New CCD advice

[Stryda]

Hello, I'm looking to buy a CCD camera for xmas.

My current setup is;

Meade LX200 12" Scope/mount with equatorial wedge. I currently image with a canon 5d mkii, and have obtained some good images with that, but hear CCD is the next step.

I've never used a CCD before and have around £450 to spend on one, can anyone advise a good one at this price? Colour or mono? Whats the difference? Will my setup be suitable for CCD imaging? Will I need a guide camera?

Any advice is appreciated!!

P.s based in UK.

[Xplode]

£450? There is no CCD at this price as far is i know and if there is, the sensor is way too small for a scope like that.

I guess you're a beginner and your setup isn't really suited at all for imaging for someone that isn't very experienced.

I could not with good conscience advice you to spend any money to use your current setup for imaging as you can just throw money at upgrades time after time and still not get very good results.

 

If you want to take good images pretty easy your best choice is to either piggyback on your current setup (or get a new mount) with a refractor or small newtonian (like the 130PDS) to use with the 5D II.

[ollypenrice]

I agree entirely with Ole.

Even with a focal reducer the 12 inch Meade will have a focal length of about 2 metres, which is pretty long. This means that you will need big pixels to acheive a remotely sensible pixel scale. With a monochrome CCD you can bin the pixels to get a sensible pixel scale. An Atik 8300 binned 2X2 with reducer would give you 1.1 arcsecs per pixel which is possible with an accurate autoguided mount. (Whenever I express doubts that this is going to be workable on a fork mounted SCT I get shot down in flames by someone who does manage to get this mount to work. And yes, some do. But I am one who didn't and I can make a list as long as my arm of other people I know who couldn't either. And of the few who could, all but one of the ones I know personally have switched to GEMs. So I stand by my doubts.)

For about £500 you could buy a second hand Atik 16HR or 314L with the excellent Sony 285 chip but, as Ole said, this tiny chip at 2 metres is going to be limited to very small targets.

If you really want to get into DS imaging I honestly would urge you to begin by reading Making Every Photon Count by Steve Richards and available from the forum sponsor. This will show you why so much of imaging is counter intuitive, especially in respect of the choice of kit. Have a look at the DS imaging boards here and elsewhere and see what people are really using.

Olly

[Jessun]

Hi Stryda!

That is quite the scope really. How come you got this particular model, aiming at imaging?

/Jesper

[pete_l]

Quote

Will I need a guide camera

( A large intake of breath )

Two sorts of imaging: planetary and deep-sky.

Planets tend to be quite bright objects, though small. As such they are good targets for your LX200, with its long focal length and therefore high "magnification". Their brightness means that exposure times are quite small, so that detail can be seen - which is lost when the image is over exposed. The short exposure times means that your mount , which will have tracking errors (all mounts do), will not affect the quality of the image. It will accurately track the plane for the few milliseconds of each exposure.

Deep-sky targets are much dimmer. They require longer exposures: 10's of seconds to some hours and DO require that the mount accurate tracks the movement of the target, to an accuracy of about 1 arc-second, which is about 1 part in a million. That is not a practical expectation from a purely mechanical system and so you will find, that for all but the shortest deep-sky exposures, then yes: you will need to guide the image and use a guide camera.

 

[ollypenrice]

14 hours ago, pete_l said:

( A large intake of breath )

Two sorts of imaging: planetary and deep-sky.

Planets tend to be quite bright objects, though small. As such they are good targets for your LX200, with its long focal length and therefore high "magnification". Their brightness means that exposure times are quite small, so that detail can be seen - which is lost when the image is over exposed. The short exposure times means that your mount , which will have tracking errors (all mounts do), will not affect the quality of the image. It will accurately track the plane for the few milliseconds of each exposure.

Deep-sky targets are much dimmer. They require longer exposures: 10's of seconds to some hours and DO require that the mount accurate tracks the movement of the target, to an accuracy of about 1 arc-second, which is about 1 part in a million. That is not a practical expectation from a purely mechanical system and so you will find, that for all but the shortest deep-sky exposures, then yes: you will need to guide the image and use a guide camera.

 

Yes, important to distinguish deep sky from planetary imaging. I'd taken this to be a deep sky question for no good reason!

However, to image at about 1 arcsec per pixel I think that the consensus would suggest a guiding precision of about 0.5 arcseconds is needed. That is not going to be easy on an LX200 in my view. I stress, in my view.

Olly