In need of a SharpCap tutor

Somewhere to ask questions about the best way to use SharpCap
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oopfan
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Re: In need of a SharpCap tutor

Post by oopfan » Mon Dec 17, 2018 6:01 pm

Same here, Joe. I'd like to do a lot more lunar work but opportunities are rare due to trees.

Brian

psy1280
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Re: In need of a SharpCap tutor

Post by psy1280 » Mon Dec 17, 2018 6:31 pm

How I envy anyone with a 360 degree view :-(

donstim
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Re: In need of a SharpCap tutor

Post by donstim » Mon Dec 17, 2018 11:08 pm

Joe,

It definitely sounds like you're on the right track. I don't know what caused your connection issue, but I have been having some erratic connection issues at times. I think these are mostly caused by weight of the camera's remote control pulling on the cable. I try to keep the remote perched on the telescope tray, but sometimes it will fall off, yanking on the camera connection and sometimes causing it to fail. If this happens, it then seems to be erratic for the rest of the session.

There can also be an issue with strain on the power connection. See this post: https://www.cloudynights.com/topic/5639 ... try7661342. I think I am going to try zip tying my cords to the camera body as shown in later in that thread to eliminate the strain on both the power and video connectors. I hope it makes my intermittent connection problem go away.

Dave, testing during the day is great for basic familiarization with camera and Sharpcap settings for previewing and video recording, but it wouldn't help with using Live Stacking, would it? Live Stacking needs stars for alignment. Is there something during the daytime that could be used as substitute alignment stars? I find that getting Sharpcap to recognize a sufficient number of alignment stars is often the most difficult part of Live Stacking. That and the big difference I get with my camera between the picture I get in preview and the picture I get in Live Stacking when retaining the same camera exposure/gain settings. When I get a nice preview shot, then switch to Live Stacking, the image is usually washed out with lots of noise.

Don

psy1280
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Re: In need of a SharpCap tutor

Post by psy1280 » Mon Dec 17, 2018 11:17 pm

Thanks Don,

I will also be most interested in what Dave has to say about live stacking as well as shedding more light (no pun intended, honest) on alignment stars. :

Joe

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turfpit
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Re: In need of a SharpCap tutor

Post by turfpit » Tue Dec 18, 2018 1:00 am

Don, Joe

I had the weight issue with cables and resolved it using video/power baluns for CCTV. See the images at
https://docs.sharpcap.co.uk/3.2/#Frame%20Grabbers. The baluns allowed the camera to PC connection to be achieved with a length of Cat5e ethernet cable which resolved the power/video cable weight issue.

https://www.ebay.co.uk/itm/1-Pair-BNC-t ... 0643.m3226

This device helped with using the menu control buttons on the back of the camera:

https://www.ebay.co.uk/itm/AHD-UTC-Cont ... 1006.m3226

It made for a civilised/comfortable connection at the PC end of the cabling.
testing during the day is great for basic familiarization with camera and SharpCap settings for previewing and video recording, but it wouldn't help with using Live Stacking
Not during the day but remember these are basically CCTV security cameras which can work at night. The answer is you can practise Live Stack in a darkened or dimly lit room at night. With the right settings, a stack can be built.
When I get a nice preview shot, then switch to Live Stacking, the image is usually washed out with lots of noise
The idea of Live Stack is to accumulate faint images and create a stack. The stack will give a better image than the single frame. If you can see the object with a single frame then using those settings for stacking will soon blow out the resultant image. This is where understanding the use of the histogram comes in. Plenty in the manual about that.

This image is a single frame in progress for a set of 180s images of M31. M31 is barely visible but the shape of the histogram is decent for a deep sky object. Before commencing the imaging run, I will have taken a single RAW frame, inspected and stretched it in FITS Liberator. Only when satisfied would I start the run - for 180s exposure that would be 20 frames to make an hour of capture. Settings like this result in images like https://www.astrobin.com/users/turfpit/. These are traditional capture and process later images. With Live Stack the image is built on-the-fly.

M31-single-frame.JPG
M31-single-frame.JPG (64.91 KiB) Viewed 316 times

The thing with Live Stack is you get hit with capture, darks, flats & processing all at once so some familiarisation of the hardware and software will be helpful.
shedding more light (no pun intended, honest) on alignment stars.
There comes a point when you have to capture for real and deal with alignment stars. This is where all the off-line preparation and practising will help.

Dave

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turfpit
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Re: In need of a SharpCap tutor

Post by turfpit » Tue Dec 18, 2018 1:20 am

Another useful task I completed on one of those rare cloudy nights was to build a spreadsheet detailing all the camera menu items and the possible settings. Over time I was able to add notes as things were understood - including useful settings for different types of objects.. I printed it double sided and laminated the doc for use at the scope.

Dave
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psy1280
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Re: In need of a SharpCap tutor

Post by psy1280 » Tue Dec 18, 2018 4:07 pm

Dave,
Thank you for offering a helping hand to Don and myself. I do hope I’m not wearing out my welcome.

Don is a bit more advanced than I am, so my questions may seem rather primitive (sometimes I feel that others begin this hobby with much more experience and familiarity with the concepts then I have. For me, it’s like learning a foreign language). Hopefully, one day you’ll write a book called, “VideoAstronomy for Dummies.” As a self-proclaimed ‘dummy,’ I’ll forge ahead with my questions.

I think I know the answer to this question, but, nevertheless, you mention that you first capture a single raw image. Is this something I should be working on/with, should I download something like Deep Sky Stacker?

Then you say that you “stretched it to FITs Liberator,” would FITs liberator be something I’d use in Adobe Photoshop? And what does “stretched” mean?

Here’s a very basic question. The camera controls in the manual are quite different than my control panel. Is this because of the Revolution Imager I’m using? Would a more expensive camera give me more options? After mastering (my lips to god’s ears, huh?) my Revolution Imager camera, would an upgrade camera make things easier?

There are so many terms and techniques, take “Binning,” as an example, as a total “dummy” do I need to concern myself with so many options offered in SharpCap (darks, flats, etc.), or, should I be 0only concerned with progressing one baby-step at a time. For example, Step 1: I now can see my terrestrial tower in the daylight and at night.” Step 2: Attempt to view stars, moon, etc., obtaining focus and experimenting with some of the controls, Step 3: ????, Step 4….. (I told you I’m mired in the “primitive” phase)

It would be wonderful to have a manual that deals with baby steps, for example, step 1 turning on the monitor, to say, step 1001 (which might be a postprocessed M31 image). I’m going to bet that your book won’t be as elementary as I would like, but nevertheless, perhaps you can keep my suggestion for VideoAstronomy for Dummies, in mind for another project. It could be a Q&A, I’ll send you a million questions, and your answers will progress from step one to 1001 (doesn’t hurt to dream, huh?)

Well, thanks for reading all this, I’ll check back after my “baby step #3.” Last question (promise) When I do get out under the night sky for step #3, do you have any preliminary goals I should shoot for? (unfortunately my eastern exposure doesn't afford a view of anything super bright, moon, etc.)

Gratefully,
Joe

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turfpit
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Re: In need of a SharpCap tutor

Post by turfpit » Tue Dec 18, 2018 8:35 pm

Joe

I assume (dangerous) that you have one of these https://www.revolutionimager.com/produc ... 8868832004 or something similar? If so there is good information on the How do I tab at the top of the web page. Topics covered include:
RI-how-do-I.JPG
RI-how-do-I.JPG (28.87 KiB) Viewed 305 times
The topics are well covered - I see the Charles Copeland (CN) SharpCap 2.7 Live Stack video is in there. Reproducing that information here does not seem to me to be a time efficient exercise. I think you will find plenty in the How Do I to get you started.

If you have the 0.5x reducer and IR filter use them both. The reducer gives a wider field of view (helps finding targets) and the filter will help with star bloat.

I have got my old CCTV camera out and at the moment the battery is charging. I will run it up in SharpCap so I can see what menus are available in the current release.

For the moment, forget about FITS Liberator (might not be appropriate here), Deep Sky Stacker, Adobe Photoshop - these all add layers of complexity that you do not need (at the moment).
what does “stretched” mean?
Post an image of the full SharpCap screen with your RI camera connected and that question can be answered better.
Would a more expensive camera give me more options
Yes, plus a space in your wallet and the same issues to overcome.
would an upgrade camera make things easier?
Just different and the same issues to overcome.
Binning
Ignore this one. Not really appropriate for a 700x500 image as it would end up the size of a postage stamp.
darks, flats
Not at the beginning. Imaging as a hobby is evolutionary (not revolutionary). You will need them sometime but first acquire some images and later look to how you improve them - dark frames would be the next logical step.
preliminary goals
Depending on what is visible to you, large brighter objects are best for starters:
  • Moon. It must be in the east sometime. The moon is an easy object because it is big and bright. The moon is a difficult object because it is big and bright. You will understand that one after you have tried it. :-)
  • M45. Just about visible with the naked eye and is large, therefore a better chance of finding it.
  • M42. Just about visible with the naked eye and is large, therefore a better chance of finding it.
In the attached document AGC (gain) and INTG (exposure) are the 2 settings which will get you started.

The astro vendors do tend to oversell the 'ease of use' aspect of this hobby. A person who starts out and spends $5k on a mount, scope and camera will have exactly the same problems you are facing now.

Dave
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psy1280
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Re: In need of a SharpCap tutor

Post by psy1280 » Tue Dec 18, 2018 9:04 pm

Thank you Dave!!!!

Guess I have to settle down and be less anxious about this very steep learning curve. And, perhaps more importantly, feel that there's a way to actually lean all this on my own (well, also with the help of good people like you)

You've been such a great help.

Joe

donstim
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Re: In need of a SharpCap tutor

Post by donstim » Tue Dec 18, 2018 9:05 pm

Joe,

When Dave says he first captures a single RAW frame, that means a single frame of the object in RAW format. It is a little confusing if you don't know what a RAW format is because there is no selection in Sharpcap to select RAW. RAW here means an uncompressed unprocessed image file, which in Sharpcap would be obtained by saving the image file as a FITS file. You can select this either as your default still image type under "File", "Sharpcap Settings", "Preferred Still Format", or by selecting "FITS files" in the Output Format selection box in the "Capture Format and Area" in the Camera Control Panel on the right side of the Sharpcap user interface. You can capture a single frame by selecting "Snapshot" in the tool bar. Since he is working with a single frame, a program like Deep Sky Stacker would not be relevant. Deep Sky Stacker is for stacking multiple images to bring out detail and reduce noise. You can also so the same sort of thing in real time using Live Stacking in Sharpcap.

Dave then opens the saved FITS file in FITS Liberator (a separate program, not used with Adobe Photoshop, at least for this purpose) so he can view it and play with the histogram a bit to make sure he has a good image before spending any more time capturing long exposure images in Sharpcap. "Stretched" here means that he manipulates (or has the software automatically manipulate) the histogram to bring out more detail in an image. For example, if you bring up the histogram in Sharpcap while Live Stacking, you can change the black level, mid level, and white level to bring out more detail and reduce noise or over exposure. See https://www.youtube.com/watch?v=zIlJHyVWei4 for a demonstration of histogram "stretching" in Sharpcap with Live Stacking. (Note: the demonstration uses an older version of Sharpcap where the histogram stretching tools are a little bit different.)

Taking the time to more closely examine a single frame before embarking on a long exposure is good practice in time management for good astrophotography. I suggest it may be better to skip this step for now and take it one step at a time to even determine what your end goal is. For example, for me, I am currently plenty content with using live stacking (at least for deep sky objects) to obtain a nice image (to me anyway), later processing it in a photo processing program like GIMP (which is a free, open source image processing program that is similar to Adobe Photoshop). Most astrophotographers would probably not consider my images to be very good, but at least at this point, they satisfy me, especially for the minimal time, expense, and effort to obtain them. I just use live stacking and the histogram in Sharpcap to get a decent image before saving it. That way, I can do it all in real time with one piece of software.

As for "binning," don't worry about that now as our camera does not have that capability. Capturing darks and flats will improve your final image, but I suggest you ignore that for now and just concentrate on getting a decent basic image and get familiar with your telescope/camera and Sharpcap. I don't know if you saw my response to your post in the Live Stacking thread, but go back and take a look at that. The 3 basic things you need to attend to first are 1) Getting the object centered in the small field of view of the camera, 2) Setting the right exposure, and 3) focusing. Without at least being "close enough" on all 3, you may not get an image at all of the object.

For now, the only camera menu settings you should really need to change during a session are the shutter speed and AGC level. The camera menu items in Dave's post are not for the Revolution Imager. I have a full description of the menu settings for our camera, but you really don't need to concern yourself with them at this point. You really only need to know the ones that are described in the information sheet that came with the camera, but for now, you should only work with the shutter speed and AGC level.

As for considering an upgraded camera, I would stick with what you have, master it, and then make that determination. My suggestion is to see what type of objects and imaging most interests you first and get an idea of what it entails to achieve that before considering another potentially expensive purchase.

And as for ideas of what to consider shooting for with your eastern exposure, maybe try the Beehive Cluster (M44) in Cancer? As an open cluster, it is too big to capture all of it, but at least it should not be a difficult object to find and it offers more than a single or double star to practice on.

Good luck!
Don

P.S. I must have been writing this at the same time as Dave was responding. Sorry if my answers are redundant or don't take into account Dave's response.
Last edited by donstim on Tue Dec 18, 2018 9:23 pm, edited 2 times in total.

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