SharpCap Forums

Hi,

I am fairly new to astronomy and new to using Synscan and Sharpcap software so apologies for any newbie poor questions etc.

I have a Skywatcher 130P with a synscan Alt-az mount and I am using an Altair GPCAM2 camera connected to it. I have gone through the setups correctly and can control the mount and camera through the laptop. However I can not see anything on the live view within sharpcap when pointing at something quite bright and lots of stars e.g Orion.

I have attached a picture from Sharpcap showing the live view and hopefully the camera control settings. I am using an exposure of 4.5 seconds and a gain of 1555. I have also tried a higher gain but with no effect. As you can see from the picture the live view is black with no stars. I have read on other posts that setting the "digital gain" could help and/or altering the gamma setting but I am unable to find either of these in the settings.

Could this be a fault with the Altair GPCAM2 camera or are there other settings I should be looking at. Any help would be appreciated.

Hi,

the most likely cause is that to get a first astro image you need to get several things right at once

* pointing at the right place (made harder by the field of view being quite small).
* right camera settings
* correct focus position

It's best to work up to this in stages - something like the five steps outlined in this post (viewtopic.php?t=5178#p28329) would be one way to do it - you work through making sure the camera works and responds to light, then through getting reasonable exposure, then focus before trying any astro imaging. If the moon happens to be about, it's by far the best target for your first astro image (after the introductory steps) - it's big and bright enough to show up even if your focus is out or you are not quite pointing at it (you should be able to see the skyglow around it).

Another you can do is use the 'Display Stretch' function in SharpCap to artificially brighten the image on screen to help show anything that is there but too faint to see - see https://docs.sharpcap.co.uk/4.1/#Display%20Stretch . Note that this only affects the image on screen, not any captured images - remember to turn the display stretch back off when adjusting exposure/gain/etc for any captures so you see the real image rather than the boosted one.

cheers,

Robin

Hi Robin,

Thanks for the reply and I have followed the steps outlined in the link (1-4) and confirmed that the camera does show a daylight image in sharpcap live view so this confirms the camera is working OK. I assume my issues have probably been focusing issues as I have subsequently read that the Altair GPCAM may need spacers when connected to a Skywatcher 130P. I will continue to investigate and see what I need to get the stars/planets visable in the live view.

Brian

Hi Brian,

OK, good to hear that you have checked the camera on daylight targets - that means its very unlikely to be a camera problem and most likely aiming or focus. The 130P is a problem for DSLR cameras if I remember correctly since the default focuser pushes them too far out from the tube and they can't be moved in enough to get focus. I think that the GPCAM should be OK in that regard as there is not the big gap between the front of the camera and the sensor that there is in a DSLR.

Here's a trick you can try - get bright target (Jupiter, Venus, Moon, etc) in view and take out camera/eyepiece. Put a bit of white card behind the drawtube and move it until you get a focused image of the target on the card. The position where you have to hold the card to get the image in focus is where you need the camera sensor to sit.

cheers,

Robin