What to look for in a CCD?

[Mitten]

So Ive been trawling places to find what ccd to go with my potential setup. It consists of either a Wo Star71 ii telescope on a HEQ5 pro mount but after ive read things about the optics on star 71 ii so i've been torn to get the Meade 6000series 70mm quad scope. Ive also decided the ccd i would potentially use should be a monochrome ccd. I dont know what to look for in these cameras except for Quantum Efficiency. Im also having trouble with picking a guidescope cam too.

[wimvb]

Real estate: get the largest sensor you can afford, but remember that large filters are expensive. Select several candidates. Then choose a pixel size to match your scope. FLO has a field of view calculator on the website.

You will also have to choose cmos or traditional ccd. Cmos has variable gain, allowing you to use long exposres at low gain, or short exposures at high gain. This may allow you to do away with guiding. But cmos benefits from a larger number of subs, and this costs download time and disk space. Ccd can do binning (of rgb).

Guide cameras are less critical. ZWO and QHY offer several models.

Have a look around this forum's imaging sections and on astrobin.com. See what people are using with your scope and targets you intend to image.

[Uranium235]

And as for the telescope... go with the Star71... its a no-brainer. (I wouldnt touch meade with a bargepole...lol).

[ollypenrice]

1 hour ago, Uranium235 said:

And as for the telescope... go with the Star71... its a no-brainer. (I wouldnt touch meade with a bargepole...lol).

Neither would I these days.

The trouble with spec sheets on cameras is that I've never found them to predict the real world results very accurately. I use three CCD cameras, two with the huge Kodak 11 meg chip and one with a small Sony. The performance 'numbers' on the 11 meg chip are awful and so is the noise when viewed on a dark frame. The Sony numbers are far better and the darks are dark and almost noise free. However, when I actually use these cameras I find that the bad old Kodaks give stacks which are beautiful to work on. (One has some pesky dead columns now but it is very old with thousands of imaging hours racked up.) The Sony, on the other hand, gives a background sky which is quite hard work to process and star colour which is far less reliable, possibly because of the shallower well depth. I calibrate the Kodaks not with darks but by subtracting a bias, applying a defect map and running a hot pixel filter. This sounds complicated but isn't because I have no need to match darks to lights in terms of sub length. The same calibration works on all subs.

With a short FL Apo a camera like the Atik 383 would give a decent field of view and a sensible sampling rate. I'd also look at the CMOS cameras, too. It is not unknown for CCD cameras to need attention or servicing so there is a lot to be said for buying on your own continent. I'm a commercial user and have had consistently great service from Atik so I'm rather loyal to them.

Olly

[Uranium235]

As usual, some sage advice from Olly there!

The Star71 and 383 has been my workhorse for a few years now and theyre a pretty good match. I dont use darks either, but I do use dark flats sometimes because of the longer exposure required in order to avoid shutter artifcats. Theyre not all that difficult to do really, its just a dark that is the same length as your flat frame - in my case 10.5 seconds in Ha.

[ollypenrice]

1 hour ago, Uranium235 said:

As usual, some sage advice from Olly there!

The Star71 and 383 has been my workhorse for a few years now and theyre a pretty good match. I dont use darks either, but I do use dark flats sometimes because of the longer exposure required in order to avoid shutter artifcats. Theyre not all that difficult to do really, its just a dark that is the same length as your flat frame - in my case 10.5 seconds in Ha.

Have you tried just using a master bias as a dark for flats, Rob? It's what I do and most of our guests likewise.

Olly

[Uranium235]

1 hour ago, ollypenrice said:

Have you tried just using a master bias as a dark for flats, Rob? It's what I do and most of our guests likewise.

Olly

I think I did (a long time ago), cant remember whether it was a success though. It was to resolve a problem with walking noise (which cleared up with dark flats). Though I must confess I dont dither! (naughty boy...lol).

[ollypenrice]

16 minutes ago, Uranium235 said:

I think I did (a long time ago), cant remember whether it was a success though. It was to resolve a problem with walking noise (which cleared up with dark flats). Though I must confess I dont dither! (naughty boy...lol).

Neither do I. Tell nobody.

Olly

[wimvb]

2 hours ago, ollypenrice said:

Neither do I. Tell nobody.

Olly

Neither do I (anymore). Dithering seems more of a necessity for dslrs. I don't use it with my cmos, but it improved my dslr images.

[Mitten]

On 25/02/2018 at 15:18, Uranium235 said:

And as for the telescope... go with the Star71... its a no-brainer. (I wouldnt touch meade with a bargepole...lol).

Ive read about issues with the star71 but nothing on the meade scope other then the price any other reasons you wouldnt go with the meade scope?

[Uranium235]

5 hours ago, Mitten said:

Ive read about issues with the star71 but nothing on the meade scope other then the price any other reasons you wouldnt go with the meade scope?

The issues you may have read about only affect the Mk1 version. The Mk2 was released in order to address this. If you order the Star71 from FLO then it will have already been checked over and verified by ES Reid - and you can't get any better than that! 

The Meade looks like an exact clone of the Star71, except more expensive - and unverified.

In these cases I would always do a Google image search to look for example images - and you would probably find that the Star71 far outweighs the Meade in terms of finished, quality images. Always better to go with tried & trusted  

1k+ is a substantial investment, and I would prefer to know that  it's going to work as described.

[Mitten]

13 minutes ago, Uranium235 said:

The issues you may have read about only affect the Mk1 version. The Mk2 was released in order to address this. If you order the Star71 from FLO then it will have already been checked over and verified by ES Reid - and you can't get any better than that! 

The Meade looks like an exact clone of the Star71, except more expensive - and unverified.

In these cases I would always do a Google image search to look for example images - and you would probably find that the Star71 far outweighs the Meade in terms of finished, quality images. Always better to go with tried & trusted  

1k+ is a substantial investment, and I would prefer to know that  it's going to work as described.

Oh ok, problem is for me FLO doesnt do financing so im outta luck on buying the scope from them. 

[swag72]

25 minutes ago, Uranium235 said:

The issues you may have read about only affect the Mk1 version. The Mk2 was released in order to address this. If you order the Star71 from FLO then it will have already been checked over and verified by ES Reid - and you can't get any better than that! 

The Meade looks like an exact clone of the Star71, except more expensive - and unverified.

In these cases I would always do a Google image search to look for example images - and you would probably find that the Star71 far outweighs the Meade in terms of finished, quality images. Always better to go with tried & trusted  

1k+ is a substantial investment, and I would prefer to know that  it's going to work as described.

FLO doesn't stock the WO mk2.... as per another thread that Steve replied to. I did wonder why, wondering if perhaps all is still not well well even with Mk2 and it just wasn't worth the hassle...... any thoughts on that?

[Uranium235]

49 minutes ago, swag72 said:

FLO doesn't stock the WO mk2.... as per another thread that Steve replied to. I did wonder why, wondering if perhaps all is still not well well even with Mk2 and it just wasn't worth the hassle...... any thoughts on that?

News to me Sara! Its been a few months since I last checked on the status of the MkII versions - so perhaps I missed any updates. Its a bit of a shame really because that telescope really was quite good (if you get a good example).

Hmmmm... I suppose an alternative would be the Espirit Pro - but even that is not without its foibles.

[swag72]

23 hours ago, FLO said:

Thank-you everyone for the endorsements but we no longer stock the William Optics Star 71.  Sorry 

Steve 

Taken from this thread .... 

 

[Uranium235]

Blimey.... that's a bit of a surprise!

Probably still a good idea to scour the net for example images from a number of telescopes in the same price bracket. 

So, with that in mind - One thing to look for though is a threaded connection to the camera, try to avoid push-fit setups because they can introduce a slight tilt into the imaging train.

[DaveS]

Astrograph do the Tecknosky version, in stock for 1-2 day delivery.

http://astrograph.net/epages/www_astrograph_net.sf/en_GB/?ObjectPath=/Shops/www_astrograph_net/Products/AGTECAG70

They say they check and collimate the scopes, but I'd give Rupert a bell.

[toxic]

i can testify to the Atik 383l+ as a great camera and yes it is a bit noisy but that come out in stacking without darks but as for scopes i only have 2 and they both work well with the 383l+ - the skywactcher 200pds and the altair astro lightwave 60 EDT but with this camera you will need 36mm unmounted or 50mm mounted filters.

[kens]

On 25/02/2018 at 10:11, Mitten said:

So Ive been trawling places to find what ccd to go with my potential setup. It consists of either a Wo Star71 ii telescope on a HEQ5 pro mount but after ive read things about the optics on star 71 ii so i've been torn to get the Meade 6000series 70mm quad scope. Ive also decided the ccd i would potentially use should be a monochrome ccd. I dont know what to look for in these cameras except for Quantum Efficiency. Im also having trouble with picking a guidescope cam too.

Things to look for in a camera:

• Sensor size determines the field of view. Whats the biggest thing you want to image?
• Pixel size determines the granularity or the images. Whats the smallest thing you can/want to resolve
• Full Well Capacity and read noise determine the dynamic range (FWC/RN). Whats the brightest thing you want to image without saturating
• Cooling capacity for noise reduction esp dark current - important for longer exposures

Plus you may also consider the ADC depth, back focus, amp glow, reflection and so on.....

[Mitten]

Ive decided to go with the awsi1600mm cooled camera  with the star wave 70edq-r quad apo.