Go Back   IceInSpace > General Astronomy > Celestial and Astronomical Events

Reply
 
Thread Tools Rate Thread
  #1  
Old 19-11-2020, 08:56 PM
pmrid's Avatar
pmrid (Peter)
Ageing badly.

pmrid is offline
 
Join Date: May 2008
Location: Cloudy, light-polluted Bribie Is.
Posts: 3,665
Imaging the Jupiter Saturn conjunction

I’m planning to image this event - on December 21st. I have been trying to decide which combination of scope and camera will work best. I will have to use a portable rig - I have chosen a site in a west-looking park near home - so already some limitations. It will have to be my HEQ5Pro mount. Now since the planets will be low (15-18 degrees) above the western horizon and barely 90 minutes after sunset, and it is likely to still be warm if not hot, and the seeing will be poor the choice of gear will be tricky. Do I try my ZWO290MC CCD and take videos, or try to get some still frames and hope?

Framing issues clearly favour getting both planets in the same frame. So matching scope to CCD will be the real challenge. I have a 10inch f3.8 newt of 952mm FL. But on a small mount it will probably be a bit unstable in an exposed location. Likewise my127mm refractor - another 950ish FL. I have an RC8 (1600mm FL) which is a bit heavy but less prone to instability if there’s a bit of breeze. I also have a ED80 which is light and portable. But the FL is a bare 600mm and getting a decent image of Jupiter (let alone Saturn) would be difficult.

I have the usual mix of old EOS 20D, 40D and even a 500D plus a great Olympus OMD EM1. and an SBIG STF8300M and an older 4MP Starlight Express SXVR H16.

Spoilt for choice. I won't be able to get both planets in frame AND get a decent image scale so I will have to sacrifice one or the other. And I think image scale loses out. So I think my rig of choice will be the RC8 and the SBIG STF8300.

There won’t be time to take multiple filters. I’m going to have to image in one colour - probably green I think. I’d be interested to see what the experts think though.

Peter
Reply With Quote
  #2  
Old 23-11-2020, 07:23 AM
doppler's Avatar
doppler (Rick)
Registered User

doppler is offline
 
Join Date: Nov 2012
Location: Mackay
Posts: 1,656
Hi Peter, the other difficulty to get around will be the large difference in brightness between the two objects. Jupiter will be overexposed to get Saturn exposed correctly and Jupiter's moons should be about the same exposure as Saturn. I will be taking various exposures and then blending 2 together in PS.

Rick
Reply With Quote
  #3  
Old 23-11-2020, 08:20 AM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Location: Lake Macquarie
Posts: 7,033
Yeah i think the technique used to properly expose Orion (M42) would work well, which is two separate sub sets, one longer one to allow capture of the nebulosity cloud, and a short one to capture the Trap detail before it burns our. Then use Photoshop layer masking to blend them together; perhaps even dialing down Jupiter's Opacity if required. There are a fair number of Orion Processing tutorials on Utube that you can work on right now to perfect the technique, for those new to the concept. Of course those two planets are much brighter than Orion's gas cloud, so the exposure differences would not need to be that large (as Orion's).
Reply With Quote
  #4  
Old 23-11-2020, 08:02 PM
pmrid's Avatar
pmrid (Peter)
Ageing badly.

pmrid is offline
 
Join Date: May 2008
Location: Cloudy, light-polluted Bribie Is.
Posts: 3,665
Thanks Rick and Glen. I’ve settled on using my RC8 with a ZWO ASI290MC which is a 2MP sensor, USB3 supporting a high frame rate so I can vary the exposure duration and gain to get the settings to work with both planets. The problem will be with the very short window of opportunity and having to run off big enough video grabs. I want to be able to work with at least 10K frames for each. The irony is, of course, that we’ll probably have stormy weather and I’ll have nothing to do but console myself withXmas cheer.
Peter
Reply With Quote
  #5  
Old 23-11-2020, 10:23 PM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Sydney
Posts: 22,060
There's going to be only an hour or so between the sunset and the planets being too low. The sky will be probably quite bright so you'll need to be quick. Best to get everything in one field rather than trying to mosaic. I don't think there will be enough time for this. I reckon a FL of 1m or a refractor barlowed x2 would be perfect. Color would be hard. Mono or IR better given the altitude and the sky brightness.
Reply With Quote
  #6  
Old 23-11-2020, 11:30 PM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Location: Lake Macquarie
Posts: 7,033
I have just been looking at Sky Safari for the night's prior to the conjunction, and there seem to be good opportunities to do some test imaging leading up to the actual conjunction on the 21st. Saturn and Jupiter are very close for a number of nights prior, and certainly can be captured in a single field shot, which could be useful for practicing your exposures. Also you can grab them at a slightly higher altitudes it would seem. Check out Sky Safari, or Stellarium or whatever you use for dates like the 17th. On Thursday the 17th at 8:55pm they are at 15 degrees altitude and already close enough in my opinion to get a good image of the two in the same frame, they seem to be less than 1 degree apart based on Sky Safari data. Maybe don't worry about the actual conjunction shot and go for getting them both in the same frame, which is pretty unique in itself.

Last edited by glend; 23-11-2020 at 11:41 PM.
Reply With Quote
  #7  
Old 24-11-2020, 06:23 AM
pmrid's Avatar
pmrid (Peter)
Ageing badly.

pmrid is offline
 
Join Date: May 2008
Location: Cloudy, light-polluted Bribie Is.
Posts: 3,665
Quote:
Originally Posted by glend View Post
I have just been looking at Sky Safari for the night's prior to the conjunction, and there seem to be good opportunities to do some test imaging leading up to the actual conjunction on the 21st. Saturn and Jupiter are very close for a number of nights prior, and certainly can be captured in a single field shot, which could be useful for practicing your exposures. Also you can grab them at a slightly higher altitudes it would seem. Check out Sky Safari, or Stellarium or whatever you use for dates like the 17th. On Thursday the 17th at 8:55pm they are at 15 degrees altitude and already close enough in my opinion to get a good image of the two in the same frame, they seem to be less than 1 degree apart based on Sky Safari data. Maybe don't worry about the actual conjunction shot and go for getting them both in the same frame, which is pretty unique in itself.
Yes, I had given that thought too. I was reminded of that adage that goes "The perfect is the enemy of the good." And on that basis, perhaps getting some images in the day or so preceding the 21st may be a "good" idea.

Peter

Last edited by pmrid; 24-11-2020 at 12:21 PM.
Reply With Quote
  #8  
Old 24-11-2020, 07:52 AM
doppler's Avatar
doppler (Rick)
Registered User

doppler is offline
 
Join Date: Nov 2012
Location: Mackay
Posts: 1,656
I'll be starting from the 17th, when the moon is close and then tighten the field of view as the two planets get closer. I will have a go at some daytime shots as well, Jupiter is bright enough not sure about Saturn though. Hopefully the weather is kind here, the wet season hasn't started yet but afternoon clouds are becoming the norm.
Rick
Reply With Quote
  #9  
Old 24-11-2020, 10:34 AM
Tinderboxsky's Avatar
Tinderboxsky (Steve)
I can see clearly now ...

Tinderboxsky is offline
 
Join Date: Feb 2012
Location: Kingston TAS
Posts: 1,031
Day time images are worth a shot. Sounds like real challenge though. I have imaged Jupiter near the meridian previously but not Saturn.
If you can make this work then you could try for the closest approach point for this conjunction. I think this is about 10am on the 22nd. The separation will be down to 6.25 arc seconds.
I am not going to try imaging this conjunction. Rather I am setting up for day time, twilight and early evening visual observing just to enjoy and commit the event to memory.



Quote:
Originally Posted by doppler View Post
I'll be starting from the 17th, when the moon is close and then tighten the field of view as the two planets get closer. I will have a go at some daytime shots as well, Jupiter is bright enough not sure about Saturn though. Hopefully the weather is kind here, the wet season hasn't started yet but afternoon clouds are becoming the norm.
Rick
Reply With Quote
  #10  
Old 24-11-2020, 10:57 AM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Location: Lake Macquarie
Posts: 7,033
I suggest using a red filter for daytime shots, as it boosts contrast. I used a red filter during a Saturn conjunction with the Moon a few years ago and it really made Saturn pop. Great to see Saturn appear to dive into the Moon.
Reply With Quote
  #11  
Old 25-11-2020, 11:44 AM
rustigsmed's Avatar
rustigsmed (Russell)
Registered User

rustigsmed is offline
 
Join Date: Mar 2012
Location: Mornington Peninsula, Australia
Posts: 3,950
I'm intending on attempting a daytime capture.

should be able to have the 2x barlow and possibly have some spare space for a bit of a crop on the system.

looking in stellarium there are going to be nice moon alignments but i'm sure these will be washed out.

cheers
Reply With Quote
  #12  
Old 25-11-2020, 01:59 PM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Sydney
Posts: 22,060
Quote:
Originally Posted by rustigsmed View Post
I'm intending on attempting a daytime capture.

should be able to have the 2x barlow and possibly have some spare space for a bit of a crop on the system.

looking in stellarium there are going to be nice moon alignments but i'm sure these will be washed out.

cheers
Jupiter is quite easy if it's high when the sun is setting but still up. Never tried Saturn though. That could be hard. For the moon I reckon it will be really hard to over expose and get them out of the sky glow.
Reply With Quote
  #13  
Old 25-11-2020, 09:11 PM
alpal's Avatar
alpal
Registered User

alpal is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 3,602
Just checked on Stellarium -
the event is only 7 degrees above the horizon in the West.
I don't think a good shot is possible.
Reply With Quote
  #14  
Old 25-11-2020, 09:40 PM
pmrid's Avatar
pmrid (Peter)
Ageing badly.

pmrid is offline
 
Join Date: May 2008
Location: Cloudy, light-polluted Bribie Is.
Posts: 3,665
Well, I’ve been experimenting with different combinations of scopes and cameras. I’ve scrapped my plan to use my RC8 (at 1600 FL). I’m not happy with it’s collimation and I haven’t the time or energy to tweak it. I’ve gone instead with my BD80ED at a native 600 FL but with an eyepiece projection rig using a 20mm eyepiece and plugging my ZWO 290MC into that. My rough figures tell me I’ll have a FOV of 0.15 x 0.09 degrees. That should get both planets and a sprinkling of moons (with a bit of luck).

I am also praying to the weather gods rather a lot.

Peter
Reply With Quote
  #15  
Old 25-11-2020, 09:45 PM
JA
.....

JA is offline
 
Join Date: Oct 2016
Location: Melbourne, Australia
Posts: 2,945
Quote:
Originally Posted by alpal View Post
Just checked on Stellarium -
the event is only 7 degrees above the horizon in the West.
I don't think a good shot is possible.
For Melbourne, perhaps something over the water in Port Phillip Bay might work, trying to miss the distant light pollution, but it's very tight: little time after sunset, low position, framing, etc ......

Best
JA
Reply With Quote
  #16  
Old 25-11-2020, 11:05 PM
alpal's Avatar
alpal
Registered User

alpal is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 3,602
Quote:
Originally Posted by JA View Post
For Melbourne, perhaps something over the water in Port Phillip Bay might work, trying to miss the distant light pollution, but it's very tight: little time after sunset, low position, framing, etc ......

Best
JA



You'd get it but it would just be 2 blurry blobs.
They are not close enough to be magnified in the same frame.
Maybe I should post a Stellarium picture?
Reply With Quote
  #17  
Old 25-11-2020, 11:15 PM
JA
.....

JA is offline
 
Join Date: Oct 2016
Location: Melbourne, Australia
Posts: 2,945
Quote:
Originally Posted by alpal View Post
You'd get it but it would just be 2 blurry blobs.
They are not close enough to be magnified in the same frame.
Maybe I should post a Stellarium picture?
Not that I'm planning to image it but I too did look at it in Stellarium as part of this discussion. I could get them in the same frame at about 0.2-0.3 arcseconds/pixel (or was it 0.5?) using a bit of this and that. Now I'll need to go back and look again.

Best
JA
Reply With Quote
  #18  
Old 25-11-2020, 11:18 PM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Location: Lake Macquarie
Posts: 7,033
Folks go back to the 17th when they are higher in the sky around 8:30pm, certainly dark enough then. Forget the actually conjunction event, and be satisfied with very close.
Reply With Quote
  #19  
Old 25-11-2020, 11:20 PM
pmrid's Avatar
pmrid (Peter)
Ageing badly.

pmrid is offline
 
Join Date: May 2008
Location: Cloudy, light-polluted Bribie Is.
Posts: 3,665
Quote:
Originally Posted by alpal View Post
Just checked on Stellarium -
the event is only 7 degrees above the horizon in the West.
I don't think a good shot is possible.
I had a look at SkySafari for Frankston on the 21st December at 7.30 pmand it shows Jupiter at 23degrees plus and 12 degrees at 8.30. Still doable.

Peter
Reply With Quote
  #20  
Old 26-11-2020, 07:39 AM
doppler's Avatar
doppler (Rick)
Registered User

doppler is offline
 
Join Date: Nov 2012
Location: Mackay
Posts: 1,656
Here's a quick overlay to show the separation compared to the moon at the same fov. And one of the moon saturn conjunction from 2019. Detail would be possible with the right exposure.
Rick
Attached Thumbnails
Click for full-size image (Untitled3.jpg)
172.2 KB91 views
Click for full-size image (moon saturn 2 nov19.jpg)
160.9 KB56 views
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 02:10 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement
Testar
Advertisement