Have I Broke It?

[Stephen]

I'm sure I saw a thread like this today, but I can't find it for the life of me

I was just (as you do) removing the finder base from my 200P - carefully holding the nuts as I removed the screws so they wouldn't drop on the primary.

As the second one came out I let out a sigh of relief, followed by what I can only describe as a girly squeal! The finder base has a backing plate I didn't spot .........

You can guess the rest. Despite me thinking I had the scope horizontal, I didn't. The plate has hit the primary and left a scratch. It's about 15mm long and 2/3mm thick. There's also a small scratch just next to it (where corner of plate impacted I'm guessing) about 2mm square.

How busted is the scope going to be now? Bearing in mind I'm trying to start doing imaging should I be looking out for a new primary?

Thanks in advance

[CGolder]

oh dear,

Strangley i did the same thing, it never did effect the views at all.

Some people suggest blacking out any damaged area to stop stray reflections

[John]

Sorry to hear about this. I guess the lesson is always to have your scope tube completely horizontal when doing any work on it - but that's hindsight of course.

I doubt you will notice any difference in the performance for visual, not sure about imaging though.

It will have put a dent in the re-sale value though, I'm afraid

[brantuk]

The 24" reflector at Keele Uni has a chunk the size of my hand out of the primary edge but they still use it for imaging and observing with amazingly good results. There will be a tiny light loss from yours but still very useable

[ronin]

It will make no difference, you would need an awful lot of damage to the mirror for the image to show deterioration. It is a property of the incoming light being collimated. The information is over the whole diameter.

[Ags]

Isn't there a major observatory somewhere in the USA with bullet holes in the primary of one of its larger scopes?

[Stephen]

Lesson learned, I shall not "think" it's horizontal again! Thanks for the input

[Moonshane]

unlucky. best bet is forget it and never look down the tube again. just enjoy the scope and never forget that there's more to most things than holding your nuts.