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how safe is Solar Observing through foil like filters ?


wesdon1

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On 25/05/2019 at 06:19, Paz said:

I agree with checking your filter every time. I hold mine up to the sun and check for pinholes by eye every time I put it on the scope.

Also, I check with my hand that it's on and solid every time I put my eye to the eyepiece.

I've also got a film filter for my finder scope which helps but a proper solar finder would be good.

Yes, I do the same with my filter. I hold it up and inspect for any holes. Like you I also use my hand to check filter placement while looking in the EP. 

The only issue ive ever had with a filter was years ago as a youngin with a borrowed glass filter. It had a small unnoticeable crack. Fortunately no eye damage. It definitely made me always check after that.

Rob

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  • 2 years later...
On 25/05/2019 at 12:11, Alien 13 said:

...  most reflectors also have the option to use a filter over the whole aperture or just by covering the additional small hole in the endcap....

Alan

Do you know (or anybody else reading this) know if there are commerical solar filters designed to fit specific endcap holes?   I've got a Vixen R130 with such a hole.  I'm on the verge of making one myself, but I like to have options and prefer not to have my equipment look too "amateur who doesn't have the requistie skills" ...

 

I'm not even sure where I'd get a replacement small-hole cap replacment?

 

Thanks,

 

Stuart

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14 hours ago, NobodyReally said:

Do you know (or anybody else reading this) know if there are commerical solar filters designed to fit specific endcap holes?   I've got a Vixen R130 with such a hole.  I'm on the verge of making one myself, but I like to have options and prefer not to have my equipment look too "amateur who doesn't have the requistie skills" ...

 

I'm not even sure where I'd get a replacement small-hole cap replacment?

 

Thanks,

 

Stuart

Is this the sort of thing you are looking for?

https://www.widescreen-centre.co.uk/white-light-filters.html

 

There are plenty of other suppliers.

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15 hours ago, NobodyReally said:

Do you know (or anybody else reading this) know if there are commerical solar filters designed to fit specific endcap holes?   I've got a Vixen R130 with such a hole.  I'm on the verge of making one myself, but I like to have options and prefer not to have my equipment look too "amateur who doesn't have the requistie skills" ...

 

I'm not even sure where I'd get a replacement small-hole cap replacment?

 

Thanks,

 

Stuart

I would go for a full aperture filter if I were you. The resolution will be much better than just using the small hole so you should see more detail.

The Baader AstroSolar film ND5.0 is highly recommended, perfectly safe if used, stored and checked correctly each time, and not that expensive.

Something like this would give you a finished product which fits securely to the scope, you just need to check the outside diameter of the scope to order the correct one.

https://www.firstlightoptics.com/solar-filters/astrozap-baader-solar-filter.html

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Stu said the exact same thing when I asked about this when I was getting geared up for solar back before the partial eclipse, and having bought the sheet of Baader solar film I was able to make filters for my 127mak ( I've  subsequently adapted that to fit my 102 'frac , which is faster to set up and catch the Sun in  brief cloud gaps ... ) and from the same sheet I managed to squeeze both full and cap aperture filters for my ST80.

Doing a direct comparison in the ST80 , full aperture vs cap , did show more resolution with the full aperture.

I really don't care about how the thing looks, so the DIY cardboard, duct tape and sheet of film works for me, and the low initial cost means if my filter gets damaged (and I give it a visual check as part of my routine before every use) I'll be fine about replacing it.  But it's been used on over 40 occasions (I just checked my log book) and shows no sign of damage.

On the ST80, the 'in cap' filter I used is simply a bit of the filter sheet stuck to the inner face of the dust cap over the hole, secured with tape, it is sat there permanently, invisible inside the cap , covered and protected by the removable small cap. If I happen to be out with the ST80 and it's the only solar filter to hand, it would be better than not being able to check out big Sun spots at all .

Heather

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