Imaging the Jupiter Saturn conjunction

[pmrid]

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

[doppler]

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

[glend]

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).

[pmrid]

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

[multiweb]

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.

[glend]

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.

[pmrid]

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

[doppler]

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

[Tinderboxsky]

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.

[glend]

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.

[rustigsmed]

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

[multiweb]

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.

[alpal]

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.

[pmrid]

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

[JA]

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

[alpal]

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?

[JA]

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

[glend]

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.

[pmrid]

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

[doppler]

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

[alpal]

I've got some Stellarium screenshot pics here.
You can see at 7.30 pm = 19.30 hours that
Jupiter is well above the horizon in daytime +35 degrees.
The second picture shows that the conjunction
is close to the horizon at 21:57:43 when there is actual darkness.

7 degrees elevation is highlighted in yellow.
The last picture is a close up.

[pmrid]

That definition of astronomical twilight - 18 degrees below the horizon is discouraging for sure and even nautical twilight as 12 degrees is to a degree. But with such an event as this, you just have to try and make the best of the situation on the day. As has been suggested, it might be worth doing some images a few days before - the separation is not a5 its minimum but seeing should be better. I’m going to try.

[glend]

The ABC is promoting the Grand Conjunction:

https://www.abc.net.au/news/science/2020-11-27/jupiter-and-saturn-in-a-once-in-a-lifetime-grand-conjunction/12895088?nw=0

[sn1987a]

28" f4 Dob, TV EPs and iPhone 8 standing by :P

[N1]

Jupiter is a daytime object, pretty sure Saturn will be visible next to it around sunset at the latest. I remember a thread where someone imaged Jupiter while the sun was up and somebody else asking what the point was of doing that...well, here were are

[glend]

I have observed Saturn conjunction with the Moon during the daytime, it is certainly possible to image it, but I would suggest a Red filter to enhance the contrast and reduce the brightness of the sky.

[pmrid]

The forecast from BOM for the 17th is grim. Heavy rain, flash flooding .... It doesn’t go as far as the 20th and 21st yet, but I am not very hopeful ATM.

[glend]

At least you can fly interstate now to escape the Qld summer.:welcome:
The hills around Coonabarabran NSW would be a great vantage point.

The next Great Conjunction is in March 2080, if you would prefer waiting.

[pmrid]

The next Great Conjunction is in March 2080, if you would prefer waiting.[/QUOTE]

Nah, the long-range forecast for 2080 is equally grim.

[rustigsmed]

Nah, the long-range forecast for 2080 is equally grim.[/QUOTE]

:lol::lol:

[glend]

There are a few random threads about the forthcoming Grand Conjunction. One of these has been discussing the luminosity differences between Jupiter and Saturn and how to image in that circumstance.

I was prompted to do some research, and found that this was also being discussed on the Cloudy Nights forum, so I am including a link to a CN thread that discusses filter options, and processing:

https://www.cloudynights.com/topic/743030-advice-needed-for-imaging-jupiter-saturn-conjunction/

Might be worth following their preparations.

[pmrid]

Thanks Glen.

[multiweb]

Clear skies is going to be the biggest challenge by the look of it. Lots of clouds and rain in the forecast. Driving to a sucker hole sounds like the only viable option but even that is like trying to find a needle in a haystack on the east coast. :cloudy::windy:

[Saturnine]

Sunday evenings cloud map on CFN is showing a definite maybe for a break in the clouds. Monday evening looks hopeless, the day of closest approach but the difference to the Sunday is not that much so may be the likely option.

[multiweb]

The maps are GFS. Still Sunday looks better than Monday or Tuesday in the various forecasts. Fingers crossed.

[doppler]

I've taken some test images and I think the biggest issue will be atmospheric turbulence. I think the best images will be taken early while Jupiter and Saturn are still reasonably high, even though the sky might not be very dark.
Rick

[pmrid]

You’re right, of course. But the difference between 14 and 18 degrees will be more apparent than real, I think. I’m setting up to image on Sunday night when the forecast is a little less gloomy. Not perfect but better than nothing. Remember the adage “The perfect is the enemy of the good.”

[pmrid]

Crikey this weather is a challenge to sanity! Forecasts swing from hour to hour almost. CFN has just squashed my good intentions for tonight but revived my hopes for tomorrow night. I will need a bit of psychiatric help by the time this is over.

[Sunfish]

Looked like a window here on sunset but that window has closed now and the prediction changed. My sister tells me it is sunny and clear on Bribie today..you might be lucky.

[pmrid]

Nope. 100% cloud by 6.30 with lightning building to the west. Prognosis for tomorrow no better.

[Sunfish]

We were teased by perfectly clear sky south of the ecliptic (oops) at 8 pm. But total cloud North and just covering the planets. Maybe a glimpse on Wednesday night.

[Simon-W]

Clouded out tonight, and I think for the rest of the year :-( But managed to get some photos last night with Canon 6D and 500mm f/4Li


2 minute video of results (good to share with newbies, too): https://youtu.be/dHEPdzKOBDY


I also took test photos and also produced an annotated timelapse to help with twilight astrophotography this summer, made with photographinng comets and conjunctions in mind: https://youtu.be/r9HtdV2dLSo


Clear skies, safety and sanity!

[ezza]

I was unprepared, for the clouds to part tonight after days of rain/clouds here in Northern NSW. I did a quick setup with the 127 mak cass/EQ6 and S20 phone through a 32mm eyepiece to get this video; https://www.youtube.com/watch?v=-dSChFMB3No

[Andrew C]

Well done! How did you adjust the exposure on your phone? Can that be done for a still shot?

[ezza]

Hi Andrew,
Thank you! Yes you can adjust exposure, shutter speed, iso, focus, white balance, zoom, etc, with the S20. However, the still shots were fairly ordinary and I thought the live view video caught the event better. I used Pro video mode and adjusted the settings as I recorded the video, so easy. A camera with laptop would have produced a much better still shot.

[Andrew C]

Yes I've now discovered how to do it - simple when you know how. My still shot attached FWIW. Cheers269797

[dreamstation]

The missus took this photo with her phone up to the eyepiece when we got a quick look between the clouds. Shame it wasn't higher in the sky, there were no clouds up there!

[multiweb]

Nice one :thumbsup: