G3 Starshoot Quality Issue

[Bigfoot 9907]

Hi All,

I have been getting pretty good images using a Skywatcher 200P, and an Unguided/unmodded Canon 1000d camera. However, for Christmas my other half bought me a G3 Starshoot Colour CCD camera. The problem I am having is that I am unable to get any remotely decent pictures from it. Perhaps I am doing something wrong.

I have followed the manual carefully and have captured using RGB Raw as specified in the manual. I have attached a link to a number of 60 second unguided stubs I have taken of NGC2244 ( the FOV is quite small).

https://www.dropbox.com/sh/lf9okb5yl01u5mi/AAB_bgMhMQzX4rWvqGLz3guea?dl=0

The CCD temperature was -3 Celsius and I did not take any Darks or Flats. The focus was achieved using a Bahtinov mask.

I aligned  the images, converted to Colour and then stacked them using the Orion Camera Studio software, the resulting tiff file however is devoid of any detail and has no colour. I even switched to RGB colour mode in Photoshop, but the image still appears as grey scale. I have also stacked using DSS with the quality of the image being even worse.

Can anyone please have look at the stubs and see if they can be processed to yield decent results. I have not had any issues with my DSLR camera

Any help would be greatly appreciated.

[Scorpius]

Hi Bigfoot 9907,

Sorry you’re having troubles with your new G3 color CCD. I have the monochrome version which is basically the same only black and white. In other words mine will only produce color images by shooting through colored filters and then combining the filtered subs into an RGB image but I thought color cameras were supposed to bypass all that and produce color images right off the bat.

At any rate I think part of your problem is capturing in RGB Raw which I believe tells the software you want - what would normally be a color image - split into different grayscale channels for additional color tweaking before re-combining them back into a single color photo. Not sure I’m right about that however, I did open one of your files in Orion Camera Studio and found out the color is there if you use a couple of the built-in commands. I’ve attached a few screenshots of what I did to bring out some color although it might be easier to figure out what’s going on if you tried to capture a target like Jupiter with known colors instead of just an open star field.

Also, you mentioned the G3’s FOV is small but a lot of that depends on the scope itself. The Starshoot has a half inch series sensor which is not huge by any means but it will give you a decent FOV in the right aperture (f/ratio) scope. Hope you figure things out and can start capturing some color photos with your color camera soon...

Regards,

Scorpius

[wxsatuser]

Quite a small fov.

You would'nt see much of the Rosette, may be just the central stars.

But looking at one fit I don't think you were on the central stars.

I have done 300sec subs at f4 on this target with a dslr and the nebula shows well, so

may be you need much longer subs.

[Bigfoot 9907]

Many thanks Scorpius, thanks wxsatuser, is your DSLR modded?

[Oddsocks]

Bigfoot 9907

I stacked your images using the Orion Camera Studio Software and carried out maximum enhancement using Startools.

Normally I use Pixinsight for everything but this time I was stumped at the debayer stage in PI as I could not find a tool to debayer the Starshoot CYMG mask, so I spent a happy few hours downloading the Orion software and reacquainting myself with Startools in the process!

You were slightly off-target and most of the fine detail at the edge of the nebular that you just caught was lost because the polar alignment was a bit off, there was too much image drift during the exposure time used and this has blurred away the fine details.

The camera has a sensor 7.40mm x 5.95mm with 8.6um x 8.3um pixels and on the 200p gives an image scale of 1.74 arc sec per pixel.

With this camera and telescope combination the Rosette would need a mosaic of approximately 12 frames by 10, allowing a little overlap on each edge, to capture the entire nebular.

The image background seems washed out and the stars lack a clear airy disk on the individual subs, I think an IR/UV blocking filter screwed into the nose piece of the camera would help clear up the background a little and restore the airy disk, which you need to be able to recover the star colour during post processing.

You are used to using the unmodified Canon 1000d which has a built in IR filter, your Orion Starshoot has no IR/UV filter as standard and will be very sensitive to both wavelengths and this can tend to overwhelm any star colour present.

All your subs have non-random noise present, you can easily remove this with bias frames and dark frames, any vignetting can be removed with flats although as the sensor is very small and the scope not very fast the vignetting should not be a huge problem, it is only visible in my processing of your image because I had to push the post processing very hard.

The maximum and minimum pixel values in your subs were not very far apart and the maximum pixel value was a long way from being reached so with better P.A. you could easily double or treble the exposure time and this would also increase your chances of producing a good sized airy disk with which to recover the star colour later.

I uploaded the final processed image to astrometry.net to find where your telescope was pointing and confirm the image scale and then did a plate solve and overlay in The Sky, the resulting image is posted below, the small, white, square patch at the lower left of the Rosette is your image overlaying The Sky's star chart.

So to summarise, fit a IR/UV filter to the nosepiece of the camera to clean up the background and the stars airy disk, take and use bias and darks as a minimum plus take time to get a better polar alignment and use a longer exposure time. Whatever processing and stacking method you use remember to de-bayer first, before any alignment or stacking routine is carried out.

William.

 

 

 

 

[StevieDvd]

Wow, way to go to help out a fellow forum member there oddsocks.

[wxsatuser]

Many thanks Scorpius, thanks wxsatuser, is your DSLR modded?

Sort of.......it's a Canon 60Da.....it comes with the filters already modded.

It works quite well and of course takes reasonable daylight photos as well.

[Chris]

@ Oddsocks - I think this is one of the most helpful posts I've read on SGL, I second the wow!   

[CSM]

Hi - just to add that I also have the G3 Colour and if you have not already done so download the latest version of the software - it is so much better than the CD that comes with the camera.

[Bigfoot 9907]

Oddsocks, you are the man! Thank you very much for taking the time to help and with you excellent reply and advice. I really appreciate it

CSM, I am using Version 1.7.2 of the software which I believe is the current version.

[Jerome65]

I own a G3 colour camera and am getting great pictures with it and I use Nebulosity for my processing , I capture my pictures in raw mode and then as I mentioned I do all my preprocessing in Nebulosity I am going to have a look at your frames and see if I can help you if you haven't got any answers back yet don't give up it is a great little camera I am very pleased with it and am now looking at doing DSLR . Here are 2 pics I did with the G3 I am not to good with processing but you can see what I have 

Jerome