Page 1 of 1

SharpCap Question

Posted: Fri Jul 09, 2021 2:56 pm
by Solar Seeker 52

I am starting to figure out how to use Sharp Cap to record my sun pics and videos. I had a question about zoom. Maybe it is a settings issue. When I want to focus on a area that to investigate, I will zoom in to lets say 200 percent. I would capture it be either video or snap shot. When I go back to review my video or picture, the whole sun is in view but not the zoomed in view. Is there a setting to select to record the area in interest but not the whole sun? I don't know if I am making myself clear. I am new at this.

Thanks for your help!

Sun Seeker

Re: SharpCap Question

Posted: Fri Jul 09, 2021 3:50 pm
Hello Jason.
I use SharpCap and know exactly what you mean.

You are correct in getting the focus exactly correct by using the zoom facility and around x200 is about correct in many cases.

This does not change the actual camera-capture though. If you require a closer-view and/or capture, you will require the use of a Barlow/Magnifier lens in front of the camera itself.

To see what effects using a Barlow lens does on your particular set-up use:-

You will need to start at the top line first as to Visual / Imaging / Bino-mode and work-down each line filling-in the relevant details. Easy to compare different set-up's (say for different Barlow etc.)...

If you have any difficulty getting to use that tool, then please reply with exactly what scope, lenses/eye-pieces (if any) and camera you want to use...

I trust that helps you

Best Wishes

Re: SharpCap Question

Posted: Fri Jul 09, 2021 5:05 pm
by Solar Seeker 52
Thank you for your reply. I am using the Coronado's SolarMax III 70mm f/5.7 Double-Stacked H-alpha Solar Telescope. I have both Coronado 18mm and 11mm eyepieces. I believe I do have a Barlow laying around somewhere. What I have been doing are screen dumps. I have been taking snap shots of the screen of my area of interest but that a little crude. lol I am surprised that the software does not record what you see on the screen if you zoom in. But it is what it is I guess. I really appreciate your help on this.


Re: SharpCap Question

Posted: Sat Jul 10, 2021 10:07 am
Of course Jason, a couple of ways of taking what is actually showing on the screen is the "Screen Capture" and of course a camera or camera-phone.

Then to crop-out what you don't want to save and try and process to the best result, might work somewhat, but ideally Barlows would be the way forward..

Whether any other telescope-camera download program has the zoom and capture of that zoomed screen-shot, is unknown to me, but perhaps checking with say Fire Capture - might have that facility..


Re: SharpCap Question

Posted: Tue Jul 13, 2021 6:25 am
by Rusted
In SharpCap the frame size [described as Resolution] alters the degree of close-up or enlargement.
The problem with that is the image shrinks in step with the smaller frame sizes.
So, in effect, you are digitally enlarging your image. Much the same as cropping.
Rather than optically enlarging it with a Barlow or GPC.

I use one of three Telescope-Service Glass Path Correctors intended for their own T-S binoviewer.
These sit on the nose of the camera [or eyepiece] and provide lower powers of enlargement than a true 2x Barlow lens.

I select a GPC power depending entirely on the seeing conditions.
Be aware than a GPC or Barlow lens will make the image dimmer.
The image brightness is being spread over a larger area even if you don't see all of the image.

T-S GPCs are relatively cheap and come in 1.6x, 2x and 2.6x powers.
Note that these numbers are a measure of their effect on the nose of a binoviewer.
Which is a very long way from the eyepiece or camera. Where they extend the light cone considerably more.
Than where I use a GPC very close to the camera or eyepiece.

I find a 2x Barlow almost always too powerful for my usual seeing conditions.
Though I am working with a 1.5m of focal length on my 6" refractor.
A shorter telescope might be a better match for a Barlow if the the seeing conditions allow.

Re: SharpCap Question

Posted: Mon Sep 13, 2021 7:25 am
by RodAstro
Hi Sun Seeker I know this is a bit late, I cant sleep so just scrolling through past messages.

In SharpCap the other way to capture a smaller region is to use region of interest ROI.
Just draw a box around the area you want by left clicking on the image and dragging a box around the area of interest.
You will be prompted is this area ok click OK, you will notice in the top right a white dot has popped into ROI.
If you want to go back to full camera view just click on the circle for the full view and the white dot will move there.
SharpCap will ask if you want to keep this ROI, this is useful if you are targeting an area with a series of captures for doing something like an animation but your mount is drifting slightly so you can go back to the same size capture when repositioning the image.
If you want to change the ROI size just draw another box in full camera mode and click OK at the prompt this will over ride your last ROI size.

Reasons for doing it this way:
If your camera setup is already pixel matched to your scope resolution then you will not gain anything by using a barlow, you will just slow the speed of the captures down and that's bad for lucky imaging.
Using ROI though you can seriously increase the speed of captures, with my Quark setup at f30 and 150mm scope I go from 5000 frames in 60 seconds to about 35000 frames when using a region just under a 1/4 of the image, this is much better for lucky imaging especially if the seeing is not to good as you will have far more good frames to stack.
Once stacked you can resize the image in something like Photoshop and achieve a better image.

I hope this is useful, you may have already found it.
Cheers Rod