38 replies to this topic

[skycamper]

Mars from last night. Why is the playback so dim??  It was far brighter on my SharpCap screen while capturing!!   Only my 2nd time really trying to get a decent try.  I Failed in 2018.    Have I failed again?

This time I used a  2.8x barlow.  Seeing looked decent but I was using the C11HD on the fork mount no wedge.  The image would move almost across the sensor which I kept at 1096x1096.  Not sure if that was smart. Also kept it at RAW16,  not sure if thats ok.  I hardly knew what I was doing
1.5 min imaging runs  ASI462MC at 200 gain and 1.5ms.  at max frame rate.     Is this data going to be useful since it was inching across this small sensor?    Any advice appreciated since I mostly do deep sky imaging.    

 

Please tell me this data is usable........

Thanks

Abraham

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Edited by skycamper, 08 October 2020 - 01:20 AM.

[Kokatha man]

Well, relating it to FireCapture you don't want an exposure/shutter speed of 1.5m/s with a 1096x1096 ROI in that camera..! 

 

The height of the ROI or sensor-size you use controls the maximum fps/frame-rate & although 1.5m/s has a theoretical 600+fps there's no way you would get that at that ROI...& gain of 200 only compounds the problem due to the fact it would be a very low histogram to try & image at!

 

But you can try to process it because the image is there & these cameras have a habit of still cranking out an image at a very low histogram, even though you shouldn't be trying those sorts of settings!

 

Use the image brightening function in AS!3 to see the image to set the MAPs boxes (it doesn't affect the data as it says when you put your mouse over it) but you will have to stretch the billy-o of the data when you drag it into Registax! 

 

[skycamper]

I should have shot it with the full sensor size youre saying?  Like I said I had no idea. Also dont know anything about planetary stacking.  Looked really good on my computer screen with Sharpcap.  Didn't think to look at a histogram.    Can you say what I should have shot this at?   Im so mad and disappointed right now.   It was really clear last night.  

 

I really would not know how to stack this yet without more reading.    

 

Can you say why it looked so much brighter on Capture???  

[Kokatha man]

<"I should have shot it with the full sensor size youre saying?">

 

NO..!

 

You should have chosen a smaller ROI (perhaps 400x400 if SharpCap has that size - I only use FireCapture) & then you would have been able to get a good fps.

 

For Mars a histogram around 55%-60% is absolutely fine...with the C11 if you use an exposure of around 3 to 4milliseconds & a small ROI like 400x400 or so you should be able to get 250fps - 300fps or so without having to use excessive gain to obtain a histogram of 55%-60%.

 

For your set-up - capture in avi (8bit, all that's needed) & run your each of your captures for 300-360 seconds. Also, you cannot use a 2.8x barlow very successfully with an F10 scope...this camera works best at around f15 which means you should only be employing a barlow that gives 1.5x at the sensor. (taking the image train after the barlow into this equation!)

 

In my signature below are links to processing planetary images - there are others elsewhere you might find more suited to your level of experience  but if you look at the tutes I provide for the ASI224MC & Jupiter you can scale them down to the size of Mars similarly...

 

That means more of the MAPs on a smaller image but it will get you started: in Post #14 here https://www.cloudyni...arlow-asi290mm/ I give a good MAPs set-up for Mars...it's for a mono camera but this aspect is the same...good luck!   

[Gary Z]

Skycamper, there are a lot of videos on planetary imaging and processing.  you have autostakkert and registax and these videos have been out there for several years now. 

 

Just search for planetary imaging and you'll see plenty of useful guides and tips to get the best imaging.  

 

I'd say give it a go with your processing using Autostakkert, then use registax for wavelet adjustments, then your your image processing software to tweak your images like gimp or photoshop.  

 

Here's some tips from probably the best known planetary imager, Damian Peach: 

 

https://www.youtube....h?v=puoh1ikzonA

 

Gary

[Jkaiser3000]

There’s a feature in sharpcap that brightens the image on the screen without affecting the data (I can’t remember what it’s called or where it is but I can find out if you want). If the feature is turned on and you adjust your camera settings based on what you see on the screen, rather than the histogram, you’ll end up with a dim video. IF this is the case, just turn that feature off next time, no big deal.

As for this data set, like they said before, just go ahead and try. You won’t loose anything by trying 

 

just stack in AS!3, apply wavelets in RS6 and then stretch the histogram. Who knows, you might be surprised at the results, as might we all too 

be sure to post the results here for us to enjoy 

[skycamper]

There’s a feature in sharpcap that brightens the image on the screen without affecting the data (I can’t remember what it’s called or where it is but I can find out if you want). If the feature is turned on and you adjust your camera settings based on what you see on the screen, rather than the histogram, you’ll end up with a dim video. IF this is the case, just turn that feature off next time, no big deal.

As for this data set, like they said before, just go ahead and try. You won’t loose anything by trying 

 

just stack in AS!3, apply wavelets in RS6 and then stretch the histogram. Who knows, you might be surprised at the results, as might we all too 

be sure to post the results here for us to enjoy 

Thanks for all the help everyone, I was pretty devastated that the data wont be optimal especially with the great luck I had with clear weather and good seeing conditions.   This shows that in this hobby youre just one setting away from a small disaster.   I even thought that the image was too good to be true on my screen!!!   Turns out I was right!  

 

One of my weaknesses has always been computers,  Jkaiser if you can let me know what that setting is I would appreciate it!    I need to buy another barlow since it appears the 2.8x unit is not optimal for this camera.  

 

Question:   I will give the data a go or find someone to help me process it, but since I gathered at 16RAW  will this make it even harder to process?  

 

Again thanks for the encouragement, now I have rain but perhaps clear weather in about a week.   Can try again.

[martinl]

This series really helped me getting started:

 

http://planetaryimagingtutorials.com

 

I’d skip the Barlow for now. Use the smallest ROI the planet will stay within and increase the exposure time (from as low as it will go) until you see the FPS start to drop (that’s the maximum FPS your camera can deliver at that ROI). Then adjust your gain to give a 55-60% histogram. Capture for 5-6mins. 

[skycamper]

This series really helped me getting started:

 

http://planetaryimagingtutorials.com

 

I’d skip the Barlow for now. Use the smallest ROI the planet will stay within and increase the exposure time (from as low as it will go) until you see the FPS start to drop (that’s the maximum FPS your camera can deliver at that ROI). Then adjust your gain to give a 55-60% histogram. Capture for 5-6mins. 

Ok,  so thats the histogram being 55-60% off the left side or a bit more than halfway to the right?   I'll check out the tutorials.

Thanks!

[martinl]

Ok,  so thats the histogram being 55-60% off the left side or a bit more than halfway to the right?   I'll check out the tutorials.

Thanks!

Yes. But it’s not critical you hit those exact numbers. A lot can be forgiven in post-processing. 

[gfstallin]

Abraham, 

 

I also have a C11 and image with an ASI462MC. I'm no means an expert, but I've collected some decent data at ~300-310 gain. Others have gone higher than that with gain with even better results, so play with settings and see where that places you in terms of data collection.  

 

Currently, for Mars with an ROI of about roughly 300x300 and gain at roughly 310 I'm getting ~250 fps and a histogram of ~70%. As others mentioned, you could go lower on the histogram to around 60% (or increase gain) and squeeze in some more fps. 300 fps is definitely doable, but you should be getting more than 180 fps with your setup. As others have mentioned, there is a spectrum of what is "correct." I capture for between 4 or 5 minutes depending on what I'm seeing on the screen. 

 

The 2.8x barlow is quite a lot for that camera. I'm not saying it couldn't work, but you are oversampling with that chip size. If you have a 2x barlow (or less) laying around, try that. You should also give it a try without a barlow. You wouldn't be undersampling by very much given the chip size at your f/10 native focal length. 

 

If you prefer SharpCap (nothing wrong with that!) you can create your own custom ROI as you can in FireCapture, though you cannot draw the ROI on the screen as you can in FireCapture (click on "Capture Area" button -- scroll down to "Custom"). The neat thing about SharpCap is that you can then move the ROI around the entire possible capture area if you'd like by clicking it and dragging it. It isn't a necessary feature by any means, but a nice perk. I switch off between SharpCap and Firecapture regularly and they each of their benefits. The program you feel most comfortable using is the one that will produce the best data. Good luck and don't fret; there is still plenty of time to get great Mars data. 

 

George

[skycamper]

Hi George, I really cant beat myself up too much since this was only my 2nd try and the first one was two years ago with a DSLR.   I really didnt do much research either, just relying on my deep sky experience which is vastly different.  

 

Jkaiser3000 mentioned a setting in SharpCap that screen stretches the data for visualization in the screen and that I should turn that off.  Do we know what that is?  

 

I did find an Orion 2x Shorty 3-element barlow.   I will try it with that and without!   

 

Another question.    Ive never worked with a fork mount but I was surprised by how well the GOTOs were at the 6500mm focal length were.    But I did see drift,  would autoguiding a fork mount with no wedge keep it centered more for just planetary imaging?   Too keep my ROI smaller?   It it ok that the image drifts across the sensor but stays inside the ROI??

[martinl]

Firecapture can auto guide on the planet. All you need is an ST4 cable between the camera and mount. Even simpler, Firecapture has a feature that will move the ROI when the planet drifts across the sensor. 

[skycamper]

Firecapture can auto guide on the planet. All you need is an ST4 cable between the camera and mount. Even simpler, Firecapture has a feature that will move the ROI when the planet drifts across the sensor. 

WHAT?????

[martinl]

Yup. It’s a pretty neat piece of software. And it’s free!

 

Google   firecapture autoguide site:www.cloudynights.com   for multiple discussions, and watch https://youtu.be/hoNJq_YmEtk for Torsten’s own tutorial on setting it up in FC. 

[phileefan]

Firecapture can auto guide on the planet. All you need is an ST4 cable between the camera and mount. Even simpler, Firecapture has a feature that will move the ROI when the planet drifts across the sensor. 

I don't know how well it will work with a fork mount unless you have a wedge.   With my GEM I can keep Mars in a 400 x 400 ROI box all night with FireCaptures autoguide feature.............

[Jkaiser3000]

Hi George, I really cant beat myself up too much since this was only my 2nd try and the first one was two years ago with a DSLR.   I really didnt do much research either, just relying on my deep sky experience which is vastly different.  

 

Jkaiser3000 mentioned a setting in SharpCap that screen stretches the data for visualization in the screen and that I should turn that off.  Do we know what that is?  

 

I did find an Orion 2x Shorty 3-element barlow.   I will try it with that and without!   

 

Another question.    Ive never worked with a fork mount but I was surprised by how well the GOTOs were at the 6500mm focal length were.    But I did see drift,  would autoguiding a fork mount with no wedge keep it centered more for just planetary imaging?   Too keep my ROI smaller?   It it ok that the image drifts across the sensor but stays inside the ROI??

My apologies, been a bit busy this past few days and haven’t had a chance to look that up but i’m free tomorrow. It’s been a while since I last used sharpcap so I don’t remember off the top of my head and in fact I may be mistaken lol

[Jkaiser3000]

Sorry about the delay. I had a chance to play around with sharpcap a while and here's the feature I was mentioning. It's the FX radio button, its function is to modify what you see on the screen without actually modifying camera settings and it's helpful for framing and focusing, especially on dim objects, and also for collimation as you can live stack 10 frames.

 

here's a screen grab pointing to the button

 

 

To give an example of what I'm saying, assume you activate the "boost more" option and then adjust the image on the screen with gain and exposure until you like what you see, without looking at the histogram. When you go back to the normal setting ("none" option) you'll see the real image you would record to be very dim. I know this happened to me at least once when I was trying the software for the first time

 

Hope this helps

[GSBass]

You really do have to use your Histogram, what you see is not what you get, guessing your monitor brightness level fooled you in to thinking your exposure was correct, I made same mistake when first starting

[skycamper]

Well looks like my next attempt is wednesday when the weather clears.  Seeing supposed to be ok as well.   I'll try and takes notes from here, and download and experiment with firecapture as well.   Looks like the difference between oct6th and oct 13th is about half a million km so not huge difference when its 62Million km away correct??  

 

I really appreciate all the responses i've had here!

Edited by skycamper, 11 October 2020 - 05:31 PM.

[RedLionNJ]

I don't know how well it will work with a fork mount unless you have a wedge.   With my GEM I can keep Mars in a 400 x 400 ROI box all night with FireCaptures autoguide feature.............

Hi Mick,

 

Given the way FC works with "autoguiding", having an altaz without a wedge really shouldn't matter - "all" FC does is notice the center of brightness is moving away in direction X and issues a "nudge" to counter this. X could be up and down, left and right, etc  it doesn't matter. A combination will keep the planet centered.

 

I've been fortunate enough to be imaging Mars with a 240 x 240 ROI recently - with no guiding necessary. The tracking on my MX+ is good enough to keep it on target by itself.

[skycamper]

Hi Mick,

 

Given the way FC works with "autoguiding", having an altaz without a wedge really shouldn't matter - "all" FC does is notice the center of brightness is moving away in direction X and issues a "nudge" to counter this. X could be up and down, left and right, etc  it doesn't matter. A combination will keep the planet centered.

 

I've been fortunate enough to be imaging Mars with a 240 x 240 ROI recently - with no guiding necessary. The tracking on my MX+ is good enough to keep it on target by itself.

Would I use the autoalign on the planet AND guiding to keep it centered using FireCapture?

 

Another question, since my camera is color, whats the filter selection?   L or RGB?

Edited by skycamper, 11 October 2020 - 10:35 PM.

[skycamper]

What do you think of these settings?  I thought my gain and exposure would be higher.   How are the histogram numbers?   Should I be using L or RGB?   Debayer is off.  No Barlow!

 

Thank you!!!

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Edited by skycamper, 15 October 2020 - 10:53 AM.

[martinl]

I don’t see anything particularly wrong with these settings. The gain does seem low, but I’m not familiar with this particular camera nor have I imaged much at f/10 so it’s probably normal. The histogram is a bit high as discussed above.

 

L is fine, you only need to mess with that setting if you use a mono camera with filters. 
 

If possible, guiding-wise, I would try a smaller ROI to get the frame rate up even higher and lower the exposure to get the histogram down to more comfortable levels (less chance of blowing highlights). Since your gain is so low in this configuration you could probably get away with 1ms exposures to freeze the seeing and still get a nice image stack with very low noise. 

[skycamper]

I don’t see anything particularly wrong with these settings. The gain does seem low, but I’m not familiar with this particular camera nor have I imaged much at f/10 so it’s probably normal. The histogram is a bit high as discussed above.

 

L is fine, you only need to mess with that setting if you use a mono camera with filters. 
 

If possible, guiding-wise, I would try a smaller ROI to get the frame rate up even higher and lower the exposure to get the histogram down to more comfortable levels (less chance of blowing highlights). Since your gain is so low in this configuration you could probably get away with 1ms exposures to freeze the seeing and still get a nice image stack with very low noise. 

This camera needs the uv/ir cut filter and I accidently removed it from the camera when I switched nose pieces.    Any idea how that will affect my images here?   WIll have to remember the filter for tonight.   Dang it this is a hard hobby.