Which ccd?

[Brycepj (Peter)]

Hi everyone
I have $300 to spend on a Ccd would like to get a Zwo asI 120mm/c but with the way the Aussie dollar is it would be closer to $400.
The question I have is what is the next best? This will be attached to me 10" Goto dob
Thanks

[Slawomir (Suavi)]

Hi Peter,

As far as I know, the camera you mentioned has a CMOS chip, not CCD.

Also, this camera has tiny pixels - might not be ideal with a large dobsonian, unless you have very accurate tracking or are aiming for planetary imaging with sub-second exposures.

Have you considered DSLR? For the same price you will get a MUCH larger and thus versatile chip.

Otherwise, perhaps a second hand CCD but with larger pixels, like Orion G3 or similar?

Sincerely
Slawomir

[Brycepj (Peter)]

Thanks
I have a DSLR (nikon d5100)I am better of using the video function rather than taking individual pix and using registax software to get good shots.
I have all the adapters and have taken some pix.
How do people get the real good quality pictures
I really struggle to get good focus even after using a Bathinov mask.

[Slawomir (Suavi)]

Hi Peter

From your response am I right assuming you are interested in planetary imaging?

Then the camera you mentioned before (ZWO) would probably we quite good for this purpose.

If you are however after DSOs, then unfortunately you would need more expensive gear, starting with a decent equatorial mount.

Bathinov mask works very well for me, just locate a bright star and try to get three spikes crossing at the same point. You may need to adjust exposure to a few seconds be able to clearly see the spikes. It helps a lot to enlarge the star in your capturing software so spikes are easily observable.

Perhaps before you rush into buying a new camera, see if you can get a good focus with your existing gear - you might be positevely surprised with the quality of images taken with the gear you have at the moment

[Brycepj (Peter)]

You are correct, planetary imaging is what I wish to do as DSO's from where I am are difficult once you get passed a visual magnitude of +6 just to much light pollution.
For example no matter how hard I try I am yet to see the sculptor Galaxy which has a visual mag of +7
I will have another go at my DSLR set up.
Another quick question how do you convert mega pixels to microns? My DSLR is 16 mp when I look at the CcD etc they state the specs in microns so it just adds more confusion.
Thanks for you advice

[raymo]

Does the 5100 have the "Live View" function which allows you to put a magnified view of a star on your LCD screen? If it does then used in conjunction with a Bahtinov mask, perfect focus is simple. If it doesn't
have the function you will have to use the brightest available star to
focus with when using the mask.
There is no one conversion factor, as different cameras can have different size pixels.
raymo

[Mosc_007 (Charles)]

Originally Posted by Brycepj

You are correct, planetary imaging is what I wish to do as DSO's from where I am are difficult once you get passed a visual magnitude of +6 just to much light pollution.
For example no matter how hard I try I am yet to see the sculptor Galaxy which has a visual mag of +7
I will have another go at my DSLR set up.
Another quick question how do you convert mega pixels to microns? My DSLR is 16 mp when I look at the CcD etc they state the specs in microns so it just adds more confusion.
Thanks for you advice

You can Calculate the Micron Pixel size by dividing the sensor size by the resolution. Not quite 100% Accurate for CMOS but close.

Eg.
The D5100 has a sensor size of 23.6 x 15.6 mm with a resolution of 4928 x 3264 pixels.

23.6/4928 = 4.78 Microns.
15.6/3264 = 4.78 Microns.


Charles

[Slawomir (Suavi)]

Originally Posted by Brycepj

You are correct, planetary imaging is what I wish to do as DSO's from where I am are difficult once you get passed a visual magnitude of +6 just to much light pollution.
For example no matter how hard I try I am yet to see the sculptor Galaxy which has a visual mag of +7
I will have another go at my DSLR set up.
Another quick question how do you convert mega pixels to microns? My DSLR is 16 mp when I look at the CcD etc they state the specs in microns so it just adds more confusion.
Thanks for you advice

Hi Peter,

Galaxies might be quite challenging to start with, why not practice first with brighter nebulae, like the Carina Nebula or the Orion Nebula?

Light pollution limits your potential targets, in particular galaxies...I shoot from a balcony 2km from Brisbane's CBD!

Pixel size needs to be looked at in conjunction with focal length of your telescope.

This might be a good read to start with: http://www.astrophotography-tonight....hy-calculator/

Regards
Slawomir