Sun filter question?

[gazza63]

Hi all

Just read Matt's idea of using the small hole on his dust cap for a solar filter, (seems a good idea). I'm looking to purchase a filter in the near future. Would using the small hole in the end cap be just as good as using the full aperature of the scope? (for viewing and imaging), also, would I lose any detail?

Unless i made my own....a pre-made 6" solar filter can be expensive. So i was thinking! if i could buy a pre-made filter cover for say a 50-60mm aperature, and fix it to the inside or outside of the dust cover, would this be suffice?

Is there anybody else, that have done it this way?

Gary

[Bizibilder]

The smallest pre-made solar filters will be too large for the small dust cap hole (they start at around 80-85mm diameter). An A4 sheet of film is only around £20 and a simple filter holder can be made with cardboard and sticky tape - there are instructions on the Baader website. Some folk use a variety of objects as holders - my own is made from a plastic ventilation pipe fitting. For a 6" scope things like embroidery rings can be pressed into service. The thing to ensure is that it cannot come off too easily - for obvious safety reasons.

As to detail - your 6" scope will be fine at full aparture or you may prefer to reduce the aparture a little. It is the atmosphere that determines the detail you will see rather than the scope aparture, due to the heating effect of the Sun on the atmosphere itself.

[gazza63]

Thanks Roger

It's just that i saw this on ebay, and thought i could use the smallest one.

http://www.ebay.co.uk/itm/One-Pre-made-Solar-Filter-Sun-Film-for-60mm-70mm-80mm-90mm-114mm-Telescopes-/181156713844?pt=UK_Photography_Telescopes&hash=item2a2dc81574

Gary

[brantuk]

I personally wouldn't buy such an item from an online auction site. There's no way to verify if it's a genuine product or highly dangerous product. Imho it would be best to go to a proper well known astronomy retailer like FLO where you can be sure you won't frazzle your eyes first time you look through it.

You'll also get other associated safety advice like - remove or cover the finder - ensure the full aperture of your scope is covered before observing - ensure the film is firmly fixed and can't accidentally be blown or knocked off - ensure the scope is guarded throughout the session especially if there are kids or casual observers around - and advice about finding the sun (solar finder) which is surprisingly difficult first time out.

[gazza63]

Very wise advice. Thank you.

[Merlin66]

In fairness to the ebay supplier, he does confirm that the Baader Solar Film is used in the product......

[gazza63]

Yes Merlin, I noticed that.

I don't think Baader would make an inferior version of their film. So it has to be safe!, surely?

It just seems a good idea to me to use the small cap hole. With the sun being so bright, I may not need full aperature. Who knows? this is all new to me. I'm wondering if anyone else has used the same method.

Thanks

Gary

[Bizibilder]

You only have one pair of eyes and £20 is not a lot to pay a reputable supplier for some film that you know is the real thing. No offence meant to the ebay seller, but I would never use a solar filter unless I was 100% certain that it had the correct material in it. It only takes a split second to blind yourself. By the way you must always test your filter before every use - they can get damaged.

I must admit that I have a personal rule of never looking at the Sun - even with a filter. I only take photographs. And, yes, I did "fry" a new Canon 1100D last summer - luckily it was repairable. (I pointed the scope at the Sun for less than 5 seconds without the filter in place - we all make mistakes!!).

[gazza63]

Cheers Roger

I think i will buy a sheet of baader film and make my own.

regards

Gary