6" f5.9 Newtonian (Astro Systems) , ongoing project …… Hinds Mirrors

[dweller25]

@Alan White I used to have the 8.5” version of your scope which I bought in 1985.

I still remember taking it out one night in the 90’s after midnight to look at Jupiter and the detail was utterly staggering.

I have had many scopes since then but none have blown me away in the same way as the Astro Systems 8.5 did.

David Hinds, Rob Miller and @Peter Drew really knew what they were doing 👍

So it’s definitely worth fixing your scope up.

 

 

 

Edited February 9 by dweller25

[GriffinUcos]

Well....... I might have a cunning plan! 

The Astrosystems 6" is now in bits and some painting has been done.

I went to the local electronics shop to buy Ferric Chloride. Sorry but we don't sell it any more, how about some nice Sodium Perchlorate! Quick intake of breath. No thanks, definitely don't want anything with sodium.

I've ended up mail ordering the Ferric Chloride. I'll have a closer look at the mirror surface when it's clean and hopefully send it for re-aluminising.

While I'm waiting I've ordered a 6" blank and grits from Stathis Kafalis in Munich http://www.stathis-firstlight.de/

Very much looking forward to trying my hand at making a decent mirror. I bought the mirror o matic disk in 2004ish but never had the time or opportunity to do anything. Perhaps the Hinds mirror on the backplate and the new mirror on an adjustable cell. 

Looks like it might be a long road!

Kind regards to all.

 

 

 

[GriffinUcos]

Look what I found in the old parts bin. Might make a half usefully spherometer with some legs.

[johnturley]

1 hour ago, GriffinUcos said:

Well....... I might have a cunning plan! 

The Astrosystems 6" is now in bits and some painting has been done.

I went to the local electronics shop to buy Ferric Chloride. Sorry but we don't sell it any more, how about some nice Sodium Perchlorate! Quick intake of breath. No thanks, definitely don't want anything with sodium.

 

 

 

 

I'm surprised that the shop offered you sodium perchlorate, if I remember correctly from my chemistry days, it potentially quite explosive. 

John 

[GriffinUcos]

Yes and now I'm glad I didn't buy it. To etch copper I've used Ferric Chloride but then moved on to HCl and copper ions.

I wonder if perhaps he meant Sodium Persulphate, which would be safer and works on copper.

Chemistry, I remember trying to silver a mirror with Nitric acid and Silver nitrate. If it gets above 18C turns in to fulminate. I think I still have a copy of Blackie's " Constructing an Astronomical Telescope" circa 1951.

Sorry, even further OT.

Edited February 20 by GriffinUcos

[GriffinUcos]

Update!

The mirror has been stripped and ready to go for re-aluminising. 

The tube and stand have been painted and ready to be re-assembled. Sadly the Astro Systems label is long gone.

The package has arrived from Stathis. The mirror blank looks superb, no sign of stress or bubbles.  To simplify things I purchased a 6" grinding kit to go with it. 

When it returns the original mirror will go back on the Astro Systems back plate.

I'll have to design some sort of tube extension to carry the new mirror in a cell. Undecided yet whether to do that or to grind the blank to a shorter focal length so I can just add the mirror cell directly onto the tube. There again maybe a new tube. So much to do so little time.

Original David Hinds 6" f6

Edited February 24 by GriffinUcos

[GriffinUcos]

Well, after a lengthy wait the re-aluminised mirror is back! The wait was due to me being tight and not wanting any shenanigans with customs. So the mirror flew out on Ryanair and sailed back on Brittany ferries.

My thanks to Terry at Vacuum Coatings for doing a fantastic job and for arranging to take delivery of the mirror from my friend Jimmy who happened to be visiting a relative in a hospital just round the corner. I love it when a plan comes together.

The "scratches" proved to be only in the coating and not the glass so I just need to mount it onto the backplate and give it some light. Oh, and converting a homemade 3 axis pcb routing table into a foucault tester, sorting something out with Robo_USB and grinding the other mirror.......

Have fun all and kind regards.