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rubecula

First image from used Atik 383L+ - HELP!!

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I recently bought a used Atik 383L+ and EFW2.  This is the first image from that kit - IC 410 Tadpole Nebula. It's 9 x 10 minute Ha subs  at -20C.  They have been stacked with 20 darks and 40 bias frames.  I haven't taken any flats yet as I wanted to grab the little bit of clear sky we had last night.  It looks a real mess! :

871488624_IC41017-01-19.thumb.jpg.1dce1cd8c83eb48fe3c8e3b09e48b361.jpg

There as some small blotches that presumably flats will remove. There are several larger doughnuts, a verticle line near the upper RH edge, an almost rectangular pale frame and the nebulosity looks awful.  The image was quickly developed from the Fits files in Startools including Wipe to remove gradients. I tried editing a Tiff in Photoshop but an attempt to stretch the image in Curves just turned the image completely black.

I bought the equipment with the camera and FW connected with the filters in place as I was advised that it would prevent the risk of handling them and so introducing finger prints etc.

I'm guessing that it would be better to dismantle the filter wheel and clean all the filters. But what about the rest of the issues? Are they due to the Camera? Filter wheel? Me?

I really would appreciate any useful suggestions.

Thanks

 

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Do some flats first, they should remove the majority of the defects.

Dave

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Oooo, not the greatest! It would be interesting to see a single sub with a simple screen stretch.

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I think that major issues are with processing and calibration.

You say 383L+ and Ha subs, so I'm inclined to think you have a mono sensor, yet image looks like has been debayered - there is color in there similar to what one gets when choosing wrong bayer matrix.

There is square "frame" of light - this happens with star tools if there are edge artifacts (from stacking) and one uses wipe tool without paying attention to parameters.

Doughnuts will be sorted with flats, and column is something that happens with CCDs (bad column) but that is supposed to be solved with proper calibration (darks should do this, right?)

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looks to me like dust motes and possible moisture on the sensor or glass. May be worth as mentioned checking your calibration files and possibly changing your desiccant tablets.

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Thanks for your responses so far. I'm not sure how to do a simple stretch. But here is a single sub opened in FITS Liberator, saved as a TIFF and then converted to jpg in Photoshop.

450413811_IC410Tadpoles_600sec_1x1__frame2.thumb.jpg.edbc3d4bac9872a621ea9e4442b57759.jpg

I've cooked the desication tablets in the over (200C for 90 minutes) I can't find anywhere to buy new ones.

The image is from a mono camera. In startools It was binned 50% and cropped before wiping.

I'll try to get some flats done over the weekend (we will have visitors so I may have to wait till next week) and see what difference that makes.

Thanks again

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1 minute ago, rubecula said:

Thanks for your responses so far. I'm not sure how to do a simple stretch. But here is a single sub opened in FITS Liberator, saved as a TIFF and then converted to jpg in Photoshop.

Before converting it to jpg ( don't do that anyway save it as PNG ) in P'Shop do Ctrl L to bring up a window then move the central slider to lighten the image, OK and repeat a few time until you can see more, you can move the left hand slider in the darken the background but don't go past the side of the histogram.

Dave

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Thanks Dave,

I've adjusted the levels a couple of times and it begins to show the dust motes and some gradient but not the doughnuts. Here is the result as a PNG:

2040349871_IC410Tadpoles_600sec_1x1__frame2copy.thumb.png.a4d8445b935882d2ef93380edaa37a5a.png

Not sure if it helps.

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The Tadpoles are just about on the image but their tails go off the edge centre bottom.
Have roughly marked their heads with x.
tadpole.jpg.7b48b8166c94ea5338f00e50a78f3c69.jpg

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I also went for this target in Ha last night and got fogged subs, which I put down to a gibbous moon less than 20 degrees away.   That, combined with a high haze, made me give it up as a bad job.   The two 600s subs I took before quitting did not look too dissimilar to yours so I would not despair yet.  I would post but I deleted them as they were unusable.

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You definitely need to fully calibrate your subs prior to any sort of processing. You didn't expand on how, what software and process you used to calibrate your images. regards imaging last night, well there was so much moisture in the air and combined with a bright blobby, it was very challenging.

Steve

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If I had bought second hand I'd be opening the filterwheel and examining filters and the camera sensor. Those dark spots look like dust on the sensor window. I had dust on my DSLR chip and it looked almost like that. Sensor cleaning kit and a blower solved it.

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Thanks for your help everyone.  You've given me a lot to look at and I've learnt something.  I'll do flats first and then take it from there. Also hope for clear skies!

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Mmmm.... the location. I got the RA and DEC for IC 410 from the web and put them into SGP and plate solved. Must try to find a more accurated co-ordinates.

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The single sub looks a whole lot less desperate than your initial image post might have suggested. I think that all is well within acceptable... except for the sky conditions, which have annihilated any chance of a recognisable image. It was terrible last night and I packed in very quickly thanks to the rank humidity in the air. I couldn’t see my target in my images at all. Your first image is just insanely stretched and creating all the weird gradients and hyper evident donuts. When the sky is actually clear, give it another go and I’m sure the results will be far more satisfactory, won’t need excessive stretching and will make you happy with your newly acquired gear. As for when... the Sky Gods are not looking favourably on us for quite some time I think. 

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Hi

I recognise the 'rectangular frame' as an artefact that Startools often creates - one of many reasons I stopped using it a number of years ago.

Louise

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Agree with Gav, the single file looks much better and it does look like something has gone wrong in calibration.

The single file stretched is typical of an image that has not had flats applied to it i.e. darker in the corners and dust motes.  Flats will get rid of both of these and make processing much easier.

I am not familiar with Star tools not even sure if it is a stacking software or post processing software, but it looks like from the comments made that you would be better off not using it at least until you find your feet.  What are you stacking with?  Most people start off with free Deep Sky Stacker. 

Quote

I can't find anywhere to buy new ones.

I got new dessicant tablets direct from Atik.

Carole 

Edited by carastro
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Carole, yes I used Deep sky stacker, with exactly the same settings that I used with the DSLR. I then tried Photoshop (I have since discovered why that didn’t seem to work, but am too embarrassed to say why) and then being anxious to see the first image with this kit I tried StarTools. I’ve had mixed results with StarTools, sometimes it works, sometimes it doesn’t. 

But I’m relieved to read that it seems to be down to two issues, no Flats and very poor seeing conditions. These days I take lots of notes to remind me what I did and whether it worked. When the clouds only allow infrequent imaging sessions it’s easy to forget where you were up to and what you did a few weeks ago.

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Desiccant - I couldn’t see it on their website, I’ll have another look, thanks.

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7 hours ago, rubecula said:

The image was quickly developed from the Fits files in Startools including Wipe to remove gradients. I tried editing a Tiff in Photoshop but an attempt to stretch the image in Curves just turned the image completely black.

With mono images in Photoshop you need to do your Curves the opposite way. Bring the curve down from the top right, not up from the bottom left. 

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1 hour ago, rubecula said:

Carole, yes I used Deep sky stacker, with exactly the same settings that I used with the DSLR. I then tried Photoshop (I have since discovered why that didn’t seem to work, but am too embarrassed to say why) and then being anxious to see the first image with this kit I tried StarTools. I’ve had mixed results with StarTools, sometimes it works, sometimes it doesn’t. 

But I’m relieved to read that it seems to be down to two issues, no Flats and very poor seeing conditions. These days I take lots of notes to remind me what I did and whether it worked. When the clouds only allow infrequent imaging sessions it’s easy to forget where you were up to and what you did a few weeks ago.

You need to change DSS workflow - you are no longer using color camera, but mono. You need to tell DSS not to debayer your frames.

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One more thing - make sure "dark optimization" setting is turned off in DSS.

Line from a bad column can well be because of this setting applied.

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Quote

Desiccant - I couldn’t see it on their website, I’ll have another look, thanks.

I E Mailed Atik about another issue and dessicant came up in the conversation, and they sent me some so I didn't order it through the website.

contact@atik-cameras.com

support@atik-cameras.com

I have always found Atik to be very helpful.

Quote

You need to change DSS workflow - you are no longer using color camera, but mono. You need to tell DSS not to debayer your frames.

Yes good advice.

Carole 

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9 hours ago, geordie85 said:

With mono images in Photoshop you need to do your Curves the opposite way. Bring the curve down from the top right, not up from the bottom left. 

Not necessarily. This depends on how you've set up your Curves menu. Every Ps tutorial I've ever seen in video or paper format has it set up like this:

Ha%20First%20Curve.-XL.jpg

Looking at 'Curve Display Options' you can see it's set to Light. That's why a 'lift' in Curves is a lift on the screen. It makes no difference really but everyone I've met sets it up this way out of habit. I wonder what Australians do?

 :icon_mrgreen:lly

Edit: The single sub comes as a great relief. Vlaiv's key observation is that there is colour in the first one, showing that something went badly wrong in the stacking. I suspect you are partly in need of flats but may also have been hit by chip window humidity. BTW, I greatly prefer AstroArt to DSS for stacking and calibration.

Edited by ollypenrice
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