What the............!!! .Never had this before

[carastro]

Just stacked last nights Lum data on the Atik460EX and WOZS71used 100s of times before.

I am hoping I just need to change my dessicant, never had to do it before so not sure what it looks like:

I checked the Red filter and that's the same.

I have found my spare dessicant so will try that for starters.  But would appreciate some feedback please. 

Carole 

 

 

Edited April 23, 2020 by carastro

[vlaiv]

Could you provide more info on what we are looking at here?

This is, I presume stacked luminance data? How was it calibrated? Is it processed in any way (like background removal or similar)?

I'm seeing at least 3 things here (or what I believe are issues)

1. Bias issue - horizontal lines look like bias signal that has not been removed

2. Shifted flats - all those beveled circles look like what happens when there is shift in flats with respect to lights.

3. That strange thing on right edge - that could be due to ice or something similar - and desiccant change would probably be good idea.

[carastro]

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1. Bias issue - horizontal lines look like bias signal that has not been removed

Correct on that aspect.  Bias I often don't use as they cause problems sometimes with them but not without, I know this doesn;t make any sense to technical people, but all I know is some images are dreadful with Bias applied, and it I don;t use them the image is just fine.   So have got out of the habit of using them, but I will try again using bias.   

Looks like this particular image will benefit from using Bias.  

Quote

2. Shifted flats - all those beveled circles look like what happens when there is shift in flats with respect to lights.

The images were done last night, and the flats taken this afternoon, camera not moved at all.  But now you mention it, that does look like the outer rim of dust bunnies on some areas, but not all.  Also there are still lots of little streaks in between the "partial dust bunny rings". 

But why, nothing different to my normal methods after 100s of images? 

Yes calibrated (except for Bias) and preliminary processing. 

I have now removed the camera to change the dessicant, so can't re-do them unfortunately even though it looks like it screwed back to the same place. 

Might have to do some experimentation.  Will try the flats again, but having moved the camera I am not sure of success.  

So - if it is Dessicant which I have now changed, do I have to wait a while for the dessicant to suck the moisture out of the camera?  If so, how long would it need. 

Carole

 

 

Edited April 23, 2020 by carastro

[Tomatobro]

Hopefully Tomato will pick up on this post to confirm. I modified some ASI178's to fit Pelter Coolers and we had issues of water droplets and ice forming on the front sensor cover. I seem to recall the subs had  those circular thingies just like yours.

[carastro]

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Hopefully Tomato will pick up on this post to confirm. I modified some ASI178's to fit Pelter Coolers and we had issues of water droplets and ice forming on the front sensor cover. I seem to recall the subs had  those circular thingies just like yours.

Thanks Tomatobro, hopefully that's what it is.

Carole  

[groberts]

I shall be interested to see the outcome of this as I've had something similar, as yet unresolved - see this recent thread + look at the lower section of the processed image, below M106. 

    

 

 

[carastro]

@Tomatobro  any chance of giving tomato a nudge.

Thanks

Carole 

[tomato]

Hi Carole,

Were you imaging at or near the zenith? When @Tomatobro fitted the Peltier cooler to the ASI 178 (which has no inbuilt desiccant chamber) water droplets did form on the sensor when the scope was at or near vertical, and they did create artefacts similar to your image. I would certainly renew the desiccant, and it does look like your flats may have shifted position also.

[Tomatobro]

I had a look through my data to see if I had a copy of the water drops but it seems that I do not. I guess Tomato deleted them also.

[Skipper Billy]

Hi Carole

I have just found a brand new unopened pack of desiccant tablets for an Atik 460 in my box of bits that I am sorting out.

Just PM me your address if you would like them.

[Jkulin]

Hi Carole, When I had my 383 it did happen a couple of times and was down to ice.

I removed the desiccant and left the cap off and left it in the airing cupboard for a couple of days and that fixed it.

My mate has it as well and he put the camera in with a bag of rice to absorb the moisture, he has been plagued with that problem.

HTH

[carastro]

Thanks Guys, Well I changed the dessicant.  

Quote

I have just found a brand new unopened pack of desiccant tablets for an Atik 460 in my box of bits that I am sorting out.

Thanks for your generous offer David, but I have about 4 spare tablets.

I left the dehumidifier on in the obsy for a couple of days and tried the camera again, and all those weird swirls have disappeared.

I do however have one stubborn swirl at the bottom, so perhaps it needs a bit more drying out.

Thanks for your help, I will know what to look for in future, or perhaps I should make a point of routinely changing my  dessicant every so often.

Carole 

[ApophisAstros]

55 minutes ago, carastro said:

Thanks Guys, Well I changed the dessicant.  

Thanks for your generous offer David, but I have about 4 spare tablets.

I left the dehumidifier on in the obsy for a couple of days and tried the camera again, and all those weird swirls have disappeared.

I do however have one stubborn swirl at the bottom, so perhaps it needs a bit more drying out.

Thanks for your help, I will know what to look for in future, or perhaps I should make a point of routinely changing my  dessicant every so often.

Carole 

How often do you have to replace the dessicant tablet on the 460?

I see a large black screw head on it , is that where you put it in?

Roger

[RolandKol]

1 hour ago, carastro said:

Thanks Guys, Well I changed the dessicant.  

Thanks for your generous offer David, but I have about 4 spare tablets.

I left the dehumidifier on in the obsy for a couple of days and tried the camera again, and all those weird swirls have disappeared.

I do however have one stubborn swirl at the bottom, so perhaps it needs a bit more drying out.

Thanks for your help, I will know what to look for in future, or perhaps I should make a point of routinely changing my  dessicant every so often.

Carole 

Glad to see you are getting it back to normal

As per desiccants, - in case you will run out of them

They can be dried in the microwave and used again

[Skipper Billy]

26 minutes ago, apophisOAS said:

How often do you have to replace the dessicant tablet on the 460?

I see a large black screw head on it , is that where you put it in?

I used to put a fresh on in at the start of each season after a similar problem to Carole's.

Yes!

[carastro]

Quote

As per desiccants, - in case you will run out of them

They can be dried in the microwave and used again

I put mine in a small dish sitting on top of the dehumidifier.  Never tried the microwave, but have used the radiator in the past for a different camera. 

Quote

I used to put a fresh on in at the start of each season after a similar problem to Carole's.

Oh dear, I have had this camera for several years now, and first time I have changed the dessicant.  Naughty me.

Lesson learnt though!!!

Carole 

[DaveL59]

I've generally dried silica sachets on a tray in the oven, didn't know you could zap em in the microwave, interesting tho they used to say it wasn't good to run a microwave empty and it'd be pretty much empty with only a small amount of dessicant in  there, surely?

[RolandKol]

33 minutes ago, DaveL59 said:

I've generally dried silica sachets on a tray in the oven, didn't know you could zap em in the microwave, interesting tho they used to say it wasn't good to run a microwave empty and it'd be pretty much empty with only a small amount of dessicant in  there, surely?

It will take around 30sec... 

[carastro]

Quote

I see a large black screw head on it , is that where you put it in?

Sorry Roger only just found this question.  Yes it's a large black round screw head.  You should have been supplied with a plastic screw driver thingy (that you then put a metal screw driver into so you don't wear out the plastic slot.  It is a bit fiddly but better than ruining the slot.  If you don't have one let me know and I'll whatsapp you a picture.

Carole 

[Merlin66]

Ten cent coin fits the groove in the plastic plug