<p>The solar elongation (angle from the Sun to the object) is about 15 degrees right now and decreasing as the comet moves in towards perihelion (closest approach to the Sun) on August 15. As <a href="https://astronomy.stackexchange.com/users/2365/james-k">James K</a> says this means that comet is lost in the Sun's glare. Anything below 30 degrees solar elongation is tricky to impossible to see. </p>

<p>Assuming it survives the close perihelion passage of 0.21 AU, it is predicted to enter the field of view of the SOHO LASCO Sun-observing coronographs on August 24:</p>

<blockquote>
  <p>Assuming there is anything left of C/2017 S3, perihelion will occur this month on the 15th at a rather small perihelion distance of 0.21 AU. Being only 2 weeks from perihelion, it is already at a small elongation of 31 degrees on the 1st. Most observers will lose sight of it during the first week of August as its elongation drops below 25 degrees on the 4th and 20 degrees on the 6th. If the comet is still a going concern it will be visible in the SOHO LASCO C3 FOV between August 24 and September 13. The comet appear around the 7:30 position, passes to the east (left) of the Sun (halfway between the Sun and edge of FOV) and exits the FOV around the 12:30 position. </p>
</blockquote>

<p>The above info is from the <a href="http://www.alpo-astronomy.org/cometblog/?page_id=23" rel="nofollow noreferrer">ALPO Comet Section</a>. Latest LASCO image and movies are available <a href="https://www.spaceweatherlive.com/en/solar-activity/solar-images/soho" rel="nofollow noreferrer">here</a> and many other places.</p>

CC BY-SA 4.0
2018-08-07T15:27:37.800Z
This is great! Thank you for taking the time to write a thorough and well supported answer. The link to ALPO is really useful, and looking forward to "seeing" the comet in LASCO soon! (some older homebrew "movies" [here](https://space.stackexchange.com/q/23609/12102) and [here](https://space.stackexchange.com/a/15429/12102)).
uhoh
CC BY-SA 4.0
2018-08-07T15:36:32.973Z
Thank you for the nice comment, hopefully it will survive perihelion. I know well the disappointment of organizing observations as part of a large campaign for a comet that didn't survive perihelion passage (C/2012 S1 ISON)
astrosnapper
CC BY-SA 4.0
2018-08-07T15:42:37.017Z
I hope you didn't lose money on travel arrangements to another hemisphere as part of the campaign.
uhoh
CC BY-SA 4.0
2018-08-07T15:55:47.527Z
No the telescope robots went off and did other people's observations instead
astrosnapper
CC BY-SA 4.0
2018-08-07T15:20:03.840Z
2018-08-07T15:20:03.840Z
astrosnapper
<p>The LiveScience article <a href="https://www.livescience.com/63268-incredible-hulk-comet.html" rel="nofollow noreferrer">Incredible Hulk? Nah, This Glowing, Green Light in the Night Sky Is a Comet</a> published just hours ago discusses Comet PANSTARRS C/2017 S3 and mentions:</p>

<blockquote>
  <p>bright bursts exploding from its surface twice in close succession — <a href="https://www.skyandtelescope.com/observing/panstarrs-comet-rocked-by-outburst-now-binocular-bright/" rel="nofollow noreferrer">first on June 30, and then again about two weeks later</a>, Sky and Telescope reported. As Hulk himself might say, "Comet flash!"</p>
</blockquote>

<p>The linked Sky and Telescope article <a href="https://www.skyandtelescope.com/observing/panstarrs-comet-rocked-by-outburst-now-binocular-bright/" rel="nofollow noreferrer">PanSTARRS Comet, Rocked by Outburst, Goes Green</a> is dated July 17, 2018 and offers the tantallizing information that </p>

<blockquote>
  <p>Comet PanSTARRS (C/2017 S3) has erupted again! Now bright enough to see in binoculars, it might become a naked-eye object if it survives until perihelion.</p>
</blockquote>

<p><strong>Question:</strong> How bright is the comet now, and how is it predicted to behave in the next week or two (baring further outbursts)?</p>

<hr>

<p><strong>below:</strong> "On July 15, Comet PanSTARRS (C/2017 S3) appeared bright and well condensed with a narrow ion tail." Photo Credit: Michael Jäger. From <a href="https://www.skyandtelescope.com/observing/panstarrs-comet-rocked-by-outburst-now-binocular-bright/" rel="nofollow noreferrer">here</a>.</p>

<p><a href="https://i.sstatic.net/Q3hyx.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Q3hyx.jpg" alt="enter image description here"></a></p>

<p><strong>update:</strong> The Universe Today's article <a href="https://www.universetoday.com/139573/catch-comet-c-2017-s3-panstarrs-in-outburst/" rel="nofollow noreferrer">Catch Comet C/2017 S3 PANSTARRS In Outburst</a> links to S Seiichi Yoshida's <a href="http://www.aerith.net/comet/catalog/2017S3/2017S3.html" rel="nofollow noreferrer">page</a> for the comet, but there's no recent data!</p>

<p><a href="https://i.sstatic.net/lriRk.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/lriRk.gif" alt="enter image description here"></a></p>

CC BY-SA 4.0
2018-08-07T10:41:18.853Z
It is now very near the sun in the sky, it is probably lost in the the twilight to earth bound observers
James K
CC BY-SA 4.0
2018-08-07T15:20:33.003Z
@JamesK thanks for that, I feel better now; that I'm not missing something spectacular.
uhoh
<amateur-observing><comets>
How bright is Comet PANSTARRS C/2017 S3 now?
uhoh
# How bright is Comet PANSTARRS C/2017 S3 now?

(Asked by: username_0 on 2018-08-07)

The LiveScience article [Incredible Hulk? Nah, This Glowing, Green Light in the Night Sky Is a Comet](https://www.livescience.com/63268-incredible-hulk-comet.html) published just hours ago discusses Comet PANSTARRS C/2017 S3 and mentions:

> bright bursts exploding from its surface twice in close succession — [first on June 30, and then again about two weeks later](https://www.skyandtelescope.com/observing/panstarrs-comet-rocked-by-outburst-now-binocular-bright/), Sky and Telescope reported. As Hulk himself might say, "Comet flash!"

The linked Sky and Telescope article [PanSTARRS Comet, Rocked by Outburst, Goes Green](https://www.skyandtelescope.com/observing/panstarrs-comet-rocked-by-outburst-now-binocular-bright/) is dated July 17, 2018 and offers the tantallizing information that

> Comet PanSTARRS (C/2017 S3) has erupted again! Now bright enough to see in binoculars, it might become a naked-eye object if it survives until perihelion.

**Question:** How bright is the comet now, and how is it predicted to behave in the next week or two (baring further outbursts)?

---

**below:** "On July 15, Comet PanSTARRS (C/2017 S3) appeared bright and well condensed with a narrow ion tail." Photo Credit: Michael Jäger. From [here](https://www.skyandtelescope.com/observing/panstarrs-comet-rocked-by-outburst-now-binocular-bright/).

[![enter image description here](https://i.sstatic.net/Q3hyx.jpg)](https://i.sstatic.net/Q3hyx.jpg)

**update:** The Universe Today's article [Catch Comet C/2017 S3 PANSTARRS In Outburst](https://www.universetoday.com/139573/catch-comet-c-2017-s3-panstarrs-in-outburst/) links to S Seiichi Yoshida's [page](http://www.aerith.net/comet/catalog/2017S3/2017S3.html) for the comet, but there's no recent data!

[![enter image description here](https://i.sstatic.net/lriRk.gif)](https://i.sstatic.net/lriRk.gif)

**Tags:** amateur-observing, comets
> **Comments:**
> **username_1**: It is now very near the sun in the sky, it is probably lost in the the twilight to earth bound observers  
> **username_0**: @JamesK thanks for that, I feel better now; that I'm not missing something spectacular.  

---

## 1 answers

### Answer by username_2 on 2018-08-07. Score: 2 | Accepted answer

The solar elongation (angle from the Sun to the object) is about 15 degrees right now and decreasing as the comet moves in towards perihelion (closest approach to the Sun) on August 15. As [James K](https://astronomy.stackexchange.com/users/2365/james-k) says this means that comet is lost in the Sun's glare. Anything below 30 degrees solar elongation is tricky to impossible to see.

Assuming it survives the close perihelion passage of 0.21 AU, it is predicted to enter the field of view of the SOHO LASCO Sun-observing coronographs on August 24:

> Assuming there is anything left of C/2017 S3, perihelion will occur this month on the 15th at a rather small perihelion distance of 0.21 AU. Being only 2 weeks from perihelion, it is already at a small elongation of 31 degrees on the 1st. Most observers will lose sight of it during the first week of August as its elongation drops below 25 degrees on the 4th and 20 degrees on the 6th. If the comet is still a going concern it will be visible in the SOHO LASCO C3 FOV between August 24 and September 13. The comet appear around the 7:30 position, passes to the east (left) of the Sun (halfway between the Sun and edge of FOV) and exits the FOV around the 12:30 position.

The above info is from the [ALPO Comet Section](http://www.alpo-astronomy.org/cometblog/?page_id=23). Latest LASCO image and movies are available [here](https://www.spaceweatherlive.com/en/solar-activity/solar-images/soho) and many other places.

> **Comments:**
> **username_0**: This is great! Thank you for taking the time to write a thorough and well supported answer. The link to ALPO is really useful, and looking forward to "seeing" the comet in LASCO soon! (some older homebrew "movies" [here](https://space.stackexchange.com/q/23609/12102) and [here](https://space.stackexchange.com/a/15429/12102)).  
> **username_2**: Thank you for the nice comment, hopefully it will survive perihelion. I know well the disappointment of organizing observations as part of a large campaign for a comet that didn't survive perihelion passage (C/2012 S1 ISON)  
> **username_0**: I hope you didn't lose money on travel arrangements to another hemisphere as part of the campaign.  
> **username_2**: No the telescope robots went off and did other people's observations instead  

---

