Solar filter size

[beamer3.6m]

Hi

I have some Baader solar film which I intend to use on my ED80 and also the 200p.

The 200p has a removal cap on the tube cover and as such I thought I would simply duct tape some Baader filter over the hole and then remove the small when I want to view the sun.

Is this ok/sensible etc.

I realise I will need to make a holder for the ED80 but I intend to use a 4-5" embroidery hoop for this?

Any comments appreciated.

Also, when I have my filter I note that you need to check it fro pin pricks etc but what do you do if you find any. I saw some mention of felt tip pen to cover them up. Confused - as I don't really want to go blind!

[NGC 1502]

If I found pin pricks, or any damage at all, I would not use a solar filter.

Some repair with tape, but what price your eyesight, or anyone elses ?

Not sure of the size of the removable cap on the 200p tube end cover,

but the idea is ok, just make certain nothing can come adrift, especially

in a breeze.

Best regards, Ed.

[beamer3.6m]

The removable cap is only about 1.5" - 2" across I would say.

Is that too small and/or what limitation would that impose if any.

[NGC 1502]

I was thinking that the removable cap might be a bit larger, but perhaps try

it & see how you like the view ? Or you could go up to about 3" and get the

aperture between the secondary spider vanes, but more work of course, cutting

the tube end cover. I think that's what I would do.

HTH, Ed.

[Demonperformer]

A lot of the 'specialist' solar scopes seem to be in the 40-60mm range, so it might be worth a try.

[brianb]

A lot of the 'specialist' solar scopes seem to be in the 40-60mm range, so it might be worth a try.

There's a difference here ... large scale structures in Ha are common, so far as white light is concerned sunspots are the only realistic targets. To get good resolution of sunspots (showing e.g. the filamentary nature of the penumbrae) together with resolution of the "rice grain" granulation on the "blank" surface takes 80-100 mm aperture, minimum (in my experience it's much easier with 110 mm than with 80mm; with only 80mm you need very steady seeing and a good technique to resolve the "rice grains", with 110 mm it takes bad to awful conditions to stop me).

Of course you can get a view of the larger sunspots with less (after all, exceptional sunspots are even visible to the (filtered!) naked eye!), also the awful "boiling" common in sunlight (caused by heat from the target object!) usually makes large apertures counterproductive, but I think you'd get better results from a 5-6" aperture filter mounted on your 200p than with a small offcentre aperture. A full aperture filter on the ED80 ought to work pretty well too & might be more manageable.