Ca-H images of August 9th

[krakatoa1883]

I have taken a couple of images this morning in clear skies and fine seeing. Unfortunately there are only few details to image as the Sun continues on its way toward the minimum of the current cycle. As usual I made use of a Quark Calcium device and a Skywatcher 80ED as I am on vacation and don't have my 150 mm achromat with me.

Btw, I am looking for a more narrowband filter to be used for imaging in the H line, or something to be put in the light path to further narrow the FWHM of my Quark. I have found lot of devices for K line but nothing for H line… Thanks in advance for any suggestions.

[ffellah]

These are great images, Raf, well done !

Franco

[marktownley]

Excellent shots Raf, the CaH quark looks to be a winner. You could try a filter from Omega Optical on Ebay maybe? http://www.ebaystores.co.uk/BJOMEJAG-EB ... 513&_pgn=1 Not sure there's anything narrow enough to be of any benefit though.

[Montana]

Very fine CaH images

Alexandra

[krakatoa1883]

Thanks Franco, Mark and Alexandra

Mark, from that vendor I could find a Ca-H 396.0 FWHM 0.2 nm (ebay object 153107244487), Quark specs are 396.8 with 0.5 nm FWHM, may be it could improve things ?

Best,

[Montana]

I have that CaH filter, it is not 0.2nm it turned out to be 0.5nm. I never use it, I am willing to sell it for a cheaper price.

Alexandra

[marktownley]

Good find Raf, that filter is specified for 25c operation, so using it on the camera nosepiece so that it gets a cool beam should work in theory and would double stack the CaH Quark. However the caveat is myself and many others have tried Omega filters with mixed results, sometimes they work, sometimes not!

[p_zetner]

Very nice images with lovely detail.
Curious about why you are imaging in CaH vs CaK.
Cheers, Peter.

[christian viladrich]

Hello Raffaello,
Forget about Omega filters. I have five of them. All are very bad. It is a loss of money.

[krakatoa1883]

Very nice images with lovely detail. Curious about why you are imaging in CaH vs CaK.

Thanks Peter. The reason why I am using a Quark CaH is that Lunt CaK modules can be used only with refractors while I wanted to do some imaging with my solar newtonian too and the Quark device allows for this because passes enough light. Having the primary mirror uncoated there is no need of an expensive front ERF.

Forget about Omega filters. I have five of them. All are very bad. It is a loss of money.

Thanks Christian, I am aware of this as I have a couple of filters from that vendor. I suppose their quality is variable and, as said by Mark above, not all filters perform fine. In some cases this may depend on an inaccurate polishing that make the filter useless at fast f/ratios. For example my 546nm is bad at f/5 but good at f/10 and excellent at f> f/12,very similar to the Baader continuum. Placed in front of my spectroscope it shows a wide weak leakage around the CWL but overall is fine.