Scary Stuff!!

[Kain]

After last night, I decided it was time to clean the primary on the dob. As I'm buy a load of trees, I tend to get little seed things that inevitably goes down the OTA and some find there way onto the mirror.

Anyway theres some screws on the bottom of the OTA, I thought I will undo them! I did and the entire bottom half of the scope came out! Wicked!

I cleaned the mirror up with just warm water and a soft shammy and then carefully patted it dry with a soft J cloth, once it was try I buffed it up gently with a lens cleaning cloth.

It's now sparkling like a new pin. I put everything back together and checked collimation - It was bump on!

Probably a pointless post really, but to me its another hurdle in the hobby that I have gotten over without any problems. In fact I now wonder what I was worried about!

Just hope for clear skies now!

Kain

[maroon bells]

They always seem to work better when they are clean!

[GordonCopestake]

Anyway theres some screws on the bottom of the OTA, I thought I will undo them!

:shock:

I buffed it up gently with a lens cleaning cloth.

:shock:

In fact I now wonder what I was worried about!

Optics are more robust than most people would have you believe. There are some links here for next time though:

http://www.astro-physics.com/index.htm?tech_support/refractors/care_refractor

http://www.televue.com/engine/page.asp?ID=143

http://www.company7.com/library/clean.html

http://www.astro-tom.com/tips_and_advice/cleaning_optics.htm

[barkis]

After last night, I decided it was time to clean the primary on the dob. As I'm buy a load of trees, I tend to get little seed things that inevitably goes down the OTA and some find there way onto the mirror.

Anyway theres some screws on the bottom of the OTA, I thought I will undo them! I did and the entire bottom half of the scope came out! Wicked!

I cleaned the mirror up with just warm water and a soft shammy and then carefully patted it dry with a soft J cloth, once it was try I buffed it up gently with a lens cleaning cloth.

It's now sparkling like a new pin. I put everything back together and checked collimation - It was bump on!

Probably a pointless post really, but to me its another hurdle in the hobby that I have gotten over without any problems. In fact I now wonder what I was worried about!

Just hope for clear skies now!

Kain

I don't want to be a killjoy here Kain, and you are obviously delighted about cleaning your mirror. The aluminium coating on the surface of your mirror, may have a hard coating over it, I don't know, if it hasn't, then it will have oxidised naturally, which will offer a modicum of protection. Whilst I am certain you were very carefull during the cleaning process, I would hesitate to touch the surface with anything other than de ionised water. I may come in for some flak here, but my only concern is maintaining the quality of your mirror.

It is quite easy to cover the surface with very fine abrasions that will barely be discernible. As they build up they will scatter light

The Telescope making book author stressed that. "A dirty mirror will always out perform a badly cleaned one". and by badly cleaned, he was not referring to it being left dirty, he meant the myriads of minute scratches placed on the surface.

I have prattled on a bit here, but believe me, my only concern is your precious mirror.

Take care.

Ron.

[geppetto]

I would hesitate to touch the surface with anything other than de ionised water

Would have to agree with Ron on this one.

Did a test on a spare bit of front surfaced mirror once and it was

quite easy to scuff the coating by rubbing with a cloth.

Should be OK though Kain but not recommended mate

[Kain]

I did use distilled water as I remember when I wrote a thread last time. The problem was there were 2/3mm seeds stuck to the primary, which did start to show on the moon, so I had no choice but to clean it.

To be honest I inspected the OTA before I just undid the screws, wasn't a case of 'Hey theres some screws, lets undo them!' It was abit more precise rather than just doing stuff [removed word] nilly.

Either way it's fantastic now.

Kain

[John]

Well done Kain !.

I've got a similar "scary" job to do on my SCT - removing the correcter plate and secondary mirror :shock:

I've got loads of helpful stuff from the web on how to do it but it's just plucking up courage and earmarking a couple of hours to do the job.

John

[barkis]

Well done Kain !.

I've got a similar "scary" job to do on my SCT - removing the correcter plate and secondary mirror :shock:

I've got loads of helpful stuff from the web on how to do it but it's just plucking up courage and earmarking a couple of hours to do the job.

John

John, I have been contemplating removing my corrector too, so I went to Jans LX90 website to read the procedure.

It does not look too scary as long as you are follow the steps carefully. I had been having a problem with not being able to achieve a sharp focus, and as I had just fitted a set of Bobs Knobs, I thought the problem might be collimation. A check and double check, showed that was not the case. I then decided to remove the plate. As I tried to remove the first little Allen screw, it became obvious that it had been over tightened, and when I checked the rest, they were all the same. I slackened them all off, left it for a couple of hours, then screwed them all back gently doing each one diametrically opposed to each other at a time in a gentle manner till each screw stopped turning with the gentle pressure I was applying The difference after that was remarkable. I have had this scope almost 8 months, and I have not had it turned to the sky yet. I have been upgrading it with various bits and pieces prior to first light. The focussing problem was detected on terrestial objects.

Anyway I was much relieved, as it was expensive to buy, and had nightmares, thinking I might have been sold a pup.

All is well now. Be careful with your corrector mate.

Ron.