small format CCD camera recommendations please

[MiguelMJr]

Just a note to my above post.........

"Recommended" is the key word. You can do whatever you like!

Have Fun,

Miguel

[fwm891]

Thanks Miguel, - for my set-up I'm looking for a pixel size of ~ 4. running 1x1 with the shorter fl scope and at 2x2 with the RC.

Still 'looking'...

[MiguelMJr]

QSI has a nice camera at 3.69um, 3388x2712 and 9.19mp. It uses a Sony ICX814 chip. It is what I plan (at this time) to get, in a year!

I don't really understand the dynamic range when stated in db, I perfer to know "full well". I'll have to look up the conversion equation.

Check it out,

Miguel

[Horwig]

I don't really understand the dynamic range when stated in db, I perfer to know "full well". I'll have to look up the conversion equation.

Hi Miguel, here's an useful table of sensor data, including well depths,

http://www.flicamera.com/pdf/FreedomOfChoiceCCDmatrix.pdf

68 dB is a ratio of 2512, dynamic range is basically max signal to noise ratio, ie,well depth divided by the read noise (as the read noise outweighs dark noise on these chips till really long exposures).

I'm also looking at the 690 and also the 6120 for next year, 

Huw

[MiguelMJr]

Hey Horwig,

Thanks for the table and the explanation.

I had already had this table downloaded to my computer long ago but didn't realize it, Talk about too much information.  

Both the 6120 and the 690 look pretty sweet. I'm still stuck between the 660 and the 690 (leaning towards the 690) as I can only afford one camera for now, a second will have to wait quite some time.

Thanks Again,

Miguel

[Horwig]

I'm also looking at the 690 and also the 6120 for next year, 

oops, this ought to read OR, not AND, as far as I know my  numbers have not come up. 

Huw

[MiguelMJr]

I'm confident that my numbers will come up tonight. I am preparing to buy three cameras and the telescopes to go with them.  

Miguel

[fwm891]

Keep dreaming....

Given a typical well depth of 40,000e- and a typical 8e- read noise, a value of 5000 levels is typical. CCD’s can be found with a DR of 2000-10,000 however. It is conventional to express the DR in decibel, dB, units. Use the formula DR(dB)= 20*log(FW/read noise)

extracted from the 'Choosing a CCD camera' pinned at the head of this section.

[Horwig]

This talk of dynamic range, signal to noise and well depth has got me thinking, which is always a dangerous thing.

Is having a shallow well depth the end of the world? Since the DSOs we image are usually nowhere near saturating the chip, all the well depth usually impacts is saturation of star cores.

If we then limit our subs to just under core saturation, and take proportionally more subs, are we back to the same place?

Huw

[D4N]

You will limit your sub length on some targets doing that. Alnitak will scupper any attempts at horse head, Orion Nebula blows out easily and even the core of M31 can blow out. There are many other awkward targets.

While in theory you collect the same number of photons in short subs as long if the total exposure is the same the image quality certainly does improve with longer subs. Not to mention the fact that it is a lot easier to process 10 hours of 15 mins subs (40 subs) than 10 hours of 30 second subs (1200 subs)

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