Subtracting darls /flats in live Stacking

Discussions of Electronically Assisted Astronomy using the Live Stacking feature.
carlwagle
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Joined: Thu Mar 07, 2019 6:58 am

Re: Subtracting darls /flats in live Stacking

Post by carlwagle » Sun Apr 28, 2019 6:00 am

I hope someone can change the SUBJECT line to Subtracting Darks from Subtracting Darls as I see a lot of people are interested in this subject and for the new comers to this avocation I hope to add to their enjoyment of this Forum and what it stands for. I almost over looked it.

No, I didn't go outside with this vague feeling of ignorance about the Process. I just knew, I was not ready for this. All along I have been dreading mastering subtracting Dark Frames and all along (until now) I was wondering what could clear this up. I want to tell some of the new comers (I guess most have such abilities of perception they can go read something else) that if you are going to master this Astrophotography you are going to have to read SharpCap with your eyes Wide Open with your best attention for perhaps 3 times, at the least. The info is there, you need more than than just glass specticals to comprehend it!

So, I got my ZWO ASI 178MC camera out of the car, plugged it into my Windows 10 ridding Dell Computer, put an olive jar cap over the entry port for light and worked in the comfort of my study. The first 'page' that comes up that allows you to do LIVE STACKING as well as take 'captures' is where I was able to simulate making and filing my first dark frame. Hit capture and a box pops up that does not let me choose how many frames I want to capture for averaging and it says hit the button cancel (which is not apparent) to stop the process and ends with the message, something like, WHAT EVER YOU DO,DONT------and ends on that word DON"T. But I do hit the start button with my heart in my mouth and nothing happens and I'm getting ready to hit the red X when a message pops up saying my Dark Frame has been stored over in this file which I quickly click on to find it later if need be. It's there. Ten frames are automatically chosen and if you chose an arbitrary one frame per second for EXPOSURE, it will take ten seconds for that pop-up message to appear.
Resting for no more than a minute I decide to do this several times more for practice.
For at least 10 minutes I could not get back to this particular window and for the life of me could not figure out why. The problem was, that on this first page the word capture is listed in 3 places across the top that you can click on. The right and only one is between the words OPTION and TOOLS. I wrote this down on what I call Field Note Cards.

Then next and almost last, I had to practice getting that file of Dark Frames into the stacking process as mentioned correctly by Robin but most dreaded by me. My trouble stemmed from me never clicking on the PRE Processing button located near the bottom on the camera controls column, I believe on this same first page. Go look, it will do you good. The only reason my eye was drawn to search for it there was that in the copy of SharpCap instructions that Robin had given the fellow starting this question about DFS, in a small box off to itself were the words PRE PROCESSING and a box to the right of it, like where you could select none. Go find that too. You want forget it! I was lucky I did not over look it,, being so unfamiliar with it.

So, the very last thing I must do before I stumble around in the cold darkness outside is get this file selected. I try but I get a message back that I need to get the Sharp Pro License to use this feature. But I can borrow it to prove that it works, just can't save the improved captures without the license. My great fortune is I read this message in the warmth of my well lit study and I feel very good about it. I will get the Pro License, but I want to understand SharpCap as well as I can without it.

Out I go after my "practicing" and notice that it has clouded up so much that not a star can be seen. Happy for the "practice"!

I come back here and write a reply before anyone can catch me with my pants down.

carlwagle
Posts: 68
Joined: Thu Mar 07, 2019 6:58 am

Re: Subtracting darls /flats in live Stacking

Post by carlwagle » Sun Apr 28, 2019 6:08 am

I'm not sure it got out the first time> I will try again:

I hope someone can change the SUBJECT line to Subtracting Darks from Subtracting Darls as I see a lot of people are interested in this subject and for the new comers to this avocation I hope to add to their enjoyment of this Forum and what it stands for. I almost over looked it.

No, I didn't go outside with this vague feeling of ignorance about the Process. I just knew, I was not ready for this. All along I have been dreading mastering subtracting Dark Frames and all along (until now) I was wondering what could clear this up. I want to tell some of the new comers (I guess most have such abilities of perception they can go read something else) that if you are going to master this Astrophotography you are going to have to read SharpCap with your eyes Wide Open with your best attention for perhaps 3 times, at the least. The info is there, you need more than than just glass specticals to comprehend it!

So, I got my ZWO ASI 178MC camera out of the car, plugged it into my Windows 10 ridding Dell Computer, put an olive jar cap over the entry port for light and worked in the comfort of my study. The first 'page' that comes that allows you to do LIVE STACKING as well as take 'captures' is where I was able to simulate making and filing my first dark frame. Hit capture and a box pops up that does not let me choose how many frames I want to capture for averaging and it says hit the button cancel (which is not apparent) to stop the process and ends with the message, something like, WHAT EVER YOU DO,DONT------and ends on that word DON"T. But I do hit the start button with my heart in my mouth and nothing happens and I'm getting ready to hit the red X when a message pops up saying my Dark Frame has been stored over in this file which I quickly click on to find it later if need be. It's there.
Resting for no more than a minute I decide to do this several times more for practice.
For at least 10 minutes I could not get back to this particular window and for the life of me could not figure out why. The problem was, that on this first page the word capture is listed in 3 places across the top that you can click on. The right and only one is between the words OPTION and TOOLS. I wrote this down on what I call Field Note Cards.

Then next and almost last, I had to practice getting that file of Dark Frames into the stacking process as mentioned correctly by Robin but most dreaded by me. My trouble stemmed from me never clicking on the PRE Processing button located near the bottom on the camera controls column, I believe on this same first page. Go look, it will do you good. The only reason my eye was drawn to search for it there was that in the copy of SharpCap instructions that Robin had given the fellow starting this question about DFS, in a small box off to itself were the words PRE PROCESSING and a box to the right of it, like where you could select none. Go find that too. You want forget it! I was lucky I did not over look it,, being so unfamiliar with it.

So, the very last thing I must do before I stumble around in the cold darkness outside is get this file selected. I try but I get a message back that I need to get the Sharp Pro License to use this feature. But I can borrow it to prove that it works, just can't save the improved captures without the license. My great fortune is I read this message in the warmth of my well lit study and I feel very good about it. I will get the Pro License, but I want to understand SharpCap as well as I can without it.

Out I go after my "practicing" and notice that it has clouded up so much that not a star can be seen. Happy for the "practice"!

I come back here and write a reply before anyone can catch me with my pants down. Carl

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turfpit
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Re: Subtracting darls /flats in live Stacking

Post by turfpit » Sun Apr 28, 2019 9:40 am

carlwagle

Darks explained here https://docs.sharpcap.co.uk/3.2/#Captur ... k%20Frames. This section includes the menu option used to start the process plus where the resultant dark is stored.

Flats explained here https://docs.sharpcap.co.uk/3.2/#Captur ... t%20Frames

How to apply dark/flat frames here https://docs.sharpcap.co.uk/3.2/#!2!Pre-processing.

Whenever I have tried to use any new equipment or software, I have found it best to practise from within my study during the daytime.

Dave

carlwagle
Posts: 68
Joined: Thu Mar 07, 2019 6:58 am

Re: Subtracting darls /flats in live Stacking

Post by carlwagle » Tue Apr 30, 2019 11:04 pm

thank you Dave.
I did go out the next night (prepared) and found that when I 'borrowed the Pro License that I could not tell if I got rid of those asteroid-like artifacts by dark frame subtraction because no stacked pictures where saved. SAVING is not allowed under borrowing. I was a bit disappointed because I wanted to borrow the license to see if I could improve the image. Perhaps I did in other ways, but I was so intent on those old show-ups of hot pixels I over looked what ever improvements occurred. The picture setup history did state that a dark frame was used,, I just could not see the results. Did I miss something here??

I bought and have installed the license today. Looking forward to smooth sailing tonight. If I have trouble, I'm going to spend the night trying to get a permanent grip on M-3, M-53, and M-51.

I hope you can help me with this perceived computer memory problem that might come up. On the night I borrowed the Pro License, and I think because I filed a Dark Frame,, a SER File got made that used something like 250MB of memory. Twenty stacked pictures of M44 only call for about 37MB. Does every Dark Frame (and Flats) cost that much memory? If so I don't see how anyone could make up a library of them.
I have just deleted that last SER File I made. As I understand it,,, I should not have more than one on file at anytime. Carl

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turfpit
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Re: Subtracting darls /flats in live Stacking

Post by turfpit » Tue Apr 30, 2019 11:48 pm

Find the image you captured. With it will be a CameraSettings file. Post that to the forum either as an attachment or copy and paste the contents into your reply. The information contained in that file will help others to answer your questions.

Dave

carlwagle
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Joined: Thu Mar 07, 2019 6:58 am

Re: Subtracting darls /flats in live Stacking

Post by carlwagle » Wed May 01, 2019 9:50 pm

Dave, last night I tried out the Pro License for the first time. Everything seemed to be going along as expected. I took two stacks of M-44 without the Dark Frame subtraction to see clearly the hot pixel artifacts,, then two stacks oh M44 in the same place with the same camera settings with a dark frame subtraction.
Immediately after finishing the last capture I began to take a look at the first one I took (no Dark Frame Subtraction) and when I meant to click off from that picture I clicked one X to far in the right hand corner of the screen which turned SharpCap off, only leaving the computer running.
When I attempted to get back to stacking more images I could not get any stars to show up on the SharpCap camera screen although the Telescope had continued to track the same point in the sky before I hit the wrong X. I tried everything I could think of to get back to normal. The camera controls all looked normal. Turned off Sharpcap and worked my way up to capture a single picture several times to no avail,,, no stars on the screen.
The one thing I did not think to do was turn the computer off, then after rebooting it, try getting SharpCarp to come back to working normally.
Can you make any suggestions? Do you think I need to temporarily remove the Pro License? If so, how? Carl

PS; I just took a look at the results of last nights stacking. The hot pixels came through the Dark Frame Subtraction process hardly changed at all. Close examination of a "Save As Is" Jpg picture shows no hot pixels in the area that Fits Liberator says they are located in, but two isolated ones in different locations can be seen. Only two out of the whole frame.

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turfpit
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Re: Subtracting darls /flats in live Stacking

Post by turfpit » Wed May 01, 2019 10:48 pm

To progress this, really needs sight of:

- a stack without dark subtraction
- a stack with dark subtraction
- the dark frame used
- any capture settings files

If these could be shared out via technology such as Dropbox then the data could be examined.

Dave

carlwagle
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Joined: Thu Mar 07, 2019 6:58 am

Re: Subtracting darls /flats in live Stacking

Post by carlwagle » Thu May 02, 2019 9:50 pm

I don't know anything about DROP BOX. But within a few days I will get this info you asked for into this forum. Thank you for your reply.

Late yesterday I was able to stack pictures with the SharpCap's manual Orion Nembula using the manuals simulated camera. I could do everything but add my old dark frame to it because of a mismatch in size of the images (mine and the supplied picture of Orion). How do I normally add a dark frame to the SharpCap Manual's Orion problem opportunity.

I will, if weather permits, go out tonight and see if I have worked through the problem last mentioned in my post about stacking stopping after me accidentally turning off SHARPCAP. It may be that completely turning off my computer was the answer.

carlwagle
Posts: 68
Joined: Thu Mar 07, 2019 6:58 am

Re: Subtracting darls /flats in live Stacking

Post by carlwagle » Sun May 05, 2019 2:51 am

Dave, I think I have it figured out.
I went back and re-read your Sunday, April 28th, 2019, 5:40 Pm posing to me, very closely. Somewhere in there was the sentence to the effect of that you could magnify a dark frame and take a look at what makes it up.
I had two dark frames saved and I decided to do just that.
I found out that the oldest and first one I took evidently did not have the dust cover cap put over the apature of the reflector like it should have been. No, you could see a faint picture with the stars of the BeeHive Cluster showing. The stars were on a wiggly track equal in length to the time it took to take the ten pictures to be taken and averaged together. That's the first mistake.

The second mistake is when I went out the next time and made a GOOD dark frame (I just magnified it) I did not select to use the GOOD one but the old one which was Defective.

I will try to send you a picture of M-44 taken with this Defective dark frame followed by the camera settings sheet. You can see there is a big time difference between the two frames. What was baffling me about a whole string of different stacked pictures was why the appeared poorly tracked, sometimes not so bad and others like the one I'm sending very bad. I had seen this mount perform WELL while the wind would gust up to 20 MPH and there was no wind on the night of this picture taking.

Picture next and text afterwards.

carlwagle
Posts: 68
Joined: Thu Mar 07, 2019 6:58 am

Re: Subtracting darls /flats in live Stacking

Post by carlwagle » Sun May 05, 2019 2:58 am

trying to send picture:
Attachments
Stack_16bits_20frames_40s,,, a stack taken with a VERY fawlty dark frame.jpg
Stack_16bits_20frames_40s,,, a stack taken with a VERY fawlty dark frame.jpg (140.49 KiB) Viewed 1811 times

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