12 June 2020 Spectroheliograms

An archive of all the best images Solar Chat has to offer!
Post Reply
User avatar
p_zetner
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1644
Joined: Sun Mar 18, 2012 4:59 pm
Location: Winnipeg, Manitoba, Canada
Has thanked: 166 times
Been thanked: 719 times

12 June 2020 Spectroheliograms

Post by p_zetner »

Hello Everyone.

Here is a collection of spectroheliograms taken on June 12. There was a bit of a delay in posting because I'm still experimenting with processing techniques. I set the instrument up for full disk views. It had previously been configured for closeups (using a ~3x barlow on the Celestron 4" SCT) and I actually regret having made the change for this session because it would have been more interesting to view the AR and prominence at higher magnification. Chalk it up to rustiness after a long time since last using the SHG. I also replaced the previous 2400/mm grating with a 1800/mm grating. This sacrifices some spectral resolution for better transmission in the UV.

The first montage shows the solar disk imaged in the four Fraunhofer lines: CaII K, H beta, HeD3 and H alpha.
Montage_CaK_Hb_HeD3_Ha_12Jun2020_lbls.png
Montage_CaK_Hb_HeD3_Ha_12Jun2020_lbls.png (587.48 KiB) Viewed 650 times
The second montage shows a series of images in H alpha. The SW limb prominence is evident in the upper frames which are composite images of prominence and disk. A blue wing image shows the expected similarity to H beta shown in the first montage. A dopplergram shows some evidence of complex plasma flow near the AR.
Montage_Ha_disk-proms_blu-wing_doppler_12Jun2020_lbls.png
Montage_Ha_disk-proms_blu-wing_doppler_12Jun2020_lbls.png (588.81 KiB) Viewed 650 times
The third montage shows some images in the UV. These are composite images of prom and disk in the CaII K line. A blue wing CaII K line and an image taken in the CN bandhead (3883 angstroms) show strong similarity. The CN molecular band is interesting because magnetic bright points can be observed there (at high spatial resolution) with greater contrast than in the CH molecular G-band (~ 4300 angstroms). The required spatial resolution would be pretty challenging for a spectroheliograph.
Montage_CaK_proms-disk_blu-wing_CN-band_12Jun2020_lbls.png
Montage_CaK_proms-disk_blu-wing_CN-band_12Jun2020_lbls.png (643.59 KiB) Viewed 650 times
The SW limb prominence exhibited some interesting spectral behaviour. If only I had opted for higher magnification! Here is an image taken with an effective spectral resolution of about 2 angstroms. A coronal loop is evident along with a higher lying wispy structure.
Ha_proms_spectral_series_integrated_mod_siz.png
Ha_proms_spectral_series_integrated_mod_siz.png (45.96 KiB) Viewed 650 times
These features were captured by a number of observers on this forum:
Eric Roel viewtopic.php?f=4&t=28475
Phil (Astrophil) viewtopic.php?f=4&t=28464
John (highfnum) viewtopic.php?f=4&t=28474
James (DeepSolar64) viewtopic.php?f=4&t=28473.

The spectroheliograph revealed that the prominence consisted of structures that varied significantly with wavelength. In order to demonstrate this, I assembled the following animated spectral sequence of the prominence: a movie showing the shape of the prominence as the wavelength is tuned over a range of about 2.5 angstroms.
Ha_proms_spectral_series.gif
Ha_proms_spectral_series.gif (1.49 MiB) Viewed 650 times
Each frame of the video represents a step of 0.058 angstroms, or, in terms of the recessional velocity corresponding to a 0.058 angstrom doppler shift, a velocity step of 2.56 km/s. The frames in the animation are labelled with the recessional velocity with respect to gas at rest on the disk surface. Negative velocities refer to approaching gas while positive numbers refer to receding gas. It looks as if the wispy prom component had a significant recessional velocity component. Was this gas in the process of being ejected?

Anyway, it's good to be making spectroheliograms again! Hope you enjoy.

Cheers.
Peter


User avatar
Carbon60
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 14209
Joined: Wed Mar 07, 2012 12:33 pm
Location: Lancashire, UK
Has thanked: 8418 times
Been thanked: 8162 times

Re: 12 June 2020 Spectroheliograms

Post by Carbon60 »

Peter, these are exceptionally good spectroheliograms. The quality is amazing.

The prom animation is absolutely fascinating and it would also be interesting to see these images stacked in colour, 'blue to red' to show in one image the entire prom and its velocity field.

Excellent.

Stu.


H-alpha, WL and Ca II K imaging kit for various image scales.
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
User avatar
Montana
Librarian
Librarian
Posts: 34563
Joined: Mon Oct 17, 2011 5:25 pm
Location: Cheshire, UK
Has thanked: 17672 times
Been thanked: 8791 times

Re: 12 June 2020 Spectroheliograms

Post by Montana »

Absolutely wonderful Peter, a thoroughly enjoyable and informative post, the animation is incredible together with marvellous views of the sun. I do like the He D3 how it is completely inverted to Halpha or CaK view

:bow :bow :bow

Alexandra


User avatar
marktownley
Librarian
Librarian
Posts: 42272
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20438 times
Been thanked: 10245 times
Contact:

Re: 12 June 2020 Spectroheliograms

Post by marktownley »

Fascinating post and excellent images Peter! Love it!


Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
Post Reply