Nescafe Baader Astro Solar Filter

[ezza123]

Afternoon,

Just wanted to share my Solar Filter with you - this is to go on my 127 Mak.

The outside diameter of the OTA is 145mm and the tin I used is 155mm.

I received the Baader Astro Solar Film from FLO this morning ordered yesterday afternoon - Thank you Martin once again!

I Cut the bottom of the Nescafe Tin off then smoothed the edges with brown tape, cut a hole out of the lid, put he film over the top, then put the modified lid back on holding the remainder of the film with elastic bands, then cut some of the film away finishing with some white plastic cover that happened to be on my colleagues desk...sure he wont mind I used it!

I have not made the film tight as I have read it does not matter, but what do you do about finger prints on it?????

I will test this when I get home today looking forward to it...if the sun stay out!

thanks for looking

[NGC 1502]

Hi, looks good, my wife is used to me hunting thru the kitchen cupboards

for DIY stuff, it's amazing how you can adapt everyday items for astro use.

You could try cleaning the fingerprints off with isopropyl alcohol (from chemist)

and a microfibre cloth. The acid in fingerprints is best got rid of I think.

The Baader film is quite tough, but go carefully anyway.

Cheers, Ed.

[Earl]

Nice Filter.

Shame about the coffee

[AstroManDan]

When I made my binocular solar viewers, telescope filter and DSLR filter I did get the odd fingerprint on the solar sheet, but they do not show up visually or when imaging, so I left them alone.

The main thing to not forget is to remove the very thin transparent film which is on one side of the Baader solar filter sheet. It's really hard to see but it is there and needs removing.

Daniel

[runoffshed]

Very neat... and nice and simple.

An alternative to the large coffee container is a 2.5ltr pot of Crown Kitchen and Bathroom paint. This comes in at around 155 mm external diameter and, being plastic, is easy to clean/prepare. Of course, this may mean undertaking some DIY first so perhaps stick with the coffee.

[stuartsmith01]

on my chinese ba6 100mm binoculars i used five inch silver metal knock out bottom cake tins, looks the bees knees. p.s. no baking was involved at any time.

[ezza123]

Does it matter if when I hold it up to the light I can see a tiny pinprick of light coming through on the center - I mean tiny I could not try on the sun as the clouds came over!

[sbooder]

Yes it dose matter, no matter how small the hole, it will damage your eyes if you look at the sun through it. It is not too much of a problem with a reflector as you can just cover the hole with a bit of Duck tape and it will not show up, but I would imagine with a refractor you will end up with a black dot in your view.

[ezza123]

Thank you! its in the center and I am using a Maksutov-Cassegrain so I assume I can just patch the middle?

[sbooder]

Yep, that should be fine. I made a filter for the Venus transit, and it is now a patchwork of duck tape, but still works, and the filter is only 3", because you do not make full aperture filters for newts.

[MikeWilson]

....because you do not make full aperture filters for newts.

Why don't you make full aperture solar filters on a Newtonian telescope? I would have thought you'd want to stop all the sun's unfiltered light from getting in the front and hence reflecting up into the eyepiece ?

[sbooder]

Well you can if you like, but I would stand back when your secondary explodes they have been known to. The reason for offset small filters is to reduce heat.

[Uplooker]

Well you can if you like, but I would stand back when your secondary explodes they have been known to. The reason for offset small filters is to reduce heat.

There is no danger in the secondary or the primary exploding. The Baader solar film blocks out 99.999% or near enough of the light. There is no danger of anything getting too hot as the light is blocked before it "gets" into the scope or near the eyepiece. Why not take advantage of the apperture that you have.

Do make absolutely certain that there are no pin pricks of light, no matter how small getting throught the filter. As said above apply a bit of tape. Always check it first by holding upto the sun prior to putting on scope.

By the way I used a 7" flower pot cut down for my filter holder

[Helen]

Why don't you make full aperture solar filters on a Newtonian telescope? I would have thought you'd want to stop all the sun's unfiltered light from getting in the front and hence reflecting up into the eyepiece ?

Just to be clear Mike, what you do is completely mask all except the part with the solar filter in it - so as you thought you do want to stop all the unfiltered light

Battle Point Astronomical Association - How to Build an Off-axis Mask

Helen

[sbooder]

OK, I think I will agree to differ on this one, you can all make full aperture ones if you like.

[MikeWilson]

Just to be clear Mike, what you do is completely mask all except the part with the solar filter in it - so as you thought you do want to stop all the unfiltered light

Battle Point Astronomical Association - How to Build an Off-axis Mask

Helen

Thanks Helen (and everyone else too!),

That makes sense to me now. My newt has a removable partial cap in it and I can see that I could put a smaller solar filter in that, possibly

Solar imaging is something I haven't done yet, but I'll leave it for later - until I'm bored of the night sky at least

[yeti monster]

My Maxwell House (ground coffee, thank you very much) solar filter worked a treat. I need to make another one though, as I gave it away with my 114mm Celestron earlier this year.

Q1: Would a full aperture filter on my 10" SNT allow me to gain higher magnification (of sun spots) than if I were to just make a small off axis filter/mask?

Q2: Would the full aperture on the 10" SNT allow me to see any surface detail at all? I know I couldn't with the 114.

[Astrokev]

Since magnification is a function of the focal length and not the aperture, using full aperture alone will not change the magnification, of course. However, what I think you mean is whether a larger aperture would allow you to use a shorter f.l. eyepiece, and thus achieve a higher magnification.

I'm no expert but, theoretically, I guess this should be possible since the theoretical resolution will increase, as will the image brightness. Being the sun of course, you may be limited more by the atmospheric seeing and possibly the limitations of the solar film.

I'd be interested to know how this works in practice from anyone who uses a full aperture.

Kevin

[SeedyF]

I made one of these but I splashed out £2.79 out on a pie tin with a removable base and duck tape to hold the solar paper in place, it's fantastic. £80 worth of solar filter for about £20.