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ALPO Comet News for November 2019

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#1 Carl H.

Carl H.

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Posted 03 November 2019 - 02:59 AM

ALPO COMET NEWS FOR NOVEMBER 2019

 

By Carl Hergenrother - 2019-November-2
 


 

The monthly ALPO Comet News PDF can be found on the ALPO Comet Section website (http://www.alpo-astr....org/cometblog/). A shorter version of this report is posted on the Cloudy Nights forum at (https://www.cloudynights.com/topic/682477-alpo-comet-news-for-november-2019/). Everyone is invited to join the discussion at our Cloudy Nights forum.

 

November finds us in-between bright comets. C/2018 W2 (Africano) is now too faint for small aperture telescopes. C/2017 T2 (PANSTARRS) is at least a month away from becoming an easy object. Luckily it will continue to brighten over the next few months and should provide a nice target for much of the first half of 2020. CCD imagers are encouraged to keep a detector on interstellar comet 2I/Borisov which will be around 15-16th magnitude this month.

 

Bright Comets (magnitude < 10.0)

None.

 

Faint Comets (between magnitude 10.0 and 13.0)

29P/Schwassmann-Wachmann – 29P/Schwassmann-Wachmann was discovered photographically in 1927 by German astronomer Arnold Schwassmann and Arno Arthur Wachmann. The duo discovered 4 comets together, three of which were short-period comets (29P, 31P and 73P) and a long-period shared with Leslie Peltier (C/1930 D1). 29P is now an evening object two months past opposition. Chris Wyatt observed 29P on 5 nights in October between magnitude 13.7 and 14.8. Other reports to the COBS site found the comet between 12th and 14th magnitude which has been the case in recent months.

 

29P/Schwassmann-Wachmann

T = 2019-Mar-07  q = 5.77 au                                     Max El
Centaur comet - 14.8-yr orbital period                            (deg)
    Date     Mag    R.A.   Decl.     r       d    Elong  Const  40N  40S

2019-11-01  12-14  00 31  +14 22   5.778   4.875   153    Psc    64   36
2019-11-06  12-14  00 29  +14 08   5.778   4.913   148    Psc    64   36
2019-11-11  12-14  00 28  +13 55   5.779   4.958   142    Psc    64   36
2019-11-16  12-14  00 27  +13 42   5.779   5.009   137    Psc    64   36
2019-11-21  12-14  00 26  +13 31   5.779   5.066   132    Psc    64   36
2019-11-26  12-14  00 25  +13 20   5.780   5.127   127    Psc    63   35
2019-12-01  12-14  00 25  +13 11   5.780   5.193   122    Psc    63   33
2019-12-06  12-14  00 24  +13 04   5.781   5.263   117    Psc    63   31

 

260P/McNaught - Robert McNaught discovered 260P on 2012 May 20 with the 0.5-m Uppsala Schmidt as part of the Siding Spring Survey in Australia. With an orbital period of ~7 years, the comet is making its 3rd observed return. During its last apparition in 2012 it peaked between magnitude 11 and 12. This year’s return is similar with a slightly smaller minimum Earth-comet distance (0.56 vs 0.58 au) and smaller perihelion distance (1.42 vs 1.50 au).

 

The ALPO received 3 images and sketches of 260P from Martin Mobberley and Michel Deconinck and 4 magnitude estimates from J. J Gonzalez and Chris Wyatt. Magnitude estimates submitted to the COBS site have the comet between 10.7 and 12.3 during the last week of October. Most of the estimates were around 12.0. The comet spends all of November in Andromeda at rather high northern declinations (> +47). The comet is now fading as it moves away from the Sun and Earth.

 

260P/McNaught

T = 2019-Sep-09  q = 1.42 au                                     Max El
Short-Period comet - 6.9-year period                              (deg)
    Date     Mag    R.A.   Decl.     r       d    Elong  Const  40N  40S

2019-11-01  12.4   02 38  +49 33   1.531   0.610   144    And    80    0
2019-11-06  12.6   02 34  +50 01   1.553   0.630   145    And    80    0
2019-11-11  12.7   02 30  +50 11   1.575   0.652   146    And    80    0
2019-11-16  12.9   02 27  +50 05   1.600   0.679   146    And    80    0
2019-11-21  13.2   02 24  +49 44   1.625   0.708   146    And    80    0
2019-11-26  13.4   02 23  +49 13   1.652   0.742   145    And    81    1
2019-12-01  13.6   02 23  +48 33   1.679   0.779   143    And    81    1
2019-12-06  13.9   02 24  +47 49   1.708   0.821   141    And    82    2

 

C/2017 T2 (PANSTARRS) – C/2017 T2 (PANSTARRS) is steadily increasing in brightness as its closes in on a 2020 May 4 perihelion at 1.62 au. While still fainter than 10th magnitude for much of November, PANSTARRS will be a nice small telescope target for much of 2020. The comet was discovered on 2017 October 7 with the Pan-STARRS1 telescope on Haleakala, Maui, Hawaii. At discovery the comet was 20th magnitude and close to the distance of Saturn at 9.3 au from the Sun.

 

The ALPO received 3 images/sketches from Michel Deconinck and Martin Mobberley and 5 magnitude estimates from J. J. Gonzalez and Chris Wyatt. A sketch by Michel Deconinck on October 26 with his Mewlon 250 showed a nice tail to the southwest.

Submissions to the COBS site during the last week of October showed a large scatter in reported magnitudes (9.4 to 12.3). The average brightness was around 11.5 so my prediction below may be a bit bright. C/2017 T2 should start November around magnitude 11.0 (or a little fainter) and brighten to 10.0 by December 1 as it moves through Auriga (Nov 1-30).

 

C/2017 T2 (PANSTARRS)

T = 2020-May-04  q = 1.62 au                                     Max El
Long-Period comet - dynamically new                               (deg)
    Date     Mag    R.A.   Decl.     r       d    Elong  Const  40N  40S

2019-11-01  11.0   05 35  +35 21   2.857   2.098   131    Aur    85   15
2019-11-06  10.8   05 32  +37 00   2.810   2.004   136    Aur    87   13
2019-11-11  10.6   05 28  +38 44   2.763   1.917   141    Aur    89   11
2019-11-16  10.5   05 22  +40 34   2.716   1.838   146    Aur    89    9
2019-11-21  10.3   05 15  +42 28   2.669   1.766   150    Aur    87    7
2019-11-26  10.2   05 06  +44 24   2.622   1.704   153    Aur    86    6
2019-12-01  10.0   04 56  +46 19   2.576   1.650   154    Aur    84    4
2019-12-06   9.9   04 44  +48 10   2.530   1.606   154    Per    81    1

 

C/2018 N2 (ASASSN) - Comet C/2018 N2 (ASASSN) was discovered 16 months ago on 2018 July 7 by the All-Sky Automated Survey for Supernovae (ASAS-SN) program. Since discovery, ASASSN has brightened slowly. ASASSN arrives at perihelion on the 11th at a distant 3.12 au. The section received 2 sketches of this comet from Michel Deconinck as well as 4 magnitude estimates from J. J. Gonzalez and Chris Wyatt. The most recent estimates were from J. J. Gonzalez on October 25 at magnitude 11.3 and Chris Wyatt on October 19 at 12.1. Submissions to the COBS site during the last week of October placed C/2018 N2 between magnitude 10.8 and 11.8. This month, C/2018 N2 is just past opposition in Andromeda (Nov 1-30) and even though it is at perihelion it should start to fade as its orbital motion carries it away from the Earth.

 

C/2018 N2 (ASASSN)

T = 2019-Nov-11  q = 3.12 au                                     Max El
Long-Period comet - dynamically old                               (deg)
    Date     Mag    R.A.   Decl.     r       d    Elong  Const  40N  40S

2019-11-01  11.4   00 43  +38 05   3.126   2.243   147    And    88   12
2019-11-06  11.5   00 32  +38 30   3.125   2.272   143    And    89   11
2019-11-11  11.5   00 21  +38 47   3.125   2.310   138    And    89   11
2019-11-16  11.5   00 11  +38 58   3.125   2.355   134    And    89   11
2019-11-21  11.6   00 03  +39 05   3.126   2.407   129    And    89   10
2019-11-26  11.6   23 55  +39 08   3.128   2.465   124    And    89    8
2019-12-01  11.7   23 48  +39 10   3.131   2.528   119    And    89    6
2019-12-06  11.8   23 43  +39 11   3.134   2.595   114    And    89    3

 

C/2018 W2 (Africano) - C/2018 W2 (Africano) is now 2 months past perihelion and in full retreat from the Sun and Earth. Since October 1, the ALPO received 1 sketch of the comet from Michael Rosolina and 5 magnitude estimates from Willian Souza, J. J. Gonzalez Suarez, and Chris Wyatt. The most recent estimate was from Chris Wyatt on November 2 when he saw the comet at magnitude 11.1.

 

As November begins, the comet is now farther from the Sun (1.66 vs 1.45 au) and Earth (1.22 vs 0.49 au) compared to only 2 months ago. As a result, it is much fainter and should fade to 13th magnitude by the end of November. It spends all month in the evening sky among the stars of the southern constellation of Grus.

 

C/2018 W2 (Africano)

T = 2019-Sep-05  q = 1.45 au                                     Max El
Long-Period comet - dynamically old                               (deg)
    Date     Mag    R.A.   Decl.     r       d    Elong  Const  40N  40S

2019-11-01  11.1   21 42.17  -38 15.2   1.657   1.224     Gru    12   74
2019-11-06  11.5   21 37.90  -39 57.2   1.691   1.367     Gru    10   68
2019-11-11  11.8   21 35.42  -41 14.8   1.727   1.508     Gru     9   63
2019-11-16  12.1   21 34.37  -42 15.1   1.765   1.648     Gru     8   58
2019-11-21  12.4   21 34.48  -43  2.9   1.804   1.784     Gru     6   53
2019-11-26  12.6   21 35.57  -43 41.3   1.844   1.917     Gru     5   48
2019-12-01  12.9   21 37.47  -44 12.9   1.886   2.046     Gru     4   44
2019-12-06  13.1   21 40.07  -44 39.3   1.929   2.170     Gru     3   40

 

Fainter Comets of Interest (probably fainter than magnitude 13.0)


2I/2019 Q4 (Borisov) – The first bona fide interstellar comet, 2I/2019 Q4 (Borisov), was discovered by Gennady Borisov on August 30 with a 0.65-m f/1.5 astrograph of his own making at MARGO observatory near Nauchnij, Crimea. Pre-discovery observations from the Zwicky Transient Facility on Mount Palomar have been found as far back as 2019 March 17.

 

A number of professional studies have been published on the arXiv e-print depository. For the most part, 2I/Borisov appears similar to long-period comets from our solar system in color and composition. Already a number of gaseous species have been observed including a definite detection of cyanide [CN] and tentative detections of diatomic carbon [C2] and daughter species produced by the photodissociation of water [O I & OH].

 

Two images were submitted to the ALPO from Gianluca Masi and Martin Mobberley. The Masi image from October 8 shows a short tail in a 2100 second co-added image taken with a 0.43-m telescope. Last month magnitude measurements submitted to COBS had the comet around 16th magnitude. The comet should continue to brighten as it nears a December 8 perihelion at 2.01 au.

 

2I/2019 Q4 (Borisov)
T = 2019-Dec-08  q = 2.01 au                                     Max El
Interstellar comet                                                (deg)
    Date     Mag    R.A.   Decl.     r       d    Elong  Const  40N  40S

2019-11-01  15.9   10 23  +07 51   2.176   2.432    63    Leo    41   11
2019-11-06  15.8   10 31  +04 49   2.136   2.353    65    Sxt    41   13
2019-11-11  15.7   10 40  +01 37   2.101   2.279    67    Sxt    41   16
2019-11-16  15.6   10 49  -01 43   2.071   2.211    68    Sxt    40   19
2019-11-21  15.5   10 58  -05 12   2.047   2.151    70    Leo    39   22
2019-11-26  15.4   11 07  -08 49   2.029   2.098    72    Crt    37   25
2019-12-01  15.3   11 15  -12 32   2.017   2.052    74    Crt    35   29
2019-12-06  15.2   11 23  -16 19   2.011   2.014    75    Crt    32   33

 

289P/Blanpain – 289P/Blanpain will approach to within 0.09 au of Earth this December. It is not expected to get bright due to its usual low activity though has experienced a number of outbursts in the past. Jean-Jacques Blanpain discovered 289P in November 1819. Likely experiencing an outburst at the time of discovery, it went unobserved for the next 194 years until it was re-discovered by the Catalina Sky Survey as near-Earth asteroid 2003 WY25 in November 2003. Observations in 2005 found it to still be an active comet, albeit at low levels of activity. In July 2013 while far from perihelion (3.9 au vs 1.0 au), Blanpain experienced a major ~9 magnitude outburst that brightened it from 26th to 17th magnitude. The Phoencids meteor shower is associated with this object. Similar to its parent comet, this shower usually shows little activity except for two outbursts in 1956 and 2014.

 

Many sites using the Minor Planet Center’s magnitude parameters currently have this comet at 10th magnitude. The only observation in October of this comet that I can find was submitted to the Minor Planet Center on October 3. MPC code A77 (Observatoire Chante-Perdrix, Dauban) reported 289P to be between magnitude 18.9 and 19.5. This is 1-2 magnitudes fainter than observations made at the end of September. We’ll need to watch this outburst prone comet to see if its more active than usual this apparition. The predicted magnitudes below are for the nucleus and provide a faint limit.

 

289P/Blanpain
T = 2019-Dec-20  q = 0.96 au                                     Max El
Short-period comet – 5.3-yr orbital period                        (deg)
    Date     Mag    R.A.   Decl.     r       d    Elong  Const  40N  40S

2019-11-01  20.8   22 25  -24 19   1.190   0.395   110    Aqr   26    72
2019-11-06  20.7   22 22  -23 36   1.152   0.379   105    Aqr   27    68
2019-11-11  20.7   22 21  -22 38   1.115   0.361   100    Aqr   28    63
2019-11-16  20.6   22 22  -21 25   1.082   0.342    96    Aqr   29    57
2019-11-21  20.6   22 23  -19 55   1.051   0.321    92    Aqr   30    52
2019-11-26  20.5   22 26  -18 07   1.024   0.299    88    Aqr   32    46
2019-12-01  20.5   22 30  -15 57   1.001   0.275    85    Aqr   34    40
2019-12-06  20.4   22 35  -13 19   0.983   0.249    82    Aqr   37    34

 

New Discoveries, Recoveries and Other Comets in the News

Periodic Comet Numberings – The following comets were numbered in the 2019 October 10 Minor Planet Circulars.

 

386P/2011 U1 (PANSTARRS)
387P/2008 Y1 = 2019 R1 (Boattini)
388P/2007 T4 = 2019 R2 (Gibbs)
389P/2006 R1 = 2019 S1 (Siding Spring)

 

C/2018 DO4 (Lemmon) – Greg Leonard used the Mount Lemmon 1.5-m telescope in southern Arizona to discover this comet back in February 2018. The object appeared asteroidal at the time and was designated 2018 DO4. Now near perihelion, a number of CCD observers have reported cometary activity. C/2018 DO4 (Lemmon) is a Halley-type comet with perihelion on 2019 August 18 at 2.41 au and an orbital period of 131 years. Peak brightness occurs this month at 15th magnitude as the comet reaches opposition. It is predicted to next reach perihelion in 2147.

P/2019 S2 (PANSTARRS) – The Pan-STARRS1 1.8-m telescope on Haleakala, Hawaii was used to discover this comet on September 28. The discovery images captured the comet at 21st magnitude with a 5” tail. Pan-STARRS pre-discovery images were also found from July 10 and August 7. Its reached perihelion back on 2019 February 20 at 3.75 au. As a result, it has peaked in brightness. This is a short-period comet with an orbital period of 10.3 years.

 

P/2019 S3 (PANSTARRS) – Pan-STARRS1 discovered this 20th magnitude comet on September 25. Pre-discovery images were found back to August 27, a day after its perihelion at 1.81 au. P/2019 S3 has an orbital period of 6.3 years and has likely already peaked in brightness.

 

A/2019 S4 – The Mount Lemmon Survey found this apparently asteroidal object on a long-period comet orbit (orbital period ~ 4200 years). Discovery happened on October 8 at 20th magnitude. Perihelion occurs next year on April 8 at 3.44 au. If it is truly inactive, the object has an absolute magnitude of 14.5 which corresponds to a diameter of 8 km for a typical cometary albedo of 0.04. 

 

A/2019 T1 – Here is another apparently asteroidal object on a cometary orbit (orbital period ~240 years) discovered on October 8 at 20th magnitude. This one was found by Pan-STARRS2 and will reach perihelion on 2012 January 14 at 4.28 au. Its absolute magnitude of 13.0 corresponds to a diameter of 17 km.

 

A/2019 T2 – The Mount Lemmon Survey discovered this object on October 9. Pre-discovery observations by Mount Lemmon and Pan-STARRS1 were made as early as August 26. Currently 20th magnitude, it should peak at 17th magnitude around its 2021 April 22 perihelion at 2.64 au. Assuming it is inactive, this object has a diameter of ~21 km. Like the last two objects, A/2019 T2 is also on a long-period comet orbit with a period on the order of 38,000 years.

 

C/2019 T3 (ATLAS) – ATLAS discovered 3 comets over a span of 4 nights. Long-period comet C/2019 T3 (ATLAS) was found on October 6 at 18th magnitude. Perihelion occurs in early 2012 on March 2 at 5.94 au. It should peak at magnitude 17 which is marginally brighter than its discovery magnitude of 18.

 

C/2019 T4 (ATLAS) – This is another long-period ATLAS find. It was discovered on October 9 at 19th magnitude at 8.6 au from the Sun. Perihelion won’t occur till 2022 June 9 at 4.25 au when it may brighten to 14th magnitude. While that may not be very bright, C/2019 T4 is likely to become the brightest comet announced last month.

 

P/2019 T5 (ATLAS) – P/2019 T5 is a short period comet with an orbital period of 22 years. It was discovered on October 8 at 18th magnitude. Perihelion was a week before discovery (October 1 at 1.53 au). It is unlikely to get any brighter than at discovery.

 

P/2019 T6 (PANSTARRS) – PanSTARRS2 found this comet on October 8 at 19th magnitude. It is a short-period comet on a 12.8-year orbit with perihelion this month (Nov 9) at 2.05 au. Not to sound like a broken record, but it also will remain a very faint object.

 

P/2019 U1 = P/2006 W1 (Gibbs) – The ATLAS survey picked up this comet as part of its survey for unknown potentially hazardous asteroids. First seen at 18th magnitude on October 21, the comet is making its first return since its November 2006 discovery by Alex Gibbs with the 0.7-m Catalina Schmidt. Back in 2006, its wasn’t seen till ~7 months after perihelion. This year it was recovered 5 months prior to its 2020 March 22 perihelion (q = 1.70 au). The comet may brighten to 16th magnitude around perihelion. Its next return will be in 2034.

 

P/2019 U2 = P/2006 F1 (Kowalski) – Kevin Hills used a 0.5-m f/2.9 astrograph at the Tacanade Observatory at La Palma on October 7, 22, and 24 to recover this comet at 20th magnitude. The comet was originally discovered by Richard Kowalski in March 2006 with the Mount Lemmon 1.5-m. The comet peaked at 17th magnitude during the summer of 2006 which was ~1.5 years before its perihelion at 4.12 au. The asymmetrical lightcurve with maximum brightness so far ahead of perihelion may be due to its recent injection into its current orbit. The comet was previously on a 40 year orbit with perihelion at 4.82 au before a very close approach to Jupiter (2003 January 4 @ 0.0096 au) (details can be found in the NK3909 Nakano Note).

 

The comet is once again displaying an asymmetric lightcurve though this time the comet is brighter after perihelion. Recovered in October 2019, its most recent perihelion was back in March 2018 (q = 4.11 au). A number of imagers attempted observations starting a few years prior to perihelion with no success till the October recovery. While predicting such a peak brightness for such an inconsistent object may not be the best idea, it is likely that P/Kowalski won’t get much brighter than its current 20th magnitude. Its next perihelion will be in 2028.

 

P/2019 U3 = P/2004 WR9 (LINEAR) - Krisztián Sárneczky used the 0.60-m Schmidt telescope at the Piszkesteto Station of Konkoly Observatory to recover this comet on October 26 and 27. The comet was 19th magnitude at recovery. The LINEAR asteroid survey program made the original discovery in November 2004. During that apparition the comet peaked at 17th magnitude. This time the comet reaches perihelion on 2020 March 31 at 1.95 au. It is unlikely to get brighter than its recovery magnitude this return. It will next reach perihelion in 2035.

 

A/2019 U5 – PanSTARRS1 detected this asteroidal object on October 22 at 21st magnitude. At discovery it was a distant 10.3 au from the Sun. Perihelion isn’t till 2023 March 29 when the object will be a much closer 3.62 au from the Sun. During the week of perihelion, the comet will also be at opposition and at a peak brightness of magnitude 15.4. If this comet stays inactive, it will make a nice target for physical characterization (rotational lightcurves, colors, spectra) by modest sized aperture telescopes. If it becomes active, it may be a few magnitudes brighter than 15th.

 

In addition to the above discoveries and recoveries, the following objects are designated as asteroids but have comet-like orbits. This doesn’t mean these objects are cometary in origin, but it makes them a good group to watch. Unfortunately, all will remain faint. The brightest is 2019 SG9 as 18th magnitude though its peak brightness has already passed.

 

Object      Disc.    Peri.   Period    H   Max Brightness  Discoverer
            Date     Dist.   (years)
2019 TX7    Oct 07   6.80     128     13.4  21-in-Oct2019  PanSTARRS
2019 SG9    Oct 20   0.87       5.5   25.0  18-in-Sep2019  Catalina 
2019 UP9    Oct 24   1.15 au    5.7   23.9  21-in-Sep2019  PanSTARRS
2019 UG10   Oct 25   1.36 au    5.7   18.8  21-in-Oct2019  PanSTARRS
2019 UJ10   Oct 25   1.28 au    5.7   19.7  21-in-Oct2019  PanSTARRS
2019 UQ10   Oct 25   1.35 au    5.6   18.8  22-in-Oct2019  PanSTARRS
2019 UH12   Oct 27   7.92 au  374     10.8  20-in-Oct2018  PanSTARRS
2019 UA14   Oct 31   1.27 au    7.1   18.9  21-in-Nov2018  Lemmon

 

As always, the Comet Section is happy to receive all comet observations, whether textual descriptions, images, drawings, magnitude estimates, or spectra. Please send your observations via email to < carl.hergenrother @ alpo-astronomy.org >.


 

- Carl Hergenrother (ALPO Comet Section Coordinator)


Edited by Carl H., 03 November 2019 - 02:59 AM.

  • Special Ed, geminijk, Aquarellia and 6 others like this

#2 Rich (RLTYS)

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Posted 06 November 2019 - 07:56 AM

Once again another great report! bow.gif



#3 Zorbathegeek

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Posted 16 November 2019 - 06:05 PM

Hi Carl, and thanks for the report. I noticed that Gideon van Buitenen has C/2019 N1 (ATLAS) reaching 3.7 magnitude at perihelion next year and 4.5 magnitude at its closest approach in early 2021. I can't find an equally promising forecast anywhere else and was wondering what your knowledge of this comet was. Thanks, Ray. 



#4 Subaru45

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Posted 17 November 2019 - 05:26 AM

I am looking for somewhere that I can ask about a comet from my childhood. The question is about Comet Arend Roland 1956 R1,  does it have a period, or is it one that I will never see again ?



#5 einarin

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Posted 17 November 2019 - 05:37 AM

From Wikipedia:
"It was traveling on a hyperbolic orbit, that is, traveling fast enough to escape from the Solar System entirely, hence implying that it will never be seen again by earthbound observers. Observations of the comet over a period of 520 days allowed precise orbital elements to be computed. However, the distribution of the orbital elements showed a wavy pattern that suggested a non-gravitational influence. Alternatively, the comet may have originated from interstellar space rather than from the Oort cloud.[12] When an orbital solution is computed that includes non-gravitational forces that vary as the inverse square of the heliocentric distance, somewhat different values are derived (see the Marsden (1970) column in the table below)."



#6 Subaru45

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Posted 17 November 2019 - 10:43 AM

Thank you for that information, I was thinking how nice it would be to see it again. Thought also many others would enjoy it with me. Again, thank you ! 



#7 Zorbathegeek

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Posted 17 November 2019 - 04:01 PM

Hello again Carl. I've been going back through your earlier reports and see that you have C/2019 N1 (ATLAS) reaching around 11 magnitude in early 2021. Maybe I should email Mr. van Buitenen with my question. Many thanks, Ray.



#8 Zorbathegeek

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Posted 17 November 2019 - 04:25 PM

I've just had a more detailed look on astro.vanbuitenen.nl and found the following with regards to C/2019 N1 (ATLAS).

 

"The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC. Two light curves are shown: The gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (6.80 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently -4.15 + 5 log[∆] + 25.48 log[r])."

 

The grey line has the comet reaching around 10.7 magnitude but the red line does show the comet reaching an estimated 3.7 magnitude. Maybe this is one to put on the calender? Although, with regards to observation, Seiichi Yoshida says, "In the Northern Hemisphere, it stays observable in good condition while the comet will be brightening gradually, but it is not observable at the high light. In the Southern Hemisphere, it is not observable for a long time, but it will be observable in good condition after the high light." Additionally, Mr Yoshida only has the comet becoming a 10th magnitude object. 



#9 Carl H.

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Posted 18 November 2019 - 01:07 PM

My guess is that Gideon's page is doing an automatic fit to the photometry for C/2019 N1. Since the photometry is noisy and covers a short range in log ® space, where r = heliocentric distance in au, his software is coming up with a 25.48 log® term that is too large. The COBS site finds a much lower 7.43 log® term. The MPC and Seiichi Yoshida assume a 10 log® term while the CBAT assumes 8 log®. Since C/2019 N1 is a dynamically new long-period comet, it's long-term brightening will likely be closer to the COBS and CBAT values. This results in a peak brightness around 11-12th magnitude.

 

I hope I'm wrong, but nothing about C/2019 N1 suggests it will be a bright object.



#10 Zorbathegeek

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Posted 18 November 2019 - 05:35 PM

Thanks for that sobering explanation. I'll temper my excitement accordingly. 



#11 Aquarellia

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Posted 21 November 2019 - 04:37 AM

I am looking for somewhere that I can ask about a comet from my childhood. The question is about Comet Arend Roland 1956 R1,  does it have a period, or is it one that I will never see again ?

Apart from this article so well written by Carl, I'm happy to read something about this old comet.

A long time ago I meet Mr. Arend and visited the equipment he used, on top of that the observatory located just 300 meters from my home!

Sorry if this is far from a real observation, but I want to post here a sample of my comet stamp collection:

 

Arend-Roland_l.jpg

 

This very specific collection is "reworked now" to make a sketch / photo / stamp presentation of some of my best observed comets.
Thanks to Subaru for mentioning this comet here

 

Michel


Edited by Aquarellia, 21 November 2019 - 04:38 AM.

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#12 Subaru45

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Posted 21 November 2019 - 08:11 AM

Michel,

ah, the good ol' days !! Glad to have done it, you are welcome.


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#13 Rich (RLTYS)

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Posted 21 November 2019 - 08:14 AM

An impressive stamp, thanks for sharing. waytogo.gif


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#14 Zorbathegeek

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Posted 23 November 2019 - 04:12 PM

I notice that on astro.vanbuitenen, 2019 N1 (ATLAS) has been revised to a forecast brightness of 10.9 magnitude. That leaves four comets reaching 10 magnitude or better next year, if 249P/LINEAR can be seen from the ground. 



#15 gvanbuitenen

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Posted 23 November 2019 - 07:28 PM

My guess is that Gideon's page is doing an automatic fit to the photometry for C/2019 N1. Since the photometry is noisy and covers a short range in log ® space, where r = heliocentric distance in au, his software is coming up with a 25.48 log® term that is too large. The COBS site finds a much lower 7.43 log® term. The MPC and Seiichi Yoshida assume a 10 log® term while the CBAT assumes 8 log®. Since C/2019 N1 is a dynamically new long-period comet, it's long-term brightening will likely be closer to the COBS and CBAT values. This results in a peak brightness around 11-12th magnitude.

 

I hope I'm wrong, but nothing about C/2019 N1 suggests it will be a bright object.

First of all... great report!

 

Secondly: You guessed right. I'm performing an automatic fit once a number of pre-conditions are met.

But sometimes there's a clever cat like C/2019 N1 that slips through.

In this case there were only relatively low initial observations compared to higher observations later on, faking just enough correlation over just enough range. 

So the pre-checks 'considered' it good enough to attempt a fit. I noticed today and collected some more observations to resolve it.

 

Still a nice telescope object for the southern hemisphere in early 2021 though. 


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#16 Zorbathegeek

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Posted 23 November 2019 - 08:37 PM

Can I take this opportunity to say how much I love your site Gideon. It's my go-to place for vicarious appreciation of comets. Many thanks.


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#17 Carl H.

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Posted 24 November 2019 - 08:08 PM

Gideon, I also want to second the adulation for your site!



#18 Aquarellia

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Posted 24 November 2019 - 10:30 PM

Can I take this opportunity to say how much I love your site Gideon. It's my go-to place for vicarious appreciation of comets. Many thanks.

 

Gideon, I also want to second the adulation for your site!

Hooo yes, Gideon, your site is super!  You make my day, with novae and supernovae as bonus, just whaw!

Michel


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#19 gvanbuitenen

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Posted 29 November 2019 - 02:53 PM

Thanks. Appreciate the feedback. It's been (and still is) a great learning experience for me putting it together and I'm happy it is of use to others now...
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