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CraigT82

Mars 15th Sep -Fullerscope

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Some really steady seeing early this morning 1am to 2am, definitely worth dragging myself out of bed for. Solis Lacus bang in the centre and Valles Marineris nicely seen.

40 mins worth of 2 minute captures with 30% stacked and derotated.  AS3>Registax>Gimp.

8.75" Fullerscope with Altair 224c (Baader L filter), 2.7x APM barlow & ZWO ADC.

2020-09-15-0049_7-L-Derotated2-final2.png

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Another super image Craig!

I'm amazed that you can derotate 40 mins of capture. I like doing long runs but in the past when imaging Jupiter I got some very odd effects when derotating beyond I think about 10 mins. Maybe Mars is different... or maybe theres some trick to it? 

With Jupiter I typically do lots of 2min runs back to back and then join them in PIPP to get the best effect. I must try the same with Mars. I'm just processing my first Mars effort this year and will post in a while. 

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So that's what I was seeing. I took a look at Mars around midnight with a 120mm frac at x200 and a #58 filter. I could see the gibbous phase, a tiny southern polar cap and a few dusky markings that coincided with your excellent image. Nice one!

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2 minutes ago, Tommohawk said:

I'm amazed that you can derotate 40 mins of capture. I like doing long runs but in the past when imaging Jupiter I got some very odd effects when derotating beyond I think about 10 mins.

Thanks! Yes Mars rotates much slower so I think you can load up to around 60 mins of data in winjupos and it should work (FL dependent). Jupiter is max 20 mins I think, but i always have trouble getting the image frame aligned on Jupiter if there isn't a moon in shot. 

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3 minutes ago, CraigT82 said:

Yes Mars rotates much slower

Yeah, didnt have my brain fully engaged - so hard drive space allowing I'll give it a go with longer runs. Out of interest, what exposure time and ROI do you use?

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15 minutes ago, Tommohawk said:

Another super image Craig!

I'm amazed that you can derotate 40 mins of capture. I like doing long runs but in the past when imaging Jupiter I got some very odd effects when derotating beyond I think about 10 mins. Maybe Mars is different... or maybe theres some trick to it? 

With Jupiter I typically do lots of 2min runs back to back and then join them in PIPP to get the best effect. I must try the same with Mars. I'm just processing my first Mars effort this year and will post in a while. 

Just wondered how you join runs in PIPP, not figured out how to do that yet.

John 

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3 minutes ago, Tommohawk said:

Yeah, didnt have my brain fully engaged - so hard drive space allowing I'll give it a go with longer runs. Out of interest, what exposure time and ROI do you use?

ROI was 375x275 and exposure was about 2.5ms I think with about 1/3rd gain... just seen Vlaiv's post on exposure times and probably should have lowered the gain and gone to 5ms exposures!

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2 minutes ago, CraigT82 said:

just seen Vlaiv's post on exposure times and probably should have lowered the gain and gone to 5ms exposures!

Yeah, thats why I asked!! But youre getting results, so if it works... 

Youre results are very consistent so will be interesting to see the effect if you do try something different. 

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5 minutes ago, johnturley said:

Just wondered how you join runs in PIPP, not figured out how to do that yet.

on PIPP first tab just load files and click "join mode"

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Nice image Craig! One question though- is the polar cap really that odd shape? Through the eyepiece it seemed well defined last night but a more rounded outline. I guess the camera can see better than me- it certainly picks out a lot more detail but that’s conspicuously different and the most well defined visual feature. Shall take another look tonight! 

Mark

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3 minutes ago, markse68 said:

is the polar cap really that odd shape?

Thanks Mark, yes it's quite irregular in shape now, you can see it in higher res in Peter's @astroman001 thread here...

 

 

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Few things are important when limiting max duration of recording - planet rotation speed, size of the planet and apparent size of the planet.

Mars rotates about x2.4 slower than Jupiter, it is much slower and it has smaller apparent size.

We could set some condition with regards to rotation. For example in duration of the movie, fastest rotating feature should not move more than 3px. In this case, no derotation is needed as AS!3 should be able to fix this with alignment points.

Btw, derotation process is hurting your data and if you can - skip it altogether (its not hurting it because of derotation but because of interpolation used - it additionally blurs high frequency detail - we can discuss this later if you like).

Let's use 8.75" scope as case study and Jupiter and Mars.

Jupiter rotates in 10h. It has radius of 69911km, this means that feature on equator moves at speed of ~43926 km/h.

Optimum sampling rate for 8.75" scope is 0.24"/px and this means that 3 pixels are 0.72" wide. Current distance to Jupiter is about 694 million km. This means that 0.72" feature is ~2422km wide. We now have speed at which it moves and we now have max distance for it to move, in what time will it do that? Result is 3.3 minutes, or 198.5 seconds

Let's do same calculation for Mars.

Feature moves at ~865.73 km/h and it is  232.98Km long - which gives 16.15 minutes or ~970 seconds of recording time.

 

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29 minutes ago, CraigT82 said:

Thanks Mark, yes it's quite irregular in shape now, you can see it in higher res in Peter's @astroman001 thread here...

 

 

Oh yes- so it is! Must try harder! It looks like a cloud in Peter”s image 

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44 minutes ago, Tommohawk said:

on PIPP first tab just load files and click "join mode"

Thanks Tom, I'll give it a try.

John 

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31 minutes ago, vlaiv said:

Few things are important when limiting max duration of recording - planet rotation speed, size of the planet and apparent size of the planet.

Mars rotates about x2.4 slower than Jupiter, it is much slower and it has smaller apparent size.

We could set some condition with regards to rotation. For example in duration of the movie, fastest rotating feature should not move more than 3px. In this case, no derotation is needed as AS!3 should be able to fix this with alignment points.

Btw, derotation process is hurting your data and if you can - skip it altogether (its not hurting it because of derotation but because of interpolation used - it additionally blurs high frequency detail - we can discuss this later if you like).

Let's use 8.75" scope as case study and Jupiter and Mars.

Jupiter rotates in 10h. It has radius of 69911km, this means that feature on equator moves at speed of ~43926 km/h.

Optimum sampling rate for 8.75" scope is 0.24"/px and this means that 3 pixels are 0.72" wide. Current distance to Jupiter is about 694 million km. This means that 0.72" feature is ~2422km wide. We now have speed at which it moves and we now have max distance for it to move, in what time will it do that? Result is 3.3 minutes, or 198.5 seconds

Let's do same calculation for Mars.

Feature moves at ~865.73 km/h and it is  232.98Km long - which gives 16.15 minutes or ~970 seconds of recording time.

 

Thats very interesting, thanks Vlaiv. I will try stacking 16 minutes worth of captures together without derotation and see how that looks. 

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Very nice detailed Image there Craig, certainly worth getting out of bed for! 👍

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2 hours ago, johnturley said:

Thanks Tom, I'll give it a try.

John 

Hi Tom

Gave it a try, it saves having to process several different images in Registax, plus I reduced the number of frames stacked to the best 30%, may have given a slight improvement. Attach images taken about 00.15 this morning, not as good as Craig's though, they are actually the same image but the second one has south at the top which I am more used to.

I wish I could find a method of increasing the image size, but I can't figure out a method of doing that other than increasing the effective focal length of the telescope by using a shorter focal length eyepiece in the eyepiece projection tube, or adding a barlow lens to the image train. The photo was taken through my 14in Newtonian, my Esprit 150 may have given sharper results, but the image scale would have been smaller, and the brighter image through the Newtonian I think allows more frames per second with my Canon 6D digital SLR. 

Mars 15.09.20 Processed 4.jpg

 

Mars 15.09.20 Processed-2.jpg

Edited by johnturley
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It's a nice image, but I think your 14" Newt will be capable of much more if you can get set up better. I'm not sure eyepiece projection is the way to go - I just image at prime focus and pretty sure Craig does too, although a barlow or powermate would help for image size. Also I wonder how you are capturing? Video presumably but you have to be careful with Canon to use uncompressed. Sorry you may know that already.

TBH might be better to start a new thread to discuss your setup etc.

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2 minutes ago, Tommohawk said:

It's a nice image, but I think your 14" Newt will be capable of much more if you can get set up better. I'm not sure eyepiece projection is the way to go - I just image at prime focus and pretty sure Craig does too, although a barlow or powermate would help for image size. Also I wonder how you are capturing? Video presumably but you have to be careful with Canon to use uncompressed. Sorry you may know that already.

TBH might be better to start a new thread to discuss your setup etc.

If I didn't use eyepiece projection and just a barlow or powermate the image size would be tiny, and as mentioned can't find a method of increasing it, the small image size may also be due to using a full frame digital SLR. Yes I took an MVI movie through my Canon, and converted the file in PIPP so that I could load it into Registax, and processed it a bit more in Lightroom, not sure whether the MVI files taken with my Canon are compressed or how to alter them.

John 

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John - it's not so much that you have a small image, as you say it's more that you have a huge sensor! I wont add more here on Craig's thread, but if you start a new thread we can pick up from there.

 

Edited by Tommohawk

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1 minute ago, Tommohawk said:

John - it's not so much that you have a small image, it's more that you have a huge sensor! I wont add more here on Craig's thread, but if you start a new thread we can pick up from there.

Yes, I suspected that might be the problem, so I assume the only solution would be to get an Astro Camera with a suitable sensor size.

John 

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22 minutes ago, Tommohawk said:

John - it's not so much that you have a small image, as you say it's more that you have a huge sensor! I wont add more here on Craig's thread, but if you start a new thread we can pick up from there.

 

Have started a new thread called 'Suitable Camera for Planetary Imaging'.

John 

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Can i just say i love the images here and i really live the help that everyone gives each other.  its so.. nice.  

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