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mike harlow's picture
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Spectrum

Hi Robin,

I did try a transmission grating spectrum this morning just for fun. Maybe shows the image of the tail in sodium light???  A bit faint but I'll try again next time I get the chance.  Larger image on my members page,

Mike.

Details: Thor labs 300l/mm transmission grating in front of 55mm lens on un-modified Canon 550D DSLR.

Robin Leadbeater's picture
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little orange comet

Hi Mike,

Yep definitely a little orange image of the comet complete with tail in the spectrum there. 

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Great images

Cracking images everyone.   For once I'm quite excited over a comet!

Gary

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Steady on

Steady Gary. 

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C/2020 F3 (NEOWISE)

Here's my attempt.  Simple capture with Canon SX50

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Attachment

Hi Brandx. You might have uploaded the image to the site, but not embedded it into your post. You can also just attach the image file.

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Lovely Comet, nice ion tail

Here is one of my stacks from Friday/Saturday night - I went out with a few friends and we observed from dusk 'till dawn.

 

full image on my members page https://britastro.org/profile?id=7740

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C/2020 F3 on night of 11/12 Jul

A fantastic observing opportunity last night. Clear throughout.

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nickjames's picture
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Fantastic images

David. The shot with the low-level NLC is wonderful. Get it printed and framed and hang it on the wall!

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F3

Yes. I do really like that pic. The Sony 85mm FE lens is very good. The other image is APS-C crop and digi zoom!

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2020 F3 NEOWISE

This morning's pics. Moon less of a problem. Some cloud at first. Another nice view in 10x50s. 10 sec shot with 50mm f/1.4 on a fixed tripod in the farmer's field. 12 stacked for highly stretched second image. Horrendous grunting/howling noise throughout the session from the direction of the Moon.....Only sheep (as far as I know) in that direction but it sounded like an angry wildebeeste heading my way..... As soon as I had finished I got the hell out of that field ASAP....

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F3

Good capture of both tails, Martin.

dgs
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Alpy spectrum last night

Caught this spectrum of the comet this morning showing bright Sodium line, C2 banding and I'm guessing CN emission on far left? 20 x30s with ASI 183mm and Alpy (binned 2x2 at 2.5A/pixel).Taken with 50cm f/4 Connaught Dome at NLO.

David

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About 23:00 BST last night

About 23:00 BST last night (11/07/2020).
Comet C/2020 F3 NEOWISE, Canon 7D Tamron 200-600 at 200mm, f5, ISO800 on a fixed tripod.

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Comet Neowise

I got a few photos around 11.30 pm and again just before 3 am.  The proper motion of the comet is visible by comparing the position of a star near the tail in just a few hours.

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Comet Neowise

Second Photo around 3 hours later

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djswan2002's picture
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Greater FL but brighter sky

I wanted to enjoy the comet through binos - and I did, so I didn't take the scope out. But on getting home I noticed the comet was accessible from my yard. Here's a single 500ms frame taken with the Hyperstar. A very bright sky at 0247 BST, but you can nonetheless make out the bifurcation of the tail clearly (no calibration performed - I would need a new set of calibr frames for these settings!)

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Using ETX 105

As an experiment I tried to image the comet through an ETX 105 with a Canon D550 (12th July 2020 at 01:54UT).  As there was no tracking, I had to keep the exposure short at 2s and used a high ISO at 6400.  It does show some structure, a bit like, but not a good as, Paul Able's drawing from yesterday at https://britastro.org/node/23148.

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a couple of time lapse videos of the comet

Here are a couple of time lapse images of the comet. 

https://www.youtube.com/watch?v=NpVRDDABx7s&feature=youtu.be

https://www.youtube.com/watch?v=GdoG84oF4vs&feature=youtu.be

Does anyone know how to calibrate RAW files and save as RAW or tif? All my software saves them as FITS which are no good for creating time-lapse videos. Or how to batch convert fits to tiff or jpg?

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Handling image series

I'm assuming you are looking for freeware or something not too expensive. Have a look at PIPP.

https://sites.google.com/site/astropipp/

Maxim does this sort of thing, but it is expensive.

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Ah - I have PIPP didn't

Ah - I have PIPP didn't realise it did this :-) thanks!

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Linux tools

I use dcraw, Imagemagick and ffmpeg under Linux for batch manipulation of images including camera raws and generation of videos. Not sure if they are available in the Windows world. 

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Thanks I'll give them a go,

Thanks I'll give them a go, ffmeg I've used for video, I didn't realise it handled FITS as well.

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ffmpeg doesn't handle FITS

ffmpeg doesn't handle FITS directly but convert (one of the command line utilities in the Imagemagick suite) will convert from FITS to any common graphic format and can stretch, crop, etc. in the process. Being command line programs they are easy to script in bash or whatever and mean that you can make timelapses very easily from raws or FITS.

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Photo from Sandwich (Kent)

Observed from 21:15-21:45 UT. Strong twilight. Comet picked up in 15x70B at 21:25 UT.
Naked eye with averted vision at end, despite very low altitude. Decent tail ~2deg.
Mag and coma estimates impossible due to strong twilight and no comp stars.
Glad to have photo. Taken at 21:45 UT. 50mm f/5.6 6s ISO 400.

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C/2020F3 (Neowise)

Third consecutive night that comet was visible.  2020 July 12/13 (Sunday night) it is still easy naked eye but tail seemed shorter tonight but also possibly broader.  Tail more like 3 deg in 10x50s.  Possibly also fainter overall but some haze in NNE so difficult to be sure.  Moon seemed much more of a problem tonight (Sunday night) than on Saturday night although Milky Way still naked eye through Cygnus.  Still a great sight and enjoyed showing it to a neighbour. Observed from 00:15 to 01:30UT.

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I shouldn't say this but I'm

I shouldn't say this but I'm pleased it is cloudy tonight with a prospect of rain so I can get some sleep. I was a bit of a zombie in work today after three consecutive all night sessions.

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2020 F3 NEOWISE

Similar experience to Stewart. Third consecutive night. Observed before midnight UT to take the pics just before moonrise. Comet looked a bit weaker, but may have been poorer transparency, or even the sky glow from Bury St Edmunds (6 miles away) which is not far from the line of sight now...... Same procedure as before. Canon 300D + f/1.4 lens on a fixed tripod. 10 secs single frames and a 12 x 10sec stack... Observed with 10x50s as well. Could not see quite as much tail, possibly for the previously mentioned reasons.....haze, Bury St Eds glow.......  Grunting, bellowing animal of the previous night had gone....maybe someone shot it?

Martin

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Comet C/2020 F3 NEOWISE - Three tails?

My image from early Sunday morning shows the dust & ion tails and also hints of a red tail/region to the left of the blue ion tail. I've seen similar on a couple of photos on-line so it appears to be real and not a image processing artefact. Any ideas what this is?

Regard, Andy Wellington

PS, my first post on the BAA forum:)

dgs
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Beautiful image! I'm guessing

Beautiful image! I'm guessing it could be due to Na emission in the yellow?

https://britastro.org/node/23206

David

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Thanks David, it is most

Thanks David, it is most likely the Na line.

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Sodium or NH2 tail ?

There has been some discussions about this reddish tail on Cloudy Nights.

https://www.cloudynights.com/topic/716780-comet-neowise-high-resolution-...

I wondered about sodium but the neutral sodium tail seen with Hale Bopp fell between the dust and ion tails rather than at a larger angle as here. I am wondering if it could be from NH2, the emission bands of which fall in the red region of the spectrum. Perhaps some mechanism separating ions by molecular weight, CN, C2 being heavier ?

Robin

dgs
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That's interesting, the

That's interesting, the colour of this certainly looks redder than sodium. But I don't see much evidence of NH2 in the Neowise spectrum, but I guess most spectra have been centred on the nuclear region.

David

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Sodium tail

There's now a NEOWISE image showing  the sodium tail embedded within the dust tail.

https://psi.edu/news/neowisesodiumtail

This image  is close in though so perhaps the sodium tail emerges from the dust tail further out to produce the narrow reddish tail. Not sure why it is at a larger angle than the ion tail rather than between them like Hale Bopp but perhaps that is a geometry effect ?

dgs
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Thanks for that link Robin.

Thanks for that link Robin. It looks as though the offset of the Sodium tail is just 3 degrees from that of the main dust tail in the PSI image. Presuming that this image shows south at the top, the Sodium image is offset in a clockwise direction. I have measured Andy's image and it shows that the red tail is offset approx 17 degrees in an anti-clockwise direction. So I don't think the red tail is Sodium.

David

dgs
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Here's a great image and

Here's a great image and spectrum by Torsten Hansen using a star analyser and 135mm lens. The sodium tail is much straighter than the dust tail, so would definitely manifest itself towards the left. See lower image here:

http://www.aau.telebus.de/Ver_7/user/Torsten_Hansen/KometNeowise20200713/SpektrumKometNeowisemitNaSchweif20200713.jpg

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tail orientation

I have checked with the SPI team who have confirmed that their published image was mirrored so their observation now agrees with Torsten's  ie the sodium tail is anticlockwise relative to the dust tail

Robin

dgs
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Thanks Robin, I thought that

Thanks Robin, I thought that was probably the case! So a Sodium tail is back in the running! 

Have you got a spectra across the tail yet?

David

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tail cross section

I have indeed. (Taken with the ALPY)

I just need to get round to reducing them (I am currently just finishing off the Doppler  shift calculations on the high resolution spectrum)

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Hi Andy, Welcome to the forum

Hi Andy, Welcome to the forum. That looks like a fantastic image. Could you post a higher resolution version please with technical details (when, where, exposure, equipment, field of view etc.). You can submit it to the Comet Section via cometobs@britastro.org. Details of how to submit are here.  Thanks.

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NEOWISE

Beautiful comet.  Managed to photograph it from a field in Wickford Essex on July 12.  First attempt.  The pic was shot with a 200mm f4 attached to a Nikon 750 set to 200 f4 for 3 seconds. ISO 400.  02.31 UT

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Reculver Towers and 'the comet'

Quick 10s image of teh comet at Reculver Towers last night.

Full image here https://britastro.org/node/23239

Simon

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Another - I'll stop boring

Another - I'll stop boring everyone now :-)

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Neowise frem Denmark

Here are two pictures from Monday morning. Canon EOS 77D 1 sec. with 50 mm lens, 4 sec. with 300 mm.

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Bright comet on CCTV

It cleared up for a while after midnight last night in Chelmsford but I was asleep. This is a picture from a cheap north-facing IP video camera showing just how bright the comet is. This is a stack of 100 video frames, so about 4s total exposure.

 

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John Mason and the South

John Mason and the South Downs Planetarium crew have done a great video for the general public on comets in general and C/2020 F3 in particular. You can find it here.

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doppler velocities

I've finally got round to analysing the high resolution spectrum from 10th July. The velocities relative to sun and earth are satisfyingly close to those published by JPL Horizons 

https://britastro.org/node/23284

Robin

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Very impressive

Very impressive result Robin.

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Stack of ~30min showing ion tail.

I stacked some images to show the ION tail - 

full-size image here  https://britastro.org/node/23294

dgs
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360 degree panorama of C/2020 F3 (NEOWISE)

Comet Neowise caught in single 20s exp. with Ricoh Theta camera last night

https://theta360.com/s/jOGdKcj6M9KsLhWHUK5I5aqwq?utm_source=app_theta_twitter&utm_medium=social

David

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