1997 Tal 2m 6" Newtonian telescope power issues

[Astr0Kaz]

Hi 

I know this is a long shot, but does anyone have a spare long cable that came with the 6" Tal 2m Newtonian scope please? I've unfortunately lost the long cable that connected the motor to the mains power supply unit 🥺

The motor has a D-Tap 2 pin connector and the power rating is 12V 50htz.  If I cannot find a replacement cable, I was wondering if it was possible to power the motor from a large battery pack instead?  I am also a bit concerned about plugging it into the mains considering how old it is! Maybe a battery pack is a safer solution?

Please let me know if you have any suggestions.

Thank you 😊

Best wishes, 

Kaz

[DaveL59]

You'd need 12v AC I believe, hence the 50Hz so a battery wouldn't do it and may cause damage since it'll be feeding DC. Not sure what the current requirement is but it may be possible to get a 12v AC supply and change the socket on the mount to suit if you can't locate a compatible unit. 

[Astr0Kaz]

8 hours ago, DaveL59 said:

You'd need 12v AC I believe, hence the 50Hz so a battery wouldn't do it and may cause damage since it'll be feeding DC. Not sure what the current requirement is but it may be possible to get a 12v AC supply and change the socket on the mount to suit if you can't locate a compatible unit. 

Thank you 😃 I'll have a look into it. Still kicking myself for losing the lead! 

[bosun21]

2 hours ago, Astr0Kaz said:

Thank you 😃 I'll have a look into it. Still kicking myself for losing the lead! 

Are you totally sure that it’s not 240v 50Hz and 12v DC?. I found someone with the same telescope and his is 12v DC. Is this your telescope. He is on SGL so you can message him and ask, his name is @CCD-Freak.👇.

 

 

 

Edited July 11, 2023 by bosun21

[bosun21]

Apparently they indeed do come with a 12v AC power supply as well. 

[Astr0Kaz]

3 minutes ago, bosun21 said:

Are you totally sure that it’s not 240v 50Hz and 12v DC?. I found someone with the same telescope and his is 12v DC. Is this your telescope. He is on SGL so you can message him and ask, his name is @CCD-Freak.👇.

 

 

 

Thank you 😃 that is identical to my scope! Although my power supply looks different (please see my photo below) , I don't have the DC adapter that is in the picture above, but maybe I can purchase one (fingers crossed) Thank you again, I'll message them 😃 

[Cosmic Geoff]

As a retired electronics engineer, I am wondering how a mount could be powered by 12v AC (clearly indicated in the photo above by 12v ~) and by +12v DC?  With AC, the speed could be locked to the mains 50 HZ, but with DC, some sort of intermediate circuitry to control the motor speed should be present.   However, the second 12v connection, with two small round holes, is clearly not keyed for polarity.   Isn't there a user manual anywhere?

A step-down transformer will be required to supply 12v AC from the mains. 

[Carbon Brush]

The TAL motorised mounts had a 240V/12V transformer.
The 'clock' or RA drive being synchronous motor. That is locked to 50Hz mains.
Whether the transformer insulation is still good 30 years on is debatable.
Of course in a modern house you have RCD protection...When did you last test it?
I would replace the transformer by something new, or if wanting to retain authenticity, put a known good isolating transformer before the old TAL transformer.
Again losing originality, yu can easily replace the 12V connectors by almost anything. XLR would be a good choice.

Somewhere in the depths of my garage I have a TAL motorised mount.
I will try to take a look (not before tomorrow evening though) and see if anything about the plugs looks compatible with modern stuff.

Congratulations on the scope. If it has been looked after, it will give very good results.
Mechanically and optically they are good.

HTH, David.

[Astr0Kaz]

6 hours ago, Cosmic Geoff said:

As a retired electronics engineer, I am wondering how a mount could be powered by 12v AC (clearly indicated in the photo above by 12v ~) and by +12v DC?  With AC, the speed could be locked to the mains 50 HZ, but with DC, some sort of intermediate circuitry to control the motor speed should be present.   However, the second 12v connection, with two small round holes, is clearly not keyed for polarity.   Isn't there a user manual anywhere?

A step-down transformer will be required to supply 12v AC from the mains. 

Thank you 😃

 Unfortunately I am a bit lost with the technical aspects, but I think a new transformer sounds like a good idea. I am a bit concerned about the original unit with it being quite old now. 

[Astr0Kaz]

6 hours ago, Carbon Brush said:

The TAL motorised mounts had a 240V/12V transformer.
The 'clock' or RA drive being synchronous motor. That is locked to 50Hz mains.
Whether the transformer insulation is still good 30 years on is debatable.
Of course in a modern house you have RCD protection...When did you last test it?
I would replace the transformer by something new, or if wanting to retain authenticity, put a known good isolating transformer before the old TAL transformer.
Again losing originality, yu can easily replace the 12V connectors by almost anything. XLR would be a good choice.

Somewhere in the depths of my garage I have a TAL motorised mount.
I will try to take a look (not before tomorrow evening though) and see if anything about the plugs looks compatible with modern stuff.

Congratulations on the scope. If it has been looked after, it will give very good results.
Mechanically and optically they are good.

HTH, David.

Thank you for your help 😃

Replacing the transformer does sounds like the safer option, if you do see anything that you think might be compatible, that would be brilliant, but please don't go to too much trouble, if your garage is anything like ours, I'm sure it contains a black hole! It probably swallowed my lead come to think of it! 

I haven't used the motor in over 10 years, although I did plug it into the mains quite recently and it made a gentle buzzing noise. I've no idea if the motor works though as I currently have no way of testing it. 

The scope has been stored in the original boxes in our garage since we moved house in 2011.  I purchased the scope from new around 1997. It still looks good, although I'm pretty sure it needs collimating as I struggled to get it in focus.  I've ordered a Bahtinov mask and I've been watching videos on YouTube about collimation, I just need to be brave enough to attempt it! 

It is a lovely scope, but it's so heavy! By the time I set it up in the garden I'm shattered lol.

Thanks again 😃 

Best wishes,

Kaz 

[The Lapwing]

I love TAL scopes, I hope you get it sorted out. TAL has a certain something other outfits don’t have, a kind of agricultural retro charm. Anyway good luck with it, I love TAL. I should buy another 100 R or RS one day 

[Astr0Kaz]

15 minutes ago, The Lapwing said:

I love TAL scopes, I hope you get it sorted out. TAL has a certain something other outfits don’t have, a kind of agricultural retro charm. Anyway good luck with it, I love TAL. I should buy another 100 R or RS one day 

Thank you 😊 it is a lovely scope. I have never used the 100R or RS, but I have heard they are excellent scopes too, I hope you find one 😀

[DaveL59]

Made the drive all the way to coventry and back just to collect the 100RS I have, lovely scope and it has a Tal-1 and Tal-M reflector for company, neither are motorised however. The 100RS is on an EQ5 so I can swap that between the Synscan goto or the dual-motor one which is on TAL wooden legs nowadays.

Good luck sorting your Tal-2, I doubt it needs much current so a 12v AC 2A transformer should do it, just be sure to put an in-line fuse between it and the mount 🙂 

[Astr0Kaz]

I am only 15 minutes away from Coventry! 😄  It sounds like you have a great collection of scopes! 

My only other mount is a skywatcher star adventurer pro 2i which holds my William Optics Zenithstar 61 refractor. I think the Tal 2m scope would flatten it! Lol 

Thank you, and for the in-line fuse tip, that is a good idea! 😃

[bosun21]

There’s a few step down transformers (240v AC to 12v AC) on Amazon rated at 3A.

[Carbon Brush]

Having read that you have owned the scope from new, my advice on swapping out the transformer may have been hasty.

The issue with old equipment is that you often don't know if someone has left it outside in all weathers, or attempted their own repairs and modifications.
You can see where I am coming from.
If you have had the scope from new, stored it sensibly and not repurposed the transformer, or modified wiring, you should be fine.

I will give you an update on the stuff I have when I have negotiated the depths of the garage. 

[Astr0Kaz]

@Carbon Brush Thank you, that does make a sense 😊 

The motor and transformer have never really been used! I was in my early 20's when I brought the Tal2m, we were on holiday in Wales when I saw it in the window of a photography shop.  Unfortunately I didn't have a clue how to use it back then, there was no YouTube in those days and I didn't know anyone else who owned a telescope.  I soon gave up trying to understand how to use the motor, I was happy just using the scope manually ☺️  

Thank you again for your help with this, I hope your mount is not hard to find 😃

 

 

 

[Astr0Kaz]

Hi All, 

I thought I would give an update on my TAL2M - It now has power!! 😃 

 

I purchased the above AC to AC power supply and it works perfectly as far as I can tell.  I am using two separate leads with insulated crocodile clips to attach the two transformer wires to the two connecting points on the motor.  It is perfect for visual astronomy and despite my poor attempt at polar alignment, it managed to keep on the target pretty well.  Viewing Saturn through the eyepiece was just magical! 😍

The only issue that I'm having is that unfortunately it is no good for astrophotography.  The motor vibrates! I can actually feel the vibrations through the entire OTA! I tried imaging Saturn with the motor on, but the vibrations caused a very wobbly image, despite a frame rate of 20 fps.  One day I might upgrade to a heavy-duty tracking mount, but for the moment I only have a Skywatcher Star adventurer 2i.  I believe the TAL2M OTA would kill it!! 

I have had fun doing up the scope though.  I spent time over the summer cleaning the mirrors (very gently!) adding a primary mirror dot (it never had one!!), flocking the OTA and collimating. Alex at FLO was a massive help with this project 🙂

I thought I'd attach a few photographs in case anyone was interested. 

This is the transformer that comes inside the original power supply

The motor.  The three screws at the back are used to balance the scope - loosen the screws to allow the scope to move freely - balance the scope with the counter weight and then tighten the screws to re-engage with the motor.  

Before and after flocking

Primary mirror, now with a central dot

TAL2M with the ZWO ASI533 MC camera attached for imaging.  These Images were taken with the motor turned off.  I adjusted the scope manually every few seconds to keep the target in the FOV. 

 

The stacked images are not perfect, the seeing wasn't great, it was a partially cloudy night and I was also having trouble focusing precisely - the focuser is quite course.  However, for a first attempt, I'm really happy with it.

Now all I need is clear skies!!! It has been over a month now, and unfortunately the forecast is still clouds, clouds and more clouds for the next week

 

Thanks again for all of your help 🙂

Kaz