HA sun poor result,

[bomberbaz]

Imaged the sun recently in HA and there were some fab proms on it. I wasn't sure about the focus, thought I had it good after lots of tweaks but the then the processed result was the image below.

There is a ghostly prom just left of top, nothing like what I was seeing visually.

Just watched the Stargazine zoom meeting and there was an emphasis on using a IR filter for deep sky imaging.

Question is, will a IR filter help here and clear up the image more. 

Equipment used: Lunt LS 35 and ZWO ASI224MC. Sharpcap recording 1500 video frames, best 250 used in this stack. 

[tooth_dr]

If you think about what the h-alpha scope is already filtering, the scope is already filtering down to a single wavelength 656nm.  Additional IR blocking filters will have nothing to block, as there won’t be any IR passing through.

I personally haven’t had much luck with a colour camera and stuck with mono (even that’s tricky).  Thin haze could affect it as could focus, or even stacking too large a % of frames where you end up including blurred ones.   The resolution with a colour camera will be 1/4 of what a mono camera will achieve too.

 

[Rusted]

The immediate response would be failure to focus.
But, the sharpness of the limb is really quite decent.
Colour cameras can easily pull out a lot more H-a detail than that.
I used a 120MC for ages before I smashed the piggy bank for a 174MM.

Tuning? I have no experience with commercial kit.
You say you saw missing detail before or during the capture?
Then the instrument was clearly working at some stage.
Was this detail on the computer/laptop screen?
Or visually with an eyepiece?

I use SharpCap every day the sun is out.
There's nowt wrong with it for solar H-a.
250/1500 frames is not unusual.
You didn't use a "flat" wrongly and remove everything else?
There are a couple of dust bunnies so probably not.

We can't use the red herring that the sun is blank right now.
Just blank of "big stuff" in white light.
You saw stuff you didn't capture.

Cue one of our solar imaging experts: 

[Pete Presland]

It could be focus, but i think it might be not exposed for long enough for the proms. Usually the disc is completely overexposed when the proms are being captured. 

[bomberbaz]

1 hour ago, Pete Presland said:

It could be focus, but i think it might be not exposed for long enough for the proms. Usually the disc is completely overexposed when the proms are being captured. 

I still have the orginal data so I could try restacking more frames to see if that helps, thanks for the tip.

[Pete Presland]

2 minutes ago, bomberbaz said:

I still have the orginal data so I could try restacking more frames to see if that helps, thanks for the tip.

Could you see the Prom on the Capture screen.

[bomberbaz]

13 minutes ago, Pete Presland said:

Could you see the Prom on the Capture screen.

Only barely Pete. I am just having a better look. In the PIPP preview pane I enlarged the image much further and it does look soft around the edges but there is a prom but its not well defined.

I am starting to think it was a poor focusing issue.  I will play around with the data and see if I can get it a better result.

 

[tooth_dr]

52 minutes ago, bomberbaz said:

I still have the orginal data so I could try restacking more frames to see if that helps, thanks for the tip.

What Pete means is that during the capture, the exposure wasnt long enough to record the faint signal from the proms.  Stacking more data now wont help that, and perhaps would even be detrimental. Stacking 10-15% seems to be reasonable, and I would typically try 5, 10 and 20% to see how it looks in the stacks.

[bomberbaz]

Ah with you, sorry.

Right ok I have to look at that next time, I will try again when the weather allows

[Pete Presland]

Look forward to seeing the results Steve.

[bomberbaz]

2 hours ago, Pete Presland said:

Look forward to seeing the results Steve.

I will spend much more time on focusing (I think it was slightly out) and getting the right exposure this time. It's all part of the learning curve