Solar prominence - 7th Feb 2022

[Stu]

Posted elsewhere but I thought I would add this here as well.

Between the clouds, I finally managed to see the huge prominence on the limb of the Sun today. The seeing was quite poor, and whilst this made the surface detail a bit blurry the prominence still showed up very well.

I was using my 102mm PST mod on an AZ75 mount with binoviewers for observing. I took the shot handheld over one eyepiece using my iPhone 11Pro’s x2 camera. Captured using ProCam 8 and shown in the first shot totally unprocessed, and the second one with a bit of inept fiddling in PS Express. I’ll try again when I have more time to see if it can be improved. The metadata says ISO 80, f2 and 122th second exposure.

[Merlin]

A good shot of the prom. Alas, it’s been too cloudy at this site for PSTing. How did you adapt the binoviewer for use with your PST? Do you use a Barlow?

 

[Stu]

1 hour ago, Merlin said:

A good shot of the prom. Alas, it’s been too cloudy at this site for PSTing. How did you adapt the binoviewer for use with your PST? Do you use a Barlow?

 

Thanks. Yes, I have a 1.25” barrel on the binoviewer and a x2 barlow element screwed into the barrel which allows it to reach focus. I’m experimenting with GPCs to see if they give any better results, I have a x1.7 and x2.6 but haven’t been able to test it out yet.

This setup is mainly aimed at high power views of prominences. Surface detail is not as contrasty as a double stack smaller scope but the proms are amazing.

[skyhog]

I popped the pst on a tripod yesterday and viewed that. Nice to see an image of it stu. Yes, huge best describes it. There was a much smaller prom on the opposite limb too. I really need to work out the orientation of the image so I know which limb I'm referring to... 

[Stu]

21 minutes ago, skyhog said:

I really need to work out the orientation of the image so I know which limb I'm referring to... 

Does the Gong data help? This is today, can’t work out how to get back to yesterday.

[skyhog]

Forgive my ignorance but I can't see any indicators on that image that refer to orientation. I know this has been a topic once or twice, defining East West etc with regard to solar observing. Not something I tend to think about whilst observing but I should have it in mind I suppose...

[Stu]

21 minutes ago, skyhog said:

Forgive my ignorance but I can't see any indicators on that image that refer to orientation. I know this has been a topic once or twice, defining East West etc with regard to solar observing. Not something I tend to think about whilst observing but I should have it in mind I suppose...

No ignorance involved, I should have thought it through more’ 🤪🤣. I assumed it would be standard orientation as we see it from Earth, but I found this info which should help:

https://gong.nso.edu/data/DMAC_documentation/Vmbical/GONG_Image_Orientation.html

[Stu]

Without allowing for the offset ie just a 90 degrees counterclockwise rotation and horizontal flip you get this, which should be roughly north up, east left. Not sure how significant the offset is to the rotation part though, I haven’t done the calculation.

[skyhog]

Yes, cheers stu.... 👍

[Peter Drew]

Don't forget that although the PST's eyepiece is a right angles to the line of sight, the prism used to perform this is a pentaprism so the orientation is that of a refractor without a diagonal.         🙂 

[paulastro]

4 hours ago, Peter Drew said:

Don't forget that although the PST's eyepiece is a right angles to the line of sight, the prism used to perform this is a pentaprism so the orientation is that of a refractor without a diagonal.         🙂 

Peter, I thought the image looking down into a PST from behind has S at the top, N at the bottom, W to the left and E to the right.  I hope that's what you mean as that's how I lable my sketches 😊. 

 

[Peter Drew]

Yes, Paul, uncorrected astro image.    🙂

[Stu]

34 minutes ago, paulastro said:

Peter, I thought the image looking down into a PST from behind has S at the top, N at the bottom, W to the left and E to the right.  I hope that's what you mean as that's how I lable my sketches 😊. 

 

Found this which may be useful 🤣

[Stu]

5 minutes ago, Peter Drew said:

Yes, Paul, uncorrected astro image.    🙂

So that’s vertically inverted, rather than upside down ie rotated 180 degrees?

[Peter Drew]

Yes Stu, a pentaprism performs constant deviation so the orientation of the view is the same with or without it other than the "bending" through 90 degrees.     🙂

[paulastro]

11 hours ago, Peter Drew said:

Yes, Paul, uncorrected astro image.    🙂

Thanks Peter, that's a relief 🤣.