Baader CaK (DS) Filter First Light

[Macavity]

Okay... It will never equal a *pukka* CaK scope! But it was my Birthday
yesterday, so I now have a Baader K-Line (double stacked) CaK filter!
(Arrived in good time from "Bern at Modern Astronomy")

Throughout, the scope setup was my Altair ED66 + Lunt 1.25" wedge!
As reference point I started off with a Baader Solar Continuum Image:

For the next FOUR hours I was chasing clouds and getting nowhere fast!
The following quality graph was rather typical (Time for a PUB lunch?)



it was clear the CaK (ASI120mm) image was a LOT fainter / noiser...
On my return, lower clouds had bigger gaps, but now I had Cirrus! 

Also, to use the CaK filter with a Lunt wedge (+ internal ND3.0 filter) 
I needed "a bit more light"? At this point a warning is appropriate:

****************************************************
Modifying *any* Hershel wedge may seriously injure Eyesight! The
Lunt wedge incorporates... the Wedge which passes 4.5% of solar
heat & light (ND 1.36) plus an addition ND 3.0 Filter for visual use.  
****************************************************

It is probably worthwhile noting also Baader ND 3.8 film is NOT
intended (unsafe!) for visual use either! But in THIS vein, if you
are sensible and competent it might be noted...

Cak Filters require ND 3.8 Solar Film. Lunt Herschel wedges use
(standard visual) ND 5.0 Solar Film. The difference is ND 1.2! So
for Photo use it seems reducing the Wedge Filter from ND 3.0
to an ND 1.8 (ND 3.0 minus ND 1.2) would be "about right"? 

Conveniently Baader make an ND 1.8 filter... I have one! Sadly
I didn't have suitable threaded adaptors to permanetly modify
the Lunt wedge. But I was able to safely TEST the system out!

Remarkably, I find that Telekope Service (DE) have a "Lunt"
(sic) adapter from the 1.25" Wedge (35mm M35x0.75) to T2:

http://www.teleskop-express.de/shop/product_info.php/info/p9449_TS-Optics-Adapter-from-M35x0-75-thread-male-to-T2-thread-male.html

I have one on order! I will use it with the T2 eyepiece clamp:

http://www.rothervalleyoptics.co.uk/baader-125-clicklock-eyepiece-clamp.html

IN ANTICIPATION (With eyeballs etc. well clear of Wedge!) 
I risked my ASI 120MM camera and found it worked... The
Cak exposure settings were within a factor TWO of a Solar
Continuum filter and previous noise levels much less too!  

DESPITE the *thickening* Cirrus cloud, I show an image
via the modded wedge + DS Cak Filter...Tantalising, Eh?

Compare NASA SDO satellite Pink(!) 140nm Ultra Violet
images: https://sdo.gsfc.nasa.gov/ (on the same scale):

NO claims made! But filtered CaK could be an interesting / budget option! 
Ultimatately you really need sustained / clear skies to be totally convinced. lol

P.S. Again - Please note the eyeball SAFETY aspects re. ALL Solar imaging.

[xtreemchaos]

great shots Chris, happy birthday for yesterday. lovely C-aK. Charl. 

[Macavity]

Thanks, Charl! What do they say now on the internet: "td; dr"
(too long, didn't read?)! But I get enthusiastic about stuff? 

White light imaging is [IMO] hard! Rewards not always clear?
Might add more incentive in (increasing) absence of spots? 

Have Fun (Everyone)!

[Davey-T]

Very interesting, belated HB, you'd 'ave thought someone would have arranged for a sunny one 

Dave

 

[michael.h.f.wilkinson]

Belated Happy Birthday from me too. A double-stacked Ca-K does give a lot more contrast than just Solar Continuum. I personally don't ever look through my Ca-K module, as my eyes cannot really make out anything at that wavelength, just a featureless, deep purple disk (why does a certain guitar riff spring to mind, suddenly ). The wider Baader Ca-K filter could show a bit more, but it might also pass more near UV, which can produce long-term harmful effects

[Peter Drew]

A birthday well spent, that's the kind of considered experimentation that appeals to me.  

[Macavity]

Thanks Michael! As ever, your CaK images are much appreciated!
Ah yes, many PURPLE references: "Purple Haze all in my brain"? 
(There are a lot of scopes through which I can see rather little!)

Filters are interesting tho? Now that I have the ND 3.8 Mylar stuff,
might replace some of my (dodgy / homebrew / ND5) solar filters.
Provided one is vaguely cognisant of what one is doing...
Might try the ND 3.8 / CaK with my MAK150!

Some folks even use the CaK's (and ilk) as VENUS Filters!
My ED 'Frac allows me to see the Phases, but I have never 
*imaged* them! At first I thought "no way". But then I do
have (neglected) Watec VIDEO Cams... I ALWAYS have to
insert *humungeous* ND filters to tame the normal gain! 

[Macavity]

31 minutes ago, Peter Drew said:

A birthday well spent, that's the kind of considered experimentation that appeals to me.  

Thanks, Pete! I always sense we are of the same persuasion!