Celestron Neximage help

[nr7286]

I just got a celestron neximage about a week ago and have been playing with it since. I was having some trouble focusing but have solved that for the most part, i built an electronic focuser that actually works really well. anyway, I was hoping for some advice on the settings. I have been trying to image saturn and can't seem to get any color. My equipment isnt the greatest but I was at least expecting to get images that look similiar to when viewing live through an eyepeice. This is probably the best I've done. Its about 700 frames stacked in registax. The gain was set at about half of max for this video and I know its best to have it as low as possible, but if I turn it down much lower I don't seem to get the rings to show up at all. This image was made using a 2x barlow.

I'd be happy with it if it had some color. Will I have to shoot separate vids with different filters in order to get any color? My equipment is as follows

celestron astromaster 114eq w/ motor drive

celestron neximage

using amcap for video capture and stacking with registax

thanks for the help

hhhhhhh2.bmp

[brantuk]

That pic's a good start to imaging. I hope someone helps here cos I've not played with my Neximage yet and I'm keen to see what advice you get. Love the focuser idea - what did you use and how did you do it?

[Demonperformer]

Set it to 5fps at 1/5 second

Push gain right down and adjust brightness to achieve a reasonable image of the planet on preview - if it is still to bright, reset exposure to 1/10 second and adjust it to get it about right for the planet.

Reduce the shutter speed by 1 stop (eg 1/10 to 1/25).

Preview will now look too dark and you will not see the rings on it.

Capture the avi.

In registax, process as normal, but on the wavelets page, increase the contrast slider (I usually aim for about 200) and increase wavelets 1 and 2 to bring out the detail.

Here is an example I got of Saturn doing it that way (exposure time was actually 1/25 on this one):

Stargazers Lounge - Demonperformer's Album: Planets - Picture

HTH

[TheThing]

I'll be watching this thread with interest.

I was out last night trying to image Satrun as well with a Meade LPi (very similar to your camera) and an Astro Engineering 1.6x barlow ep. My results were very similar to yous!

[nr7286]

brantuk: I actually used a motor and gear drive out of an old vcr. (a worm drive so it moves very slow) mounted one of the gears on the focuser and made a handheld switch. I was pretty suprised how well it worked.

demonperformer: Thanks for the advice I will hopefully have another shot at it tonight if its nice. I like your picture

[nr7286]

was able to get a better picture from the same vid by reprocessing in registax. adjusting wavlets 1 and 2 like you said really does bring out some detail. Hopefully its nice tonight so I can experiment with lower gain settings so its not so overexposed

correction: this was a different vid than the first but previously had very similiar results

[brantuk]

Thanks nr7286 - so vcr's are still useful after all lol - second attempt is a lot better - keep at it - Demon's advice seems to be paying off

[Specman]

Hi,

I share in your frustration. I've been trying to do exactly the same thing and getting the same results.

I got my image using the NexImage and a 2x barlow on my NexStar 4SE, I couldn't get the image to show any detail either. I think I was working beyond the useful power of the scope.

I also tried using the NexImage reducer lens without success, this just made the image a smaller white blob with a line through it!

I have a 5mm Barlow, however the main problem I have is centring Saturn and getting the NexImage to display on the computer screen. Half the time it's there, just out of focus

If I toned down the brightness/contrast I lost the rings, I share your frustration. I will watch this thread with interest.

Clear skies all!

Mark

[Demonperformer]

If I toned down the brightness/contrast I lost the rings, I share your frustration. I will watch this thread with interest.

I have found that if you can see the rings clearly on the preview screen the final image will be vastly overexposed. The secret I have found is to reduce the brightness to a point where you cannot see the rings on the preview screen, then after stacking in registax, increase the contrast slider on the 'wavelets' tab to about 200. Wavelets 1&2 will then bring out any details present. Take a series of avis, reducing the shutter speed by one step at a time, you will find the right one in there somewhere (probably a lot shorter than you expect).

When trying to centre the image with a barlow, first centre the planet on the preview screen without the barlow. When you add the barlow, you should now have the planet on the screen (way out of focus) and can apply small shifts to the position to centre it. The focus point with a barlow is considerably different to without, and with practice, you will get there.

HTH

[Specman]

I have found that if you can see the rings clearly on the preview screen the final image will be vastly overexposed. The secret I have found is to reduce the brightness to a point where you cannot see the rings on the preview screen, then after stacking in registax, increase the contrast slider on the 'wavelets' tab to about 200. Wavelets 1&2 will then bring out any details present. Take a series of avis, reducing the shutter speed by one step at a time, you will find the right one in there somewhere (probably a lot shorter than you expect).

HTH

Hi Demonperformer, thanks for the reply. Some very useful info, tried out your advice the other night but the mist came down before the stars came out, typical!

Perhaps you could advise, I notice you use a 6SE. I don't see Saturn in all her glory as per pictures posted around the site. I see it clearly but as a bright, white, sharp image through my eyepiece. I can make out the shadow of the rings on the planet and a couple of moons at best with my 8mm Celestron X-Cel eyepiece.

Here in the smaller image (slightly poorer than my visual) is the kind of thing I see through my eyepiece with say a 25mm lens.

Now when I fit the 2x Barlow and the webcam I get this

I can't focus any detail and if I reduce the shutter speed and gamma to a minimum I get a finished stacked image with no rings.

Here my settings:

Set frame rate to 25fps then reset to 5fps before capture. In Options uncheck full auto. Leave white balance set to auto. Set gain and gamma to min. In video capture pin set output size to 320x240.

Capture about 1000 frames and process in RegiStax.

Perhaps I'm expecting too much from the 4SE and a cheap NexImage. Saturn's moving away now. I might try Jupiter.

Its all good fun. Thanks in adance for any advice

[zedds]

I found fitting a IR Block filter let me bring out more detail on the screen and so to the final stacked image. I think its a bit of trial and error really.

[nr7286]

I have been thinking of getting an ir blocker myself. Good to hear it can help some. Got out tonight for the first time in a couple weeks, weather has been bad here, I was out for about half hour tonight before the clouds shut me down. about to see if I got any useful data...

[nr7286]

specman: i notice on your images there is a slighly blue hue on one side of the planet, and a yellowish reddish hue on the other. I forget what this is called but I have the same problem and can't really figure out whats causing it or how to correct it

[Specman]

specman: i notice on your images there is a slighly blue hue on one side of the planet, and a yellowish reddish hue on the other. I forget what this is called but I have the same problem and can't really figure out whats causing it or how to correct it

Yes, now you mention it its quite obvious. How strange

I'm going to try an IR filter

I can't actually focus my image much more and can't get any detail, I think I'm trying to squeeze blood from a stone with the NexStar 4SE. I'm going to get a digital Canon SLR body and try that, see if I get better results.

I would be interested to hear from anybody with the same type of scope, see just what's possible and what isn't with the NexImage and a 4inch scope.

Has anbody got any decent pics with the NexImage?

[Brinders]

I think you must accept that unless you have excellent seeing, the Neximage will struggle with the planets. It is a small chip (1/4", I think) and a limited fame rate if you are not going to run not into compression atifacts (the camera uses USB 1 rather than the higher streaming from USB2). 5fps appears to be best for capture, though I have sometimes got acceptable results at 15fps.

I also use a CCTV security camera that uses a larger 1/3" Sony CCD chip and uses USB 2 via a frame grabber at 30fps. This nevertheless gives simialr results to the Neximage.

Saturn has been very unco-operative for me this apparation, but here is a link to some pics I obtained with the Neximage last year and also to Jupiter:-

http://stargazerslounge.com/imaging-planetary/76692-saturn-march-10-2009-a.html

http://stargazerslounge.com/imaging-planetary/89177-jupiter-grs-last.html

http://stargazerslounge.com/imaging-planetary/86004-jupiter-wo-megrez-72-apo.html

[nr7286]

nice pics. anyone have any recommendations for the saturation setting?

[BlueAstra]

I used to have a NexImage. Settings I have used are:

1/30, Gain: 40, Sat: 100, Gamma: 0

and

10fps, 1/25, B: 90, Gain: 0, Sat: 50-100

Generally keep the B high and the gain just high enough to detect the rings.

The planetary shots in my album were taken with a NexImage and a C8 SCT:

Stargazers Lounge - BlueAstra's Album: Astro Pics

The colour shift across the image may be due to refraction in the atmosphere acting like a prism. You can correct it with the RGB align in Registax.

[nr7286]

rgb align worked nicely thanks for the tip. only if skies would clear up...