14 replies to this topic

[Jon Rista]

So I picked up a solar filter to fit my 600mm lens, as I'm heading up to Wyoming to try and capture the whole event (not yet sure which camera to use...5D III or ASI1600...I kind of want color, but...). I've been trying to test it out for over the week since I got it, and every time the sun gets out from behind the trees, the clouds rolled in. Today was the first chance I had. I'd swapped out my Ha filter for the OIII filter to image OU4 the last couple of nights, and at first I didn't want to mess with the imaging train for fear of having to acquire additional flats if I messed with the train. So I imaged with both the solar filter and the OIII filter. I ended up changing out the filter for the Ha one in the end anyway, but I was quite intrigued by the fact that the OIII frames seemed to be brighter with sharper detail than the Ha frames. 
 
I switched to the Ha filter to see if I could pick up any solar prominences, which I figured probably don't show up well at the OIII band. I think I did find a few, one for sure, but they were really faint and I'm not sure I have enough data on them. I have a few sequences that I need to try to integrate together in AS3 to see if it brings those details out more. If it is clear tomorrow, I am also going to try with the AstroDon R broadband filter and see what I get. 
 
Anyway...first serious solar image, acquired with the ASI1600MM-Cool, with a half-frame ROI, frame rate around 30fps. First in OIII:
 

 
Along with a detail crop of the sun spots:
 

 
Only processing was with the Restoration filter in PixInsight, Weiner filtering. LOVE that filter for planetary work. If anyone has both RegiStax 6 and PI, I recommend they give the Restoration filter a try.

Edited by Jon Rista, 18 August 2017 - 08:49 PM.

[Jon Rista]

The Ha version. Not a lot of difference, although it looks a bit less spherical, was lower contrast over the surface area, and the sunspots moved between the time I was acquiring the OIII and the time I managed to acquire the Ha (so, sadly, combining them into some kind of color image is not really an option).

[PirateMike]

Are these taken with the regular Ha and OIII filters in the filter wheel?

[Jon Rista]

AstroDon TrueSense NB filters, yes. I had them screwed into the 1.25" filter adapter that screws directly into the camera, though. I've moved to the Geoptik EF adapter, and the filter wheel doesn't fit with that. Waiting on one of the ZWO filter wheels to come in to replace the Atik EFW.

[PirateMike]

I would think that I could do the same with the Baader NB filters. Correct?

 

Is that with or without the solar filter on the scope?

[17.5Dob]

I tested my rig out this morning as well.....

$250 APO and an "antique" Nikon D7100

"Money can't buy you cloudless/smokeless skies love"

Edited by 17.5Dob, 18 August 2017 - 11:44 PM.

[Jon Rista]

I used both the solar filter and the NB filters concurrently. I wanted to see what it did. I am going to use just the solar filter, then the solar filter and R E-series concurrently tomorrow, and see how things go.

[Jon Rista]

I tested my rig out this morning as well.....

$250 APO and an "antique" Nikon D7100

"Money can't buy you cloudless/smokeless skies love"

Nice!

Gonna drag out the old antique 5D III tomorrow as well. ;P Hope the nasty background banding doesn't gyp me of some potential color data. The 5D III may be THE camera I use, not sure yet. I do want color images. I am thinking that BYE can do some amount of "ROI" with Canon DSLRs, so hopefully that will help. I remember that puppy being limited to about 20fps tops though...

[PirateMike]

Thanks Jon.  

[t_image]

Jon,

Fun to see you bring your intelligence to a new area of AP=solar!

 

I switched to the Ha filter to see if I could pick up any solar prominences, which I figured probably don't show up well at the OIII band. I think I did find a few, one for sure, but they were really faint and I'm not sure I have enough data on them.

Maybe you are using wrong terminology,

but solar prominences outside of TSE cannot be detected with night time H-A NB filters, because they don't approach the small tolerances needed (within .5-1nm of 656.3) found in dedicated Solar h-a tuneable etalon filters and scopes.

The off-band reds (even within the NB of the night-time h-a filter put out from the other parts of the Sun) are too bright and overwhelm the data and prevent the detail from the h-a emission line that is found in solar scopes from being seen, ie no prominences.

Thus the difference between "white light" and "hydrogen-alpha" solar obs/imaging......

 

Interesting some solar imagers in the white light arena enjoy using a 540nm green filter for more contrast:

http://agenaastro.co...uum-filter.html

[entilza]

Nice and sharp! How convenient there are sunspots for the eclipse! What would give you the best image of the corona, the colour one? If so I would use the DSLR.

[Jon Rista]

Jon,
Fun to see you bring your intelligence to a new area of AP=solar!
 

I switched to the Ha filter to see if I could pick up any solar prominences, which I figured probably don't show up well at the OIII band. I think I did find a few, one for sure, but they were really faint and I'm not sure I have enough data on them.

Maybe you are using wrong terminology,
but solar prominences outside of TSE cannot be detected with night time H-A NB filters, because they don't approach the small tolerances needed (within .5-1nm of 656.3) found in dedicated Solar h-a tuneable etalon filters and scopes.
The off-band reds (even within the NB of the night-time h-a filter put out from the other parts of the Sun) are too bright and overwhelm the data and prevent the detail from the h-a emission line that is found in solar scopes from being seen, ie no prominences.
Thus the difference between "white light" and "hydrogen-alpha" solar obs/imaging......
 
Interesting some solar imagers in the white light arena enjoy using a 540nm green filter for more contrast:
http://agenaastro.co...uum-filter.html

Thanks!

Yeah, after reading about Lunt telescopes, the Ha NB bandpass is far too wide. Those Lunt solar scopes are amazing, down to as little as 0.5 angstroms bandpass!

It seems like the clouds are returning today, at least in Colorado (hoping it stays clear up in wyoming), so I don't think I'll have a chance to do any more solar imaging yet.

[ChrisWhite]

At this time my plan is to just shoot mono.  Other than the ability to easily set up autobracketing I don't see much benefit to shooting in color.  With a white light solar filter you'll end up with greyscale anyway and can add false color in later.  I'm only going to see a partial where I am, so my hopes aren't that high other than just enjoying it.  Forecast is for clouds anyway. 

 

If I had clear skies though and totality I think the ability to autobracket and change exposure quickly and easily would be a nice benefit.  Hope your skies are clear!

[Jon Rista]

Hope it clears for you, Chris! This thing has become a phenomena, it's the event of the decade now. So many people are already hitting the roads to head to either Wyoming or Nebraska from Colorado. Everything is sold out, booked up, or gone (i.e. gas!)

I decided to try for an Ha/OIII blend of the data. Could only do it around the sunspots, as those were the only features to reference for a dynamic alignment of the two channels. I used ChannelMatch to tweak the color channel alignments and semi-compensate for the movement and change in shape of the sunspots:

Edited by Jon Rista, 19 August 2017 - 11:19 AM.

[ChrisWhite]

In seven years there will be another total eclipse that passes right overhead.  I'll have to wait until then to image the real deal!  I'm really looking forward to seeing the images you all get though from the path of totality.  Good luck!!!