Rodents have scratched my mirror is it bad...

[Quatermass]

I had a great night last night but when I put my scope away I forgot to put the dust cap on the end and a mouse got in the tube and scratched the mirror aaaghhh heres the damage that he has done is this going to be bad or will it be ok does a scratch effect the image if I am imaging?? Dam that mouse grrrrr

[Black Knight]

Sorry I can't advise you, but oh dear!

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[hemihaggis]

a mouse did that ??????? that does not look good ... tiny little scratches dust ect will not cause too much problems ,but that loooks serious sorry

[johninderby]

I think that you will have to remove the mirror and probably clean it to see just how serious the damage is. Hopefully it's just a mark that doesn't go through the coating.

John

[MjrTom]

Yeah I suspect there will be a fair bit of light scattering caused by that kind of scratch.

[Astrogeordie]

Maybe it is just the coating.

At first I would remove the mirror and soak it in luke warm water with some washing up liquid in it. Then, after rinsing, you may apply a bit of alcohol (Isopropylic alcohol or Methylated spirits) to remove the last residuals. Also distilled water can work here.

Then look through the mirror at a diffuse light source. If you see the scratch, it went through the coating. It may have damaged the mirror but not necessarely did this.

You may just use a fine line permanent black marker to blacken this scratch off against stray light, or you may go ahead to get the mirror recoated.

Light loss wise the problem is negligible, but you may get some stray light. Hence the suggestion to blacken it out.

I cannot really see a mouse scratching glass unless it had some sand on it that worked it's way in.

However it is helpful to assure no animals get near optics.

[Beulah]

One way to find out whether a mouse has been in the OTA is to check for little pea sized residual marks (mouse urine) and small dry pellets around 5mm long. Mice are incontinent.

Oh - you'll smell them too.....

[vlebo]

I've never seen a mouse with hobnail boots on

[Nexus 6]

Really bad luck Quatermass, at least you have the benefit of the advice given from members of the forum, hope its not as bad as it appears.

[cotterless45]

Bad, should produce a spikey effect on stars. If you're keen on faint deep sky objects it might be ok.

Sort out that mouse first.

[Astrogeordie]

The spike effect may be not as strong as anticipated as the scratches appear curved. So the direction of the diffraction changes along the scratch while the contribution in each direction is very small.

The same as in a curved vane spider.

By the way -- how has the picture been made ? If you use bright lights as a flash gun, even dust grains make hell of an appearance which is completely dramatising the effect they really have.

[Smeg]

Mice are incontinent.

Oh - you'll smell them too.....

Learn something new every day

[Quatermass]

Thanks everyone well I calibrated it all up this evening and it does not appear to have badly effected the viewing I focused on Vega and pulled back out of focus to see what the calibration was like and it showed nice clean circles all the way as I focused in on the star which was pin sharp so I may have got away with it. But the scratches have taken the coating off I can see right through them when I took the mirror out for a closer look sigh.

Oh well lesson learned keep that cap on when its in the shed. It was indeed a mouse found the dropping in the end by the mirror looks like it had crawled along my fishing net hopped on the scope and found its way inside. My be it was a bidding mousestronomer!. These Suffolk mice are very clumsy with there moon boots.

Astrogeordies budgies seem quite happy sitting there lol nice pic.

Oh well live and learn hey. Off out now to take another crack at the Milkyway again and lay down some mice traps

[Nexus 6]

Glad to read you have managed to get away with it.

Perhaps this little chap was looking for this lot

HubbleSite - Picture Album: "The Mice" (NGC 4676): Colliding Galaxies Stream Stars and Gas

[barkis]

Hard to Imagine a Mouses feet doing that kind of damage, unless it had clogs on. My guess would be the little critter saw it's own reflection and attacked it with it's very sharp, and protruding front teeth, thinking it was an adversary.

You could use a black fibre pen to paint out the scratches, It would make it look worse, but prevent light scatter, which will be negligble anyway.

Ron.

[Beulah]

Mice do constantly knaw at things to keep their constantly growing teeth at a manageable length. However, you would suspect the scratches would be a lot shorter than in the photograph.

[Quatermass]

No it was most defo a mouse found the dropping I reckon he had a file in his back pocket myself little vermit

[Nexus 6]

If your ok with cats get one, am led to believe mice are terrified of the smell of one so will leave the vicinity.

[Quatermass]

Sorry but I can stand cats they creep me out. I have a dog but his only good for chasing cats lol I will make sure I keep the dust cap on nice and tight and keep the scope away from the keep net that hangs near it as that is where the mouse got on to it Im sure. Cloudy tonight so no had to come in after a few quick shots of the milky way sigh

[Nexus 6]

Aaa, sorry to read you are not a fan, was not that keen myself until we took in a stray, she was in a bad way but we kept her going for 18 months but sadly had to let her go recently. Was not the sort of cat for chasing mice anyway, just slept most of the time

Still have the dog though.

[Quatermass]

Well I used to live with someone who had 35 cats Belive it or not many years ago but they drove me crazy. Funny how some people are cat or dog people I just like dogs better I guess. My dog sleeps most of the time as well

[Nexus 6]

35 cats! ....no wonder you have gone off them

[Quatermass]

I think it was the smell of the cat box that got to me in the end lol

[Nexus 6]

Here's my mutt Cosmo, American Bulldog/ Presa Canario, she is a real charm I worked at the kennels where I bought her from, one of the bosses guard dogs in waiting but she will play with anything in a friendly fashion, is now 2 year old so is still a pup really. Only problem are her ears which have needed a lot of attention over the year we have owned her.

[Quatermass]

Nice. ;-) I love my dog his getting on a bit now but still likes to chase a stick.

Id love to have an owl that would be cool