Oh what have I done.

[Doc]

Oh No I've knackered it......

I haven't yet got round to putting wheelbarrow wheels on my dob yet but I saw it was a clear night so I had to go outside.

Remember that this is a 16" dob and weighs a fair bit. Both myself and other half both grab a handle to lift it over the conservatory step maybe 6" high and she dropped it.

It went with a loud bang and I went "OH NO".

Anyway before clouds came in I checked and all seems ok with mirrors but something is way out.

I'm not even getting donut shapes, it's like really bad coma on the stars. I looked at Jupiter it looked blurred and even the moons had tails like comets.

It's too dark to do much now will have to wait till tommorow.

Any ideas guys.

[Keagle]

I have no authority on which to say this, but perhaps one of the mirror cells has "slipped"? Causing the mirror to heavily tilt to that side.

Kurt

[Doc]

Thanks for the reply.

I did check the clips once I got it back in doors annd all seems well.

I hate it when this happens.

[barkis]

Doc. with luck, at worst, the violent shock of the impact will have dislodged the secondary mirror, and it will very askew in it's relationship to the main mirror. The main mirror too may have shifted position, so probably all you will need to do is re collimate your optics..

Plenty of guidance on here if you need to do that.

Good Luck.

Ron.

[jonbarr87]

Ok well I cant offer any advice beyond the "obvious".... but I HAVE TO give you credit for not using a few other "choice words" at the time of the incident..... As well as not curling into a ball and crying lol

[knightware2]

Doc,

This does sound scary, but you may be able to reassure yourself (and the other half who must feel terrible.) Look carefully at the primary and the secondary for a chip. If you don't see any, you can recover.

Most likely as the others have pointed out, you've knocked out the collimation, probably to some degree on both mirrors. Do you have, or do you know someone with collimating tools - at least a site tube and cheshire?

- Phyllis

[Doc]

Thanks Phylis...

I've checked it for chips and there are none so thats cool.

I only have a celestron collimation cap and have always just used this and have always got it pretty close.

I had a look today and both mirrors, but especially the primary were way out.

Anyway re collimated so will see the next clear night.

I still have a nagging doubt in my mind as to why it would move so far, surely the mirror is not that loose in it's holder.

[wingman]

Hope it's all ok Doc, it must have been a horrible feeling for both of you.

[Astro_Baby]

Ewwwwww - bad moment there and although I am largely pretty even tempered ( patince is a virtue and me being a woman and all that ) but with me anyone touching the scope when I am in the room does so at their own risk

[steppenwolf]

One of my big fears this, although my Newtonian is only a 'baby' 10". I hope the re-collimation has done the job - it is at times like this when at least setting the ball rolling with a laser collimator can be a godsend as you can immediately see what has moved where!

[Doc]

Just to let you guys know that I have just looked at Jupiter and collimation seems pretty good can see the bands, as it's very low with lots of atmospheric probs it's not looking bad.

Stars are not pin point however but not to bad. I need to get one of these cheshire collimators.

Even though skies are clear seeing as normal is rubbish. Why can't I live at a darker site.

[barkis]

It has been rather warm today Doc. At least it has up here in Cumbria, so I hope you allowed plenty of cool down time. And don't forget, the mirror is always chasing the outside temperature as it cools down. You really ought to see the havoc that causes just above the mirrors surface.

Ron.

[benjiman46]

Might sound a bit obvious but are you sure it hasn't put a dent or slight ding in the optical tube? shine a torch down the barrell and have a look. If nothing is found then try 're-aligning' as i call it because i cant pronounce or spell collimitating or whatever it is lol Good luck!!!

[Davree]

I'm glad it's not seeming as bad as it first was!!

I don't know what I would do if that happened to my scope. I would probably curl up and :crybaby: .

Hope it's sorted soon!!

[scotastro]

Doc

Hope everything is ok.

If things still look iffy something else to check is the mirror cell itself. I remember reading about the old solid tube 12" revelation that the primary mirror support was a bit weak. A 16" mirror weights a lot more so it could have distorted the support a bit.

Fingers crossed for you.

Mike

[knightware2]

Doc,

You don't want the primary bound *tightly* because that would actually flex the mirror enough to distort images. It doesn't seem so, but glass does flex. On the other hand, it should not be loose enough to move around.

What is the f ratio of your primary?

- Phyllis