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Saturn and Mars - two planets before breakfast

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#1 Lacaille

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Posted 15 April 2024 - 09:52 PM

Hi all,

 

I tried last week to capture a fairly close approach between Mars and Saturn at dawn using a 6SE and a focal reducer, but without success due to circumstances beyond my control, aka incompetence.

 

Undeterred, I spent yesterday evening fettling up the C14, collimating it etc, and went out at 430 this morning to have a go at the two as separate targets.  I used a 678MC and ADC but no Barlow (pixel size in the 678 is 2 microns). Both planets were close to the treeline at around 30 deg.

 

In the images below, Saturn's rings are now getting to be edge on. Not much surface detail is visible and the colours seemed washed out, perhaps due to the altitude. This will improve later in the year, for us in SE Australia..

 

Mars is still tiny at 4.6 arcsecs but the coming opposition is aphelic and so it will not get much bigger - about 14 arcsecs, and for us in SE Australia it will remain fairly low throughout the approach.  As Christophe Pellier pointed out elsewhere, however, the aphelic oppositions are interesting in that there is a chance to image white clouds on Mars.

 

In the image below you can make out a bright SPC, with a slight notch in it at Long 350, lat 67S, perhaps signs of break up as the southern summer solstice approaches.

 

Mars and Saturn 15 April 2024 No 1.png

 

Also, for a bit of fun, I did a photocomposite of the two planets to the same scale as they are in the eyepiece, oriented as they currently are in the southern dawn sky, as a slight compensation to myself for the missed conjunction of last week.

 

Mars and Saturn 15 April 2024 No 2.png

 

Thanks for looking

 

Mark


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#2 RedLionNJ

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Posted 15 April 2024 - 10:08 PM

Nice (really nice) work, Mark!


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#3 Foc

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Posted 15 April 2024 - 11:45 PM

Champion work Mark!


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#4 Kokatha man

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Posted 16 April 2024 - 02:59 AM

Great work Mark - hard graft this early in the year without adding the seeing, low elevation and size, especially for Mars atm..! waytogo.gif waytogo.gif waytogo.gif

 

Remember that we'll still be able to get good images if the seeing cooperates later in this apparition with Mars - for you and me (almost identical latitudes) WJ tells me that in mid-November a minute before Sunrise here, Mars will be at 33° and 10.4" in diameter.

 

With decent seeing that should provide excellent opportunities..! grin.gif  fingerscrossed.gif


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#5 KiwiRay

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Posted 16 April 2024 - 11:28 AM

Good work, Mark! The Martian features are easily recognisable even at 4.6". Saturn is pretty crisp. It won't be long before someone Down Under like you or Darryl captures an early Rhea or Dione transit.


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#6 KMH

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Posted 16 April 2024 - 02:42 PM

Really nice early season results!  I like the composite.

 

Kevin


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#7 Lacaille

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Posted 16 April 2024 - 08:34 PM

Thanks for the likes and kind comments - very encouraging after months of lean pickings!

Mark

#8 Ashman

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Posted 17 April 2024 - 02:03 AM

Nice images Mark!!


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#9 Jcoogler

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Posted 17 April 2024 - 05:28 AM

Very nice!!
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#10 dcaponeii

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Posted 18 April 2024 - 02:21 PM

Nicely done. Giving Daryl a run for his money!!
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#11 Kokatha man

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Posted 18 April 2024 - 09:39 PM

...meant to ask you how you find the ADC correction with these smaller-pixelled cameras Mark..?

 

Not that I intend getting one, the mono & os cams I have are more than enough imo but I did wonder whether the C14's native f/l allowed for good correction..?

 

My gut feeling is that their f/ratio should be sufficient and (possibly?) by pushing the focal point further out past the ADC it should be able to effect decent correction without enormous lever separation - what have you found here..?


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#12 Lacaille

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Posted 19 April 2024 - 06:51 AM

Hi Darryl, interesting question. The setting I arrived at for this was about one notch each side of the centre point for Saturn and I left it the same for Mars as time was short with dawn approaching. I’m afraid I don’t keep a track of my ADC settings and can’t offer any comparative data, but the settings I’m currently using don’t seem abnormal to me compared to past experiences at various (sometimes excessive) focal lengths.

#13 Kokatha man

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Posted 19 April 2024 - 06:40 PM

I'd consider that minimal lever separation Mark - surprising in fact because of their elevation! confused1.gif

 

ps: By way of comparison our ADC's lever separation is between 2-3 gradations with either planet around 30°: we use the "coloured circles" method set to 25 frames and consider the ADC set when the x/y co-ords consistently flick between "0-0" & "0-1." 


Edited by Kokatha man, 19 April 2024 - 08:16 PM.


#14 Lacaille

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Posted 19 April 2024 - 10:36 PM

The mysterious ADC! I don’t know what is going on here Darryl. I use the coloured circles, flickering around 0-1, as you do.

Just went out to look at the ADC which I had left in its last setting and it is definitely at one notch either side. I do have a manual filter wheel between it and the camera (no Barlow). My C14 is an Edge of which the internal optics could cause differences from yours?

#15 Kokatha man

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Posted 20 April 2024 - 10:23 PM

Perhaps you might be getting better correction apropos the light cone with your ADC>FW>camera Mark..?

 

I wouldn't think the Edge scope would make any difference and I do have a reasonable distance between the rear of the ADC and the camera. (EFW>barlow>ADC>camera)

 

Back in the 2020 Mars apparition (our personal "best") we were shooting Mars mainly with the ASI290MM and that same arrangement with the ADC levers marginally more than 1 notch apart served us well with Mars maxing out at 48°.

 

Interesting - maybe I should consider one of these 2um cams and shoot at native scale..! lol.gif


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#16 Lacaille

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Posted 21 April 2024 - 05:33 AM

Yes, could be the FW in the imaging train.

Also there’s elevation above sea level- dispersion is apparently quite sensitive to that. We’re at about 650 m.

Reference here:
https://www.glitteri...eric-Dispersion

Edited by Lacaille, 21 April 2024 - 05:38 AM.



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