PST

Solar Images in H alpha, Calcium K and Visible

Most of my solar images have been taken in visible or H alpha , the Baader CaK filter in conjunction with a Herschel wedge provides a relatively “cheap” way of imaging in CaK.

Images in Visible light give detail of the photosphere , which we can consider as the Suns “surface”, above this is the chromosphere, the upper part of which is viewed in H alpha and mid section can be viewed in Ca K wavelengths. (Not quite this simple as there is some overlap, but broadly works this way) The Cak is sensitive to magnetic fields and the stronger the magnetic filed the brighter the image, this gives more detail of the plages around sunspots and more detail of how magnetic field varies in these areas.

After some time setting up a system to image in all 3 wavelengths a fine clear day arrived on Friday 22nd June and I imaged the sunspots and prominences , then went away, which is why I’ve only just finished processing images.

All images were taken using a mono CCD camera : Imaging Source DMK41, the H alpha images were taken using a Coronado PST, the Visual White light images with a Herschel wedge with a ND.3 filter and Baader continuum filter on the camera, using a Skywatcher Evostar 120 refractor. The Cak images were taken with a Baader Cak filter attached to DMK41 and using a Herschel wedge with either a ND.3 or ND 0.6 filter on Skywatcher  ST102 ( for full disc) and / or Skywatcher Evostar 120. All Images were 600 frame avi’s stacked in AutoStakkert, wavelets tweaked in Registax 6 and final processing in Photoshop CS6. Not having imaged for a while I soon realised that I needed to do some cleaning before the next session as the “dust bunnies”  were more numerous than usual, luckily I was either able to manipulate image to avoid most of them or eliminate them in processing.

I have left the images as mono as features show up better for comparison rather than processing in false colour.

Whole disc in CaK and H alpha, no prominences visible in CaK.

 

 

 

 

 

 

 

 

 

 

 

 

 

Main surface features in Cak in Evostar 120, left to right : faculae, AR2715, AR2713

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Faculae in Halpha x2 barlow

 

 

AR2715 In Cak, Vis,  H alpha (x2 Barlow)

 

 

 

 

 

 

 

 

AR2713 in Cak, Vis , H alpha (x2 Barlow)

 

 

 

 

 

 

 

 

Prominences x2 Barlow

 

 

 

 

 

Solar Array

Today allowed me to finally get my Solar array set up. After several attempts at balancing and positioning all the components and making modifications I was able to set up all 3 scopes in a balanced configuration.

Then using the Kendrick Solar finder on the central scope (Evostar 120) and setting the tracking to solar rate I then adjusted the alignment of the ST 102 and the PST, so that all 3 scopes showed full disk of sun in centre of field of view.

The idea is that:

the central scope will give white light images of the sun using a Herschel wedge with an ND3 filter.

the smaller ST102 refractor will give CaK images using a Herschel wedge without any filter and imaged with DMK41 mono ccd camera with Baader Calcium K filter fitted.

the PST will give H alpha images.

Today I was only using set up visually , to align scopes, so I used filtered Herschel wedge in the Evostar 120, a baader Solar film on front of ST 102 and the PST was used as normal. There were no sunspots visible and in H alpha a noticeable prominence at 4/5 o-clock position as registered by Roger this morning, no other prominences visible, nor was there much surface detail. No CaK detail as was not using camera, the sun was very variable , but there were enough bright spells this afternoon between 2 and 4pm to allow the alignment of all three scopes.

The mount was constructed with a piece of 10mm thick Aluminium bar 10cm wide and 35 cm long attached to upper side of lower vixen bar via two M6 bolts.

Two vixen bars were then attached to upper surface of Aluminium bar via M6 bolts, two sets of ADM mounting rings of suitable size were then clamped onto these vixen bars.

(ADM rings and vixen bars from First Light Optics.)

By adjusting screws in Rings I was able to align both scopes to get full disk in centre field of view, to remove scopes the top adjusting screw only in each ring is taken out, so when  scopes placed back in , tightening this screw only should put them back in aligned position, all bar a slight tweak.

To ensure the system was balanced about the axis running along the length of the Evostar, extra masses were added under the PST, these were attached via an M10 bolt with head removed and centre tapped with M6 thread, then attached to vixen bar with M6 screw head bolt through Vixen bar and M10 bolt to hold masses in place., this can be seen on photo below with scopes removed from rings.

By experiment on table top , approx. 1.5Kg was required on PST side to balance rig, brought 4 small masses from Astro Buy & sell, and drilled out centres to fit bolt. All we want now are some clear skies and sunspots!!

Thanks to Lee for advice on design and initial drilling and tapping of holes / threads.


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Solar Observations 26th May 2017

Not only was the evening observing good at the last RAG meeting, earlier in the day afforded the opportunity for some Solar observing. Although we are approaching the next Solar minima, there was a sunspot group present and some prominences were visible. The prominences were more of the spicule type that are very short lived and at the end of the imaging session the prominences recorded had disappeared, checking on GONG time-lapse  these prominences appeared and disappeared.

First 3 images taken in H alpha using Coronado PST and DMK41 mono CCD, best 50 of 1000 frames stacked in Autostakkert, wavelets in Registax 6, Photoshop CS^ for combination of disc and prominences, colourising and final tweak.

1.Full disc and prominences. 2 Close up of sunspot x2Barlow 3, Close up of prominence xBarlow.


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

 

 

 

 

 

 

 

 

 

 

 


 

 

 

 

 

 

 

 

 

 

 

 

Next two images are in White light, using 120mm Evostar refractor, with Lunt Herschel wedge imaged with DMK41 with Baader continuum filter. Best 50% of 1000 frames stacked in Auto stakkert, wavelets in Registax 6 and finished in Photoshop CS6

1. Sunspot 2,sunspot x2 Barlow