NEWS
13th November 2006
Hello all,

Hi all,

We will be going to Golden Grove again on Sunday 26th November 2006, we are usually there from about 10:00 am till 5:00 pm, all visitors welcome, anyone coming to help gets paid with coffee and biscuits :-)

Open Day

Starry Nites are holding a public viewing evening on Saturday 9th December from dusk until 10:30pm Cost is $20 per head Bookings are essential. Please call Brian or Astra on 9272 3798  mobile 0409 297 681

kind regards
Roy

22nd October 2006
Hello all,

power is now on too, and outside, the shed. Thanks very much to Garin and his wife for all their hard work.

The power points outside is on a timer. To turn it on, you have to go into the "old" roll on/off shed. In the left hand corner of the shed is a electrical switch board. Next to it is a button. Press it and power will be on outside for 10 hours, after which it will turn off automatically.

Also this shed now has a tumbler lock on it. All members who have paid there site fee are given the combination to use, when ever they want.

Please do not give this out. Only those members who are up to date with their site fee should have this. Please remember it does cost us to be there, and improvements can only be done with cash from site fees. It is unfair on those that have contributed for others to use it for free, except on specific club nights.

kind regards
Roy

15th September 2006
Hi everyone,

i forgot it was the busy bee last weekend so i arrived just as they were finishing - very embarrassing! It's looking good up there now, they've extended the viewing platform out the back, and re-wired up the power to the sheds. Also it seems relatively clear of mud despite the rain, which is a big improvement on last year.

The detector we buried under the ground appears to be still working the same - we had nothing else running for a week to ensure it was not picking up the signal from one of the other receivers, so now we have reconnected the 1420MHz receiver for comparison. Next we will leave a second unit there also for comparison, once the second unit is adjusted to give the same level output we will then move that one off site to compare the readings in different locations - hence ruling out local interference.

We will be going up there this Sunday.

1st September 2006
Hi everyone,

we will be at Chittering at the normal time this Sunday.

As for our "magic" detector that i described last time, we have various tests still to do, but right now the emphasis is on filtering out electromagnetic, the reason is we were expecting this to be a "gravity" detector ... but it turns out to look similar to the "galactic" background noise as modulated by the influence of the sun.

The one at chittering is now buried nearly a metre underground, enclosed in a small aluminium box, which is wrapped in approx 2cm (10kg) of lead sheet , then enclosed in a 10cm diameter steel cylinder sealed at both ends, with double shielded cable bringing the signal a distance of less than 3m to the recorder. The 1420MHz recorder is currently off so as to eliminate any possibility of cross-talk at the recording stage. When we left last Sunday afternoon it appeared to be still working - we'll find out when we get back there.

18th August 2006
Hi all,

the "busy bee" went well last time - we not only moved both sheds, but laid some concrete slabs and put the roof on the veranda - thanks to all involved.

We will be back there this Sunday (~10am to 4pm) hopefully we'll get some astronomy done too.

There's an interesting little experiment running at the moment ... obviously to view a small source you need the large dish, a quiet receiver, and lots of gain, but other work can be done with very inexpensive equipment.

The sun is a strong radio source so to observe it or it's effect on the ionosphere we had to turn the receiver gain down as low as it would go, we then got a distinctive trace over 24hr. Although there are variations from day to day, pointing away from the sun the overall pattern is higher and more active at night, lower during the day, with the minimum being around dawn. By using the same receiver but with a smaller pre-amp and just a dipole on the roof we were able to achieve the same result by turning up the gain a little and doing away with the need for the large dish.

Now for the really cheap version ... we have basically a detector with a load on it, lots and lots of gain but no antenna!! - Sounds a bit weird but the original idea was to seal it in an earthed metal box to screen out ALL electromagnetic radiation and see if it was still effected by anything (eg gravity). Turns out that the trace follows the same pattern as the dipole on the roof - which we didn't expect. Now due to the large gain the obvious answer is that it's just noise or temperature instability - i wont detail here all the checks/precautions we've done, but there is no correlation with temperature and you'd expect internal component noise to be steady or random or follow some pattern - but this follows the same pattern as the sun!?

Possibly there is still some E-M leaking in - but in that case we've just created a very cheap sensitive receiver, (which is a good thing), or there is some other explanation we haven't found yet - either way it's interesting. What we plan to do on Sunday is isolate it further by enclosing the metal case inside lead sheeting, digging a hole and burying the whole thing. At least it will give us another data point.

cya

4th August 2006
Hello all,

further to my last message, please see email from Keith below (thanks Graeme for the extra info)

mike

Hi All,

There will be a sausage sizzle at Golden Grove this Sunday 6th August, following the busy bee.

The busy bee will start at 10am. The aim is to relocate the shed onto the new pad area.

The workers will be treated to a sausage sizzle following the busy bee.

The latest newsletter is now on the BTOW website.

Keith Williams
Binocular Telescope and Optical World (BTOW)

Unit 5 / Malaga Centro
41 Holder Way (Corner Malaga Drive)
MALAGA WA
Tel: (08) 9249 6825

3rd August 2006
Hi all,

work has been progressing at GGO ... just a quick note to let you know we will be there again this Sunday, when amongst other things we plan to move the storage shed to allow more room for the viewing platform.

For anyone who turns up we offer payment in the usual currency ... (ie coffee and TimTams)

cya

4th May 2006
Hi,

we'll be going back this Sunday, we've got some interesting recordings over the last week, with two very different receivers showing remarkably similar outputs.

AGWA have been doing more work up there - there is now a sand pad laid down to put slabs on so as to extend both telescope viewing areas, with a retaining wall to hold it at the rear and side nearest the shed. The roll-off shed, and possibly the smaller one, will be moved to give more viewing area. The car park has been finished, and the roadway graded, with the path down the hill angled away from us so that the run off from the rain will be channelled into the adjacent field rather than flooding us ... so hopefully we wont see a repeat of the boggy conditions we had last winter. There's another area at the rear of the viewing pad that has been made level with the concrete to provide a grassed area for those who prefer to set up their telescopes an that. Someone (i don't know who but thanks anyway) has donated a sink to go with tap - now all we need is a bench to put it on and we'll have a proper kitchen area. Also the water pipe leading to the tap at the hut has been connected with drinking water, and the pipe buried so that the water isn't boiling by the time it reaches us. A big thanks to all those who helped collect the slabs, and compact the sand etc, etc ...

cya

24th March 2006
Hello eveyone,

for a combination of reasons we've not been able get up there much this summer - but we will definitely be there this Sunday.

Over the "holiday" we have rebuilt the back end of the receiver with a new 8 channel Analogue to Digital converter with provision for individual DC amps/integrator/time constant etc, on each channel. Brian's rebuilt the low frequency (30kHz) receiver, and also a new one on 1.4GHz dedicated to work on the sun. And Scott is planning a Magnetometer.

AGWA have also been doing work up there (we now have running water !!) ... i'll try to find time for a more detailed account next time ...

cya

13th Feb 2006
There will be an open day at Golden Grove next weekend 18th Feb which has been organised by Keith Williams from Binocular Telescope and Optical World (BTOW). It starts at mid day and there will be a BBQ? WARO are not sure of the details at this point - watch this space!
18th Novenber 2005
Hi all,

well i'm back from holidays ... (yippee)

We've been doing a bit of tidying up of the cables etc (it's seems to be never-ending) this week we hope to finally finish off the limit switches on the big dish. i'll be there on Saturday, and Brian too on Sunday, and anyone else who shows up ...

cya

12th August 2005
Hi all,

well Murphys Law was certainly in evidence last time, but despite the early disappointments we finished the day with some success...

First the hydraulic ram (or rather the electric motor attached to its pump) chose that day to stop working. Water had been leaking in and corroded the inside, but it looked worse than it was. We stripped it down, cleaned it, replaced two of the springs on the brushes, reassembled, and waterproofed it all before lunch. Then we had problems with the power supply on the azimuth, and i had forgotten the power supply for the portable pc etc ...but in the end we got it all working just before home time.

We had just time to locate Centaurus A before we left and the signal came in very strong (as you would expect for 2700 Janskys) but it was encouraging to see the receiver preformed so well - we had to turn the IF gain down to it's minimum just to keep the trace within the limit of the screen.

So this Sunday we will not only be better prepared, but have identified some fainter sources to test the sensitivity of the receiver with. Guido has prepared tables showing their position in ALT-AZ throughout the day as the tracking still has to be done manually until we switch it over to the softwares control.

28th July 2005
Hi guys, do you want the good news or the bad news . . .

Good News - i went to the observatory last night and photographed the sky, and have printed it out showing the exact position of south (we were pretty close)

Bad News - tried to put the dish up to clear the camera, and it only went a few inches in a hesitating fashion then died. The solenoid still seems to operate but not the pump, even if i put the 24v straight to the motor ... it was too hard to do much in the dark, but if the contacts are ok (they looked to be) then we may have to open it up and see what's gone wrong inside ... any ideas?

27th July 2005
Hi all,

i can't make it this sunday, so we are going up on Saturday instead.

The attachment of optical shaft encoders to the 9m dish worked well last week, so although we still don't have the software to enable tracking, we can at least see where the dish is pointing.

Calibration of the position still needs to be done, but due to the shape of the dishes frame we should be able to use a spirit level on the bottom of it to measure when it's pointing straight up, giving us a starting point for the Altitude measurement. For the Azimuth i will (weather permitting) take a long exposure of star trails in a southerly direction from a camera located over the axis of the dish, from that we should be able to match true south with a place on the horizon (near Roccos shed) then the dish can be turned to align with that spot during daylight, and zero the shaft encoder, which will then accurately measure angular deviations relative to south.

If the above procedure is successful then we have identified some bright sources (Vela X and Centaurus A) that should be detectable in the morning and afternoon.

As usual the going pay rate for anyone who turns up to help is free coffee and chocolate biscuits!

cya

16th July 2005
Hi all,

well the weather has been a bit of a wash out the last few times ... but we are going back to chittering this sunday (ie. tomorrow).

Rex has welded up the brackets for the shaft encoders, so if Brian brings the small pulley, we should be able to hook everything up in it's final configuration.

Hope to see you there ...

13th May 2005
Hi all,

we will be going to Golden Grove again this Sunday (15/5/2005)

The drive mechanism worked last week, all we have to do now is ... tidy up the wiring so we can control the dish from the computer, or manually from either the shed or at the dish, secure the optical shaft encoders in place, arrange the cables in a loop around the base leaving enough slack for the dish to rotate one half rev in either direction (obviously we can't have it go round in circles because of the cables from the receiver) without tangling the cable or interfering with the belt for the shaft encoders, build a cover to keep the sand/rain/sheep off the belt/cables/and motor, put a window in the side of the shed facing the dish so we can see where we are driving it, etc etc . . .

28th April 2005
Hi all,

we will be going to Golden Grove again this Sunday (1/5/2005)

The drive motor (a truck windscreen motor donated by Kenwick Motors) has been attached to the dish and works well. This Sunday we will attach relays to switch the azimuth motor on and off in either direction, and on the solenoids to raise and lower the hydraulic ram. Also there will be Reed switched at the end of the travel as a secondary fail safe, to stop it trying to go too far if left running.

The main gearbox, which takes the weight of the dish as well as turning it, is one that used to rotate the drum of a concrete mixer truck (donated by Bill Ryan Contracting ) it's used to rotating 10-20 tons every few seconds - so turning our dish (approx 2 tons) once a day, is hardly stressful. It has a gear ratio of 144:1 on top of that we have a worm drive of 30:1, this not only provides more gear ratio, but also acts as a brake - the worm gear stops wind loading on the dish (or people trying to push it around!) from being transferred back as harmful torque to the much smaller motor. Added to that is the 24volt wiper motor that has an inbuilt worm drive - giving a total of nearly 200,000:1 which explains why a small windscreen wiper motor can easily turn a 2 ton dish. Also keeping everything on 24v DC avoids any problems that could arise from the 50Hz AC hum if we used mains power.

We also hope to test the drive computer, this as a Celestron Asto Computer donated by Graeme Clement. As well as switching the motors on/off it has two optical shaft encoders to supply feed back on the position of the dish. One encoder is 4000 steps/rev which we plan to use directly coupled to the pivot point for the Altitude, this will give a resolution of slightly less than 1/10th of a degree which is sufficient for us as the beamwidth of the dish is of the order of a degree. The other encoder has 2000 steps/rev and will measure rotation in the Azimuth via a belt around the circular base - despite it's fewer steps/rev, this will provide greater accuracy due to the ratio of the pulley sizes it will rotate several times for one turn of the dish, also it will eliminate any problems due to slack there may be in the lengthy gear ratio.

For anyone who shows up we offer free coffee, biscuits (including double choc tim tam - Scott), and lots of work ...

Mike Handley

18th March 2005

just a quick note to say we will be going to chittering this sunday ... cya there if you can make it ...

4th March 2005

Hi all, just a quick note to say we've missed a couple of weeks, but will be there this Sunday,

4th February 2005
Hi all,

we will be going to chittering again this sunday.

Graeme Clement has very generously donated an astro computer and two optical shaft encoders from a Celestron telescope - so we plan to use it for making the 9m dish track. The hydraulic ram is setup so that only needs a relay to switch it up or down for elevation, all we need is a small motor for the azimuth, with the gear ratio we have already, we probably only need something like a windscreen wiper motor!

Brian has been working on some of the low frequency receivers, and i've just about finished rewiring the analogue to digital interface to remove the cross-talk we've experienced. Also i've got a newer pc for use by Guido and the SETI crew.

The AGWA guys have been extending the slab area for optical viewing, and will be resurfacing the parking area and driveway soon (maybe).

Thanks again to Graeme, and will see you there (maybe)

:-)

21st January 2005
Hi all,

This weekend we'll be going to chittering, but on the saturday instead of the sunday.

The receiver on the large dish is working well. There was a slight problem with the recording equipment last time which was resolved by going to great lengths to ensure all electrical earths came back to one point - something Noel had warned us about some time ago but which we hadn't followed diligently enough, i guess some mistakes have to be made yourself to be appreciated, but thanks anyway it helped to know the solution straight away.

Work is now progressing on the motor drive, positioning sensors, and tracking software ... there's always more to be done!

If any of you can make it on saturday, we can offer you a free coffee, and maybe even some oranges ... :-)

7th January 2005
Hi, hope you all had a good christmas and new year.

just a quick (and late) note to say we will be going to chittering tomorrow (saturday) instead of the usual sunday - see you there if you can make it.

2nd December 2004
Howdy everyone,

We will be going back to Chittering this sunday. The tests on the sun last time seemed to indicate that the large dish was working, so we want to try to pick up some other sources. As Guido points out below, Centaurus A is relatively bright at that frequency (1420MHz) and will be overhead at about 9am, so we aim to make it an "early come, early leave" day compared with our usual schedule of late.

We've had a look at rigging up some digital readouts for the position of the dish, and will need to work on a method of making it track soon ...

Mike Handley

19th November 2004
Howdy everyone,

just a quick note to say we will be going up to chittering this sunday.

Guido - if you are coming, bring your whipper snipper - you can barely go down the path to the dish for paterson's curse at the moment !

1st November 2004
Hello everyone,

there's been steady progress at Chittering, so there's a few thankyous to go out.

First, thanks to Chris and his father, who came up last week and detached the hydraulic ram from the dish, (after propping it up of course!)

Secondly, a big thank you to Peter, who not only dismantled the ram, but on the same day managed to free the fourth stage and reassemble it all. Rex was right about the 4th stage being deliberately locked off - it was welded to the 3rd stage all around by about 200mm of weld, so there was never any chance of it moving before! Peter did a great job of machining off the weld to free the last stage, after that it was found to be intact inside, with circlip and seals still in good condition.

Then yesterday Al came and reinstalled the ram, tested it, and sure enough we can see approx another 13 degrees of sky, so yet another thank you there.

And last but not least, thanks to Scott and his nephew Liam who painted the roof. Next we will seal the joins between the roof sheets, just to ensure we don't have a repeat of the leaky roof saga again next winter!

The next trip up there will be this Sunday the 7th, when we we'll finally be able to get back to calibrating the 1420MHz receiver.

cya,

22nd October 2004
Hello everyone,

We are going up again this Sunday (24th), the power is back on so at least we'll be able to boil the kettle for a coffee!

The plan is to get there by 9:00am and remove the hydraulic ram from the dish so it can be serviced. If we lift the dish up a little using the ram, then prop up the two corners with the large feed horns, and lower the ram till the weight of the dish is on the supports, we should be able to open the valve on the ram to release the pressure and manually push the ram down lower than the level of the dish so it can be removed by undoing a few half inch bolts - sounds easy!

If anyone has, and could bring along, a large (at least 150mm diameter) pipe wrench - the sort with a strap or chain that wraps around the pipe, we could try unscrewing the circular base of the ram to see why one section is jammed. But if not it's no prob, we'll just give it to Peter as is and i'm sure he can fix it up.

Then in the afternoon we might get some hissing noise out of the receiver ...

Mike Handley

15th October 2004

Hi everyone,

The power is back on ! (hopefully permanently this time)

Although we had sealed the conduit correctly, what we didn't realise is that it was not sealed near Rocco's shed, so the water got in there and ran down hill inside the conduit to where our join was, shorting it out again. We cut off the burnt section and basically repeated the same job we did last time, with new PVC boxes, connectors, and cable, but this time we also filled the junction boxes with a two part epoxy resin that electricians use for below ground work. This is guaranteed to be waterproof and carry 1kV, so the big test will be the next rain - if it survives that we should right.

On the issue of the hydraulic ram, Peter has offered to strip it down and attempt to free the jammed final section for us, if we remove it from the dish and drop it off at his place, so we will do that when we next have enough people up there to help.

We've tidied up the main shed and put the equipment rack (aka tardis) next to the wall to replace the old smaller box, and cleaned out the fridge after it being off so long, so it's looking a bit more civilised now.

Our next trip up will be Sunday 24th, if you come along at least we'll be able to boil kettle for a coffee!

cya,


Mike Handley

Radio astronomers remove the blindfold

UK radio astronomers at the Jodrell Bank Observatory, working with colleagues from Europe and the USA, have demonstrated a new technique that will revolutionise the way they observe.

To create the very best quality images of the sky, they routinely combine data from multiple telescopes from around the world - a technique called Very Long Baseline Interferometry (VLBI). They have now combined this with the power of dedicated internet resources to send data from all the telescopes to a special computer, to combine the observations in real-time (e-VLBI).

Read the full article here.

30th September 2004
Hi all,

Last week the observatory was still without power so we are going back this Saturday to try to fix it ourselves - Rocco thinks he knows where the cable was cut so we just have to dig it up and join it.

Didn't achieve a lot last weekend due to the loss of power but we did put the mounting for the small dish back up, so we can test that once the power is restored ...

Al can't make it this week (i think he is just scared of getting electrocuted - though after what happened to him last time i don't blame him) but if any of you feel like manning a shovel ... come along!

cya.
:-)

Mike Handley

21st September 2004
We finished the concrete base for the small dish, looks good, so we'll put that back up next week.

Tested the hydraulic ram on the big dish, and at the minor cost of nearly decapitating Al (as it was he only lost an arm) managed to prove that the reason only 3 of the 4 stages go up is not because the pump can't lift the weight, but rather the 4th stage is seized. Tried to loosen it with no effect, if we want that extra height we may have to have the ram replaced or serviced - i'll see if Peter (who built the base) has an idea of the cost ... or how else to fix it.

Also Rocco is still having trouble with the electrical wiring - last week we only had 2 phases, this week we had none! He's promised to fix it but was too busy on Sunday - there were more cars there than i've ever seen before, the car park was full and they were even parked out on the verge.

We'll be there next Sunday, so if you're passing ... drop in!

19th June 2004
Hi all,

sorry for the lack of emails lately ... i've been off
line for a while.

Here's an update of what's been happening - we've got
the new receiver and installed it in the big dish.
However the results aren't what we expected. So in
order to have something to compare it with, we have
setup the 2.5m dish so it is steerable and can be
connected to the same receiver. The advantage is that
it has a fixed focal point, separate pre amp, and can
easily be pointed to a strong source such as the sun,
hence we can test whether the problem is with the
receiver or the big dish.

We will be going up there again tomorrow (Sunday 20th)
to try it on the sun. If any of you guys can make it
you would be very welcome.

cya,
mike.

PS my mobile phone has changed to 0439 976 888.