Scratch on primary (8" Dobson)

[johnnyd]

Hi guys!

Well, this is my first post, and yes, this is yet another "OMG, help, my mirror is scratched/dirty"-topic and I want to apologize in advance for bothering you. However, this is my first scope and as you can imagine I'm pretty worried right now so I hope you'll understand.

Ok, now to the problem, I bought an 8" Dobson (Skywatcher) two days ago and the first thing I did was to inspect the optics ..well I'm pretty new to this so all I could do was to look at the shinny thing at the end of the tube ..and then I noticed something that had me worried, a scratch:

My question is simple, should I send it back or is the size and position of the scratch still in the "green area" thus being negligible ?

Thank you for taking the time to read my post,

Johnny.

[bish]

If I bought anything brand new that was damaged I would return it. It may be that the you never even notice the scratch when observing but it's obviously going to play on your mind.

[callisto]

Hi Johnny,

If it were me I'd call the suppliers, explain the situation and you're worries then see what they can do.

Mark

[oldfruit]

Hi, whilst it would not affect performance too much, i too would take it back if it is new.

[johnnyd]

Thanks for the replies, the problem is however that I had to wait for a month to get this scope and when I finally got it, it was the only one they had ... which would translate in another month waiting time if I would demand a new one

Yes indeed, Germany sucks when it comes to astronomy products.

[oldfruit]

Would it not be possible for them to send you a new scope and collect the damaged one at the same time? That way you could still use the scope until the new one arrives. Just a thought, not saying that the company would.

[NGC 1502]

Hi Johnny, well it sure looks like a scratch, at 10 o'clock on the mirror.

But is there any chance it could be a hair or similar ?

Either way, as others have said, it won't affect the view, but it would

bother most people, so I would sort it. You will always be looking at

it, and could cause a problem if you tried to sell it.

Imagine the advert "bit of a scratch" would put many folk off.

Good luck, Ed.

[johnnyd]

Hi Johnny, well it sure looks like a scratch, at 10 o'clock on the mirror.

But is there any chance it could be a hair or similar ?

Either way, as others have said, it won't affect the view, but it would

bother most people, so I would sort it. You will always be looking at

it, and could cause a problem if you tried to sell it.

Imagine the advert "bit of a scratch" would put many folk off.

Good luck, Ed.

I was also thinking that it might be something else so I took another dozen pictures hoping to see more detail.

This is the best one:

ignore the "doubliness", that's from not being able to hold my camera still. I think that it's either a scratch or some sort of smudge. It can't be a hair because it fades out at both sides.

Either way, thanks for your replies. Unless my supplier can provide me with a new scope before Christmas, I think I'll stick with this one.

[oldfruit]

It is really hard to see from your photo but does look like a scratch. Just remember that you are a paying customer and that you are not happy with something that you have paid for in full and expected to receive in full brand new condition.

You dont need to be rude to them but you should certainly try to get them to resolve the matter for you in a way that works for you and not just for the company you bought it from.

Hope you get sorted.

As has been said in a previous post, you will struggle to sell it on if you wanted to upgrade to a bigger scope

[johninderby]

It's very easy to remove the mirror so that you can take a closer look. Just remove the screws around the bottom of the OTA and pull the mirror and cell assembly out of the tube. It's only a minutes work.

Then you'll be able to see if t is indeed a scratch or just a hair that can be blown off the mirror.

John

[brantuk]

Looks like a scratch to me - hope it isn't. But if it is then I'd follow advice above to try get it replaced (or a brand new mirror). When you come to re-sell I don't think many would buy a scratched mirror unless it was dirt cheap.

(Someone might have dropped a collimating tool down the tube or something like that - or it coulda been "ding'ed" when it was assembled)

[xboxdevil]

Ermmm....it looks more like a hair to me! have you got anything that will blow a blast of clean air down the tube to see if it shifts or not?