Gina

Here is a list of the equipment I have to date :- Audio-Technica AT-LP3 Turntable. Pioneer A-209R Amplifier - secondhand Yamaha NSF51 Floorstanding Speakers - Black Sometime in the future when funds permit I may buy a sub-woofer such as :- Yamaha NS-SW300 sub-woofer - review here

Being much older and less capable with my hands I felt I wasn't up to positioning the pickup by hand, even with the ability to lower the arm hydraulically. This led me to go for an automatic deck rather than a fully manual like I had before. I had reservations about an automatically controlled tone arm but knew that buying online would enable me to return the deck and get my money back if i wasn't satisfied and maybe buy a fully manual one. I needn't have worried - I am totally delighted with the deck I bought.

I found the sound quality of analogue reproduction was smoother and cleaner than digital. As a scientist and engineer I couldn't see a logical reason why analogue should sound any better than digital - sampling rate and resolution both seemed more than adequate and yet I have found the analogue sound definitely better than digital having done a direct comparison. I wasn't satisfied to take other peoples views on this I wanted to see for myself and now I have I'm totally convinced. Now I have resurrected my interest in playing music and I'm really enjoying it.

A friend asked my to see if I could fix her record player and amplifier setup, which I did. I had already decided it was time I started listening to music again to relax and this prompted me to think about my own vinyl record collection. I have a number of records that haven't got a CD version and that I would like to play. My original hi-fi system got partly lost and partly damaged in a house move and a few years ago I tried buying turntables but didn't find any that worked well enough so gave it up as a bad job. This time I decided to buy a reasonably high quality turntable and make a proper go of it.

Decided to resurrect my vinyl record collection so bought a decent turntable, new loudspeakers etc. This blog describes what I've bought and setting it up.

I might have abandoned this project as not being worthwhile in view of the amount of work required to get it to work but for two reasons - several of my friends are very interested in this project and also that I don't like to just give up

Having found that the pendulum won't synchronise unless the period is already very close to correct, it seems that some sort of period adjustment is required anyway. In vintage clocks this is usually a thumbscrew on the pendulum bob to move it up or down. Adjusting the other end is equally valid. This could be manual or servo controlled (automatic) and I like a clock that looks after itself Now since it seems that a servo controlled period could do the whole job of timekeeping it seems unnecessary to use magnetic synchronisation as well. The above approach differs from my previous idea which was to manually adjust the period until close enough to synchronise by mechanical levers etc. from the auto-winder.

Thinking about pendulum timing control servo system, it might be worth doing this in two stages viz. coarse and fine :- Measure the cycle time and adjust to make it 2s. Compare pendulum phase with RTC phase and fine adjust to produce synchronism. All this can be done with the Arduino I'm already using to drive the auto-winding system. The mechanism for controlling the pendulum length could be a threaded rod driven by a stepper motor.

Been looking again at slave clocks and those with pendulums seem to use solenoids mostly. In my clock design I have been using levers and a spring running off the auto-winding mechanism which is timed from a Real Time Clock module. Magnetic drive to the bottom of the pendulum might be better. Another possibility I was trying before was to vary the effective pendulum length by lifting the steel spring support while still holding it in the gap. This shortens the pendulum and reduces it's swing time. I could measure the swing time and control the lift with a servo system until the swing time was exactly 2s. I have worked with servo systems in the distant past and used to know all the maths involved including damping coefficients I have a horrible feeling that I might be past that now! What I don't want is an unstable system that deviates more and more from correct timing Looking back at where I got to before, I see I didn't even get the clock to run continuously without any timekeeping control so on a practical level (when I get back to it) I shall need to produce a decent escape wheel and get everything set up for a running clock.

Since posting last I have made good progress on the "GinaRep Mini" 3D printer but most projects are on hold until I shake off a heavy cold. Also, this project has to take a back seat to astro projects and I need a calendar more than another clock - the Moon Dial Clock is working fine. OTOH while I'm resting with this cold there is no reason why I shouldn't think about this project and after a considerable break I may have some new ideas :D. I have one serious problem with this pendulum clock - the pendulum and escapement. I can't expect to make a perfect time-keeper with just a weight driven pendulum clock - even the most expert clock maker has not achieved this, so synchronisation to a true source of perfect time is what I have been trying to do. So far I have not achieved this. I know I need to make a better escape wheel but also I need to sort out a workable way of driving the pendulum from my time source. Slave timepieces have been made in the past so I see no reason why I shouldn't be able to do the same.

I'm just relaxing, playing some very old records that I haven't played for decades As a scientist and engineer I can't explain why analogue reproduction sounds smoother than digital but it does I can only think that the human ear/brain combination is more finely tuned than can be explained by science. I've also ordered a couple of vinyl records in the hope that these will be free from clicks and pops that my old records have and that no digital processing has been used in their production.

Thanks very much Steve

I've picked up another cold from somewhere and feeling far from inclined to do much so I won't be Worst of it is a sore throat together with cough and muzzy head. I shall just have to take it easy - as long as I sit quietly I don't feel too bad. Until I feel a bit better all projects are on hold

I had a 28mm f2.8 lens delivered today That will go on my dual widefield rig

The Pentax-M 28mm f2.8 lens arrived today - very good condition Fits the adapter I bought for it too Now I just need to find the EOS-T2 adapter that I bought a while back for another lens I checked focus with the M42 screw mount 28mm f3.5 lens and it was on the limit - may need a bit more spacing. I've ordered a 12-16mm adjustable T2 extension. I checked the spacing and I reckon 14mm would be about right.

Another idea, I could try the zoom lens off my Canon 1100D - minimum FL of 18mm at f3.5. I have a Canon EOS mount to T2 adapter (somewhere).

Having looked at images of The Milky Way in the Widefield forum, I'm thinking I would like to image with a wider FOV than the 28mm lens but not as wide as my all sky camera. The ASC covers the whole of the MW but with lower lower resolution than I would like - probably less than 2000 pixels for the whole length. Also the ASC is luminance only. It would be nice to capture it in higher resolution and colour. Hmm... I could try a DSLR No, no, no, mustn't take on yet another project - I already have too many on the go!!! What I really had in mind was to use an old SLR lens of shorter focal length than 28mm but this takes me into the fish-eye range and rocketing prices eg. Pentax Fish-Eye-Takumar 17mm F4 Manual Focus Lens Pentax Screw / M42

Let's look at a calculation... Back focus of M42 is 45.46mm. Back focus of camera is 6.5mm. We want 45.46mm plus 1mm for Astrodon filter = 46.46mm. So distance from lens to camera faces wants to be 46.46-6.5 = 39.96mm. ZWO EFW is 20mm so about 20mm of extension wanted. Since the lens moves forwards for focussing extending the spacers required the extension required with EFW is 20mm+ depending on the lens focal length. The 28mm only moves 3mm whereas the 135mm lens moves 13mm.

I've managed to get both of these lenses to focus on the distant horizon within their focussing range by swapping extension tubes around. Since these are 55mm the longer focus lenses should be alright. I have yet to check the 28mm f3.5 lens and the 28mm f2.8 lens has a Pentax K mount which will need an adapter or two so I don't yet know about that.

Been trying the cameras for focus and despite the calculations I can't get focus on either of them - one is past the infinity setting and the other is past the nearest setting. There is something very odd going on here as both imagers are correct by calculation and camera to lens distances match within a fraction of a millimetre.

Been sorting out extension tubes and rings for Asahi Pentax M42 lenses and the ASI1600MM-Cool cameras, one with ZWO EFWmini, the other with fixed filter held inside the 11mm extension ring with ZWO adapter (supplied with camera). Back focus of M42 lens is 45.46mm. Back focus of camera is 6.5mm. We want 45.46mm plus 1mm for Astrodon filter = 46.46mm. So distance between the faces of the lens and camera wants to be 46.46-6.5 = 39.96mm. ZWO EFW is 20mm so about 20mm of extension wanted and the full 40mm (approx.) for the other camera. Since the lens moves forwards for focussing extending the spacers required, the extension required with EFW is 20mm+ (and 40mm+ without) - depending on the lens focal length; longer FL lenses move more. Here is a photo of the dual rig with 55mm f1.8 Super Takumar lenses. All the M42 thread mount lenses have the same back focus so should be fine with these extension tubes/rings.

Amazingly a clear night and I made what I consider a valiant attempt to get imaging with my single widefield rig. Unfortunately, things didn't go according to plan (now there's a surprise!!!) and severe problems with focussing which I find very puzzling as I feel sure I had this rig working some time ago. Anyway, with apparently no chance of any more imaging for a week or more I shall move on to the dual widefield imaging rig - the second 28mm lens should arrive in the next day or so. I have learnt that I could do with finer focussing for the KStars/Ekos/INDI auto-focussing system to work properly so at least last night wasn't a complete loss

I guess I made reasonable use of this month's clear night but I seem to be a bit further away from being ready for imaging than I thought. I think for the auto-focus to work properly I need finer focussing which can be obtained by a higher gear ratio and micro-stepping of the stepper motor.

Well, I think I've just about had enough for tonight and I don't think I can achieve much more ATM. I need to sort out the focussing and I think I can do that in the daytime using a distant tree or trees.

That was overexposed so here is a 20s image.