Camera arrived today

riklaunim

It's here and it's working. As the sky is as usual I just played with basic dark/bias/flat. Dark current is very low compared to e2v ruby sensor, but the horizontal lines are clearly visible, especially on high gain. Flat frame has some horizontal interference-alike bands (is that normal?) - http://www.flickr.com/photos/riklaunim/sets/72157640268601723/

As for temperature Fire Capture was reporting 35.X C when the camera was running at home. I've put USB powered Peltier unit (from a USB freezer ) and now it's showing 17,1 C, so quite a nice drop. The Peltier is just lying on the camera.

cooling.jpg

As looking on http://www.astrotreff.de/topic.asp?TOPIC_ID=150474&whichpage=1 it looks like there is a cold finger in the camera housing (does it touches the back of the sensor via therm-conductive paste?) I would say that the housing is bit below 10C (but above 0C as the Peltier itself isn't that cold).

Sam@ZWO

yes, the horizontal lines is there. but should not be so visible

there is an "Anti column noise" function of the sensor and which is enabled automatically when start.

but this function may runs not well if you start long exposure like some seconds when just open the camera.

there is another way to activity it just enable or disable "Flip Horizontal". I think you can have a try.

I attached a dark frame with my ASI120MM.

Flat frame has some horizontal interference-alike bands is because of the daylight lamp which use AC.

I think it will gone if you test at daytime without the lamp

attach a TEC to the back of the camera is not very effective but the simplest way.

the cold figure touched the sensor in our new cameras with ST4.

Sam@ZWO

I attached another dark file show "Anti Column noise" does not work.

it will not work if click "Flip Horizontal" when do long exposure such like more than 1s.

So start from short exposure is a good way to avoid this problem.

"Flip Horizontal" is not implemented in FC. so you can test with SharpCap

it in the "video capture filter" dialog

you can tell this file is very like the dark file in your test.

so I think this function didnot work in your test

riklaunim

I'll compare it with SharpCap to seek how the noise changes. Either so such lines are constant and should be easily removed by dark frames. Methane band or other dark band would need a dark frame even so.

It is the ST4 version. Peltier lying on the housing made it cooler, so anything inside also dropped few degrees. I did that just to check how the temperature would change. All-plastic PGR Chameleon reports around 15C when it's working on a -15 to -20C night. The ASI case is metal and it seems quite capable of sucking heat from the inside so the difference between outside and the sensor temperature should be smaller.

Sam@ZWO

its usually 8-10 degree more than envrioment's temperature from my test.

johnk

Hi Sam,

Is this a mod that is being offered or a new camera variation?

Best Regards,

John.

Sam@ZWO

JohnK wrote:
Hi Sam,

Is this a mod that is being offered or a new camera variation?

Best Regards,

John.

Hi John

this mod is DIYed by Piotr himself.

this is not hard just beware of dew

johnk

Sam wrote:
JohnK wrote:Hi Sam,

Is this a mod that is being offered or a new camera variation?

Best Regards,

John.

Hi John

this mod is DIYed by Piotr himself.

this is not hard just beware of dew

Thanks Sam - I really think that you guys should commercialise something like this as an add on - I would certainly pay for it as I have no time or the skills to do this!

riklaunim

It could screw to the tripod thread on the back. Looking at temperatures during imaging the housing on it's own cools the sensors quite well. Temperatures were much lower compared to those from plastic case cameras (like PGR Chameleon).

Sam@ZWO

JohnK wrote:
Sam wrote:
JohnK wrote:Hi Sam,

Is this a mod that is being offered or a new camera variation?

Best Regards,

John.

Hi John

this mod is DIYed by Piotr himself.

this is not hard just beware of dew

Thanks Sam - I really think that you guys should commercialise something like this as an add on - I would certainly pay for it as I have no time or the skills to do this!

Hi John

there is still something you need to do even if we provide it.

you need to protect the PCB from dew. otherwise may damage the camera.

so we didn't provide it for the safety.

and the DIYer suppose to have the ability to protect it well.

chripell

riklaunim wrote:
Dark current is very low compared to e2v ruby sensor

Hi, just a question: how did you measure dark current? I guess ASI120MM has Black Level Correction activated like the ASI120MC, or this is not true? I would like to measure it to characterize DN/e- gain, etc.

riklaunim

e2v Ruby sensors are EPI doped to get insane QE. That leads to insane dark current. Micron sensor definitely has lower dark current than those Ruby ones. Black level may also do something (like I had to use almost max gain to try getting Venus night side - on lower the background was almost clean black killing weak signals). I didn't caught the night side - either due to conditions or something with camera settings for this.

http://www.flickr.com/photos/riklaunim/sets/72157640268601723/