Just a couple of FDs today (23rd Feb 2023

[Carbon60]

Despite a beautiful morning of horizon to horizon blue sky, the seeing was a tragedy, rendering any close up views completely useless. Anyhow, I really wanted to trial my CaK setup, which comprised a Baader K-line filter, an Omega filter at 393 +/-2nm (apparently, although I don't have the specification) and my Lunt CaK yellow filter. I stripped away the Lunt standard CaK ITFs completely as these are showing signs of ageing. I don't yet have a suitable L1 UV filter, but may purchase one to fit on the front of the 2" tube used to mount the constructed stack. I used my 72mm Altair Lightwave stopped to 43 mm to give an f10 light cone, as recommended by Mark T.

I'm pleased with the results, but I'm also keen to try it out over a range of conditions and on my larger scope (125mm stopped to 80 mm).

Here's the FD imaged as a mosaic:

20230223_CaK_FD_K-Line_Omega_Lunt BF1800 by Stuart Green, on Flickr

I reverted back to the original Lunt B1800 configuration as a baseline comparison:

20230213_CaK_FD_Lunt B1800 by Stuart Green, on Flickr

Here's the first one again, in colour:

20230223_CaK_FD_colour by Stuart Green, on Flickr

A good start, I would say, so further trials planned when the good weather returns.

I finished off with a Ha FD on my Lunt 60. This is a nine pane mosaic, presented in mono and colour. There's a bit of brightness variation across the disk from poor tuning of the triple stack

20230223_Ha_FD_mono by Stuart Green, on Flickr

20230223_Ha_FD_colour by Stuart Green, on Flickr

Thanks for looking.

Stu.

[vineyard]

Gorgeous images. I think the first Ca image with your trial CaK setup is better than the Lunt B1800 - the contrast seems better and the brightness more uniform?

Seeing your images and also Franco's images with his Daystar CaH, I have to say Ca imaging is becoming very very tempting!

[DeepSolar64]

Stu,
Very nice CaK and Ha discs. I especially love your CaK work.

James

[pupak]

Very nice set of photos.

[marktownley]

Great disks Stu!

The CaK mod setup is a clear winner over the Lunt CaK.

Next steps, crank the brightness right up with the mod setup, find the ghosts (reflections) and then tilt the appropriate elements to throw them off the disk. If this doesn't work split the 2 elements of the baader k-lin to give considerably more distance between the 2.

Mark

[rigel123]

Excellent disks Stu, the new set up for CaK is extremely good!

[DeepSolar64]

Excellent disks Stu, the new set up for CaK is extremely good!

Agreed!!

[Martin_S]

H Stu, the first Cak image is really crisp , I think it's a winner!!!

Martin

[Carbon60]

Great disks Stu!

The CaK mod setup is a clear winner over the Lunt CaK.

Next steps, crank the brightness right up with the mod setup, find the ghosts (reflections) and then tilt the appropriate elements to throw them off the disk. If this doesn't work split the 2 elements of the baader k-lin to give considerably more distance between the 2.

Mark

Thanks, Mark. Certainly this will require further tweaking. The filters are held in place with PTFE plumbing tape currently

Stu.

[marktownley]

The filters are held in place with PTFE plumbing tape currently

Heck, that's one of the best ways to do it

[ffellah]

Great looking disks, Stu ! Both lights.

Franco

[MAURITS]

Wonderful images Stu, very clean.

[arnedanielsen]

Great results despite the seeing, Stu!

Your new CaK mod looks very promising!

Best regards,
Arne

[Carbon60]

Many thanks, Franco, Maurits and Arne.

Stu.

[MapleRidge]

Outstanding images Stuart

The modded CaK filter set is certainly an improvement over the original Lunt unit. Does this modded CaK unit allow you to capture any proms?

Brian

[Rusted]

They really are amazing images Stu.

A well deserved SPOD.

[Carbon60]

Outstanding images Stuart

The modded CaK filter set is certainly an improvement over the original Lunt unit. Does this modded CaK unit allow you to capture any proms?

Brian

Thanks, Brian. I’ve yet to give it a full road test, but this is certainly in the plan.

Stu.

[TareqPhoto]

Wonderful great results for sure, specially that Cak one the first one.

Now i have questions as it made me confused about things here and also asking to learn.

What is that Lunt CaK yellow filter? How come that CaK is yellow, i didn't see any Lunt CaK yellow filter around unless it is old filter discontinued.

What is Omega filter 393? How different is that from Baader K-Line filter as well? From where did you get that Omega filter then?

You mentioned the filters and the scope, but didn't mention the camera, which one?


-Tareq

[Carbon60]

Wonderful great results for sure, specially that Cak one the first one.

Now i have questions as it made me confused about things here and also asking to learn.

What is that Lunt CaK yellow filter? How come that CaK is yellow, i didn't see any Lunt CaK yellow filter around unless it is old filter discontinued.

What is Omega filter 393? How different is that from Baader K-Line filter as well? From where did you get that Omega filter then?

You mentioned the filters and the scope, but didn't mention the camera, which one?


-Tareq

Hi Tareq,

Thank you for your questions:

What is that Lunt CaK yellow filter? How come that CaK is yellow, i didn't see any Lunt CaK yellow filter around unless it is old filter discontinued.
The 'yellow' filter is the blocking filter at the eyepiece of a Lunt CaK module. It works together with the silvered ITFs that allow 'blue' light through to narrow the bandwidth suitable for CaK line imaging.

What is Omega filter 393? How different is that from Baader K-Line filter as well? From where did you get that Omega filter then?
The Omega 393 filter is similar to the Baader K-line, but has a narrower bandpass (2nm is claimed). I got it off ebay several years ago (2017/18 I think), but I don't think they are available anymore. There's some discussion on possible alternative filters here: viewtopic.php?t=39541

You mentioned the filters and the scope, but didn't mention the camera, which one?
I used my Basler acA 2440-75 um for these images on a 2.7x Barlow (over sampled) to image disk quadrants that were stitched into a FD mosaic.

I hope these answers help.

Stu.

[TareqPhoto]

Wonderful great results for sure, specially that Cak one the first one.

Now i have questions as it made me confused about things here and also asking to learn.

What is that Lunt CaK yellow filter? How come that CaK is yellow, i didn't see any Lunt CaK yellow filter around unless it is old filter discontinued.

What is Omega filter 393? How different is that from Baader K-Line filter as well? From where did you get that Omega filter then?

You mentioned the filters and the scope, but didn't mention the camera, which one?


-Tareq

Hi Tareq,

Thank you for your questions:

What is that Lunt CaK yellow filter? How come that CaK is yellow, i didn't see any Lunt CaK yellow filter around unless it is old filter discontinued.
The 'yellow' filter is the blocking filter at the eyepiece of a Lunt CaK module. It works together with the silvered ITFs that allow 'blue' light through to narrow the bandwidth suitable for CaK line imaging.

What is Omega filter 393? How different is that from Baader K-Line filter as well? From where did you get that Omega filter then?
The Omega 393 filter is similar to the Baader K-line, but has a narrower bandpass (2nm is claimed). I got it off ebay several years ago (2017/18 I think), but I don't think they are available anymore. There's some discussion on possible alternative filters here: viewtopic.php?t=39541

You mentioned the filters and the scope, but didn't mention the camera, which one?
I used my Basler acA 2440-75 um for these images on a 2.7x Barlow (over sampled) to image disk quadrants that were stitched into a FD mosaic.

I hope these answers help.

Stu.

Stu,

Thank you very much for your answers, it surely answered my questions, i hope i can find similar items you used to do for myself.

Tareq