NexImage 5 Woes

[IanPozz]

Hi, I recently bought a Celestron NexStar 4 and NexImage 5 imager off eBay. I spent plenty of time getting to know the scope and installing software for image capture and manipulation. Tonight I observed the moon which looked perfectly focused in the telescope but when I switch to the NexImage 5 the video that's sent to my laptop is completely different, it's almost like I'm zoomed in on a very small area of the moon and there's no way for me to improve the image.

I can't help but think I'm making an obvious mistake somewhere but I have no idea what it is. I've tried pretty much every video resolution, refocussing the telescope and tinkering with every option I can see on iCap, the image/video capture software, but I'm still struggling to see anything clearly.

Any idea where I may be going wrong?

Many thanks

Ian

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[Thalestris24]

Hi Ian

I'm afraid it's the combination of the long focal length of your scope combined with the small camera sensor with tiny 2.2 micron pixels giving you a small fov. Have a look on here and put in the scope and camera data.

Louise

Edit: it should give you good images of Venus, Jupiter and Saturn!

[MarsG76]

It is normal to see a smaller FOV on your laptop from a CCD than what you see through an eyepiece and focusing becomes much more critical.

It might also be over exposed, try a faster shutter speed and lower or NO gain... 1/200th is a good start.  On a histogram make sure that the brightest level is not above about 80%.

Try to increase the contrast of your preview by using the contrast slider or drop Gamma to 0.5 (50%) and increase your preview to 200-250%. The exaggerated contrast will help you to hit that focus sweet spot and you will be ready to capture video sequences for stacking.

[IanPozz]

Lovely, thanks for your feedback, pleasing to hear that I've not bought a broken camera which was my main concern.

All the best.

Ian

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[JamesF]

If the image isn't clear that's probably down to being out of focus.  It takes a bit of practice to get the hang of focusing with a camera.  The focal point won't be the same as for your eyepieces.

With a focal length of 1325mm the image of the Moon will be just under 12.5mm in diameter at the focal plane.  According to Celestron the sensor in the Neximage 5 is only 5.7mm x 4.28mm, so you will see only quite a small fraction of the Moon at a time.

If you have a DSLR that would actually be a better choice for getting a full disc image of the Moon.  If you want to use the Neximage for that then you'd need to make a mosaic from a sequence of overlapping images.  It's not hard, just takes a bit of time to get the hang of.

James