Solar Filters

[Gazereths]

I am interested in Solar viewing, I obviously need a solar filter for either my C90 Mak or Skywatcher 130. Does anyone have any suggestions?

Is DIY a reasonable option? I've seen the solar film available quite regularly but the pre made filters always seem to be sold out (as with most things atm)

Does aperture matter when viewing the sun as it's so bright? Could I mod the main cap of my 130mm newt? (it has a small removable circular cap on the main cap, would that be suitable to modify? see pic below)

 

Any advice is most welcome, thanks.

[Louis D]

I made Baader Solar Film filters for two scopes about 20 years ago when it was first introduced.  Both are still going strong.  I followed the instructions and used sheets of craft foam board, double sided tape, strips of poster board, and clear packing tape.  It wasn't difficult at all.

Larger scopes do seem to make for a brighter solar image, but a moon filter or colored filters can be used to cut down the brightness.  I've taken to adding an IR-cut filter intended for imaging because it seems like there is an excess of IR energy causing discomfort to my observing eye.

[Merlin66]

I’m surprised you found a concern with IR transmission.

The Baader solar film has been around for many years with no reported issues.

I do recommend a Continuum or similar filter for improved contrast.

 

[Waldemar]

9 hours ago, Gazereths said:

I am interested in Solar viewing, I obviously need a solar filter for either my C90 Mak or Skywatcher 130. Does anyone have any suggestions?

Is DIY a reasonable option? I've seen the solar film available quite regularly but the pre made filters always seem to be sold out (as with most things atm)

Does aperture matter when viewing the sun as it's so bright? Could I mod the main cap of my 130mm newt? (it has a small removable circular cap on the main cap, would that be suitable to modify? see pic below)

 

Any advice is most welcome, thanks.

Hi, Gazareths,

Yes, DIY is the way to go.
Just buy a little sheet of Baader Solar Film and cover the little hole with it.
Or, if you have a spare EP cap, you can make a big hole in that and use it as a filter frame,
glue the Baader Solar Film over it (not tight, wrinkles are ok) and voilá, there is your filter.
Be sure there are no pinholes or other openings or scratches in the solar film. Your eyes are not replaceable...

[jonathan]

3 hours ago, Waldemar said:

Be sure there are no pinholes or other openings or scratches in the solar film. Your eyes are not replaceable...

This should be emphasised, safety is paramount when observing the sun. 

I've seen people use the Baader solar film on those small holes in the objective cover, should be fine so long as you take care of it (perhaps add a ring of thick card on the back side too to help prevent scratches).

I followed the Baader guide and made solar filters for my binoculars using thick white paper/card and PVA glue.

[Louis D]

On 07/01/2021 at 01:32, Merlin66 said:

I’m surprised you found a concern with IR transmission.

Yes, the longer I observe, the more it feels like my eye is being cooked despite there being no pinholes nor excessive brightness.  There is a general feeling of fatigue and soreness in my observing eye after a time without the IR blocking filter.  I noticed that the Lacerta Herschel Wedge recommends using an IR block filter, so I don't think I'm losing my mind.  They claim mainly for photography, but that means it's getting through if a camera sensor can pick it up:

IR/UV Blocking filter and Baader Solar Continuum Filter is also recommended, especially when used for photography.

If a Herschel wedge can pass IR, I have little doubt Baader Solar Film can pass it as well.

Remember, too, I'm in Texas where the sun's intensity can sunburn a fair skinned person in 10 to 20 minutes during summer noon.  I always wear a wide brimmed hiking hat when I'm outside in the summer for more than 10 minutes at a time, such as at fairs or when solar observing, to protect my bald spot, ears, nose, and neck:

[Neil H]

Thats interesting if i start to feel the same i  will pop in a IR cut filter i have one for my asl224 

[Merlin66]

Here in Australia we can get some intense sunshine - followed by drought, fire and torrential rain. Luckily not all on the one day!

 

Edited January 9, 2021 by Merlin66

[johninderby]

Yes you have had some extreme weather in Oz lately. 🙀

[Louis D]

On 09/01/2021 at 14:24, Merlin66 said:

Here in Australia we can get some intense sunshine - followed by drought, fire and torrential rain. Luckily not all on the one day!

 

Texas shares a lot of the same problems with Australia.  Of course, California has been trying to overachieve in the realm of wildfires lately.  We'll see if they get heavy rains followed by landslides next.