Lunt B1800 CaK diagonal - first light report

wow, now thats an impressive visual representation of it, I presume if you could see anything in the calk pst, then you'll see this. Now thats something to look forward to.

Dave - I second that Wow.

Michael - do you know why you haven't captured the detail that you see visually?

Don't get me wrong - striking images - but I would expect an image to capture more detail than the eye (but maybe I'm just wrong on that assumption).

Any chance of someone solar-capable (any filter) doing a time-lapse of promenances/features etc so us non-solar folk can be re-inforced on the time-scale of visible changes.

I've seen some stuff that leads me to believe that things visibly change over hours not minutes. I feel that such a project would be sweet - but that's in my ignorant and humble view point (I know didley squat about the Sun)...


Mark

mjc wrote:

Michael - do you know why you haven't captured the detail that you see visually?

I'm wondering that as well.
I'm still trying to get my head around the settings to use in the DMK control panel and CaK imaging is something new so I may get better images with more practice.

mjc wrote:

I've seen some stuff that leads me to believe that things visibly change over hours not minutes. I feel that such a project would be sweet - but that's in my ignorant and humble view point (I know didley squat about the Sun)...

Weather & time permitting, that is a project I hope to do this summer. In H-Alpha in particular where proms are easier to see, I have seen time sequence movies taken over the course of a few hours where noticable movement takes place.
From my own observations, I have seen noticable changes in proms over the course of 5-10 minutes, but the movements are too slow to notice with the human eye under constant observation.

Michael.

After another few observing sessions with it, below are a few comments:

The colour of the solar disc when viewed through the filter is closer to purple than the blue shown in the above images.

The visual image is less contrasty than the above photo appears. The initial first few seconds through the filter just show the brighter whiter active regions. The remainder of the detail can be seen but is more subtle than the image shows. A 100mm scope with the filter will show more detail than an 80mm scope, so if getting this, aim to use it with a 100mm scope if possible. However, all the detail in the above image can be seen with a 100mm scope, but takes a little longer to see than the first few seconds.

Think of it like a sketch of a deep sky object. A deep sky sketch may take 30 minutes of observating time to put together. If you show the sketch to someone else, they may expect to see all that detail in the first few seconds of observing.

I didn't see any proms with this filter yet. I don't know if this is due to a lack of proms or that they are too faint to see visually. Time will tell.

In terms of what can be seen, think of this filter as somewhere between white light and h-alpha.

A black cloth is recommended to keep stray light out of the observing eye.

Michael.

Interesting report, I didn't think you could see prominences witha cal-k filter, it is possible so?
I have to say, I thought that was the preserve of h-alpha filters and eclipses.

Dave_Lillis wrote:

Interesting report, I didn't think you could see prominences witha cal-k filter, it is possible so?
I have to say, I thought that was the preserve of h-alpha filters and eclipses.

They are there alright.
Some examples from Greg Piepol:
sungazer.net/cak.html

Just a question now whether they are visible to the eye - further observations will tell.

Michael.