ATIK 414EX artefacts....

[Marky1973]

Hi all.....all set up and ready to go and this appears in ARTEMIS Capture..... what on earth is it?

It seems to be reducing over time, but I am a little concerned as to what it might be - can't see anything interfering with the visuals, although, as everything is set up and it is midnight I obviously haven't looked at it too closely...

Slightly worrying....

[johnrt]

Looks like ice on the camera window. What temp are you running at and how quick did you cool? Does the 414ex have the desiccant chamber that needs refreshing?

[Marky1973]

Thanks John.

Set point is -20, temperature is -19.9. I set up and left everything outside, unpowered for an hour or so, then went down and switched everything on and started cooling via ARTEMIS. I thought it looked ice-like (and that would make sense) but didn't think it could be as the day is warm, but I guess rapid cooling could do that - should I run at a higher temperature, or cool to -10 and leave it for a bit before cooling further, for example?

[Uranium235]

Time to bake your desiccant mate, 180deg middle shelf in the oven for about 2 hours. Pop it back in the camera, wait a day or two and it should be fine.

[Marky1973]

How long should it last? I only bought the camera in March/April!

[Ibbo!]

depends on how damp its been

[Marky1973]

Hopefully fairly dry as I've not usednit over the summer and it has been stored inside...but no harm in recharging it!

[Ibbo!]

not very helpful I know

sorry

 

Mine does not have a dessicant so if it does that it gets zapped with the hairdryer.

[Marky1973]

No no, it is... I just expected it to last longer. It has gone now, so clearly something temporary....so ice is a pretty good bet

 

Thanks all!

[Uranium235]

Humid weather also has an effect on it, and this Summer its been pretty muggy at times.

[Marky1973]

Best get my oven gloves on then! :-)

 

[Marky1973]

Well, had another play this afternoon to finish of some flats/bias for last and noticed the same thing.

The first image is just after switching on

And the second after 15/20 minutes of cooling

So clearly condensation as was suggested. Another 5 minutes on from the above picture, the "blot" is just on one side of the image and shrinking fast. I guess this is what the dessicant is meant to prevent - can understand the condensation when cooling from an ambient temperature...makes a lot more sense, and is less "scary" in the daylight! :-)

So I guess I will get the dessicant recharged this afternoon and see what happens later.

Thanks to everyone for easing my panic..... :-)

[Marky1973]

Well, its not completely over - will definitely try the reheat of the table tomorrow - I didn't want to tonight as I am apparently supposed to leave it for 24 hours before using the camera again - and we have clear skies.

Tonight, the same issue, but the whole of the inside of the clear cover over the sensor is fogged, only clearing when the cooling is turned off. Switch it back on and it forms straight away - it is so bad, I have had to pack up and come in which is a frustrating waste of an evening. I do hope it is the tablet, otherwise I am concerned.

[MattJenko]

Drop a note to Atik and ask. They have been very helpful in advising me whenever I had questions with mine.

[Marky1973]

Thanks Matt. I may well do that - I am definitely going to bake the dessicant tablet tonight and then check it out in a couple of days. If the problem is still evident, then i will get in touch with ATIK. I didn't have this problem previously, so I am hoping that a few months sitting around doing nothing means the tablet just got "soaked" - will plan to store the camera in a load of dessicant sachets etc, if I knock imaging on the head for longer than a week or two in the future.

[ollypenrice]

It my be worth your buying a couple of spare tablets so you don't have the wait each time.

Olly

[Marky1973]

Thanks Olly.... Yeah, was just looking at that - I just thought they would last longer! :-)

I'll contact ATIK and see if they can supply them... they don't seem so easy to come by otherwise!

And, isn't it just the way? Having searched for similar issues, today, when looking on the web for replacement desiccant, I find two previous threads asking the same question... so sorry for the repetition!

[FLO]

It does look like the sensor has iced up. Odd that it has happened so soon. Remove the desiccant port cover then leave the camera somewhere warm and dry, like an airing cupboard, for 24 hours and re-charge the desiccant by baking it (see Uranium235's post) for about an hour at around 180 deg. When you re-install the desiccant into the camera and screw on the cover, the camera should then be fine. If not then please email us (I think it's one of ours). Atik will also happily send new desiccant if requested, or contact us and we'll send you some. 

HTH, 

Steve

[Marky1973]

Thanks Steve, will give the baking a go tonight - we have a few nights of clouds coming up for a change, so I will be at a loose end astronomy-wise.... :-) Will stick it in the airing cupboard with some desiccant sachets for good measure!

Cheers

Mark

 

 

[Marky1973]

Hi all...one last stupid question if you can indulge me...

I too the desiccant out and cooked it for a couple of hours as per the instructions. I also left the camera in a bag with more desiccant sachets for a few days and have just put it back together.

The question is, is the tablet okay just being put back in the chamber and the lid screwed on? I only ask as, when I took it out, it was lightly stuck to the lid. I was wondering whether it should be stuck to keep it off the filter, which looks very fragile, or whether it is okay just sitting in the chamber?

There is a tiny bit of foam inside the lid which is not sticky, but might have just stuck to the tablet after they were in there together for several months.

Told you it was daft, but I worry about these things...especially these expensive things!

[Marky1973]

Okay, I don't want to bang on about this, but I finally got the camera out tonight and the same thing has happened, even after having baked the desiccant as per the instructions. I even left the camera in a dry place with some desiccant sachets to help dry it out.

All set up tonight and put the camera on with cooling and it is frosted up. I started off cooling to -8 just to take it slowly and then I got to that point I dropped it to -15. Am I pushing it too far in this weather or is it time to ask FLO about some new desiccant tablets... or, dare I say it, does the camera need returning for a service/replacement?

I just wonder if I am doing something wrong.

It does clear, but it takes a long time....half an hour so far.

[Oddsocks]

Going straight from ambient to -8 is probably being a bit aggressive.

As I use automation software I have a cool down sequence programmed for my QSI and don't really think about it that much but looking at the script this evening I have programmed cool down steps of five minutes per step, -5 per step and set temp is -15. Thats thirty five minutes prep time from a starting temp of 20 deg ambient. The QSI is five years old now, still on the original desiccant tablet, desiccant chamber has never been opened.

I do sometimes get condensation on the outside of the CCD aperture window if it is very humid and the camera has been operating for five or six hours and I have added a dew strap around the filter wheel cover to prevent that but have never had ice or moisture forming inside the chamber or on the CCD chip.

The automation software does all this for me during twilight so its not a bother, I guess having to follow this procedure manually would be a bit of a nuisance but I think it is fairly common amongst imagers?

The other thing that no one has mentioned is how are you baking your desiccant?

If you are baking in a gas oven that will make it hard to drive out the moisture because burning natural gas in a confined space produces a huge ammount of water, gas ovens should really be classed as steam ovens!

Baking in an electric oven is best but in either case once the baking period is over the desiccant capsule (or beads etc) should be placed in an airtight container as soon as possible and not left to cool in the oven or in the open air as it will just take up moisture from the air as it cools, at high temperatures silica gel is very moisture grabbing, at room temperature and lower it becomes less active so you need to to protect it from the air while it is cooling.

The way we recharged silica gel in our chemistry lab at school (fifty years ago, what a memory!) was to pour the crystals onto a pyrex dish thinly, heat them in an electric oven at 160 deg C for an hour and while still hot and using OVEN GLOVES take the pyrex dish out of the oven and wrap aluminium baking foil around the dish to keep the Silica away from the air until it was fully cool.

Talking to a friend who is a Professor of Chemistry a while back he said they recharge silica gel beads in a microwave oven these days as it is much more efficient and they cool down much quicker,  just a few minutes on defrost cycle with the beads spread out on a pyrex plate but this does fracture some of the beads if there is a lot of water in them, which is often the case in lab work, so they have to sieve the dried beads to get rid of the dust and broken bits....would not recommend this for the camera capsule but ok for recharging loose beads etc that you might, when cool, put in a sealable plastic sandwich box to store the camera while not in use.

So next time out, try dropping to target temp in five deg steps and leave for five minutes at each step, this will protect the CCD from thermal shock and should stop icing directly on the CCD. Recharge the desiccant tablet again but keep it away from the air while it is cooling and put it back in the camera as soon as it is cool, finally dry out some silica beads using the microwave method and place the cool beads in a sealable box to store the camera in while not in use, wrap the camera in a silk handkerchief to keep any silica dust from contaminating the camera while in the box.

If you still have problems after this then assume that either the CCD window seal or the body/chamber seal is broken/loose/missing and contact the retailer/manufacturer for advice.

William

 

 

[Marky1973]

Hi William

Thanks for that - I was beginning to think that I was probably expecting too much. The mist cleared after a while last night and I managed over 5 hours of Ha subs, so I guess I just need to be patient. I also probably need to be more careful when baking the desiccant from what you say. I do have an electric oven, but the tablet was left cooling in the "air" so I suspect it picked up more moisture that way. I tend to leave the scope/camera all set up ready to go out, but might try fashioning a "nosebag" to hang off the filter wheel with some desiccant sachets in, so I can cover the camera in that when in storage.

I'm not always patient (yeah I realise astrophotography is probably the worst thing for me to be trying) and am a bit of a worrier when it comes to expensive equipment... but hopefully I can calm down and work on a better set-up process that gives the camera more time to cool effectively.

Cheers

Mark

 

 

[johnrt]

I think you said this was a new camera bought earlier this year? Time to return it to the vendor / Atik to be looked at under warranty in my opinion if that is the case.

The desiccant takes a long time before it needs a refresh under normal circumstances, I have owned an Atik 314l+ & 460ex for a combined total of about 5 years and have had to refresh a total of 0 times.

[Marky1973]

Hi John - my main concern might be that I am running the cooling too hard and fast, so will try a more staged approach next time I am out but, if I get the same trouble doing that, then it might be time to think about what else might be going on. Fingers crossed the clear night forecast for tommorrow holds!