Showing posts with label comet. Show all posts
Showing posts with label comet. Show all posts

Sunday, 12 July 2020

OT: Comet C/2020 F3 NEOWISE

click to enlarge
The image above shows comet C/2020 F3 NEOWISE, which is currently visible low on the northern horizon after sunset and before sunrise. From my 51 degree latitude, it is circumpolar, so visible all night, although very low in the sky. For the Northern hemipshere, this is probably the best comet since Hale-Bopp in 1997.

I took the image (or rather: images, as it is an image stack) last night around 00:58 UT (2:58 CEST) from Polderpark Cronesteyn on the outskirts of Leiden. It is a stack of 45 images of 0.6s exposure eacht, at ISO's 1600 and 4000, taken with a Canon EOS 80D + Samyang 2.0/135 mm on a fixed tripod (i.e. no tracking). The comet was only 8 degrees above the N-NE horizon at that time.

Apart from the bright bent yellowish dust tail, a hint of the straight, faint blue ion (gas) tail can be seen.

It was a very nice night (with owls calling), but a bit moist, with a carpet of low fog over the meadows. I had an USB dew lint and USB battery with me, and was glad I did. My glasses fogged over at times.

The comet is visible with the naked eye (even from my urban environment) with a few degrees of tail. It is impressive in 10 x 50 binoculars. the brightness is somewhere around magnitude +2.

The 2.0/135 mm Samyang turned out to be a superb lens for this comet, by the way. I am surprised by what I can achieve with it on this comet without a tracking mount.

Monday, 10 November 2014

Live blog from ESOC, Darmstadt: Philae (Rosetta) Landing on comet Churyumov-Gerasimenko:

 LIVE BLOG

 
I (am) was on-site at ESA's European Space Operations Center (ESOC) in Darmstadt for the Philae landing on comet 67P/Churyumov-Gerasimenko
This blog-post will be live updated as the events unfold. 
Be sure to hit refresh upon a new visit!
 I will also  be tweeting through @Marco_Langbroek)

15 Nov

01:45 The communications link has broken. This is it. Philae has gone to sleep, perhaps to never wake up again...or will it? So far it has kept amazing us all, after all...!

01:29 Philae has been switched into standby mode. All instruments powered off, but communications llink still active. Time to go to sleep now, brave little friend....

01:00 Battery power is dropping fast but Philae is not giving up! More and more data is being received. This is History written large, with a capital H. Truely epic science History!

00:28 Philae's rotation, over 35 degrees, was successful.
https://twitter.com/philae2014/status/533393729156308992

00:20 Philae is alive and the drill has worked! At the moment, they are trying to rotate the lander to get more sunlight on the panels. I think we can safely say now that nothwithstanding all that went different from what was planned, the mission has become a resounding success!

14 Nov

15:10 Brief recap of the Google+ briefing of this afternoon: Matt Taylor apologizes for #shirtgate. Contacts Rosetta-Philae are very stable. 80% of the most important science data from the first science sequence are now in. Rosetta has not imaged Philae on the surface yet, but there are still images in the pipeline and the search continues.  Holger Sierks suggests that in fact, they should have caught the lander just before touchdown at 500 meter above the surface, and during the first bounce in the images from the first two hours after touchdown, which have not been downloaded yet. These images should give the direction of the rebounce.
Lomatsch told that Philae has not moved at all since finally settling. Philae is in a difficult position however, surrounded by walls, limiting sunlight reaching the solar panels.From what she said, I get the impression that hopes for a lander revival once 67P/ is closer to the sun, should not be too high.
During the Q&A Ulamec indicated that it is unlikely that cometary jets will blow the lander from the surface as activity increases, as it has a too high density.
The DS2 drill is already extended 25 cm below base plate, but as there is a (scheduled) loss of contact right now, it is unsure whether it can/has reached the surface yet. New (and perhaps last) contact with Philae near 22 CET this evening. A command to go into low power mode did however not reach Philae, so it is going to get really close wether the next contact will be successful.


9:55 Philae's batteries will run out of power tomorrow. Coming night the operators will try to rotate the lander such that the largest solar panel will be facing the sun (via @elakdawala)https://twitter.com/elakdawalla/status/533179905610371073

4:55 Although it will be under "very risky conditions", SD2, the core drilling tool, will be employed. it will take subsurface samples that will be analysed by COSAC and Ptolemy, two instruments that o.a. look for organic compounds and determine the isotopic composition of water in the comet. The latter will yield information whether water may have been brought to Earth by comets.
https://twitter.com/rosettasd2/status/533056385819607040

00:45 MUPUS is communicating the first "science" temperatures (but not subsurface yet) https://twitter.com/philae_mupus/status/533040327058534400

13 Nov

23:25 After first attempt failed, second upload attempt of MUPUS commands succeeded!
https://twitter.com/philae_mupus/status/533021560593219584

21:58 The commands to deploy MUPUS failed to upload: https://twitter.com/philae_mupus/status/532998982193397762

20:55 Tonight the MUPUS  (MUlti-PUrpose Sensors for Surface and Sub-Surface Science) instrument will be deployed, for about 20 cm of its 30 cm length. The probe, which contains several temperature sensors, will be slowly hammered into the subsurface. The goals are amongst others to gather data on subsurface consistency, and a subsurface temoperature profile. It also provides calibration data for the thermal mapper onboard the Rosetta orbiter. 

    19:40 More details have been released. Philae bounced twice, at 15:34 GMT (first contact of lander with comet) and 17:25 GMT, before settling on the cometary surface at 17:32 UT. It rotated around the Z-axis (the vertical axis) after the first bounce (this rotation was the first sign yesterday evening that the lander did not settle at first contact). It is working though, although there are indications that some of the solar panels are in shadow (perhaps due to a nearby boulder? [update: it's a cliff]). It hence does not have full power. 

    So that first bounce took two hours, while the second bounce appears to have been mild. As the harpoons did not work, Philae is not well anchored to the comet. This will interfere with some of the planned activities (e.g. coring the subsurface).

    See also: http://blogs.esa.int/rosetta/2014/11/13/philae-the-happy-lander/

    17:20 (This post comes belated as I am still travelling homewards...)
    ESA has released the first panoramic image by Philae. It is obviously a rather dark world out there... Of all the extraterrestrial landscapes imaged, I feel this one beats them all! This truely is a Primeordial world... (photo: ESA)



    16:30 (back on Dutch soil, but stil in the train) The place where Philae finally landed has been located. It is about 1 km offset from the original location. In the image below, the cross is the original landing site, the box where it finally ended up.


    (image: ESA)

    12:05 News now is that Philae is on the comet, but not anchored well. This means the coring of the subsurface cannot happen, which is a bummer. Still, no doubt much new scientific data will be gathered. Given that we knew this landing effort was very risky, we can say Philae is a big success anyway!

    I am at Darmstadt railroad station currently, about to return home to the Netherlands, so this will be my last blog update today for now.

    11:50 CET  Great news! Philae is alive and has send the first images of the comet' surface!
    below you can see one of the lander legs, and part of the surface. The image is a composite of two images taken by Philae's CIVA camera.



    Image : ESA


    12 Nov

    20:25 Gist of the press briefing: some data might indicate that Philae briefly left surface again after touchdown, i.e. it bounced and then settled again at a slightly different spot. Data need to be evaluated now. Next briefing is tomorrow 14:00 CET. No word about those images shown by the French...

    19:10 This is reportedly the first image of the comet's surface (but image is unconfirmed, at least it has not been shown yet here at ESOC):



    18:12 Ulamec just told reporters that a lot is still uncertain about the spacecraft condition and safety. Also said option to try to re-fire harpoons is risky, as the non-working gas thruster cannot produce the counterforce necessary. This mean the counterforce of (re-) firing the harpoons could result in Philae being ejected from the comet surface.

    17:42 Flight controller Geurts reports that the gas thruster indeed did not work, and that the anchors did not fire. Incredible that the landing nevertheless still seems to have been succesful!
    Geurts mentioned they might retry to fire the anchors.

    17:04 Philae has landed!!!!! They are receiving telemetry. Harpoon has been fired, landing gear is in. Its on the surface!!!!

    16:50 Nailbiting at ESOC!



    16:28 Touch down window has started.....fingers crossed!

    15:52 https://twitter.com/spaceflight101/status/532546694593126400 cool image of Philae on its way down as imaged by the Rosetta orbiter! note the three extended landing legs.
    Think about what this image exemplifies: To boldly go where no-one has gone before! Exploration!



    15:18 Image of Rosetta imaged by Philae has been shown now. Descend so far is "going as planned". Image is here:  https://twitter.com/esa_rosetta/status/532537918557265921

    12:33 Deployment of Philae landing gear confirmed.

    12:07 Datalink Philae-Rosetta confirmed! Datalink with both objects is healthy. This is an important moment! Over the next hours Philae data from the descend phase will be relayed to the control center. In about 5 hrs from now, Philae should touch down.

    11:00 My ESOC source tells me that for the cold gas thruster to work, a membrane was to be punctured. And this might actually have happened, but the returned sensor data that should confirm this was "contradictory". So the system might actually work, but it is not certain.

    10:20 First data relay from the still descending lander expected about 2 hours from now. Telemetry plus a picture of th orbiter seen from the lander. The lander will reach the cometary surface in about 7 hours from now. The big wait has started.....

    10:20 Dr Churyumov:


    10:04 Separation confirmed!!! Alea Jacta est, to quote old Julius

    9:50 Matt Taylor: "This is our Longest Day" 

    9:36 Separation of the lander is actually happening now, but we won't know for a while as it takes the confirmation signal 28 minutes to reach us

    9:30 The problem with the cold gas system means they have to land without it. This introduces the risk that the lander will bounce back from the cometary surface because of opposite forces when they fiire the anchor harpoon.

    8:15 We have a GO!

    8:00 CET - The go/no of last night has been delayed. The cold gas sytem of Philae has a problem. This cold gas drives the small thruster on top of Philae that pins the lander to the comet surface in the first few minutes.

    11 Nov - The go/no go decision of this evening has given a 'go' as verdict. Early tomorrow morning there will be a second, and last, go/no go moment.




     (player provides a live stream from ESOC by ESA)

    Monday, 15 September 2014

    Rosetta's landing spot. In 3D. Woah!

    image: ESA

    Put on your red-cyan glasses and take a look at the image above (high-res here on the ESA website). It is the chosen landing site of Rosetta's Philae lander on comet 67P/Churyumov-Gerasimenko. Woah!

    Sunday, 28 April 2013

    PANSTARRS and Polar Light - Finland, March 2013

    From 17 to 24 March I was in Finland, having fun in the snow at the Arctic circle. We stayed at Basecamp Oulanka at Juumajärvi, 66.26 N, from where we did snowshoe hikes, a husky sled tour, some cross-country skiing, and a trip to a world-famous bird shelter in order to see the Golden Eagle.



    Of course, when going to the Arctic circle you hope for Aurora Borealis - the Northern Lights. I had seen Northern Lights before, from the Netherlands (where it is rare but on occasion can be seen), and it was stunning. So my hopes were high for an even better Arctic display. In addition, comet PANSTARRS was slowly moving out of the solar glare around that time. My secret mission: to get an image of the comet with Northern lights.

    Mission accomplished, on the very first evening:

    click image to enlarge

    The photograph is a stitch of two images made with the EOS 60D and a Tamron 17-50mm at 17mm. It was made in late evening twilight of March 17th, the start of an evening with incredible Northern Lights. An M1-class solar flare on the 15th resulted in an earth-directed CME which arrived at the 17th - our first evening in Finland. The result: astonishing Aurora all over the sky, with two especially intense periods between 20-21h local time and around local midnight. The first peak was very colorfull, with a.o. deep purples in addition to green. During the second peak near midnight, it was mostly green Aurora It was very lively, significantly changing on sub-second scales. Rays, dancing curtains, multiple corona's, it was all visible. Seeing Northern Lights in Orion was quite special too.

    This all with friendly temperatures of -25 C... As I repeatedly worked the camera with my gloves off, my fingers got numbed, resulting in some images later that night where the camera had moved during exposure, because I hadn't thightened the clampscrews of the tripod head enough. I also used one of my woolen gloves to put the Aputure timer in, as the batteries suffered from the cold. The camera itself help up remarkably well though.

    During the first peak I took pictures from the nearby lake Juuma: during the second peak I photographed from the basecamp itself, using the wooden chalets to create some scenic foregrounds. Lenses used were a SamYang 3.5/8mm semi fish-eye, and the 17-50mm Tamron. Here are some pictures (exposures range from 2 to 10 seconds:

    click images to enlarge










    I took a number of series for a time lapse, resulting in this movie (put it on HD and full-screen: it is 1200x800 pixels):


    As it turned out, that night was the only night with aurora that week - but what a splendid show it was! The local Fin people claimed it was the best show of the season.

    The next evening, I targetted comet 2011 L4 PANSTARRS in evening twilight, using the Zeiss 2.8/180mm. The following image is a stack of 9 images of 1s each, taken from an unguided stationary tripod:

    click image to enlarge

    Just before leaving for Finalnd, I already had some views of the comet from (near) my home town Leiden in the Netherlands as well. This image was shot on March 12th from the Cronesteyn polder just east of Leiden:

    click image to enlarge




    After I returned from Finland, I took a last picture of the comet in the evening of April 2nd, when it was close to M31, the Andromeda Galaxy. This image is a stack of 21 images of 1s each taken with a SamYang 1.4/85mm at F2.8. I had to do quite some image processing, as the images were suffering from light pollution:

    click image to enlarge

    Wednesday, 31 August 2011

    OT: comet 2009 P1 Garradd with the new 1.4/85 mm lens (updated)

    Yesterday evening (30 Aug 2011) started reasonably clear, so I set up the small Meade ETX-70, put the Canon EOS 450D with the new Samyang 1.4/85 mm lens piggyback on it, and made a series of images of the Sagitta-Vulpecula border area, where comet 2009 P1 Garradd is currently located.

    Sky conditions were variable. Out of 97 images (of 10 seconds exposure each), I selected the 34 best for the stack below. The comet (small, but with a clear tail) is in the center, parts of Sagitta with M71 are at left, the "coathanger" cluster is at right:

    click image to enlarge


    A detail of the image at full pixel resolution:

    click image to enlarge

    Tuesday, 24 February 2009

    Comet C/2007 N3 Lulin from Leiden

    The weather is horrible these days, so I was much surprised by short clearings developing around local midnight last night. These allowed me a short peek and photo session on comet C/2007 N3 Lulin.

    In the ETX-70 (small 7 cm refractor) at 14x, visually the comet was a nice fuzzy ball with a tail in NW-SE direction. Easy to find, especially as it was only a few degrees from Saturn.

    I had only a short window of opportunity to photograph the comet before clouds came in again. Below image is a stack of 24 x 10 second exposures, made with the Canon EOS 450D (@800 ISO) and EF 50/2.5 Macro lesn (@ F2.8) between 23:18 and 23:26 UTC (23 feb).

    Note that the conditions were far from perfect: not the best of skies, the comet low in the sky (35 degrees), and in the middle of Leiden town! So I am happy with the result.

    (click image to enlarge)

    Monday, 31 December 2007

    Comet 17P/Holmes coma now over 5.5 million km wide: 4 times size of the sun!

    Using my photograph of the 29th, astrometrically measured with Astrorecord, I updated my diagram of the growing size of comet 17P/Holmes' coma.

    The coma is now over 5.5 million km wide. That is 4 times the size of the sun!

    Sunday, 30 December 2007

    Two comets in one picture

    After a week of clouds, the 29th December was a clear day. So in the evening I took the opportunity to bicycle 25 minutes to my dark spot "De Wilck" (Cospar 4354) a few km outside the town, with my new small portable Meade ETX-70 rich-field telescope.

    The goal: getting some pictures of comets 17P/Holmes and 8P/Tuttle with my small Canon Ixus compact camera piggyback on the telescope.

    I managed to shoot a nice picture showing both comets in one wide-field image, with the galaxies M31 and M33 as a bonus. It is shown below: it is a stack of 8 photographs exposed 15 seconds each.

    (click image to enlarge)


    I also made a series of images of 17P/Holmes with the Ixus zoomed in at maximum. Unfortunately, after 13 images the battery of the camera was empty. Below is the stack of these 13 photographs, exposed 15 seconds each with the ETX-70 as guiding scope:

    (click image to enlarge)

    Tuesday, 4 December 2007

    Comet 17P/Holmes, 3 December

    Yesterday evening saw very dynamic weather, with the sky changing from open to overcast and back to open again in matters of minutes. During the short clear periods, the sky was however very transparent.

    Comet 17P/Holmes was easy to see with the naked eye, as a large diffuse cloud somewhat to the right of alpha Persei.

    Between 23h and 0h local time I managed to shoot 40 photographs of 5 second exposure duration each. The stacked result of these photographs is below (Canon Digital Ixus 400 compact camera on fixed tripod):

    (click image to enlarge)


    I revised my series of coma diameter measurements. I had been measuring astride the nucleus, but as the position of the nucleas grew more and more a-centric, that no longer resembled the largest coma diameter (perpendicular to the outflow axis, to avoid the tail). So I re-measured all images, this time determining he true maximum diameter.

    Revised diagrams are below. 17P/Holmes is currently some 3.7 million km large.

    (click images to enlarge)



    Friday, 30 November 2007

    Comet 17P/Holmes getting larger and larger

    Yesterday evening saw a period with clearings, which allowed me to photograph comet 17P/Holmes again. It is still visible by the naked eye, but less easy than 2 weeks ago (but still easier than M31). It is large now, going towards a degree (I measured a coma diameter of 50').

    Below is a stack of 71 images of 5 seconds each with my Canon Digital Ixus 400 pocket camera on fixed tripod, and the lens on maximum zoom (3x).

    (click image to enlarge)


    I again combined last evening's image with previous images, showing the growth of the comet in 3 weeks time:

    (click image to enlarge)


    It was still clouded during the LEO satellite visibility window, alas.

    Thursday, 22 November 2007

    Comet 17P/Holmes, 21.9 Nov 2007 (2)

    In my previous post, I posted a 29 image stack of comet 17P/Holmes. I took 46 images that night but the software couldn't handle more than 29.

    Using other software that can handle all 46 images, I get the result below, going deeper and showing the comet better:

    (click image to enlarge)


    I used the earlier 29 image stack to make a comparison again with images obtained the previous two weeks. This again illustrates nicely the clear expansion of the comet during these two weeks:

    (click image to enlarge)

    Comet 17P/Holmes, 21.9 Nov 2007

    Yesterday evening it unexpectedly cleared. A bright waxing gibbous moon was in the sky, but nevertheless I managed to obtain a fine image of comet 17P/Holmes again. Visually, the comet was still visible by the naked eye, but less easy than previous due to the moonlight.

    From the image obtained, I measured the coma to be 34.0' wide (that is more than an apparent moon diameter) at 2007 Nov 21.90. This corresponds to 2.4 million km in reality.

    Below is the image obtained. It is a stack of 29 images of 5 seconds exposure each, taken with my Canon Digital Ixus 400 pocket camera at maximum zoom (3x) on a fixed tripod. Below the image are the updated size diagrams.

    (click image to enlarge)





    Sunday, 18 November 2007

    Comet 17P/Holmes over 2 million km large now

    Another clear evening yesterday, so another photo-shoot on comet 17P/Holmes. It is still an easy naked-eye object even from the center of Leiden town, visible as a small cloud next to alpha Persei.

    Compared to two nights ago the brighter inner part of the coma has now elongated and bifurcated. Below image is a stack of 29 images of 5 seconds each, taken from a fixed tripod with the Canon Digital Ixus 400 at maximum zoom (3x):

    (click image to enlarge)



    The bifurcation is more readily apparent in this false-colour version of the image:




    A wide-field view ( a stack of 9 images of 10 seconds each) taken with the Ixus:

    (click image to enlarge)



    Using ASTRORECORD I measured the coma size on the zoomed image to be 29.0' (Nov 17.97), corresponding to 2 million km in reality:


    Friday, 16 November 2007

    "Follow that comet!" (updated)

    Yesterday (Nov 15-16) around local midnight it cleared again, and with comet 17P/Holmes in the zenith this meant some nice photographic results again.

    The comet is still growing in size, the growth being virtually linear. Yesterday (Nov 15.98 UTC) it was 25.8' large, as measured with ASTRORECORD.



    Size measurements like these can be used to calculate the true size of the cometary coma in kilometers (that's a fairly easy calculation actually, as the distance to the comet is known). This is the result:



    University of Hawaii astronomers recently used a 3.6 meter telescope do determine a size of just over 1.4 million km on Nov 9th: as can be seen above, my simple Ixus camera does the job as well as the 3.6 meter telescope in getting a similar size result ( I marked the Nov 9 size as I find it in the diagram with red lines).

    Below image is the image I took last night (stack of 25 images of 5 second exposure each with the Canon Ixus at 3x maximum zoom), with parts of earlier images taken Nov 7 and Nov 11 put in at the corrects scale, position and orientation.

    (click image to enlarge)


    Below image shows a wide-field view. It is a stack of 7 images of 10 seconds each with the Ixus.

    (click image to enlarge)

    Monday, 12 November 2007

    Continued 17P/Holmes coverage

    Short but bright clearings between hailshowers late last evening allowed me to image comet 17P/Holmes again. It still is a naked eye object, and still growing rapidly. It was notably larger yesterday than 4 days before.

    Below is a stack of 16 images exposed 5 seconds each with the Canon Digital Ixus 400 on a fixed tripos and maximum optical zoom (3x):

    (click image to enlarge)


    A false-colour version of this image draws attention to a slightly curved jet of gas flowing outwards (direction to the lower right in the image), and the egg-shaped coma (hint of a tail onset) that is the result:

    (click image to enlarge)


    Below, I have combined last evening's image with that taken 4 days earlier, to show not only the movement but also the visibly growing coma diameter in these 4 days time:

    (click image to enlarge)


    Next I used ASTRORECORD to measure the size of the coma on both images (these sizes were taken at an angle perpendicular to the sun-comet line). As the distance to the comet for these two dates is know, this allows a calculation of the actual size of the gas coma in km/miles. Last evening, this was 1.6 million km, or 1.0 million miles, growing at a rate of about 55 000 km/day or 2000 km/h:

    date___________ _size____true size (km)__ _(miles)

    2007 Nov 7.96___19.6’__ 1.380 million___0.862 million
    2007 Nov 11.90__22.6’___1.599 million___0.999 million