cleaning or recoting 8'' dobsonian primary mirror

[ZekeP]

Hi

I got this 8'' dobsonian I bought second hand like 10 years ago, and I notice it has a lot of chips on the primary mirror , like the coating has gone

Is there something that can be done? Will it cause a big reduction in the quality of the images? I had some very bad views the last time i use it

I have also problems with the finder scope attachment. The tube is deform where the , so it cannot be align to be centred properly, so i was starting to consider buying a new scope al together, maybe even upgrading to a 10 or 12 inches or a newtonian in a mount.

What do you think

[Saturnine]

Hi Zeke

I notice that no one has replied to your scope problems so thought I may . Firstly, yes the coatings are peeling off and will need to be re-done. Don't know if there are any re-aluminising services in Melbourne, you will have to try and find one or, it may be just as easy to buy a new mirror, you don't say if it is an GSO or Skywatcher scope but you can buy a new GSO mirror for approx $230 + postal costs from several retailers, stock does seem to be a problem atm though. The new mirror should fit straight back in the existing cell , in place of the old one.
The tube deformation, dents, an be easily repaired, just remove the secondary and spider and the focuser and using a small rubber or nylon hammer, panel beat the dents back into shape. May not be possible to get it perfectly round again but good enough for the finder shoe to sit firmly again. You may like to touch up the paint after that if it scuffs up while doing the repairs, some ultra flat black for the inside and whatever shade of white is required to match the outside.
Just like doing simple dent repairs on your car, or does nobody do self repairs these days, showing my age I suppose, coming from an era when it was a right of passage of car ownership that you DIY'd, or made your own scopes because they used to be very expensive. The experience and learning curve are invaluable.

Cheers

[Hans Tucker]

https://palmwayoptical.com/

[ZekeP]

Hi

thanks for the answers

I have been contact by someone who does recoating here in Melbourne, so i will talk with him

Lets see how it goes