5 replies to this topic

[Borodog]

Poor seeing. SV205 + SV106 + 1.5X Barlow. At capture resolution. F/6 = 4.3X pixel size in microns. Green channel data only. Two panels stitched in ICE, each 10% of 2000 frames. Deconvolution in Astra Image.

 

https://cdn.astrobin...74cbaa0ff9b.png

 

Any feedback is welcome.

[Borodog]

I see in the cool light of the day that this image is very soft and low contrast. I think that is perhaps an artifact of pushing the gain up to avoid the posterization problems I was having with this camera before. Unlike other cameras, the gain on this camera does not seem to be multiplicative; rather it seems additive. The histogram is not stretched to the right, it is shifted to the right, which makes the image brighter but compresses the dynamic range. I also had a lot of trouble with a "haze" in the blue channel and soft focus in the red channel; hence I chose green to process. But there may be some of the blue haze softening the image up. It's strange, because I haven't noticed this blue haze with the same camera/scope/Barlow combination previously. I tried using an IR/UV cut filter but the result was terrible; like I was shooting through vaseline. Not sure what was going on, frankly.

 

I think it needs to be presented at a lower resolution, with higher contrast and significant resharpening at the final resolution.

 

Tom Glenn and aeroman I'd be interested in your thoughts on this image in particular.

[aeroman4907]

Hi Mike,

 

It is apparent to me this camera unfortunately isn't worth the $90.  I think you have done just about everything to make it work, or at least close to it.

 

Based upon your other image taken with the 10" Dob and the Sony a6000 which is a very nice image, it is readily apparent your ability to capture and process a good image far exceeds the capabilities of the SV205 that you have in possession.  As painful as it may be, you should look for a better and more modern camera.  They say time is money and I can see this particular camera costing you lots of time with the payoff of frustration and limiting your progress and results if you stick with it.

 

Steve

[Borodog]

As I've said before, I've certainly gotten more than $90 of enjoyment out of it. ;O) I do wish I'd thought to swap out the 205 for the 305 and shoot the exact same shot to make an apples to apples comparison between the two. They have very similar sensor size (somewhat different aspect ratio) but the 305's pixels are a little over double the size (so 2 Mpxl vs 8). But the 305 takes really excellent pictures, is actually usable as a color camera, has much more usable camera controls, records much more sensible files sizes, etc. It seems like I have to reduce every image shot with this camera by 50%, so what's the point of the smaller pixels? On the other hand, I have literally never used this camera when seeing was not poor to terrible. On the other other hand, shooting at this image scale in a 60mm refractor really does limit the effects of poor seeing. On the other other other hand, who the heck knows.

 

I'm pretty much set that when I'm ready to get a real camera it will be a 20 Mpxl IMX183 based camera. It will work well with my focal lengths (prime focus on the C8 and a simple 2X Barlow for the Dob) and the huge number of pixels is really the most important factor for lunar photography. I am losing interest in DSO frankly and am leaning toward an uncooled version. DSO is just so ridiculously expensive to do well that I may just stick to wide field and use camera lenses with the a6000.

[Tom Glenn]

Mike, I don't really know what is going on with this image, but obviously you are disappointed in the outcome, and also it is apparent that your Sony is taking far superior images.  Unless a miracle takes place and you discover something fundamental that is going on with the camera and is easily correctable, then I think it is time to retire this camera.  The image looks extremely blurred, like you said shooting through a layer of grease, and this is not the case with images from your Sony.  

[Borodog]

Agreed.