeris is in error.

For further information on the APT or PEP contact R D Pickard