pinholes in Baader solar film

[janoskiss (Steve H)]

Finished my solar filter for tomorrow. Then shock horror, on close inspection at a halogen desk lamp: pinholes!! Not just one or two either, but quite a few! Now I'm looking up Baaders info, and their instructions actually state:

...inspect the cell for light leaks prior to using it on your telescope or binoculars. You must be sure that absolutely no unfiltered light gets through. Use a black felt-tip marker on the inside of the filter (for esthetic appearance) to cover tiny pinholes in the filter material. Now
your “do-it -yourself” filter is ready. Enjoy!

So they are actually expecting you to find pinholes in the stuff! .. and a black marker to save you from blindness! okay I know I'm exaggerating, few small pinholes will not cause blindness, but still, I appreciate why some dealers refuse to stock the stuff and insist on solid glass filters.

So it's a stop off at the newsagent's for a permanent marker before work tomorrow. (although the forecast is not looking too good)

[rogerg (Roger)]

I haven't found any in my film yet but I have been waiting for them to appear, it feels like such flimsy stuff. I decided not too long after buying mine that I'd only use it for photographic work, I simply don't like risking my eyeball. The webcam I don't care about, it's cheap and replaceable.

Scary that you found so many. How old is your sheet of it?

Roger.

[casstony]

Doesn't sound too flash at all. I've used Baader solar film for a few years and haven't had any pinholes - I just now checked it again after your post Steve. I've mostly given up using it in favor of the PST; the solar film shows sunspots better but I just like the added safety of the PST. I gave myself quite a shock once by almost looking through my scope before attaching the filter.

[janoskiss (Steve H)]

Roger, you're right that it feels very flimsy.

This is brand new stuff I have here. The pinholes are indeed very tiny (except for one that is not very tiny, just tiny). You need to hold the film right up to a bright lightsource to see the pinholes easily. They are not all over the whole sheet but in several relatively localised areas.

I'll give the filter a go tomorrow if the clouds clear, but I'll invest in a solid glass filter after that. Astro-optical tell me that they can have them custom made for any scope (to fit OTA to the mm), so it's a snug fit. Costs about the same as ready-made ones in fixed sizes.

I think I'll go the custom fit job for the Mak. A 6" scope should be a nice aperture for solar observing... no? I'm thinking the Sun must be plagued by thermal noise more than any other celestial target, so any more resolution than a 6" scope has is not needed...

[spudrick]

I have the Baader film as well and this morning watching the Transit i noticed the pinholes you describe. When changing eyepieces i looked through the back and could clearly see some very tiny pinholes.
Must be in the manufacturing process as the Film is brand new and used for the first time.

[OneOfOne (Trevor)]

I have read similar instructions my self. Rather than use a "texta" I would put a dob of white out on the hole, just to be sure!

[acropolite (Phil)]

I bought the thousand oaks film, Zero pinholes and a pleasant orange colour when viewing as well.

[stephenmcnelley]

Janoskiss i have had similar issues with the film, but having kept lots off small off-cuts i cover the occasional pinhole by gluing a tiny patch over the fault using something inoquous like a water based gluestick.
It works well and doesnt effect image quality providing you use a minimum size patch.

[Omaroo (Chris Malikoff)]

Originally Posted by acropolite

I bought the thousand oaks film, Zero pinholes and a pleasant orange colour when viewing as well.

Phil - I agree with you. I've been fortunate enough to get Ving's offcuts - large enough still for full aperture on my ETX-60 refractor. The Thousand Oaks film is totally devoid of any pin holes, and is actually thicker, I think, than the Baader film. It's more like x-ray sheet film in it's feel. I have absolutely no wrinkles or holes over the 60 mm or so that I'm covering.

[ving (David)]

and from the original sheet my 8" full aperture thousand islands... i mean oaks has not a single pinhole in it and gives a nice natural orangey colour.

if only the clouds would go away.