Omega bob's CaK filter
- marktownley
- Librarian
- Posts: 42564
- Joined: Tue Oct 18, 2011 5:27 pm
- Location: Brierley Hills, UK
- Has thanked: 20834 times
- Been thanked: 10503 times
- Contact:
Re: Omega bob's CaK filter
Very interesting set of images Walter. Sadly it has confirmed what I thought might be the case...
Did you overexpose any shots with Bobs filter to see if we have any ghosts with it.
Thank you for all your hard work with this.
Did you overexpose any shots with Bobs filter to see if we have any ghosts with it.
Thank you for all your hard work with this.
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!
Re: Omega bob's CaK filter
Walter, thank you for this info, really appreciated and well done!
I have two questions if you do not mind:
1.) I could not figure out why you needed to tilt the Omega Bob filter?
2.) Question that I have been thinking for a while, now that you have the Omega filter. Do you think it can be successfully double stacked for imaging?
I have two questions if you do not mind:
1.) I could not figure out why you needed to tilt the Omega Bob filter?
2.) Question that I have been thinking for a while, now that you have the Omega filter. Do you think it can be successfully double stacked for imaging?
- marktownley
- Librarian
- Posts: 42564
- Joined: Tue Oct 18, 2011 5:27 pm
- Location: Brierley Hills, UK
- Has thanked: 20834 times
- Been thanked: 10503 times
- Contact:
Re: Omega bob's CaK filter
Tilting is to throw the reflections.
I don't think I would buy one of them, let alone get 2 for double stacking. Double stacked that uneven illumination is just going to be worse...
I don't think I would buy one of them, let alone get 2 for double stacking. Double stacked that uneven illumination is just going to be worse...
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!
- swisswalter
- Way More Fun to Share It!!
- Posts: 17948
- Joined: Thu Feb 06, 2014 4:28 am
- Location: Switzerland
- Been thanked: 1 time
- Contact:
Re: Omega bob's CaK filter
Hi Valery, Mark and Brett thank you very much
some of the questions are already answered by Mark.
I have informed Bob well ahead of publishing these pics. He is on the way to find out what exactly the issue is. I can only speculate, my Money is on an uneven sputtering of the layers (something like the Daystar Quark etalons suffered from for a short time).
Valery the Gamma used is usually 800-1000. I adjust the gamma on the monitor to give me the best looking life view. By most of the pics with the Bobfilter I had to use Gamma 512 , which is the lowest, to give at least some contrast.
some of the questions are already answered by Mark.
I have informed Bob well ahead of publishing these pics. He is on the way to find out what exactly the issue is. I can only speculate, my Money is on an uneven sputtering of the layers (something like the Daystar Quark etalons suffered from for a short time).
Valery the Gamma used is usually 800-1000. I adjust the gamma on the monitor to give me the best looking life view. By most of the pics with the Bobfilter I had to use Gamma 512 , which is the lowest, to give at least some 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
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
- grimble_cornet
- Way More Fun to Share It!!
- Posts: 3537
- Joined: Tue Jul 10, 2012 5:10 pm
- Location: UK West Midlands
- Been thanked: 47 times
Re: Omega bob's CaK filter
Wow - gamma 512 is VERY low ........... don't think I have ever captured at that setting
I find that I am often disappointed with the results when I use settings which make the image look good ON THE SCREEN with the GS3 so I have been running a few experiments to determine what works best with my scopes and my usual processing routine.
I usually frame and focus at G=800 where the image looks good on the screen and then capture at G=1000 (or 900-950 in poor seeing).
This seems to produce the best results with my 'off the shelf' Lunt CaK1200.
I'm not sure if you used a standard Lunt unit in your trial?
I compared a couple of my images taken on the 4th Jan with your set and mine seem to be quite similar to your 'standard filter stack' - whatever that is?
Thanks again for sharing your experience and expertise Walter - it is saving me vast amounts of money experimenting with filters in an attempt to improve my results
I find that I am often disappointed with the results when I use settings which make the image look good ON THE SCREEN with the GS3 so I have been running a few experiments to determine what works best with my scopes and my usual processing routine.
I usually frame and focus at G=800 where the image looks good on the screen and then capture at G=1000 (or 900-950 in poor seeing).
This seems to produce the best results with my 'off the shelf' Lunt CaK1200.
I'm not sure if you used a standard Lunt unit in your trial?
I compared a couple of my images taken on the 4th Jan with your set and mine seem to be quite similar to your 'standard filter stack' - whatever that is?
Thanks again for sharing your experience and expertise Walter - it is saving me vast amounts of money experimenting with filters in an attempt to improve my results
.
.
.
Mike Garbett
Selection of Solar and Deep Sky images on Flickr: https://www.flickr.com/photos/mikegarbett/
.
.
Mike Garbett
Selection of Solar and Deep Sky images on Flickr: https://www.flickr.com/photos/mikegarbett/
Re: Omega bob's CaK filter
Thanks for informing Bob. I wonder if he could get this sorted out if he would send us a replacement filter?
- Montana
- Librarian
- Posts: 34722
- Joined: Mon Oct 17, 2011 5:25 pm
- Location: Cheshire, UK
- Has thanked: 17974 times
- Been thanked: 8907 times
Re: Omega bob's CaK filter
Bob's filter with a K line looks alright for those on a tight budget (if they have the K line already). Certainly is seems that if you only have £200 I would buy a bob filter rather than a Baader K line on it's own as you will see more structure.
Alexandra
Alexandra
- swisswalter
- Way More Fun to Share It!!
- Posts: 17948
- Joined: Thu Feb 06, 2014 4:28 am
- Location: Switzerland
- Been thanked: 1 time
- Contact:
Re: Omega bob's CaK filter
Hi Mike, Brett and Alexandra
thank you very much
@Mike and Valery My Standard set up is the LUNT CaK wedge B1200, followed by a K-Line, a CaK-PST#1 and a TS UV/IR cut filter
After having done these experimental shots, I'll switch to the following combination as my new standard:
starting from the objective : UV/IR cut 2" Beloptik, one hot mirror of the LUNT CaK wege B1200, PST CaK #1, distance 50 mm, PST CaK #1, LUNT CaK stack, UV/IR cut 1,25" from Beloptik on the camera nose. So it is a tripple stack with almost no ghosting. You can use the same setup without the LUNT CaK stack with almost the same results
thank you very much
@Mike and Valery My Standard set up is the LUNT CaK wedge B1200, followed by a K-Line, a CaK-PST#1 and a TS UV/IR cut filter
After having done these experimental shots, I'll switch to the following combination as my new standard:
starting from the objective : UV/IR cut 2" Beloptik, one hot mirror of the LUNT CaK wege B1200, PST CaK #1, distance 50 mm, PST CaK #1, LUNT CaK stack, UV/IR cut 1,25" from Beloptik on the camera nose. So it is a tripple stack with almost no ghosting. You can use the same setup without the LUNT CaK stack with almost the same results
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
- swisswalter
- Way More Fun to Share It!!
- Posts: 17948
- Joined: Thu Feb 06, 2014 4:28 am
- Location: Switzerland
- Been thanked: 1 time
- Contact:
Re: Omega bob's CaK filter
Hi Markmarktownley wrote:Very interesting set of images Walter. Sadly it has confirmed what I thought might be the case...
Did you overexpose any shots with Bobs filter to see if we have any ghosts with it.
Thank you for all your hard work with this.
yes I did, but did not record it, because there was only one small prom on the westside. the new setup showes hardly any ghosting, the Bob filter did not introduce more gosting. Of course I have to wait for a good limb with proms , then I can conform or not
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
- swisswalter
- Way More Fun to Share It!!
- Posts: 17948
- Joined: Thu Feb 06, 2014 4:28 am
- Location: Switzerland
- Been thanked: 1 time
- Contact:
Re: Omega bob's CaK filter
Montana wrote:Bob's filter with a K line looks alright for those on a tight budget (if they have the K line already). Certainly is seems that if you only have £200 I would buy a bob filter rather than a Baader K line on it's own as you will see more structure.
Alexandra
Hi Alexandra
you are absolutely right, as soon as bob has sorted out the reason of the "banding" on his filter
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
- swisswalter
- Way More Fun to Share It!!
- Posts: 17948
- Joined: Thu Feb 06, 2014 4:28 am
- Location: Switzerland
- Been thanked: 1 time
- Contact:
Re: Omega bob's CaK filter
Hi BrettBrett wrote:Thanks for informing Bob. I wonder if he could get this sorted out if he would send us a replacement filter?
I'm sure he will sort that out. Just leave him some time to do the job
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
- swisswalter
- Way More Fun to Share It!!
- Posts: 17948
- Joined: Thu Feb 06, 2014 4:28 am
- Location: Switzerland
- Been thanked: 1 time
- Contact:
Re: Omega bob's CaK filter
Hi Mikegrimble_cornet wrote:Wow - gamma 512 is VERY low ........... don't think I have ever captured at that setting
I find that I am often disappointed with the results when I use settings which make the image look good ON THE SCREEN with the GS3 so I have been running a few experiments to determine what works best with my scopes and my usual processing routine.
I usually frame and focus at G=800 where the image looks good on the screen and then capture at G=1000 (or 900-950 in poor seeing).
This seems to produce the best results with my 'off the shelf' Lunt CaK1200.
I'm not sure if you used a standard Lunt unit in your trial?
I compared a couple of my images taken on the 4th Jan with your set and mine seem to be quite similar to your 'standard filter stack' - whatever that is?
Thanks again for sharing your experience and expertise Walter - it is saving me vast amounts of money experimenting with filters in an attempt to improve my results
the standard Lunt CaK B1200 wedge is a wonderful filter set. I thought, it is the best we can get, until Mark T. jumped into my garden, grabbed my scope, added a CaK PST #1 filter and dang ;-).
As soon as I get my promissed 14mm filter fittings I can report on double stacked LUNT CaK filterstacks. I guess my supplier fears the results and therefore is postponing the delivery date almost every month
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
- swisswalter
- Way More Fun to Share It!!
- Posts: 17948
- Joined: Thu Feb 06, 2014 4:28 am
- Location: Switzerland
- Been thanked: 1 time
- Contact:
Re: Omega bob's CaK filter
Hi ValeryValery wrote:Thank you very much, Walter for your titanic labor work. It is clear now what is what.
Only few questions remain:
1. What were the gamma setting for this experiment?
2. Does the Skybender consists it's own CaK filter?
3. What is your regular filter combo for CaK imaging?
4. Can you make one more experiment - Bob's filter alone with and without tilt and at maximum contrast gamma setting?
Valery.
thank you very much
#1 was answered but I will publish the Gamma and exposure time for each avi that was stacked and published
#2 the Skybender 1,25" Version and the 2" Version come without any filters at all . You mount the filters you want to play with
#3 see my answer in that thread to Mike
#4 I did make the runs already (with and without tilt) , about the gammy, see my list which will be soon published
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
- swisswalter
- Way More Fun to Share It!!
- Posts: 17948
- Joined: Thu Feb 06, 2014 4:28 am
- Location: Switzerland
- Been thanked: 1 time
- Contact:
Re: Omega bob's CaK filter
Hi ValeryValery wrote:Another my thought - I still believe, that Omega Bob's filter can be used for large scale high resolution imaging
in the CaK instead of full disk imaging. For this it must be placed as the last element in the optical train, after a
barlow lens, near camera (as near as possible).
Valery.
an interesting thought. But why should I get an filter with banding, which works only in a certain Situation/configuration if I can get a filter (CaK PST #1 or LUNT filterstack) which work almost perfect in any situation ?
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
- marktownley
- Librarian
- Posts: 42564
- Joined: Tue Oct 18, 2011 5:27 pm
- Location: Brierley Hills, UK
- Has thanked: 20834 times
- Been thanked: 10503 times
- Contact:
Re: Omega bob's CaK filter
I've just designed it now on the computer, i'll laser cut it in the morning and post it saturday. Expect delivery in Wolfhalden early next week.swisswalter wrote:As soon as I get my promissed 14mm filter fittings I can report on double stacked LUNT CaK filterstacks. I guess my supplier fears the results and therefore is postponing the delivery date almost every month
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!
- marktownley
- Librarian
- Posts: 42564
- Joined: Tue Oct 18, 2011 5:27 pm
- Location: Brierley Hills, UK
- Has thanked: 20834 times
- Been thanked: 10503 times
- Contact:
Re: Omega bob's CaK filter
Because the filters in the Lunt or the coronado are a completely different design than Bobs... Bobs are designed for energy rejection rather than to be used in a visual / imaging context.swisswalter wrote:But why should I get an filter with banding, which works only in a certain Situation/configuration if I can get a filter (CaK PST #1 or LUNT filterstack) which work almost perfect in any situation ?
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!
- marktownley
- Librarian
- Posts: 42564
- Joined: Tue Oct 18, 2011 5:27 pm
- Location: Brierley Hills, UK
- Has thanked: 20834 times
- Been thanked: 10503 times
- Contact:
Re: Omega bob's CaK filter
Maybe i'm being too critical here, but i'm not sure I agree with this. I think there is not a huge difference between the detail with a K-line and the Bob, but the Baader will certainly give a much sharper and even image. Especially knowing you had gamma down in the 500s, says to me there's not much contrast there in the first place with the Bob...swisswalter wrote:Montana wrote:Bob's filter with a K line looks alright for those on a tight budget (if they have the K line already). Certainly is seems that if you only have £200 I would buy a bob filter rather than a Baader K line on it's own as you will see more structure.
Alexandra
Hi Alexandra
you are absolutely right, as soon as bob has sorted out the reason of the "banding" on his filter
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!
- Valery
- Way More Fun to Share It!!
- Posts: 4059
- Joined: Sun Nov 18, 2012 3:13 pm
- Has thanked: 156 times
- Been thanked: 893 times
Re: Omega bob's CaK filter
Hi Walter,swisswalter wrote:Hi ValeryValery wrote:Another my thought - I still believe, that Omega Bob's filter can be used for large scale high resolution imaging
in the CaK instead of full disk imaging. For this it must be placed as the last element in the optical train, after a
barlow lens, near camera (as near as possible).
Valery.
an interesting thought. But why should I get an filter with banding, which works only in a certain Situation/configuration if I can get a filter (CaK PST #1 or LUNT filterstack) which work almost perfect in any situation ?
You personally don't need to do so for YOUR imaging practice. I mean that it is worth to do as the test of capability of using Bob's
for CaK imaging. At least several peoples are waiting for your conclusion - is it worth to buy this Bob's filter for CaK imaging.
And my limited experience with CaK imaging tells me that the best what can be achieved with this filter is to image in high a resolution
mode when the filter is the rear element and as near to the camera as possible.
Thanks,
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.
- swisswalter
- Way More Fun to Share It!!
- Posts: 17948
- Joined: Thu Feb 06, 2014 4:28 am
- Location: Switzerland
- Been thanked: 1 time
- Contact:
Re: Omega bob's CaK filter
Hi Mark, Hi Valery
thank you very much.
@Mark Ah, great to hear about the filter housing
@Valery I'm sure you have read inbetween the lines, on top of that, the pics speak a clear language
thank you very much.
@Mark Ah, great to hear about the filter housing
@Valery I'm sure you have read inbetween the lines, on top of that, the pics speak a clear language
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: Omega bob's CaK filter
Walter, you stated that the performance of the Bob filter was not dependent on the f ratio. Did you verify this? What was the longest focal length that you attempted to use the filter on?
Reason for my question is that, maybe due the Bob filter having a different coating and design, that the focal ratio might play a bigger role than we are aware of. I would like to see how the banding issue is influenced when you take a test at about f/25 to f/30?
Reason for my question is that, maybe due the Bob filter having a different coating and design, that the focal ratio might play a bigger role than we are aware of. I would like to see how the banding issue is influenced when you take a test at about f/25 to f/30?
- swisswalter
- Way More Fun to Share It!!
- Posts: 17948
- Joined: Thu Feb 06, 2014 4:28 am
- Location: Switzerland
- Been thanked: 1 time
- Contact:
Re: Omega bob's CaK filter
Hi Brett
thank you very much. I used only f/6 f/7,3 and f/10. It does not make sense to me to use f/25 or f/30 for a full disk shot. I was expecting that the 2A filter is performing like or outperforming the CaK PST #1 or the LUNT CaK stack, neighter of that was true. On top of that, if the filter showes banding at f/6 through f/10 it will show it at f/40.
thank you very much. I used only f/6 f/7,3 and f/10. It does not make sense to me to use f/25 or f/30 for a full disk shot. I was expecting that the 2A filter is performing like or outperforming the CaK PST #1 or the LUNT CaK stack, neighter of that was true. On top of that, if the filter showes banding at f/6 through f/10 it will show it at f/40.
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
- Valery
- Way More Fun to Share It!!
- Posts: 4059
- Joined: Sun Nov 18, 2012 3:13 pm
- Has thanked: 156 times
- Been thanked: 893 times
Re: Omega bob's CaK filter
Hi Mark,marktownley wrote:
Maybe i'm being too critical here, but i'm not sure I agree with this. I think there is not a huge difference between the detail with a K-line and the Bob, but the Baader will certainly give a much sharper and even image. Especially knowing you had gamma down in the 500s, says to me there's not much contrast there in the first place with the Bob...
I saw one of Walter's CaK photo taken through a 6" refractor and 5A DayStar filter. The details are great.
So, if Bob's CaK filters have <4A FWHM and the base of their transmission is like in DayStar filter, then these
filters can be used for CaK imaging. If they are not of very high optically, then they need to be used very near
the focal plane and better after a Barlow lens.
I bet, that Bob's Ca K Walter tested, can be used near focal plane in resulting F/20 or slower.
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.
- marktownley
- Librarian
- Posts: 42564
- Joined: Tue Oct 18, 2011 5:27 pm
- Location: Brierley Hills, UK
- Has thanked: 20834 times
- Been thanked: 10503 times
- Contact:
Re: Omega bob's CaK filter
Hi Valery,Valery wrote:Hi Mark,
I saw one of Walter's CaK photo taken through a 6" refractor and 5A DayStar filter. The details are great.
So, if Bob's CaK filters have <4A FWHM and the base of their transmission is like in DayStar filter, then these
filters can be used for CaK imaging. If they are not of very high optically, then they need to be used very near
the focal plane and better after a Barlow lens.
I bet, that Bob's Ca K Walter tested, can be used near focal plane in resulting F/20 or slower.
Valery.
Don't get me wrong, I want these filters to be a success but i've seen no images from them yet that would make me want to go out and buy one. Any results from yours yet?
Mark
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!
- Valery
- Way More Fun to Share It!!
- Posts: 4059
- Joined: Sun Nov 18, 2012 3:13 pm
- Has thanked: 156 times
- Been thanked: 893 times
Re: Omega bob's CaK filter
marktownley wrote:Valery wrote: Any results from yours yet?
Mark
Not yet.
"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.
- michael.h.f.wilkinson
- Way More Fun to Share It!!
- Posts: 2559
- Joined: Wed Jul 11, 2012 8:36 pm
- Been thanked: 1 time
Re: Omega bob's CaK filter
Interesting thread, I was certainly contemplating Bob's CaK filter behind my Beloptic Triband ERF. Doesn't seem like a good idea. It is probably better to go towards a B1200 CaK (or even just a B600 in my 80mm F/6)
Solar kit: GP-C8 with Thousand Oaks Solar filter, APM 80mm F/6, Lunt Herschel Wedge, Solar Spectrum 0.3Å H-alpha filter, Beloptic Tri-Band ERF (80mm free aperture), Thousand Oaks 90mm ERF, Coronado SolarMax II 60mm with Double Stack Unit. Lunt straight B1800 Ca-K module.
- marktownley
- Librarian
- Posts: 42564
- Joined: Tue Oct 18, 2011 5:27 pm
- Location: Brierley Hills, UK
- Has thanked: 20834 times
- Been thanked: 10503 times
- Contact:
Re: Omega bob's CaK filter
michael.h.f.wilkinson wrote:Interesting thread, I was certainly contemplating Bob's CaK filter behind my Beloptic Triband ERF. Doesn't seem like a good idea. It is probably better to go towards a B1200 CaK (or even just a B600 in my 80mm F/6)
I would agree Michael.
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!