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Imaging struggles

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#1 James Paulson

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Posted 08 August 2022 - 05:13 AM

Spent Saturday night trying to image the planets for the first time with my ASI462MC and Celestron Ultima 8 and this was the best result that I got. I think my focus is soft. Maybe I have more issues than just focus.

 

First time out, I left the F/6.3 reducer in, and I put the ADC, with no barlow, in the optical train. I was using Firecapture. I had no idea on gain settings, exposure or even gamma, I was just shooting blind. I even had to deal with automated sprinkler systems that I forgot to turn off.

 

Yes it was not my best night imaging. Makes me wonder if I should just stick to deep sky.

 

 

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#2 sctbrd

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Posted 08 August 2022 - 06:21 AM

Check your backfocus requirements with the ADC?

 

https://www.cloudyni...o-focal-length/


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#3 BKMaynard

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Posted 08 August 2022 - 06:25 AM

Remove the reducer. Add a Barlow. Check collimation. Wash, rinse repeat.


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#4 Tapio

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Posted 08 August 2022 - 06:25 AM

Just needs practice.
Focus could be better yes.
How many frames did you take and leave in the final stack?
Did you sharpen it using Registax wavelets or something else?
Take the reducer out next time. And wait for good seeing.
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#5 James Paulson

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Posted 08 August 2022 - 06:49 AM

Check your backfocus requirements with the ADC?

 

https://www.cloudyni...o-focal-length/

I'm a  bit confused with this.

 

Right now the way it is set up is

 

Telescope---> Reducer-----> 2 inch Visual Back----> 2" to 1.25" adapter----> ZWO ADC ----> 1.25 inch ASI462MC camera nosepiece

 

Are they saying I should put an extension tube between the ADC and the camera? Or between the 2" to 1.25" adapter and the ADC? That is very confusing.

 

James



#6 RodgerDodger008

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Posted 08 August 2022 - 07:16 AM

Hi James, I'm new to this like you and hopefully my ASI585 arrives on Wednesday.

I have only done this with a phone so probably not one to give great advice but I do like reasearch and I have done tons of it.

The FAQ at the top of this thread is excellent honestly recommend you read it, more a "how to" than a "faq" imo.

Reducer does not make sense on planetary you want to use a barlow or no barlow and no reducer even to start. You want longer focal lenght not shorter like you would if shooting wide field dso. The planets are only small after all. The faq will teach you about the optimal 5x rule.

Best of luck you will get there, that cam you have is a awesome tool also suggest you play with dummy cam on FC abit to get used to the layout etc

#7 RedLionNJ

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Posted 08 August 2022 - 12:37 PM

I'm a  bit confused with this.

 

Right now the way it is set up is

 

Telescope---> Reducer-----> 2 inch Visual Back----> 2" to 1.25" adapter----> ZWO ADC ----> 1.25 inch ASI462MC camera nosepiece

 

Are they saying I should put an extension tube between the ADC and the camera? Or between the 2" to 1.25" adapter and the ADC? That is very confusing.

 

James

Lose the reducer. Add an IR-cut filter. Ideally have a barlow 'before' the ADC, but you can skip the barlow for now until you have the hang of focusing.


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#8 bunyon

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Posted 08 August 2022 - 12:50 PM

I agree with the advice to remove the reducer. I mean, it isn't even advice, it's an absolute necessity. Imaging at 2032mm to start would be fine, but 1200 won't get you much.

 

However, it should be easier to focus at 1200 than 2032 (or higher). When you focus, how do you do it? Do you have an electronic focuser? Either way, you should confirm that you have enough travel to go through focus. At focus, on Saturn in good seeing (though maybe not at 1200mm), you should see Cassini's division. With varying seeing, it may go in and out. I find Cassini's is a nice feature to get close to focus (before shifting to cloud bands). If you aren't seeing Cassini's on the live view, you either aren't in focus or the seeing is very poor. Or, I suppose, you might just not have the focal length.

 

You mention DSO imaging. You aren't by chance focusing on a star with a Bahtinov mask and then leaving it unchanged at the planet are you? That's a pretty common error moving from one type of imaging to the other. 

 

Also, the question about sharpening is a good one: Have you used wavelets or deconvolution to sharpen?

 

Planetary imaging is very different than DSO imaging. Most of what you know in one is marginally useful, or even sometimes harmful, in the other.

 

Hang in there. You have a long season of the two big ones (and then Mars!) still ahead of you and the reward is well worth it.


Edited by bunyon, 08 August 2022 - 01:09 PM.

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#9 James Paulson

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Posted 08 August 2022 - 01:43 PM

I kept the reducer in this time just to widen the field and make it easier to align my finder with my main OTA on camera. I will remove it.

 

I also should have mentioned that I did install a UV IR cut filter in the camera nosepiece. I also used a Bahtinov mask to focus.

 

I've read the FAQ section. I'm well aware they are very different - planetary and DSO.

 

Next time I will move to f/10 and native SCT focal length and go from there.

 

And I did do some work with Registax though it made little difference. Garbage data is garbage data.

 

James


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#10 bunyon

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Posted 08 August 2022 - 01:46 PM

Yeah, sharpening tools won't save you if focus, collimation or seeing are bad. 

 

Definitely try focusing on the planet directly. In lucky imaging, focus will change in less than a second in bad conditions. Usually, I pack up then. But those nights can be good to practice and play with settings/technique. It's counterintuitve from DSO imaging, where focusing by eye on a star almost never works out. With planets, it's really the only way to go.


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#11 bunyon

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Posted 08 August 2022 - 01:51 PM

If you're still reading, settings will vary with transparency and f/number. With the 462C at f/14, I usually image Jupiter with gain = 250, exposure 4ms and gamma off. That gets me a histogram that is ~50-60% full. You will see/read quite a big variance around these figures. Don't clip the histogram for sure. Don't let it fall too low. But, within a range, the settings don't really matter that much. What matters first is the seeing. Then collimation, focus, and thermal management. Based on the image up top, I'd think you had decent settings. When you switch to f/10, you may need to increase exposure time some (or gain). 


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#12 BKMaynard

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Posted 08 August 2022 - 03:09 PM

 

I also used a Bahtinov mask to focus.

This is also a big no no with planetary imaging


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#13 dcaponeii

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Posted 08 August 2022 - 03:38 PM

You want your f/ratio when your imaging to be 5 times the pixel size of the camera.  Definitely remove the reducer.  Use enough Barlow to get you to 5x pixel size or as close as you can.  Focus on the target.  Read Andrew's FAQ's pinned at the top of the forum lists.



#14 kevinbreen

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Posted 08 August 2022 - 09:07 PM

You want your f/ratio when your imaging to be 5 times the pixel size of the camera. Definitely remove the reducer. Use enough Barlow to get you to 5x pixel size or as close as you can. Focus on the target. Read Andrew's FAQ's pinned at the top of the forum lists.

Not true. Well OK, We all want 5x, granted, but it's only practicable if the seeing supports it. I'm in a region where the seeing is mostly sub optimal and 5x is a luxury once in a blue moon. Use a reducer by all means if it means getting a result that pleases you. I know I have, whatever floats your bolt as they say.
But it all comes down to the seeing in the end. You can be all dressed up but the seeing will leave you with nowhere to go.

It's at this point that some people say "your milage may vary" but personally I have no idea what that means.

5x is an aspiration.
When seeing allows for it, go for it!

Edited by kevinbreen, 08 August 2022 - 09:14 PM.

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#15 dcaponeii

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Posted 09 August 2022 - 04:57 AM

Not true. Well OK, We all want 5x, granted, but it's only practicable if the seeing supports it. I'm in a region where the seeing is mostly sub optimal and 5x is a luxury once in a blue moon. Use a reducer by all means if it means getting a result that pleases you. I know I have, whatever floats your bolt as they say.
But it all comes down to the seeing in the end. You can be all dressed up but the seeing will leave you with nowhere to go.

It's at this point that some people say "your milage may vary" but personally I have no idea what that means.

5x is an aspiration.
When seeing allows for it, go for it!

7x is an aspiration.  5x is "normal" rule of thumb.  If the seeing won't support 5x then you watch Star Trek until the seeing gets better.  Going much below 5x pixel size just yields disappointing results IMNHEO (In My Never Humble Enough Opinion).  OK for majestic Lunar vistas but for planetary, nah!!
 



#16 kevinbreen

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Posted 09 August 2022 - 05:49 AM

7x is an aspiration. 5x is "normal" rule of thumb. If the seeing won't support 5x then you watch Star Trek until the seeing gets better. Going much below 5x pixel size just yields disappointing results IMNHEO (In My Never Humble Enough Opinion). OK for majestic Lunar vistas but for planetary, nah!!


Oh I see. Thanks for clarifying that. Looks like I and a good few others, including you were mistaken in their appraisal of my imaging session here

https://www.cloudyni...c11-se-ireland/

I thought they were worthy of posting. You said they were "great images" in fact. So what is it then? Make up your mind or just don't comment on my threads, I can do without that kind of thing.

You could do with a spell of imaging in less-than-favourable climes at higher latitudes than yours....
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#17 mayhem13

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Posted 09 August 2022 - 06:25 AM

Oh I see. Thanks for clarifying that. Looks like I and a good few others, including you were mistaken in their appraisal of my imaging session here

https://www.cloudyni...c11-se-ireland/

I thought they were worthy of posting. You said they were "great images" in fact. So what is it then? Make up your mind or just don't comment on my threads, I can do without that kind of thing.

You could do with a spell of imaging in less-than-favourable climes at higher latitudes than yours....

 

This is a pretty amazing and accessible community of people dedicated to assisting others on their planetary journey......not sure the tone of this reply exemplifies the inclusive culture that’s here on CN. 

 

Many here who understand atmospheric systems and your location would agree that your location is plagued by both the Gulf and Jet streams.....but both of these systems current location and intensity can be viewed on various astronomical atmospheric forecasting sites. Along with the process, known as Lucky Imaging as the name and system implies.....finding moments of stillness and clarity is not only possible, but probable when extracting a suitable amount of individual frames from tens of thousands.

 

Here’s to wishing you many nights of good seeing!



#18 dcaponeii

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Posted 09 August 2022 - 08:09 AM

Oh I see. Thanks for clarifying that. Looks like I and a good few others, including you were mistaken in their appraisal of my imaging session here

https://www.cloudyni...c11-se-ireland/

I thought they were worthy of posting. You said they were "great images" in fact. So what is it then? Make up your mind or just don't comment on my threads, I can do without that kind of thing.

You could do with a spell of imaging in less-than-favourable climes at higher latitudes than yours....

I did not say you could never use less than 5x pixel size.  That's why I put "normal" in quotes.  Those images of yours were great images, especially given the challenges you've been describing.  One statement does not negate the other at all.  If you go back even just a week or so you'll see that I've posted some less than optimal images as well.  But I've also been re-watching all of the Star Trek movies in order to fill in the gaps.

 

The point that I think is most important is that you design your optical train to take advantage of the best seeing conditions when they arise and then you settle when they don't.  The worst position to be in (because I've been there) is to NOT have the right optical train when the conditions warrant.  Worse still you spend a limited budget that some of us have on equipment or accessories that would NEVER get you to great images when the conditions allow.   I think the 5x "rule of thumb" is the bare minimum that someone should spend their money on to design their system.  I agree, leave the Barlow out if conditions are crap, but you'd better have it handy when you do get those great skies.
 



#19 kevinbreen

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Posted 09 August 2022 - 09:19 AM

This is a pretty amazing and accessible community of people dedicated to assisting others on their planetary journey......not sure the tone of this reply exemplifies the inclusive culture that’s here on CN.

Many here who understand atmospheric systems and your location would agree that your location is plagued by both the Gulf and Jet streams.....but both of these systems current location and intensity can be viewed on various astronomical atmospheric forecasting sites. Along with the process, known as Lucky Imaging as the name and system implies.....finding moments of stillness and clarity is not only possible, but probable when extracting a suitable amount of individual frames from tens of thousands.

Here’s to wishing you many nights of good seeing!


The tone was measured. I disagree with the original advice to watch Star Trek if f/5 is not obtainable. Some more sensitive than me might see that as an insult maybe. Worse, for newbies it could be construed as misinformation.

Yes, I've been lucky imaging, well for the most part unlucky imaging, for a number of years and I know well how rare it is that all the ducks line up to produce good results. Clear skies.
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#20 dcaponeii

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Posted 09 August 2022 - 09:27 AM

The tone was measured. I disagree with the original advice to watch Star Trek if f/5 is not obtainable. Some more sensitive than me might see that as an insult maybe. Worse, for newbies it could be construed as misinformation.

Yes, I've been lucky imaging, well for the most part unlucky imaging, for a number of years and I know well how rare it is that all the ducks line up to produce good results. Clear skies.

Not intended as an insult at all and my apologies if it sounded that way.  Typing is a dangerous form of communication and sometimes I'm a little too over the top for my own good.
 



#21 bunyon

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Posted 09 August 2022 - 09:29 AM

To the OP, if you're trying to make sense of Don and Kevin's tete a tete, forget about it.

 

As you progress, optimizing your focal length will come. As Don says, when the seeing is good, go long. In excellent seeing, you can really crank up the focal length with Barlows. But, as Kevin says, sometimes that ain't possible. Don't fret if you have to dial back. In poor seeing, I'd rather have more frames and a brighter image, anyway (also ignore that, for now).

 

In your case, dear OP, just starting out, I don't think you should be trying to get "perfect" images. You build to that (and will screw plenty of things up after you get images you're happy with). My advice to ditch the reducer is that your native f/10 and 2000mm focal length are both really good starting points. You certainly can use the reducer but it reduces scale and adds some glass when it simply isn't needed. f/10 is lower than "optimal" but a very nice starting point


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#22 RedLionNJ

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Posted 09 August 2022 - 11:20 AM

I was about to drag my moderator hat out off the top shelf in my closet (for the second time in two days!), but I think our friends from Ireland and Texas can adequately self-moderate.

 

Thank you, gentlemen.


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#23 kevinbreen

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Posted 09 August 2022 - 12:30 PM

Not intended as an insult at all and my apologies if it sounded that way. Typing is a dangerous form of communication and sometimes I'm a little too over the top for my own good.

I'm very sensitive, prone to bawling my eyes out for no apparent reason!

i'Ll lEt YoU bE mY fRiEnD iF you LiKe?

Edited by kevinbreen, 09 August 2022 - 12:32 PM.


#24 dcaponeii

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Posted 09 August 2022 - 01:17 PM

I'm very sensitive, prone to bawling my eyes out for no apparent reason!

i'Ll lEt YoU bE mY fRiEnD iF you LiKe?

No issue from this side of the pond either.  I thought it was just pleasant banter!!  I guess we have to play nicer.  We'll be good.  Promise.
 



#25 kevinbreen

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Posted 09 August 2022 - 01:41 PM

No issue from this side of the pond either. I thought it was just pleasant banter!! I guess we have to play nicer. We'll be good. Promise.


I thought it was just pleasant banter!!

I must try harder next time so!
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