SolarChat!

first and only one for now - see discussion in mod section
I think both Valery and Walter are correct
Ill play some more

Oh BTW Unitron 60mm F/15

Good first light, very similar to a Baader K - line.

yes
I notice that even Walter's caH was more muted that his other ca shots

If you put two Bob's Ca H filters, the unwanted transmission will be totally blocked and the base of the transmission curve will
be almost 100% attenuated. The contrast will rise dramatically.

I believe, that Bob can borrow you a second filter for such an experiment.

Valery.

Valery I mailed Bob - to try your idea
are you kind of sure about your Idea?

highfnum wrote:Valery I mailed Bob - to try your idea
are you kind of sure about your Idea?

I am quite sure in the reason I see what the contrast is so low.

I need to note also, that you will need to place your two filters
somewhat apart to exclude reflections, may be some tilts will help too.

Valery

Hi John

a nice first light. I stick with the CaK

swisswalter wrote:Hi John

a nice first light. I stick with the CaK

I agree, CaH is a little muted for me...

Valery , Montana, Walter

Bob is send me another caH for DS

so I let you know when I have a chance

I hope Valery your on the money and thanks

Oh dear, it looks just like a Baader K line which I already have. I am really starting to regret I ordered this.

Alexandra

Montana
try to DS Kline and cah

I will report on ds asap
dont give hope just yet

OK Valery , Montana

1) Valery I did DS with caH I got a bit better contrast and some less noise
but it still nothing like a caK

2) Montana - I going to have to agree if you got a K line its basically the same

3) I will first post bob caK 2A filter as a reference - sky conditions were not great - so excuse softness - this is not a pretty picture post but a preliminary test posting

here is what I got with caH

it appears caH gives a hint of what is to come in caK , if you look closely

have DS did help get better contrast in center area of sun
I found this to be my favorite

this is from Friday - caH spots near edge

1) if expectations were for filter to do same as K or what Wah did
well it aint - stay with K

2) I have not seen any caH images with a filter that does what Wah did or what a caK filter does

3) walter's guess on performance was basically correct , Valery tip did correct some noise but not enhance basic image

4) any other tip are welcome

highfnum wrote:1) if expectations were for filter to do same as K or what Wah did
well it aint - stay with K

2) I have not seen any caH images with a filter that does what Wah did or what a caK filter does

3) walter's guess on performance was basically correct , Valery tip did correct some noise but not enhance basic image

4) any other tip are welcome

The image "centercah.jpg" is VERY much like the image which Walter took with his 5A CaK and 6" (or 5" ?) refractor.
Walter's image is much sharper and a bit more contrasty. But the nature of the "surface" or "granulation" is very similar if
not the same. And it is different to what we can see at Ca K.

I think, that it is necessary to take pictures (with DS Ca H) in better conditions (seeing, telescope and camera) and only
then judge about the performance and if it worth to make such a filter to image the Sun at Ca H line.
In any case it is better significantly than K-line.


As for tip. I believe that Omega Bob's Ca K filter, if used as DS will work well. I saw the movie (however through tree's branches)
on Youtube. Contrast is OK and if the scale, seeing, telescope and camera will be appropriate, the results will be worth to look at.


Valery.

To Stephen R.

Please, move this thread to the "Solar scopes modifications" forum. Then this thread will not sink.

Thanks,

Valery.

Valery thanks
so you think its a bit better than
Kline?

I agree I need more time with filter

If you ever come to NY area for NEAF
Sent me a note
do you have link to Walters caH shots

Also I think you made few errors in the H K ca types

highfnum wrote:If you ever come to NY area for NEAF
Sent me a note
do you have link to Walters caH shots

Also I think you made few errors in the H K ca types

Probably, I will never come to NEAF or even the USA. I live in Ukraine, eastern Europe.

I didn't any mistake concerning Ca H and Ca K.

Are you able (yourself only!!!), distinguish with confidence these two pictures? Which one is Ca K and which one is Ca H ?

Valery.

Hard to tell
I guess second one is cak
cause it has more 'white'

highfnum wrote:Hard to tell
I guess second one is cak
cause it has more 'white'

Your guess is wrong! The second one (bottom) is the Ca II H.

This simple experiment should tell you, that at a fairly narrow filter there is only a weak difference between the
K and H lines details wise.

So, when Bob will make Ca H filters narrow enough, about real 2A with well supressed base (around the peak itself)
of the transmission curve, then the Ca H filter will be useful in the same extent as the Ca K.

The Ca K seems better made by Bob and have abut 3A FWHM. Stacked as DS, the Ca K will, probably, work same
good as Lunt Ca K. Of course, they need to be more uniformly made.

On a final note - Bob's work seems not a hopeless. I personally hope, that he will reach a level when his filters will be
in use for a good reason.

I can give Bob my advise: make the main narrow filter (very narrow - 2A or even less) very near the 393nm area only
as the part #2 of the filter and the second element as the blocking filter #1 (ahead of the main filter).
The main filter can be as small as 12mm clear aperture, which will help to make them more uniform in transmission
across the aperture.


Valery.

Thanks for all your work with this filter guys. I've moved the thread to the mods section.

"In any case it is better significantly than K-line."

1) Valery why did you say that ?

I guess Montana and myself are not seeing a great difference from Baader K-Line

2) so your guess is that FWHM some where in 4A-6A area with this filter?(caH)

highfnum wrote:"In any case it is better significantly than K-line."

1) Valery why did you say that ?

I guess Montana and myself are not seeing a great difference from Baader K-Line

2) so your guess is that FWHM some where in 4A-6A area with this filter?(caH)

1. Bacause I see much finer details in 5A Ca H line than at images with K-line 80A (!!!) filter.
The image made by Walter with 6" refractor and 5A Ca H is FUUUUUULL of fine details never imaged with K-line filter.

2. I guess it is about 4A FWHM. The problems are:

a) Poor seeing.
b) Equipment.
c) small scale

Thanks Valery for always answering
sorry to hit you with so many questions
but I value the responses
And its a learning curve

highfnum wrote:Thanks Valery for always answering
sorry to hit you with so many questions
but I value the responses
And its a learning curve

Don't worry. You are welcome. I learning here too. Wonderful TOS free solar site!

Hi Mark

thank you very much. We have to extend that discussion and it will take time. Another 12 days gone without having had even the chance to capture the disk very heavy dark side syndroms, I'm suffering

VALERY Would stacking another caH filter
3of them would make band more narrow
or does law of diminishing return
set in ?

highfnum wrote:VALERY Would stacking another caH filter
3of them would make band more narrow
or does law of diminishing return
set in ?

I don't think this is a good idea - to stack three Omega filters. Too expensive! Even two filters are too expensive cause it is
possible to buy CaK PST or Lunt B600 for comparable or even less money and have CaK with narrow enough bandpass.

Valery

well
I took a few tips from Valery to heart
1) CAh with extra element filter that bob sent me
2) increased FL now F30 for more parallel beam

BUT seeing conditions were horrible - sun looked like I was at bottom of a pool
high winds - i was forced to use my 60mm unitron which is pushing that little baby

none the less if you look close thru the mess
it looks like I have potential for a good image - surface looks more caked
I feel silly posting such a mush image but that is what I have now

Hi John

bravo you went out despite the horrible seeing conditions. The result however is not convincing me

Well until weather breaks
I'm taking a break
it is just to fustrating
my answer is I dont know

I have a question about daystar caH
this is mostly geared towards Walter
but anyone may chime in

why was 5.0A chosen instead of 2.0-3.0A like thier caK??

highfnum wrote:I have a question about daystar caH
this is mostly geared towards Walter
but anyone may chime in

why was 5.0A chosen instead of 2.0-3.0A like thier caK??

To make it visually usable for those, who can see this light, IMHO.


First thing what you need to improve is the camera.

highfnum wrote:I have a question about daystar caH
this is mostly geared towards Walter
but anyone may chime in

why was 5.0A chosen instead of 2.0-3.0A like thier caK??

Hi John

as simple as that, it was the only filter available. Soon I will receive Bobs CaH and can double stack

Walter thanks for taking risk on this one

but I wanted to know why Daystar chose that bandwidth

highfnum wrote:Walter thanks for taking risk on this one

but I wanted to know why Daystar chose that bandwidth

I repeat for you: To make it visually usable for those, who can see this light. Ca K is worser for visual than Ca H.