Solar filters

[Rob63]

I am about to buy the AstroZap Baader Solar Filter for my 200p dobsonian and was wondering if I should also get the Baader Solar Continuum Filter.

Does anyone have experience of this?

I am not expecting Coronado PST performance but it would be nice to be able to see some granulation and sunspot detail.

[JB80]

Make of this review what you will...

I say if it's affordable then get one.

I wouldn't mind one to be honest, something to look into for the future.

[Bizibilder]

I would just go for the Baader filter to start with (Make sure you get grade 5.0 for visual observing !) and then get others as you see fit. You will see sunspots and faculae (bright areas) and should see granulation when the seeing is good (which it often isn't!). If you are handy just buy a sheet of film and make a filter holder - you only need around 3"-4" aparture and you can do this off-axis so the light just comes into the scope between the secondary holder legs. There is little to be gained with apartures greater than this for Solar work (seeing is the limiter here - the Sun makes the atmosphere horribly turbulent and the image often wobbles and boils before your eyes.)

[RichieP]

I have one and do feel it makes a slight difference, although some may not like a green moon.

Only drawback I find is that it reflects back stray light entering the eyepiece so some sort of observing hood (e.g. tea towel) is called for.

[RichieP]

Green sun I meant to say!!

[Stu]

I re-bought one of these recently when I bought a Herschel wedge for white light observing. Ironically I sold my last one to Moonshane who reviewed it in the link JB80 posted :-).

I would hold off for a while until you've gained experience just with the Baader Film in varying seeing conditions. Whilst it does seem to sharpen things up a bit (mainly by turning everything green!), to my eyes the effect is still quite subtle and I would say the best enhancement is on areas of faculae. To me, granulation is clearer without it, for example I was able to see it over the whole disk yesterday without the Continuum filter.

Everyone is different though and it also depends a lot on the scope and conditions but I would wait and see how you get on before spending the cash.

Cheers,

Stu

[ronl]

If you are a DIY type make your own

http://www.bbc.co.uk/programmes/p014hpkh

[Rob63]

Thanks for the advice people, I think I will just go with the solar filter just now and maybe get the later on after gaining a bit of experience.

interesting point about making a filter holder and viewing with a stopped down apeture.

if I reduced my scope from 200mm (1200mm FL) to around 90mm off-axis would this have the effect of making the scope an f13.3 ?

is the slower f-ratio of benefit for the sun?

[rwilkey]

To be honest, I find using a colour filter set quite satisfactory, the #56 Green is a good one but I often use the #15 Yellow-Orange to make the white-light more interesting on the eye, the set I use is the Lumicon set as follows: Lumicon 2" Lunar & Planetary Filter Set, LF5045, a set of four (4) lunar and planetary filters: the LF1025, #15 Yellow-Orange; the LF1060, #56 Green; the LF1070, #80A, Blue; and the LF1085, Neutral Density 25. The ND25 used on the Moon is also brilliant, just the right amount of density. Thoroughly pleased with this set, bought s/h as well.

[Bizibilder]

Yes - If you reduce the aparture to 90mm the f-ratio becomes f/13.3.

The problem with observing the Sun is that it is so darned hot! it makes the atmosphere very turbulent and you will often get an image that is "boiling" furiously as you look at/photograph it. Although a scope of greater aparture will theoretically give better resolution (the ability to see fine detail) this is totally masked by the poor seeing - therefore you will not see any more detail by using an aparture of much over 4" (100mm). The advantage is you can make a smaller Solar filter for a larger scope and save a few pounds in the process (In fact a sheet of Baader film is not quite A4 when you get it and won't make a full aparture filter for a 200mm scope anyway, especially as you have to hold a bit round the edges with tape).