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A Sun observer's nightmare


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Hi everyone,

I set up my scope with my filter today, and after a few minutes of solar observing, I removed the filter for a naked eye look, but stupidly left the scope pointing at the Sun for about 10 seconds :):iamwithstupid::icon_scratch:. I can't believe I did it, but there you go. There appears to be no mirror damage, but I did melt the edge of one of the eyepieces. I have cleaned it up and tried it again and it works as before, with the only noticable difference being to the shape of the field of view (it is no longer circle). I've inspected the mirrors and they show no damage, and they gave the same views as before, but I am devastated that I did it, and I am constantly worrying that I have done some damage to my scope (130mm reflector). Here is the damage:

SANY0854.jpg

Here is the view down the focuser - is it likely to be damaged?

SANY0855.jpg

:mad::(:)

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Just shows you always need to be careful with the Sun ....

I suggest you check the collimation as your image shows a considerable offset. However it could just be that the camera was not exactly on the axis.

The danger with an unfiltered Newtonian pointed at the Sun is that the secondary mirror will crack. I think you've got away with it, with a larger scope you probably wouldn't have done. Should be OK so far as permanent damage is concerned if you can't see any effect. Just check that the secondary is still properly fixed to its holder (before you check the collimation) in case there has been any melting of the glue which is used to stick it to its carrier. The primary mirror will definitely be OK.

As for the eyepiece - you wanted an excuse to buy a better one, didn't you? :)

For naked eye views: use a pair of "eclipse glasses" or an offcut of solar film mounted in a cardboard frame, removing the scope filter is obviously a good way of having an accident.

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Thanks for the advice - it's good to hear. I guess it is an experience I will learn from, and it gives me a new respect for the Sun (credit to those who have never had such a scrape!). I'll go and check the mirror now (I'm glad about the primary - that's what I was worrying about). As for the eyepiece, I might just keep it as I gave it a clean inside and it seems to give better views now than it did, with more surface granulation visible. It's just the shape of the FOV that has changed. As for collimation, I think that's a good idea (does the fact that it burned the side of the eyepiece and not the centre suggest that it is off)?

Seeing smoke from burned plastic coming from the scope will be in my nightmares! :S

Edited by george7378
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The secondary is secure, and I looked again for damage, but there isn't any, and the views I am getting are better than yesterday (I think it's the better seeing rather than the heat!). Is it possible that the secondary is weaker, or more brittle than before, or if it didn't crack, does that mean that it's OK?

Thanks for your consolidation!

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if it didn't crack, does that mean that it's OK?

Yes.

BTW the off centre burn on the EP is very likely just because the sun drifts across the field and/or you nudged the tube a bit when removing the filter. Don't worry about it.

the views I am getting are better than yesterday (I think it's the better seeing rather than the heat!)

Very likely ... I've had a quick session before the cloud moved in (lucky to get anything at all according to the weather forecast!) & my seeing which was reasonable yesterday is appallingly unsteady today, it does vary a lot ...

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