Remove dust from inside OTA?

[stefski]

Hi All,

Looking inside my Meg72, I saw lost of dust on the inside of the OTA, especially a big bit on the inside of the objective!!!! I was thinking, could I put in the hose from our Dyson vacuum cleaner and just suck it up? Is there any reason why I shouldn't do this? Do any of you have a better suggestion?

stef

[acey]

If it's not making any difference to the view (and it probably isn't) then I'd say leave it alone. But if it's a really big bit and it's really annoying you that much, the vacuum sounds a reasonable solution, with the proviso that sticking anything inside and close to the objective creates a risk of scratching the optics, depositing more dust, etc.

[Dangerous-Dave]

Another possibility might be to use something with an electrostatic charge, like a length of nylon rubbed against your jumper for a few seconds. It's not something I've tried though!

[Talitha]

Hi Stef, I had that problem with Lyra (my 120 achro:p). I got her in a trade from a friend and soon discovered she'd apparently been stored lens-side down without a cover on the other end.. there was a small 'puddle' of dust on the inside of the lens.

Lyra's pretty long, so what I did was cut and straighten a wire coat hanger and tape a cotton ball onto the end of it.. I think you call it cotton wool over there?

Then I put Lyra on her perch and arranged the Dec and RA so her lens was pointed straight up. Then very carefully I inserted the wired cottonball into the OTA and very gently touched it on the dusty lens while holding the vacuum cleaner's tube nozzle on the eyepiece end of the scope to catch and remove any falling dust.

Can't really say whether or not it helped the view though, because this was done before I took her out for a night test. But it sure felt good knowing that I'd given it my best shot before first light (which, btw, was M57 in Lyra, hence her name. )

[Psychobilly]

You could unscrew the ring from the end of the dewshield slide it back and then you can unscrew the lens cell and clean the optics inside and out... only the outer surfaces resist the temptation to take it apart any further than this....

and give the ota a good blow out the same time...

Peter...

[surfindogg]

Hi Stefski.

I am with Peter on this one. As long as you are careful, it is not as scary as it might seem. The only thing to watch out for is any stray bits and bobs from the tube itself. On one of my scopes I had loose bits of anodised aluminium in the screw thread of the lens assembly which fell into the tube so had to clean that out as well.

I have used something called ROR [residual oil remover] to clean optics - worked quite well for me.

Still enjoying the bins by the way. Found some fuzzies with them in March which I could then just make out with my eyes - completely forgot to identify them later!

Best wishes.

Andrew.

[stefski]

Thanks for the ideas guys....I'll have a look at all the possibilities. It's the 'big' bit I'm concerned about (about 2x1mm). I'm not sure what it's made of.....Anyway, I'll have another look tonight.

Glad to know the binos are working out for you, Andrew!

Stef:)

[johninderby]

Removing the lens cell to clean the optics is as easy as mentioned in the previous post.

One thing not to do however is to wipe any dust from the inside of the tube as this can leave marks or streaks on the non-reflective coating that can't be removed. Just blow the loose dust out.

John