November 26, 2015: Lunt Ca-K B1800 SECOND light!!

[michael.h.f.wilkinson]

If you already use and like the H-alpha Quark, the Calcium Quark should be fine.  The Lunt Ca-K modules are OK up to 4" aperture. Some pre-filter is needed beyond that.

[Montana]

Quark 5A !!!!!!! no way!!!! that will be no difference to WL!!!! I have a CaH filter from Omega Bob for £200 which is 5A it is rubbish and utterly useless as 5A covers the adjacent bands. I did buy it as it was stated it was 2A, I bought it and the graph showed 5A and it certainly was, I felt ripped off for £200. I can't believe the Quark will be 5A. Here is an image of CaH at 5 A https://www.flickr.com/photos/alexandra4/16590188769/in/album-72157650715279858/ basically WL.

Alexandra

[Pete Presland]

Quark 5A !!!!!!! no way!!!! that will be no difference to WL!!!! I have a CaH filter from Omega Bob for £200 which is 5A it is rubbish and utterly useless as 5A covers the adjacent bands. I did buy it as it was stated it was 2A, I bought it and the graph showed 5A and it certainly was, I felt ripped off for £200. I can't believe the Quark will be 5A. Here is an image of CaH at 5 A https://www.flickr.com/photos/alexandra4/16590188769/in/album-72157650715279858/ basically WL.

Alexandra

That certainly does not look anything like the Ca-K images we are use to seeing. Like you said more like a white light view for £200!

[Drop Of Sun]

Shame Bob's filter didn't work for you, it looked interesting on paper!

I just think, Daystar know what they are doing, they have a 5Å $4,000 Calcium H-Line filter, next to which is a little image from Dutch Open Telescope.

http://www.daystarfilters.com/calcium.shtml

Some images here:

http://www.staff.science.uu.nl/~rutte101/dot/albums/images/album.html

Some of the Calcium Quark technical blurb:

NOT COMPATIBLE WITH RED OR YELLOW GLASS ERFS.  RECOMMENDED FOR USE WITH A UV/IR CUT FILTER FOR SAFETY.

•     Calcium H line (3968.5Å), approx 5Å FWHM.
•     Integrated 25mm blocking filter, 21mm clear filter aperture.  No barlow or focusing elements included.
•     Best performance with F/10 - F/30 refractors full aperture, or SCTs and Maks.
•     Full disk viewing possible on refractors up to ~1800mm focal length
•     No aperture limitations. May be used on larger refractors for higher magnification views

More of the blurb:

https://www.astromarket.org/solar-astronomy213747/daystar-quark-h-alpha-filter/quark-h-alpha-eyepiece----chromosphere-03-05367553?language=en

Anyway, I already have a Quark that does white light   (the h-alpha is bust, waiting to hear back from SCS Astro/Daystar).

Quark 5A !!!!!!! no way!!!! that will be no difference to WL!!!! I have a CaH filter from Omega Bob for £200 which is 5A it is rubbish and utterly useless as 5A covers the adjacent bands. I did buy it as it was stated it was 2A, I bought it and the graph showed 5A and it certainly was, I felt ripped off for £200. I can't believe the Quark will be 5A. Here is an image of CaH at 5 A https://www.flickr.com/photos/alexandra4/16590188769/in/album-72157650715279858/ basically WL.

Alexandra

[Montana]

Honestly, if you read the journals, the professionals are using CaH at 0.1A increments NOT 5A!!!

It has to be a typo, it must be 0.5A to be useful. Even 2.2A is not tight enough.

Alexandra

[Drop Of Sun]

Honestly, if you read the journals, the professionals are using CaH at 0.1A increments NOT 5A!!!

It has to be a typo, it must be 0.5A to be useful. Even 2.2A is not tight enough.

Alexandra

I wouldn't know if it's a typo or not, I know hardly anything about how these filters work! I just think Daystar know what they are doing, it must offer something over white light? But I'll wait for the first light reports, for me bottom line is how it performs in the field/in images!

I like the idea of a brighter image if the image is good enough, with my Quark Chromosphere I have to use quite a bit of gain with the ASI174's fast frame rate to get the image bright enough.

Speaking of which, Michael, do you need to use any gain with your Lunt CaK and ASI174?

Some blurb from one of the Daystar manuals:

Calcium II K and H Line Filters:

Calcium II line filters are aimed at one of two important emission lines of Calcium at either 3933Å or 3969Å. The Ca II H-Line filter is designed for visual use. At 5.0Å wide, and higher into the visual spectrum, it offers a brighter and easier image to see. It is offered in

a Tilt-tune housing like the T-scanner, as tuning isn’t as critical due to the wide emission line. The Ca II K-Line 2.0Å filters are for professional applications intended for observations of the sun’s atmosphere. It is offered in the Quantum style

housing in order to precisely target subordinate lines inside the main K line.

http://www.scsastro.co.uk/userfiles/file/SolaREDi%20Odyssey%20Manual.pdf

[michael.h.f.wilkinson]

Opps, can't edit.

When I first got my CaK (Lunt diagonal) -  I wasn't expecting to see anything visually. But in actual fact even though I'm north of 40y, I could see most of the detail that I was seeing on the imaging side. 

So its worth a look even if you think you cant.

DP

I did spot a deep dark blue disk, but didn't see any detail. Didn't try for very long, however.

[Montana]

I can see just as much detail in the Lunt CaK module as with a Hydrogen alpha filter, it is so bright and absolutely the same as what I see with the camera, it isn't just for imaging. This is not the case with the CaK PST, I can barely make out that there is something purple there.

Alexandra

[michael.h.f.wilkinson]

I can see just as much detail in the Lunt CaK module as with a Hydrogen alpha filter, it is so bright and absolutely the same as what I see with the camera, it isn't just for imaging. This is not the case with the CaK PST, I can barely make out that there is something purple there.

Alexandra

Your eyes are probably younger than mine. I looked through the scope ate about 22x magnification (exit pupil 3.67mm) and still the image was pretty dark. I assume you are using the Ca-K module in a somewhat larger scope, which may also help

[Drop Of Sun]

That's interesting, Alexandra. Are your exposure times much shorter for CaK than with h-alpha? I'd love an excuse to use the ASI174 more, I have been using the Grasshopper 3 for h-alpha as I don't have to turn up gain and it has no obvious issue with Newton's Rings. Those two advantages might be gone for CaK/CaH? I prefer the ASI174 for white light with its faster frame rate and I don't need to turn up gain for that with the much brighter image using the appropriate ND filter for imaging. I should say, the ASI still performs well with gain cranked up for h-alpha, but I like the idea of gain low.

I can see just as much detail in the Lunt CaK module as with a Hydrogen alpha filter, it is so bright and absolutely the same as what I see with the camera, it isn't just for imaging. This is not the case with the CaK PST, I can barely make out that there is something purple there.

Alexandra

[michael.h.f.wilkinson]

I took these with the ASI174MM, and work at around 2-2.4ms exposure, vs 7-8.5ms for H-alpha.

[Montana]

Mine were with the Lunt CaK module at 100mm aperture. I have just gone on to see what exposures I used and I have deleted them sorry, that was a bit useless of me. But it seemed bright, it is for my eyes (42).

Alexandra

[michael.h.f.wilkinson]

My eyes are eleven years older, which might explain the difference.