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Following JWST through Orion to L2

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Following JWST through Orion to L2

The James Webb Space Telescope is now scheduled for launch on Ariane 5 flight VA256 on Christmas eve at at 12:20 UTC.

Following launch it should be a relatively easy object for us to follow as it transfers to L2. The magnitude is a bit uncertain but Gaia was 10th magnitude on the first night after launch, fading to 18th mag 3 nights later and around 20-21 at L2. Gaia was particularly faint, WMAP and Planck were both between 18-19 at L2. JWST is much bigger than these so should be brighter but this will depend on the exact solar aspect angle and properties of the sunshield. It will be interesting to see how bright (or not) it is.

You can get an ephemeris from JPL Horizons. Just search for JWST and make sure to configure your observatory location since there will be considerable parallax early on. Attached is the ephemeris for my observatory (it is a text file, just change the ending to txt to view it). The first night after launch it has a very high apparent motion in Orion but should be an easy visual target. It stays in Orion until Jan 4 when it moves into Monoceros.

Please post reports and images on your members' page. Let's see how far we can follow it. 

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Good suggestion.

I will see what I can do, but as Tacande Observatory won't be back in operation until February at the very earliest it will likely take relatively long duration imaging. Gaia is still within range of my kit (must try for it one day) so JWST shouldn't be too much of a problem.

Thanks for suggesting this target!

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Excellent!

Nicely placed for observation from the UK then. I'm looking forward to imaging this.

How far apart will it be from the vehicle that launched it?

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It is very well placed for us

It is very well placed for us and everyone but that is not entirely a coincidence. It is going in the anti-solar direction and the launch is scheduled to avoid getting too close to the Moon. Winter is definitely good for us in the northern hemisphere since L2 is currently high in the sky.

There's not much detail available about what will happen to the cryogenic upper stage following JWST separation which occurs at around 30 minutes after launch. JWST is directly injected into a transfer orbit to L2 so the upper stage will probably be close by but it will probably do some form of deflection burn and JWST itself will do its first course correction at L+12.5h so the two will drift apart. There is another course correction burn scheduled for L+60h. I don't know how bright the upper stage will be but on the first few nights I would expect it would be detectable and fairly close to the spacecraft. I've imaged Centaur upper stages at ranges of more than 700,000 km and the Falcon 9 upper stage at 400,000km but the Ariane upper stage is smaller I think. The Centaurs also do propellant dumps which can be interesting to watch. I assume that the Ariane stage does something similar.

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JWST through Orion

 Thank you for the  heads up Nick.  The 26th looks an interesting point to start this imaging project. 

I  plan to get  some new reference images of  Orion's Belt using  a 85 mm F1.4 Samyang lens  for semi wide angle shots and also  some other  frames  of a narrower angle perhaps  the 500mm F 5.5 Star Sky  weather permitting  and  hopefully with the launch on  schedule and  clear weather   possibly spot the   JWST on the  images  as an interloper . . 

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JWST delayed

Unfortunately due to weather conditions the launch is delayed until at least Saturday and from what I have seen the forecasts for Korou do not look much better then. Not sure how this impacts where it can be seen. Bit of a shame with the rocket and satellite now ready the weather throws its usual spanner in the works.

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Since the launch window opens

Since the launch window opens at about the same solar time every day the chart should remain valid by just offsetting the dates, so, for instance, if it does go up on Christmas day then substitute 27.0 for 26.0 and so on. There will be an eastward drift of 4 mins a day in RA as well. In any case the JPL Horizons ephemeris will be updated to reflect the actual launch time.

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Jwst

Hopefully the weather will improve but the link below is to the NASA press release 

https://www.nasa.gov/feature/james-webb-space-telescope-launch-update

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JWST launch delayed

From a selfish point of view I welcome the delay in launching JWST, at least until there's a chance of any clearing in this interminable cloud cover to observe it. The JWST will get to L2 before I see any stars again...!

Alex.

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JWST

Just Wait, Still Terrestrial.

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No elements provided

When i enter the info asked for i get a load of stuff about JWST in red, but no list.  Is there a glitch with the system?

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Most likely you have a start

Most likely you have a start time set before the launch time. The last line of all those error messages is:

No ephemeris for target "James Webb Space Telescope (spacecraft)" prior to A.D. 2021-DEC-25 12:48:00.0000 UT

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Here is a revised chart for

Here is a revised chart for the current Dec 25 launch. You can see that it follows pretty much the same path, shifted around 4 minutes east a day.  

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JWST

Happy Christmas all! Fingers crossed that JWST launches without a hitch today, and that the whole sequence of further manoeuvres (and unpacking) goes as planned. The weather forecast for NE England over the next week shows a lot of cloud unfortunately. But I would love to image it whilst en route to L2.

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JWST

Now watching the pre-launch coverage on NASA TV...   :-)

Alex.

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JWST

It has just unfurled its Solar array great launch

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JWST

3 minutes early...

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It was great to see the solar

It was great to see the solar array deployment live via the upper stage camera. The launch certainly added some excitement to Christmas lunch and the Ariane 5 performed very well. Now, if only we could get a clear patch between the torrential rain...

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Denis Buczynski (Tarbatness)

Denis Buczynski (Tarbatness) managed to get the spacecraft tonight at mag 12.3 which is a bit fainter than I expected. Luca Buzzi reports via MPML that the upper stage is around the same magnitude and about half a degree west of the spacecraft. There will probably be a significant effect on the magnitude when the sunshade gets deployed. Total washout here.

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JWST

The Launch certainty added a new dimension to cooking Xmas lunch, dashing between  Kitchen and  Nasa TV on Computer.

Its  the best Xmas present the Astronomical Community could wish for  lets  hope that it continues to deliver its potential as it  slowly   deploys.  

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Denis managed to get another

Denis managed to get another image of the spacecraft last night at around mag 14.5. I've had no luck since the weather has been cloudy here and all of the iTelescope systems that I have tried to use have had "roof closed" even when the all-sky camera showed clear sky.

The Horizons ephemeris is good for the spacecraft. There has been quite a bit of amateur astrometry of the upper stage and you can get an ephemeris of that from Bill Gray's artsat ephemeris page here.

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In Orion

The HB front cover of Constellations & How To Find Them (W. Peck) indicates the direction of JWST. Follow church spire up a bit and there it is.  The only imaging i've done in 10 days ! 

Edit: Congratulations to Denis for some fine images on successive days, and good news (on 30th) that fuel reserves are greater than expected due to the excellent  Ariane launch profile.

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Paralax

I see on Denis's images that JWST is about 3' arc North of the HORIZONS position at my location in Oxfordshire.  This is what my college maths gives me:  (300/350,000) x 57.3 x 60  = 2.9'   ( Denis is 300 miles north of me). I don't expect any prizes, but its good to exercise the brain cells from time to time.

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JWST last night

I acquired a set of frames last night: 2021-12-29T21:17:18 - 2021-12-29T21:25:46

Really pleased to get it, as the weather here (for astronomy, anyway) has been so poor.

https://1drv.ms/v/s!AmVPu5waSVQujUm14QmkUhMqHGiZ?e=ccmLJi

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David - well done. Still no

David - well done. Still no opportunities for me! It looks as if the complex deployment is going very well (https://blogs.nasa.gov/webb/).

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Weather

Same in Wiltshire. Impressed by the Highlands having 4 clear nights in the last week when we cannot manage 1.

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I got images of the JWST

I got images of the JWST spacecraft (2021-130A) and the Ariane upper stage (2021-130B) last night. They are currently around 2 degrees apart on the sky. JWST is much brighter tonight as the sunshield was being deployed. The magnitude was 14.3 at a range of 687,000 km. From the timings in the NASA blog I think that the sunshield was half out when this image was taken but this implies a magnitude of around 16 or so at L2. Astrometry of the upper stage is valuable since it is not being tracked by radio and I assume it is now passive.

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Starboard deployed

No clear night here in 2 weeks.

I think the blog now says the starboard boom is out and the tensioning of the sunshield will begin.

Your JWST mag report is very hopeful for getting images at L2.

What mag was the rocket body? Can I assume that won't reach even a semi-stable orbit and will quickly drift away? Might be an interesting observation target for a while.

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JWST upper stage

Grant, The upper stage was 16.5 last night. It will be passive now so optical astrometry is useful to determine where it is going. JWST will be injected into a halo orbit around L2 and will require periodic station keeping to keep it there. Since L2 is unstable the upper stage will move off into a heliocentric orbit with a period of around 380 days. Using astrometry from Peter Carson and myself I've integrated this forward and it is likely to return to the Earth's vicinity in the summer of 2047 when it will be around mag 20 (see plot attached). The more accurately we can get astrometry as it departs the better we can predict where it will be in 2047 so surveys in 25 years time will know what it is.

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JWST again

New Year report from Tynemouth: windy conditions, with clouds scudding across the sky. JWST is still within reach of moderate equipment: I am able to pick it up on individual 10 second frames taken through an 8 in RASA. Frame 5 start 21:35:26; frame 67 start 21:45:57. I have enough frames to make a reliable (I think) estimate of brightness - I'll plate solve and find some suitable comparison stars.

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Mag 14.5 at 800,000km with sunshield fully deployed

Nice image David. As of tonight (Jan 2) with the sunshield fully deployed but not yet tensioned JWST was mag 14.5 at a range of 800,000km.  When it gets to L2 it will be twice as far away (1.5 million km) so probably around mag 16 although this will strongly depend on the solar aspect angle. That is 4-5 magnitudes brighter than Gaia.

The Ariane upper stage was magnitude 17.4 tonight at 890,000km. At this rate it will drop below mag 20 in early February when its range exceeds 2.5 million km.

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Webb Captured New Years Eve & last night.

Thanks to Nick posting details about this, I have managed to catch Webb on two nights so far:
www.star-gazing.co.uk/blog

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Tracking

I asked Jonathan McDowell about the value of tracking the Ariane for as long as possible.

He responded that it would be very useful to get as good an orbit as possible so that it can more easily be recovered when it returns to this neck of the woods in 2047.

The astrometry is being co-ordinated by Bill Gray at http://projectpluto.com and I urge anyone here, especially the asteroids people, to follow it as long as possible.

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JWST

I caught the JWST last night and made the video linked below, after reading on here that the Ariana upper stage was still visible I checked and I think I have that as well. Could someone confirm this please, it is brighter and slower than the JWST but definitely traveling in a similar orbit.

Thanks Mel

https://youtu.be/j1fP9IMw9cE

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Hi Mel,

Hi Mel,

I've looked at your YT video and haven't been able to ID the field yet and have to rush off to work now. I'll have another look when I get in tonight. To help confirm that you have got JWST I attach an image I took just at the start of your set  (Jan 4 at 22:29). The trail of JWST is marked. The upper stage is around 3 magnitudes fainter than JWST and around 2.5 degrees west of it so your other object is not the upper stage. I can probably identify it if you let me have an accurate position.

You can get an accurate ephemeris of both JWST and the upper stage from here:

https://projectpluto.com/sat_eph.htm

This is based on amateur astrometry of both objects and is pretty well up to date.

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JWST

Hi Nick

Thanks for your help, your image does agree with mine so JSWT confirmed. The second objects position at approximately the same time was RA 06h 30m 27s DEC +00° 50’ 05”  as you can see from the video it’s travelling in exactly the same direction and line as the JWST but quite a bit slower.

Mel

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JWST

Hi Nick

Here‘s an image covering the object and JWST if it helps.

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JWST

Hi Nick

Just been checking myself and I think it’s an asteroid -

(787) Moskva is a 13th magnitude Asteroid appearing in the constellation Monoceros. It orbits the sun every 4.0 years at an average distance of 2.5 AU. It is a main belt asteroid which orbits the Sun between Mars and Jupiter.

(787) Moskva, a small asteroid, is roughly 27 kilometers across.

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Yes, it looks to be 787

Yes, it looks to be 787 (Moskva). Well done spotting it. As you've confirmed you got JWST as well.

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JWST 05/01/2022 Variation in brightness

I imaged JWST on 05/1/2022 for just over an hour and in that time its brightness seemed to vary quite a bit as seen in this stack:

This graph shows the brightness of JWST over the period compared to 3 other field stars of similar brightness

I was wondering what caused this variation because I assumed the spacecraft is not rotating and that the change in viewing angle over this time period would not be that great. 

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That's a really nice

That's a really nice observation. If you look at images of JWST you can see that we are mainly seeing the 21x14m sunshield but there is other stuff on the sunward side of the spacecraft including the solar panel and the spacecraft bus and propulsion units. Some sunlight will be scattered back to us from these other components but there will be strong glints from the sunshield which will be highly dependent on the relative angle between the sun and the observer. Given JWST's configuration even small changes in this angle will make a significant change to the magnitude we see.

When the telescope is operating at L2 it is in a large radius halo orbit and the attitude will change for each observation since the telescope and sunshade are fixed to each other. It will be an interesting project to try to predict when glints would occur given the target list that the telescope will be aimed at.  

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JWST brightness

Thanks Nick,

As you say maybe the sun / telescope / observer angle doesn't have to change much for a big variation in brightness given how shiny it is. 

It will be an interesting project to see if glints are predictable. I previously did some work predicting glints from classified satellites with some success. The calculation is basically a whole load of co-ordinate transforms. 

Cheers

Phil 

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JWST brightness

Hi Phil,

This posting on the MPML forum (Archive visible to all) confirm its changes in brightness

JWST 095 Observations (groups.io)

After observing other targets last night I had a look at JWST to get some video astrometry. By then thin cloud was coming and going. I haven't reduce my data but at Jan 7.903472 it was near to mag 15, but a while later at 7.905556 it looked to be around mag 14.5.

Cheers,

Alex.

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JWST first light

JWST first light...

This tongue-in-cheek image has been doing the rounds

Originally a bit of fun by ESA staff for an earlier mission

https://twitter.com/esa/status/1479405861130977280/photo/1

Alex.

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All deployed

The entire deployment sequence seems to have gone without a hitch with both folding sides of the primary mirror now locked in place. That is pretty amazing given the complexity.  

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JWST deployment

I've been following it closely: yes, quite amazing.

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moving parts

Phew! Now lets hope all the 126 actuators which align the mirror segments work ok. The number of moving parts in the instruments is mind boggling too.  NIRSpec apparently has a matrix of a quarter of a million focal plane "microshutters"  

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I know some people are still

I know some people are still attempting to image both objects. The ephemerides available from Project Pluto are still good but the magnitude of the upper stage was quite faint last time I imaged it on Jan 12.9. It is around mag 19 at the moment. The magnitude of JWST is highly variable depending on the precise orientation of the spacecraft.

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JWST brightness

Further to my earlier observation of JWST I did a follow up observation last night (14/01/2022). Interestingly the brightness followed exactly the same curve as on 05/01/2022. In the graph I have plotted the two curves together to do this I time shifted the data for 14/01/2022 by 9d 1.173 hours which gave the best alignment. The 2 additional spikes in the data for the 14th were also seen by a friend who observed on the 12th. So it seems the pattern repeats on a daily basis. What this means for the movements of the spacecraft or the angle of illumination is an interesting question!       

                                                                              

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Phil - That is a really

Phil - That is a really interesting observation.

I assume at the moment the spacecraft attitude will be quite stable. I don't know whether the solar array can be steered to some extent relative to the bus but for now I would guess that they are keeping the spacecraft sun-pointing although I don't know that for sure. If that is so then the brightness variations will be due to the phase angle (i.e. sun, spacecraft, observer). The repeatability here implies a diurnal variation. At the current range (about 1.2 million km) the Earth has an apparent diameter of 0.6 degrees so the effect of parallax on the phase angle is very small although certainly large enough to affect the timing of specular glints depending on where you are.

It would be very interesting to get two observers separated by a long baseline to do photometry at the same time. I suspect that they would see quite different profiles.

Once JWST goes operational the spacecraft attitude will be continually changing depending on the target so these glints will become much more (apparently) random.

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I'll be talking about JWST at

I'll be talking about JWST at the meeting tomorrow. If you have any recent observations please let me know by tonight. I got some astrometry of the Ariane upper stage a couple of nights ago and it is now around magnitude 19. The observatory was mag 16. Everything seems to be going very well with the mission so far.