View Full Version here: : Canon HA Filter on the Sun
13-03-2012, 02:06 PM
I took some images of the Sun, prime, using my 5d which has the HA filter.
Are all the spots on the image sun spots or mainly dust.
No sign of dust normally taking deep sky images. Well, almost none.
13-03-2012, 02:54 PM
Well, I have done some more testing and it is clear to me that the camera need a good clean out by Canon.
Don't you agree ?
13-03-2012, 02:56 PM
Apart from allowance for shooting through the atmosphere, rotation and colour it looks pretty much the same as the image at http://sohowww.nascom.nasa.gov/data/realtime/hmi_igr/512/ but you'll have to be quick as that updates.
13-03-2012, 03:38 PM
Thanks for pointing out another solar image. I looked at a few more after that one.
I am still not sure about any dust present. Actually, the Mylar filter is pretty crappy after many years, so I do intend replacing it with new filter material.
One more thing. The purpose of me trying out the HA filter in the 5D, was that I was hoping it would show similar images of the Sun as one would when using a visual HA filter.
It looks although I was expecting too much ?.
13-03-2012, 03:50 PM
Thanks Andrew for pointing out another solar image, I did look at a few more after that. I am still not convinced about the dust. Actually, the Mylar filter I used is pretty crappy,seen lots of wear over time. I will replace it with some new solar material I have got. The purpose of me taking the images of the Sun through the HA filter in the 5D was that I was hoping to get similar images to those one get using (dedicated?) HA filters on scopes . But not so?
14-03-2012, 09:57 AM
The solar scopes have filters that go down to <1 angstrom , typically 0.7, 0.5 or 0.3 Angstroms.
The standard Ha filters are nowhere near the same league
e.g. a 12nm one = 120 Angstroms
Also, the solar film effectively blocks nearly all the Ha light anyway (I think?!?).
To get results like those with solar scopes, you need an expensive <1 Angstrom Ha filter, and an Energy Rejection filter that lets Ha through.
These cost the same or more than a dedicated scope, there is no cheap way unfortunately.
The cheapest option is to modify a PST to work with a larger aperture scope, but you are still looking at over a grand by the time you are done.
14-03-2012, 10:02 AM
Take a look at the sensor, you will be able to see if it needs a clean or not, and you can do it yourself with:
14-03-2012, 11:14 AM
As Peter says, solar Ha needs specialised filters.
If you are using the Baader solar film (non mylar) then the addition of a UV-IR block filter and a green (or continuum filter) will enhance the images. Great for surface features.
14-03-2012, 01:47 PM
Thanks for your replies.
I was, at best, hoping to bring out some details on the surface of the Sun. The check for dirt on the filter was done early in the piece. I have just finished framing the new non-Mylar material from Baader in a cardboard holder, this should improve things a little. Also, the idea of the the usage of the UV-IR filter with the Continuum filter looks promising.
15-03-2012, 11:03 AM
Regarding the advice from Merlin66
re: the usage of a UV-IR filter and the a Continuum filter in order for me to, hopefully, see some details on the surface of the Sun.
I sought availability of the Continuum filter, and the staff from both the two stores
were unsure as to what could be seen on the surface of the Sun, besided the sunspots.
using those 2 filters, In particular, why the UV-IR filter?
Just to repeat. I have the latest non-mylar solar filter material from Baader, and a Canon 5D with a HA filter installed, replacing the original filter.
My scope is an 12 inch Newt.
I am looking for some more light (shielded,of course) on this matter.
15-03-2012, 03:21 PM
The continuum filter only enhances the visible features - surface granulations, umbra/ penumbra etc.
When you say you have a "replacement Ha filter" fitted - what do you mean?
The normal replacement is just a UV-IR blocker.
The Baader Solar film has a slight IR leakage which doesn't affect visual but can give some loss of contrast with non= IR blocked CCDs.
Hope this helps.
15-03-2012, 04:42 PM
The replacement CMOS filter is an Baader 2459214
DSLR ACF Astro conversion filter
I probably wrongly described it. Hope this helps
15-03-2012, 04:52 PM
Yes, That's just the UV-IR (400nm-700nm) blocking filter.
15-03-2012, 05:07 PM
What?, it sounded far more sofisticated then that when I bought it.
So, all I need now is the Continuum filter in order to see some granules a. s. o. on the surface of the Sun?
15-03-2012, 05:26 PM
It's real function is to replace the optical thickness of the colour balance filter which is removed to enhance the red response.
This allows auto focus function to work 100%
(The filter that is left behind....the front dust shake/ anti alias filter is actually a UV-IR cut filter! So if you don't really need 100% accurate auto focus, you don't need to replace the colour filter! I use my Canon with no replacement and mum and the kids can't tell the difference)
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