4.5.20 Magnificent pillar of destruction!

[Rusted]

I've been struggling with coarse grain on my ASI174 all day!

So don't kill the messenger!

 

 

Edited May 4, 2020 by Rusted
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[richard ashbee]

super photos

[MarkAR]

WOW, that's a prom and a half.

[tooth_dr]

Epic. 

[Ibbo!]

its still there

well it would be if that bit of cloud would do the decent thing

 

[Debo]

Brilliant 

[Peter Drew]

Nice rendition, been mostly sunny here today so I have been keeping an eye on it.  Several decent areas of limb activity.  The prom in the images is relatively faint in my 60mm Coronado, wish I had my big "gun".        🙂

[Davey-T]

Super prom, I managed to miss half of it.

Dave

[Rusted]

I wish I could have done a much better job of it but my ZWO ASI174MM is following the ASI120MC downwards into a permanent, coarse mask overlay on every image.
Almost like water droplets on plastic. Except that the droplets last all day and every day now. Which is impossible if it were really dew.

I am using the equivalent of doubled Baader D-ERFs plus extra UV/IR filtration. I have checked and double checked. There is no dew anywhere on any optical surface.
The camera and LUNT B1200S2 both go back indoors overnight to protect them from the overnight cold in the dome. They aren't very cold and are in sealed containers in poly bags.
So no condensation occurs when brought into the warmer environment. I tried removing the protective filter [temporarily] from the ZWO ASI120MC but nothing changed.

Has anyone else suffered similar symptoms? I wondered if it was electrical "noise" on the system. So removed everything except the laptop and camera. I have unplugged all PSs.
Unplugged all the cables. Tried moving the cables around. Changed the camera cables to different examples. I have several of each in different lengths.
The mounting is earthed to a 2m long ground rod in damp, clay soil with a 5m long x 6mm^2 cable.

I went through all of this with the ZWO ASI120MC and never found a cure. Could it be the popular, capture and processing software producing permanent "grainy" artefacts over time?
Why only me? I have no idea. Perhaps it is the sheer number of hours the camera is exposed to H-alpha?  It certainly isn't dust or dried dew on the camera sensor or covering filter!
I have deliberately avoided removing the ZWO SI174MM filter to avoid getting any dust on the sensor. The filter gets a squirt of air from a blower bulb now and then.  

 

[Merlin66]

Russ,

19 minutes ago, Rusted said:

a permanent, coarse mask overlay on every image.
Almost like water droplets on plastic. Except that the droplets last all day and every day now

I'm at a loss to understand what may be happening. I have and use the ASI 174MM a lot of the time both in H alpha and CaK . The pixel size is a little large, at 5.86 micron for the ED80 unless I'm using Barlows. Unfortunately the weather and seeing down here has meant most of the recent work has been done with the ASI 1600MM. It does work very well with the longer focal length Spectroheliograph.

It may be your getting 2x2 binning unexpectedly via the software?

I'd like to see a flat image.... When testing my cameras for "dust" I found using a normal refractor (ST80) at around f12 to f15 (barlow/ Powermate etc) and a single plastic bag over the aperture, focused at infinity and pointed to a bright sky gave the best (unfortunately the worst!!!) results and showed clearly any all dust motes on the cover glass AND the sensor.

If nothing else this "flat test" would show if the camera itself had an issue.

 

 

 

[Rusted]

Thanks.

I have not knowingly added binning but will double check.

Fortunately I have just made a "flat" screen and have been using it on my recent images.
Translucent poly bin bag over a light metal cell. It works wonders with the PST's foibles.

I'm afraid I have been having a bit of a rant about the ZWO camera.
I  spent a lot of money on the ZWO ASI174MM.
Then find myself going down exactly the same plug hole as the 120MC.

My minimum focal length with my 150mm/10 is 1500mm. I often use the WO 2x Barlow for 3m.
This is ideal for the ASI174. Which is why it is a popular camera in the solar imaging world with longer focal lengths.
Though the smart money seems to favour the alternative 174 sensor cameras albeit at a much higher price.

[Merlin66]

Russ,

I’m suggested a flat on a standard refractor, not the usual H alpha  set-up you would use.

This isolates any camera issues from the rest of the system.

 

[Rusted]

46 minutes ago, Merlin66 said:

Russ,

I’m suggested a flat on a standard refractor, not the usual H alpha  set-up you would use.

This isolates any camera issues from the rest of the system.

Aha! I shall see what I can do. I'll be back.

Here are two images I captured this morning:

The first is ugly but the second is better. Though still coarse and grainy.

Edited May 5, 2020 by Rusted

[Rusted]

I have captured a flat pointing at the sky using my 90mm f/11 with 2.6x GPC and completely out of focus.
Captured in SharpCap [no binning] run through AS!3 as an AVI. No sharpening. No obvious artifacts.

[Merlin66]

Russ,

Hmmmmm.

OK

Let me think about it.....

Ken

 

[Rusted]

Thanks Ken.

Some more images from this afternoon Captured during a lull in the agitated seeing, for you to ponder over:

The first is unsharpened. The second was given one touch of sharpening in PhotoFiltre.
At a glance it look sharper. In close-up it is all grain. Which is why I never sharpen.

 

 

[Pete Presland]

A magnificent Prom, excellent capture!

[Montana]

I wish I could see this more clearly what you are talking about here. I also get a very annoying grain in all my solar images with the ASI174 which the Basler and Grasshopper versions don't seem to suffer from. I have to use very heavy denoise to get rid of it but sometimes I think, is this solar structure or noise as it is so consistent. I'd love to see close up exactly what you mean to compare to mine.

Alexandra

[Rusted]

1 hour ago, Montana said:

I wish I could see this more clearly what you are talking about here. I also get a very annoying grain in all my solar images with the ASI174 which the Basler and Grasshopper versions don't seem to suffer from. I have to use very heavy denoise to get rid of it but sometimes I think, is this solar structure or noise as it is so consistent. I'd love to see close up exactly what you mean to compare to mine.

Alexandra

Hi Alexandra. You must be psychic.

I was just about to post these two images captured at 41C and 31C according to SharpCap.
The ASI174 was cooled off in the fridge between snapping these two still images in SharpCap.
Cropped and enlarged in PhotoFiltre. I think the difference is clear. ASI174 + Heat = NOISE!
Whoops! I seem to have messed up the enlargement judging by the arc of the limb. 
I'll be back later with a better match for scale.

I am still trying to work out why AS!3 automatically sharpens my AVIs when no sharpening is selected.
When I open the resulting images from AS!3 in ImPPG they are already showing hideously coarse grain even at the default settings.

[Montana]

Wow!! maybe the Basler and FLIR versions have better cooling systems for the chip! I need to check my temperature of my ASI174 next time I am out, maybe it needs a cooler attached? it probably has Covid-19

Alexandra

[Merlin66]

I gave up on the ASI 174 on the ED80. It’s OK with longer fl, but the ASI 1600 gives better results.

I haven’t checked the camera temperatures (I use FireCapture) but I’m not sure that it is an issue. You could cover the scope/ camera with a thermal blanket.

I also have an ASI 1600MM-C so could experiment with different camera temperature settings.

 

[Rusted]

On 07/05/2020 at 16:12, Montana said:

I wish I could see this more clearly what you are talking about here. I also get a very annoying grain in all my solar images with the ASI174 which the Basler and Grasshopper versions don't seem to suffer from. I have to use very heavy denoise to get rid of it but sometimes I think, is this solar structure or noise as it is so consistent. I'd love to see close up exactly what you mean to compare to mine.

Alexandra

Sorry. I meant to get back to you on this but wanted to confirm first whether the new ZWO driver download had helped my cause.
The trouble is I'm fighting cloud. Which doesn't offer any opportunity to capture anything at all! I'm on full gain and peering through the clouds!