Live Stacking Beginner help

Discussions of Electronically Assisted Astronomy using the Live Stacking feature.
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turfpit
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Re: Live Stacking Beginner help

Post by turfpit » Tue Sep 25, 2018 1:18 pm

Don
M27-3.PNG
M27-3.PNG (112.69 KiB) Viewed 796 times
My first M27 taken with this camera https://docs.sharpcap.co.uk/2.9/#Frame%20Grabbers

posted in the hope that it will entertain and encourage you and others to persevere.


Dave

donstim
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Re: Live Stacking Beginner help

Post by donstim » Tue Sep 25, 2018 4:36 pm

Thanks, Dave. With all the help you have provided already, I hope to at least get a little better. I feel way behind the power curve right now with so much to learn. First there's the equipment - imager and telescope that came as a bundle from Orange County Telescopes (so the imager was basically free!), then all the software - SharpCap, Autostakkert, Registax, Nebulosity, Siril, GIMP, etc., which are all new to me.

I have only had the equipment for a little over a month and have only been able to observe a handful of times, but it seems like I have encountered plenty of problems for which you need a lot of patience! My very first night, while trying to balance my scope, I loosened the dovetail screw too far and managed to drop the OTA onto a hard concrete patio. I was very fortunate that it didn't crack a mirror or something before I'd even had a chance to see anything through it!

Since then I've had the batteries in all the electronics - telescope, laptop, cell phone - wear down (though not all at the same time). For example, last night unbeknownst to me, the telescope battery was wearing down. I had the imager plugged into the telescope's USB port for power, and the imager kept resetting. I would be in the menu changing exposure and it kept re-initializing, reverting all of my changes. I feared there was something wrong with the imager, but didn't know if it was associated with the power input or the video output. I finally noticed the power light blinking, but didn't know why. I decided to connect the camera to a separate battery, the problem was resolved. It was only then that I noticed the Celestron logo light was pulsing which I think was telling me that the telescope battery needed recharging. (At least I hope that was the case and not that the USB power is going to to be an ongoing issue.)

For that M27 picture, I almost gave up so many times. I just could not get anything at all to show up in the SharpCap preview screen. With such a small FOV for the camera, and the focal plane of the camera being so different than an eyepiece, I never know for sure if a lack of an image is due to the object not being in the field of view or it being way out of focus. I can switch back and forth with an eyepiece to try to make sure the object is centered, but it takes a lot of trial and error to get the focusing close enough to even see such a dim object. Or I can go to a nearby bright star or planet to get the focus right, but if I come back and still can't see the object, then I have an alignment issue. Anyway, it took me long enough to even see an image that I almost gave up more than once. But when I got that first image, I was amazed!

It appears that you started with a very similar imager/camera. Now it seems like you have (or have tried) several cameras? What was that progression like?

Don

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turfpit
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Re: Live Stacking Beginner help

Post by turfpit » Wed Sep 26, 2018 9:24 am

Don

Batteries suffer outside in the cold, so be prepared. A 17Ah power tank is a useful starter. Multiple batteries for the laptop if away from mains power.

Have a look at the attached - comments welcomed. It is a rough guide which might help you along. I used to set-up with finder scope and eyepiece now I set-up with finder scope and imaging camera with reticule turned on in the capture software. The reason is that I discovered swapping optics can cause an 'image shift'. So if doing deep sky and using a focal reducer, then I align the mount with those optics in place. The exception would be using a Barlow. This reduces field of view (and brightness) so is not a good idea when hunting for stars during alignment.

If finder scope/camera seems too much then start of with finder scope/ eyepiece. Practise where possible during daylight and from inside the house. TV masts, mobile masts, pylons, trees all make good test objects.

Typical beginner approach (thinking of myself here). First time use, set up telescope and camera outside in the dark, read manual with a torch. Decide to image the faintest object available... :(

Consider this - Live Stack adds a layer of complexity, so if using that then check the option to allow all frames to be saved as well, That way, as well as the stack, you have some material to study and process in the traditional way.

The approach outlined in the document was my first big leap of progress. There is a lot more but at your stage it would be overload. Next thing in progression would be to inspect a single image before commencing a run. No point capturing all night then finding out the next day (or later that day) the disk is full of dud images.

Good luck with this, if the document gets a thumbs up, I can expand and put into the Tutorial sub-forum.

I posted a couple of new documents last night which you might find useful, plus new images in the Gallery.

viewtopic.php?f=35&t=1157
viewtopic.php?f=35&t=1156
viewtopic.php?f=18&t=1151

Dave
Attachments
Getting Started with Deep Sky Imaging.pdf
(259.9 KiB) Downloaded 52 times

donstim
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Re: Live Stacking Beginner help

Post by donstim » Wed Sep 26, 2018 3:04 pm

Dave,
Just a few comments on your excellent tutorial document:
1. You are using SharpCap 3.2, which is a temporary beta version. Nice to be using the most recent version, but I don't typically use beta software. (I will now in this case!)
2. When the instructions say "Apply Display Histogram Stretch" and "Turn on the reticule," do you think new users will know how to do this without specific "how to" instructions?
3. In the screen capture just after "Achieve 'eyeball quality focus,' you have a red highlight box around the exposure camera control. I don't see any related discussion, plus for those of us with web cameras that are not controllable by SharpCap, this control is not available. Exposure needs to be set through the web camera's own menu system.
4. There seems to be an unsaid "restart" between the practicing in the daytime bit and going to actual nighttime use. For example, in the focusing on a star near the object of interest instructions the reticle is off for the Bahtinov Mask focusing, then the user is instructed to turn it on. Similar for the histogram stretch.
5. In the instructions regarding the desired shape of the histogram, would it be better to say, "The histogram should have a small gap at the left hand side, that is, it should not touch the left hand side" instead of "Histogram has a small gap at Left-Hand side." This way the instructions would state what is desired (as is the statement about the right hand side) rather than just noting what the example histogram looks like. This would be more consistent with the instruction to "Adjust exposure, gain...until satisfied" (or maybe "until these qualities are achieved.")

I hope this helps. It is the least I can do after all the work you've put in. I will be out of town until Tuesday, so I may not much of a chance to review any additional material before then.

Don

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turfpit
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Re: Live Stacking Beginner help

Post by turfpit » Thu Sep 27, 2018 1:55 am

Don

Thanks for the comments.

My previous post said
It is a rough guide
and that is what it is. It took less than an hour to create and was not proof read or the instructions tested. My usual process to produce a document of commercial quality would be:
  • gather the screens in an imaging session
  • create a high level structure for the document - section, subsections
  • import the images into the appropriate place
  • create text
  • edit images to add red boxes to draw the reader's eye, add arrows, text
  • proof read/correct the document
  • test the instructions, which would need to be done at the scope
  • apply any corrections
The detailed step by step guide would probably take 2 -3 working days to complete, include 2 visits to the telescope, be around 20 pages long and include links to appropriate material in the manual . From your previous post it looked like you needed some pointers as you were struggling. You got a response in hours.


To answer your questions:
1.
using SharpCap 3.2
I am currently reviewing the manual for 3.2 so it is reasonable to use that version.

2. Fair comment, I would expect to include those elements in the embellished version.
Apply Display Histogram Stretch
here http://docs.sharpcap.co.uk/3.2/#Mini%20 ... %20Stretch
Turn on the reticule
here http://docs.sharpcap.co.uk/2.9/#Reticule%20Overlays

There is no manual for 3.0 or 3.1 - fallout from the epic 7 week effort to produce the 2.9 manual. The production metric was around 3 pages per day.

3.
red highlight box around the exposure camera control
you got me fair and square. ;)
Exposure needs to be set through the web camera's own menu system
good point, I need to consider that not all cameras present control when writing documentation.

4. I use 'rough document' in my defence. ;)

5. Comprehensive histogram explanation here http://docs.sharpcap.co.uk/2.9/#The%20Histogram
I will be out of town until Tuesday, so I may not much of a chance to review any additional material before then.
I admire your optimism.

If there is sufficient interest in the material produced then I will, in due course, create a comprehensive set of instructions on this topic.

Dave

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