CaK blocking filter question
CaK blocking filter question
Hello Everyone,
Firstly, this is my first post here on the forum. By way of introduction, my name is Brett, I live in South Africa and have just recently completed my own white light newtonian with a herschel wedge.
I have been reading and have gained a lot of information on this forum. I am hoping that there will be much more to come. On to my question then:
I am building a CaK telescope for myself for photography use. I am noticing that everyone uses the basic train of filters: ERF, narrowband CaK, broadband normally around 394nm (like Baader k line). If an ERF is used, what is the reason for the extra broadband filter? The narrowband filter already rejects these wave lengths? What am I missing?
Firstly, this is my first post here on the forum. By way of introduction, my name is Brett, I live in South Africa and have just recently completed my own white light newtonian with a herschel wedge.
I have been reading and have gained a lot of information on this forum. I am hoping that there will be much more to come. On to my question then:
I am building a CaK telescope for myself for photography use. I am noticing that everyone uses the basic train of filters: ERF, narrowband CaK, broadband normally around 394nm (like Baader k line). If an ERF is used, what is the reason for the extra broadband filter? The narrowband filter already rejects these wave lengths? What am I missing?
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Re: CaK blocking filter question
Hi Brett
welcome to that wonderful site. Have fun in the sun.
In my setup using an additional K-line filter gives a tad more contrast
welcome to that wonderful site. Have fun in the sun.
In my setup using an additional K-line filter gives a tad more contrast
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
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Re: CaK blocking filter question
By using additional filters, you get greater out of band blocking, which, like Walter says, gives extra contrast.Brett wrote:What am I missing?
Welcome to the forum btw
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Re: CaK blocking filter question
Thank you Mark, Gus and Walter.
So it is then my understanding that the narrower the band width of the blocking filter, the more contrast one will have when combined with a good narrow band CaK filter?
So it is then my understanding that the narrower the band width of the blocking filter, the more contrast one will have when combined with a good narrow band CaK filter?
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Re: CaK blocking filter question
Hi Brett
yes exactly. I hope to post today some pics with double stacked CaK filters taken yesterday at less than optimal conditions
yes exactly. I hope to post today some pics with double stacked CaK filters taken yesterday at less than optimal conditions
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
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Re: CaK blocking filter question
Hi Walter!swisswalter wrote:Hi Brett
yes exactly. I hope to post today some pics with double stacked CaK filters taken yesterday at less than optimal conditions
Where you will post them? Here on in imagining forum?
Valery.
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.
Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.
Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.
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Re: CaK blocking filter question
Hi Valery
yes here . Where else
yes here . Where else
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
Re: CaK blocking filter question
I am also wondering if it would not be better to use a second CaK narrow band filter in stead of a blocking filter. By going for the Baader as a CaK, on could just pay a liitle more and rather get Bob's CaK as a blocker.
I am waiting for my first Bob CaK, but am now wondering if I would be better off by just. Double stacking and leaving the blocker out.
Of course the appropriate ERF will be used to protect the filters.
What do you guys think?
I am waiting for my first Bob CaK, but am now wondering if I would be better off by just. Double stacking and leaving the blocker out.
Of course the appropriate ERF will be used to protect the filters.
What do you guys think?
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Re: CaK blocking filter question
I think I would see how you get on with just the one filter from Bob at the moment.
What ERF were you thinking of using?
What ERF were you thinking of using?
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Re: CaK blocking filter question
Mark, I was thinking of using a 45 degree dichroic mirror as a diagonal. The mirror would block out everything above 405nm.
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Re: CaK blocking filter question
Hi Brett
it is better to have the blocking filter even narrower, that's what practise is telling me.
it is better to have the blocking filter even narrower, that's what practise is telling me.
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
Re: CaK blocking filter question
Walter, do you mean that the blocking filter should be even narrower than the Baader CaK filter or narrower than Bob's new Omega CaK filter?
Mark, why do you suggest staying with one filter from Omega Bob? At this stage my concern is to get the best blocking filter for the job. What would you suggest?
Mark, why do you suggest staying with one filter from Omega Bob? At this stage my concern is to get the best blocking filter for the job. What would you suggest?
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Re: CaK blocking filter question
Hi Brett
I can only speak about the configurations I used so far. The blocking filter as such is important but the preblocking is at least as important. I use the LUNT hot mirror and the K-Line as prefilters followed by CAK PST #1 and LUNT CaK stack. Me too I just can't wait to see how the new Bob CaK stack performs without the CaK PST #1 and LUNT CaK stack. Finally I will stack up to five filters to see what we get.But for that I need sunshine
I can only speak about the configurations I used so far. The blocking filter as such is important but the preblocking is at least as important. I use the LUNT hot mirror and the K-Line as prefilters followed by CAK PST #1 and LUNT CaK stack. Me too I just can't wait to see how the new Bob CaK stack performs without the CaK PST #1 and LUNT CaK stack. Finally I will stack up to five filters to see what we get.But for that I need sunshine
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
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Re: CaK blocking filter question
At the moment we only have seen pictures from from highfnum using the omegabob filter, personally, I would like to see more images from more people to see how it performs.Brett wrote:Mark, why do you suggest staying with one filter from Omega Bob? At this stage my concern is to get the best blocking filter for the job. What would you suggest?
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Re: CaK blocking filter question
Hi Mark
maybe today is the day
maybe today is the day
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
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Re: CaK blocking filter question
Hope so!
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!