Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.


Sign in to follow this  

Sun 21-7-2012 Ha + CaK

Recommended Posts

The bright thing in the sky appeared again. So I shot it.


Baader CaK + ND5 filters, DMK41, Canon 100-400L


Sun 20120721 Ha by Crestie Crazy, on Flickr

DMK41, Celestron X-Cel 2x barlow element, Coronado PST

Trying avistack for first time today so both stacked by it. Wavelets applied in Registax 5.1, finish in PSE9. Both files were just over a minute for over 1000 frames each. I have no idea what I'm doing in avistack but have now found the full auto mode. That'll do for now! This is now my best ever detail level in H-alpha.

Still got a LOT more data to go through! Will concentrate on the Ha data, due to field of view limits with the barlow, I have to do the sun in two halves. So I've got two sets for prominences and another one for surface to go, then the nightmare of blending it that I never got working well... The CaK data still isn't sharp... in part this might be reaching the limits of the 100-400L and I need to get a bigger scope on the job, once I've ordered the appropriate mounting bits.

Share this post

Link to post
Share on other sites

CaK is always difficult due to the shorter wavelengths.

Your images show great promise, no need yet to go for larger aperture...just go easy on the wavelets - they look a little over cooked.

Onwards and Upwards

Share this post

Link to post
Share on other sites

Optically speaking, I thought the shorter wavelengths would actually help by delaying the onset of diffraction effects?

Am I overcooking the wavelets? I am wondering if this might be a case of something I don't or can't see yet... I know I'm not there yet on the CaK one, with the wavelets not doing much at all unless turned up to 11. I am quite happy with the H-alpha one though, putting aside I haven't started tackling the prominences separately yet, or the missing half...

Share this post

Link to post
Share on other sites

I have my wavelets settings stored as a RMV files (registax wavelets file) - this I use as the starting point on each and every solar image that I take. On most of them I don't do anything else in Registax.

I can mail it to you if you want to give it a go?

I've never had a go with a CaK scope, so cannot help... But the Ha one looks good, if it was a DSO image I'd say you'd over sharpened, which I guess would be the wavelets...


Share this post

Link to post
Share on other sites

Thanks for the offer, I'd like to give that a try.

I did process this as if I was doing terrestrial photography, where I aim for a reasonable of apparent sharpness at pixel level without introducing artefacts like excessive contrast or halos. And this was the first time I had data capable of providing that... after my tinkering with wavelets I applied further fine sharpening in PS.

Share this post

Link to post
Share on other sites

It was a bit of a miracle to see the sun again and you got some fabulous pictures, well done :)

I think what Merlin means about the wavelets is, if you see a white edge with a black halo next to it in your image you have pushed a little far. As soon as you see this effect, edge back until it just disappears, then you have the wavelets perfect.


Share this post

Link to post
Share on other sites

It's been near enough clear all yesterday and today so far.

As for the wavelets, I know about clipping and generally it isn't a problem except on the limb where it seems no matter what setting I use I get the ringing (similar to using unsharp). The only way to prevent that is to back off so far you don't get any significant benefit elsewhere. I suppose I could try a blend optimised for different areas...

Share this post

Link to post
Share on other sites

Hi Stephen,

Thanks for sending me over the Tif. I've had a bit of a play - it's lovely to have a bigger file to play with - I love the DMK21, but the images are on the small side.

Here is my attempt at processing.

1. I used my standard Wavelets Scheme in Registax5.

2. Then into PS, carefully (I didn't do it carefully enough) mask around the solar disc.

3. Then invert selection, copy. (delete selection from background layer).

4. Create another layer and paste

5. I then use my "Colourise Sun" action on both the prom layer and disc layer.

6. Did some small curves adjustments on the prom layer.

Save as JPG

Cheers Stephen, enjoyed that :)


Share this post

Link to post
Share on other sites

Yup, you definitely bought out the prominences. Think I'll have to try that. I also got some data exposed for the proms, but then I have the fun of re-integrating them...

Part of why I went for the DMK41 over the smaller/faster ones was the size. Coming from a SLR background, all astro sensors that have a sane price tag seem really small to me! I know in this specific application, the data transfer bandwidth will limit things, but still...

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Similar Content

    • By acr_astro
      Hi all,
      as well today the sun is shining brightly here. I set up the Lunt to have a look at it, at first just for observing. However, somehow I cannot resist and have to do a sketch This time I've chosen reddish pastels on grey paper to better catch the color of the view in the eyepiece.

      Telescope: Lunt LS50THaB600PT
      Eyepiece: Celestron X-cel 10mm
      Date & Time: May 15th, 2020 / 1400-1430 CEST
      Location: home terrace, Dusseldorf region, Germany
      Technique: red and orange Koh-i-Noor pastels and pastel pens on grey Canson Mi-Teintes pastel paper
      Size: 24 x 32 cm
      Clear (and sunny) skies!
    • By Bajastro
      I finished observations of the Mizar A spectroscopic binary.
      Calibration for the Hα line made on water lines contained in the Earth's atmosphere.
      I used LowSpec spectrograph with 1800 grooves/mm reflective holographic grating, APM APO 107/700, QHY163M camera and HEQ5 mount with guiding.
      It turned out that the Earth's movement practically compensated for the radial velocity of the Mizar A system.
      Based on the analysis, I received the result:
      vr = -8.8 km/s
      in fact the system is approaching at a radial velocity of -6.3 km/s.

      I also determined the phase plot of radial velocities based on my measurements for the Na (together for both lines) and separately for Hα line:

      Error is based on half my spectral resolution (0.2 Å/pix corresponds to rv = 10 km/s). Each measurement corresponds to the stack a few images.

      The most important purpose of observing this binary system was to record the historical Ca II line (often called as CaK, 3933.66 Å).
      The distances in the violet part of the spectrum are almost 2x smaller than the corresponding shifts for the Hα line. This line initiated the discovery of spectroscopically binary systems, and Mizar A was the first discovered system of this type.

      These were the spectroscopic observations in the 19th century:

      Source: https://www.leosondra.cz/en/mizar/#b20

      I've made several observations of this line in the last two weeks:

      Animation showing the changes in the CaK line based on my observations:

      Not only the Ca II is split, but the surrounding lines also, shown below in a wider environment:

      Balmer hydrogen lines are becoming more dense as Balmer's gap approaches (3646 Å).

      Observation result of the Hα line:

      And animation showing the changes in this line:

      The Na I doublet was much more difficult to observe, because stars with A spectral type contain very faint lines of this metal:

      Animation showing the changes in the sodium doublet:

      We received the sodium quartet
    • By Bajastro
      1. Alcyone (Eta Tauri, η Tau, 25 Tau) in the Pleiades open cluster, spectral type B7IIIe+A0V+A0V+F2V.
      This star is a multiple system, but my goal of observation was the H-alpha profile of the main component:

      Horizontal axis scaled to radial velocity:

      2. Pleione (28 Tau, BU Tau) also in M45, spectral type B8Vne, variable star, the brightness changes in range: 4.83 - 5.38 V. 
      This is the faintest star, which I observed with using APO 107/700 & Low Spec spectrograph 1800 l/mm. 
      It was difficult, but obervation was positive (high gain, exposure time 4 min):

      3. Tianguan (Zeta Tauri, ζ Tau), spectral type B1IVe+G8III: (mark ":" according to the VSX database means uncertainty).
      This is an eclipsing binary with variability type E/GS+GCAS, period is 133 d. The brightness changes in range: 2.80 - 3.17 V.

      4. Cih, Tsih (γ Cas), spectral type B0.5IVpe, variable star with a magnitude range of 1.6 to 3 V:

      5. Alnitak (Zeta Orionis, ζ Ori), spectral type O9.5Ibe+B0III. Variable star with a magnitude range of 1.74 to 1.77 V.
      Spectral lines have characteristic P Cygni profile, below H-alpha:

    • By Hughsie
      I first came across the term ‘Solargraphy’ on this forum and was directed to website dedicated to the art of Solargraphy.
      This is a basic photographic method of recording the path of the Sun as the year progresses. This image commenced on 22 June 2019, the day after the Summer Solstice when the Sun was at its highest altitude in the noon day sky and finished on 22 December 2019, the Winter Solstice when the Sun is at its lowest point at noon. The silhouette of the neighbouring properties can also be made out in the picture.
      Using a basic pinhole camera I was able to record every clear day the track of the Sun across the southern sky, each day  the Sun’s altitude was getting slightly lower.
      Whilst the camera is basic, the main challenge is to avoid water damage and as you can see from the image some rain has managed to find its way inside. However, the pinhole camera is cheap to make with the following purchases made via Amazon;
      100 cable ties £5.49
      20 35mm plastic film canisters £8.88
      100 sheets of Ilford Multigrade 4 glossy photographic paper £25.98
      The remaining items were already in the house (drill bit, tinfoil, electrical and duct tape).
      Given the potential for disaster I made two pinhole camera’s and one of them provided this image, the other was washed out due to rain water getting in. Making more than one camera certainly improves the chances of success. The camera's themselves were attached with cable ties to the down pipe of the guttering and facing South.
      Anyone wishing to learn more about Solargraphy and how to construct the pinhole camera should check out Tarja Trygg's website http://www.solargraphy.com/index.php .

    • By rotatux
      Designed on electronic paper, then printed and cut, all in a few hours.
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.