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Understanding Image Capture settings

Posted: Sun May 12, 2019 6:28 pm
by rottielover
I need some help understanding how I messed up...

Let's start with the camera, a ZWO 1600MM-Cool Generation 2. The 1x1 images are 4656 x 3520 pixels

Somehow I managed to capture lights and flats which are 3493 x 2641 Prism error's when calibrating them because the sizes don't match.

I genuinely have no clue how I managed this. I was manually imaging, meaning I was using the camera control window, and I setup a Sequence on that window.

I noticed that Prism says "Zoom = 1/3" when I open the subframes, so I must have done something incorrectly, but what, and how do I keep myself from doing this again?

Re: Understanding Image Capture settings

Posted: Tue May 14, 2019 2:23 pm
by rottielover
I did not figure out what I did wrong but at least last night I was able to use Automatic Observations to get some M101 data...

I created an LRGB sequence using the button "Duplicate for LRGB" after adding my object.

I selected the option "Loop this Sequence" with Infinite, and I had assumed that this would have prism switch between filters (*take a lum, then take a red, then a green, then a blue). Instead it completed all the images in order (all lum, then all red), seemingly ignoring the checkbox to loop the sequence, is there something that I have done wrong?

Related, I finally noted last night that my Baader filters are not parfocal as I had assumed. I used Automatic Focus on each filter to get the focus value in steps (I have a moonlight focuser, and I cannot find any option to enter this in microns anywhere, it appears to only allow steps). I noted that Prism did not use the focus step values when changing filters, it just kept the focuser in the same position all night, what am I missing in order to get prism to move to focuser to the correct focus position, or will I be doing autofocus on every filter change no matter what?

But at least all of the captures have the expected number of pixels now :)

Re: Understanding Image Capture settings

Posted: Wed May 15, 2019 8:53 pm
by rottielover
OK I'm not that smart...

SO my baader filters ARE parfocal, I just went through and re-ran all my data and my Focuser was at 1867 after autofocus for Lum, it came up with 1824, 1826, and 1870 for R G and B respectively. So very very close. I FINALLY figured out where the offsets are stored, you have to go into hardware settings, and go to the Filter Wheel setup, and then enter the offsets into the filter wheel driver. That one was driving me insane.

Finally I would also advise that if you keep getting a message during autofocus about your star going off the window edge go to the Image Grab tab and set the "Half Window (pixels) to something like 160.

Re: Understanding Image Capture settings

Posted: Fri May 17, 2019 10:02 am
by Hamza Touhami
rottielover wrote:
Sun May 12, 2019 6:28 pm
I need some help understanding how I messed up...

Let's start with the camera, a ZWO 1600MM-Cool Generation 2. The 1x1 images are 4656 x 3520 pixels

Somehow I managed to capture lights and flats which are 3493 x 2641 Prism error's when calibrating them because the sizes don't match.

I genuinely have no clue how I managed this. I was manually imaging, meaning I was using the camera control window, and I setup a Sequence on that window.

I noticed that Prism says "Zoom = 1/3" when I open the subframes, so I must have done something incorrectly, but what, and how do I keep myself from doing this again?
This typically happens when there i windowing options selected in the camera control panel, that is a good place to start looking

Re: Understanding Image Capture settings

Posted: Fri May 17, 2019 10:17 am
by Hamza Touhami
rottielover wrote:
Tue May 14, 2019 2:23 pm

I selected the option "Loop this Sequence" with Infinite, and I had assumed that this would have prism switch between filters (*take a lum, then take a red, then a green, then a blue). Instead it completed all the images in order (all lum, then all red), seemingly ignoring the checkbox to loop the sequence, is there something that I have done wrong?
Mmmmmm there seems to be an issue there for sure, it is supposed to rotate your filters as you noted. Let's look more into this. Can you do another sequence and see if this is reproducible ?

Re: Understanding Image Capture settings

Posted: Fri May 17, 2019 10:55 am
by rottielover
Hi Hamza, I did find the windowing options, I apparently clicked one before taking my flats I guess. I set it back to "Full Frame" and have not had the issue again.

I am supposed to have clear skies tonight so I will try another sequence with a loop and see if I get the same result. I'll try and take more careful notes of what I'm doing as well.

Re: Understanding Image Capture settings

Posted: Wed Nov 20, 2019 7:20 pm
by Joe in Mobile
I have the same camera, where do select the gain, etc. before taking pics. I am used to sharpcap.
How do I determine the offset for the filters also?

Joe in Mobile

Re: Understanding Image Capture settings

Posted: Wed Nov 20, 2019 7:46 pm
by rottielover
Hi Joe,

If you are using the native ZWO camera drivers (picked ZWO when setting up the camera in Prism) then there is a tab in your camera 1 box when it's connected (i don't recall the tab label off the top of my head) but if you go from tab to tab you should find gain and offset with a "set" button next to them that will essentially let you change them "on the fly".

If you are using the ASCOM driver for the camera then the only way to change these is to go into the driver setup of the camera and change it there.

In order get the offsets I did Automatic focus runs on each filter (might have to change the exposure time, narrow band for sure). Then I took the MM of the focuser when on the reference filter (Lum usually) and subtracted the MM of the focus for that filter. You have to enter these numbers into the driver setup for your filter wheel usually (this is true for my ZWO EFW I have the 8 slot model).

Some filters might be + or - from your reference filter so make sure you pay attention to the MM numbers. My Baader filter set (LRGB, Ha, Oiii Sii) are very nearly parfocal, I could probably get away with not entering offsets but since I did the focus run work I went ahead and entered the numbers anyway, this way prism will move the focuser that extra tiny fraction for just that much more of a sharp focus on that filter. Probably not needed but it doesnt' "cost" me anything to do this now.

I hope this helps. Have you joined us for the Google Hangout's call on Saturday's yet?

Re: Understanding Image Capture settings

Posted: Thu Nov 21, 2019 3:53 pm
by Joe in Mobile
What hangout and how?

Joe in Mobile

Re: Understanding Image Capture settings

Posted: Thu Nov 21, 2019 6:11 pm
by rottielover
@Hamza Touhami started a Google Hangout's group and we meet every Saturday night

I think most folks are participating on Facebook now instead of the forums. If you have facebook lookup Hyperion Astronomy and join the group.

The Hangout Link is : https://hangouts.google.com/call/0GaZat ... pdG95BAEEE

I think we start sometime around 8 pm Central time if I remember correctly.

Re: Understanding Image Capture settings

Posted: Thu Nov 21, 2019 6:15 pm
by Hamza Touhami
Absolutely, we have a live hangout every single Saturday to offer help and just share images. Scott has provided the right link above.