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First H-Alpha pics!
Yesterday morning the seeing seemed to be good. The Sun revealed a great number of details in the PST. There where filaments, prominences, plage's, and active regions visible. I also had a chance to use a wide array of eyepieces ranging from 20mm to 5mm (all Vixen Lanthanums. The different views were fascinating. I also shot some images with the Nikon Coolpix 4500, which I include in this observing report. I also fiddled around with adjusting the images in different colour channels. It produced some interesting results that form a base for future improvements.

This sketch should give you a general idea where the different features where situated on the solar disk.


1. Three large QRF’s (Quiet Region Filaments)
2. Active region 791 with a sunspot and two plage’s (white areas around Sunspot)
3. Active region 792 appearing at the limb of the Sun with bright plage
4. Big prominence, probably an active Class II eruptive (from Zirin classification)
5. Large hook shaped prominence.

The first two images where shot with a 10mm eyepiece and 2x optical zoom, 1/4s, f 10.3, ISO 100. The first image is the original image, slightly altered with some level adjustment and unsharp masking. Two filaments and the big prominence (4 on the sketch) are visible as well as the brighter area of Active Region 792 on the limb of the Sun (about 1 o’ clock). The second image shows only the green channel from the first image. The prominence disappears but the surface features are much better visible.



The next image shows a large part of the Sun, again only in the green channel. The original image was shot with a 12mm eyepiece, no optical zoom, 1/30s, f 6.6, ISO 100. Again some unsharp masking and level adjustments have been applied. On this image you can see the three filaments and at the bottom centre active region 791, a sunspot with some bright plage’s above and to the right.


The last image shows the big prominence. This image is an RGB one, but I split the colour channels, did some level adjusting, unsharp masking and curves adjustment only in the red channel, before merging the three channels together again. This produced a more or less realistic image of the big prominence, but a lot of testing and training has to be done. However, this being the first images shot through the Coronado PST, I am very satisfied. If you want to comment on the images or have some more tips for me, please feel free to do so! You just have to register once and you can always log into the comment fields.


Clear skies to all of you!

UPDATE friday 29 July 2005 at 14.00 hrs UT !!!!!

At the moment there is a big prominence visible as well as the active region AR 792. Here are some images from some two hours ago (click to enlarge!)

image image

Enjoy the images for now. Details on the images will follow within the next few days. I will keep you updated.

Posted by Math on 07/29 at 03:50 AM
Solar log • (4) Comments • (0) TrackbacksPermalink

Very nice and detailed photos of the Sun. I belive they are the best I could see from a PST. Congratulations !!!
I own the Coolpix 4500 and also a PST and would like to do some pics. I tried once without any success. I just obtained “red balls”.
Please keep us informed in your blog about settings of the camera and your post processing techniques.
Thanks a lot for sharing your info.
J. Cesar
Madrid, Spain

Posted by Julio Cesar  on  08/01  at  05:35 AM

Hi Julio,

I wil try to publish the details on my last two images by the end of this week or next weekend, but I can tell a few things in advance.

1. Start with an eyepiece that makes it possible to shoot an image of the whole disk of the sun.
2. Shoot single images with all different exposure times that are possible. I started with 8 seconds and went through them all untill 1/2000 second.
3. The most important thing I did then was examining all images one by in different color channels. This you can do with a image processing software.

Normally you would expect that you only see something on the image in the red channel, because the Coronado PST lets only red light pass. But because all compact cameras, including the coolpix, let light “leak through” in the green and blue channel, you will be suprised at the results. A totally over-exposed red channel can be the right exposure in the green channel.

So start experimenting with this. One other tip: in the sky and telescope of july 2004 you will find a long article about this technique.

Clear skies for now. I will be back soon.


Posted by Math  on  08/01  at  03:59 PM

Thanks for the info Math.
I’m also concerned about focusing as I tried to focus manually with the focusing system of the PST. The result was not good. Have you used the autofocus in the CP4500? Anyway I have to do some more tests.
I will check the S&T review and try to learn more.
Thanks again for your kind assistance.
Julio Cesar Monje

Posted by Julio Cesar  on  08/02  at  05:04 AM

I use the following method for focussing:

1. Insert a low power eypiece (20mm) into the PST.
2. Mount the camera.
3. Zoom in on the edge of the Sun at maximim zoom (including digital zoom)
4. I get under a dark cloth
5. I then point a magnifying glass at the lcd screen of the coolpix and with the focus knob of the PST I try to a view that is as sharp as possible (watch the edge of the Sun while focussing).
6. When ready, zoom out and start shooting images. Never use the digital zoom when shooting images, only the optical zoom. The digital zoom is only usefull for focussing.

By the way, I use the same method for my lunar images. Works fine!

Clear skies

Posted by Math  on  08/04  at  02:49 PM






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