Solar Continuum Filters

[Purplehayze104]

Hi All

just curious, i've read posts where people are using solar continuum filter in a white light setup, my question is.... are they just used with just Herschel wedges or can they be used with solar film too, if so do they work as well with the film ?

clear skies all

regards

john

[spaceboy]

They can be used with either but in my personal experience I found it didn't work as well with film as it does a HW.

[Moonshane]

Agreed.

[Stu]

They can be used with either but in my personal experience I found it didn't work as well with film as it does a HW.

Yep, agreed here too

[Purplehayze104]

thank you all for your replies

glad you cleared that up for me could of been a costly error, hoooraar for the members of SGL

kind regards & clear skies

john

[ArmyAirForce]

I have a Baader Sol Cont filter that I use for imaging with Baader ND5 film. The Sol Cont leaks IR light, so needs to be used in conjunction with a good IR block filter. Whether this improves the view when using it visually I don't know as I haven't tried, but the IR block makes a big difference when imaging.

[Qualia]

For the solar film you don't need any other filter, although a Wratten #58 will be useful to help tweak detail of penumbra and faculae. For a good while I simply used Baader's solar film and a blue and yellow filter together to get that continuum green look (until a proper filter turned up secondhand and I felt I was ready to use a Wedge) and from time to time, I used a red filter to enhance detail in the umbrae.

[ArmyAirForce]

I did this test with an ASI120MM before getting the Sol Cont filter, and the green clearly gave better detail than the rest. The Sol Cont filters a narrow band in the green part of the spectrum, so you could just try using a green filter with Baader film which should enhance the views before committing to a Sol Cont.

[David Smith]

I use a #56 green visually with Baader ND5 film as I find it brings out details nicely. I must try other colour filters I have as I have read of a few people using blue and red filters to look for specific features.

With a 120mm aperture, brightness is an issue for me and I find sometimes that I still need to stack another ND filter at the eyepiece to allow me to see detail. I may try an aperture mask at some point. Photographically I just use the Baader film filter at the front end. I did experiment with using the #56 in the imaging train but did not really see much gain from it.

I have not purchased a Continuum filter on the basis of comments made on this forum about it being more effective with a wedge. I will get around to a wedge at some point and a Continuum will probably come with it

[niallk]

For the solar film you don't need any other filter, although a Wratten #58 will be useful to help tweak detail of penumbra and faculae. For a good while I simply used Baader's solar film and a blue and yellow filter together to get that continuum green look (until a proper filter turned up secondhand and I felt I was ready to use a Wedge) and from time to time, I used a red filter to enhance detail in the umbrae.

Nice suggestions! I've never tried any additional filtering with my Baader film. Maybe my colour filters will get some use after all :)

[spaceboy]

I had totally overlooked mentioning the wrattan #58 filter as an option. I had originally use one in my HW with good results so should be good to use with film having not got the reflective coatings that the SC filter has.

This link goes over some of the benefits of filers for imaging but no doubt similar results are obtained visually http://www.schursastrophotography.com/solar/Articles/solararticle3.html

[YKSE]

I did this test with an ASI120MM before getting the Sol Cont filter, and the green clearly gave better detail than the rest. The Sol Cont filters a narrow band in the green part of the spectrum, so you could just try using a green filter with Baader film which should enhance the views before committing to a Sol Cont.

Excellent pictures to reveal the differences of colour filters

I've only done visual with Baader wedge in 120ED, with both ND and Continuum filter, I would say the view are noticeable crisper than the color filters have shown.

[ArmyAirForce]

The seeing wasn't great when I did the tests, but still shows the green to be ahead of the rest.

Here's a Sol Cont image in better seeing.

[Purplehayze104]

thanks very much guys for all your comments & images to show the differences much appreciated

will look into a green filter as does seem to make things look a little sharper, also I think i'm using a ND5 solar film in cell, would it be worth me getting hold of the ND3.8 film as I tend to image more than I do visual really, I bought the ND5 when I was starting out with scope, trying to make the most use of it.

thanks again for all your info

kind regards

john

[ArmyAirForce]

From what I've read, ND3.8 lets more light through, allowing faster shutter speeds to counter poorer seeing. In practice, I've not found exposure to be a problem either with my Evo80ED or Explorer 200PDS, with or without barlows when using ND5 film and the Sol Cont and IR block filters. Perhaps it has other qualities that make it better for imaging, but I've not felt the need to splash out on any. I get reasonable results with the ND5, and daytime seeing, especially in the warmth of Summer, is never the most steady.

Evo80ED 5 panel mosaic at 600mm FL. Plenty of detail in the spots, surface granulation and faculae.

[Purplehayze104]

great images, ok well think I need to get a bit more practice in as been a while since done any white light pics.

regards

john

[Vox45]

Regarding the solar continuum filter, this is from the documentation:

"When using apochromatic (fully color corrected) APO-refractors (e.g. Astro Physics, TEC, Zeiss) the Solar Continuum filter may be removed, in order to observe the Sun in integral white light with the same contrast as is only achievable using the Solar Continuum filter when observing with ordinary achromates"

As I own an 80ED I thought that I could remove this filter (less glass in the imaging train) but then it says:

"At the same time, the Baader Solar Continuum filter greatly improves seeing conditions by suppling a steadier Solar image because the short portion of the Solar spectrum below 535nm is being blocked (thermally induced seeing effects become less prominent with longer wavelengths of light)"

So now I am not sure ... I'll do some tests. The fact that it makes the sun look green is not an issue for me but when doing imaging do people leave the filter and then change the color when processing ?

[Purplehayze104]

think if the image is done with a mono camera the green shouldn't affect the output from what I understand.

regards

john

[LukeSkywatcher]

Not so long ago i bought a Hershel Wedge,ND 3.0 filter,variable polarising filter and a SC filter. 

I didnt think i'd use the SC filter much. It turns out that i do use it and the one i dont need to use much is the variable polarising filter.

Can a SC filter be used with solar film?...............

Probably. Ive never tried it.

If you are thinking about a W/L setup, then a wedge is a good way to go with with an ND3.0 and SC filter.

I use mine with the 70mm Celestron Travel scope.

[allen g]

I started a thread pertaining to solar filters on the AstronomyForum Website(Eyepiece section). Received some excellent feedback and advice. It fact it change my view as to what to purchase. Give it a look well worth a good free read.

[Stu]

I started a thread pertaining to solar filters on the AstronomyForum Website(Eyepiece section). Received some excellent feedback and advice. It fact it change my view as to what to purchase. Give it a look well worth a good free read.

What advice did you receive that was different Allen? What do you think you will go for?

Couldn't find your post.....

[Vox45]

I started a thread pertaining to solar filters on the AstronomyForum Website(Eyepiece section). Received some excellent feedback and advice. It fact it change my view as to what to purchase. Give it a look well worth a good free read.

Could you post a link to that thread ? I could not find it either

[YKSE]

I assume this is the thread

http://www.cloudynights.com/topic/504185-solar-filter/

[Stu]

Not sure, was on the AstronomyForum....., not CN

[Purplehayze104]

Not so long ago i bought a Hershel Wedge,ND 3.0 filter,variable polarising filter and a SC filter. 

I didnt think i'd use the SC filter much. It turns out that i do use it and the one i dont need to use much is the variable polarising filter.

Can a SC filter be used with solar film?...............

Probably. Ive never tried it.

If you are thinking about a W/L setup, then a wedge is a good way to go with with an ND3.0 and SC filter.

I use mine with the 70mm Celestron Travel scope.

I have the very same lil frac, ive tried imaging with it but has got bit of a sloppy focuser (mind you was with a Nikon D3100 hanging off back) but spose I could try the QHY in it, what wedge did you get ? think the 1.25" lunt one is more in my price range.

regards

john