Friday, 9 November 2018

Comet 46P/Wirtanen - Current Status

Updates - Visit

18 Oct 2018

Detection of water production
We have our first report of a water production rate for Wirtanen. Dave Schleicher detected OH using narrowband filter photometry on 6 October (r=1.38 AU). Haser models give an OH production of Q(OH)2.0×1027 molec/s. This converts to a water production rate of Q(H2O)=2.3×1027 molec/s.
Production rates for other species on the same date: Q(CN)4.5×1024 molec/s, Q(C2)6.3×1024 molec/s, and Afrho(5260A) = 20 cm.
With no comparable pre-perihelion measurements from previous apparitions, it is not clear whether Wirtanen is behaving as expected, or if changes are occurring on this apparition.

Monday, 29 October 2018

Southern Comet Chasers

38P/Stephan-Oterma in Gemini, magnitude: 8.08. (Click to enlarge images)

Comets visible in Southern Hemisphere from end of October 2019 till early November 2018 for best viewing.
Date Chart 1- 7: 7 November (New Moon). Comets 2 Day interval and 20 Days on chart. 

38P/Stephan-Oterma in Gemini will next reach perihelion in early November. In mid December this comet will pass within 0.8 AU of the earth. It is predicted to reach maximum brightness of magnitude 6.7 in late November.
 46P/Wirtanen in Fornax: An evening comet visible in small telescopes. This comet begins the month in Fornax at magnitude 11.3. Look for a 5' coma. It should brighten rapidly. The best visibility is late in the month as seen from the southern hemisphere.

21P/Giacobini-Zinner in Canis Major reached perihelion in early September. Also in early September this comet will pass within 0.4 AU of the earth, when it is currently predicted to reach maximum brightness of magnitude 7. A morning comet visible in binoculars. This comet begins the month in Monoceros at magnitude 8.2. Look for a 2.5' coma. It should fade rapidly, moving into Canis Major by month's end.

C/2016 M1 (PANSTARRS) in Circinus passed perihelion in early August. Maximum brightness of magnitude 8 occurred in late July.  A southern hemisphere evening comet visible in small telescopes
This comet begins the month in Centaurus at magnitude 10.2. Look for a 3' coma. It should fade slowly, moving into Circinus by month's end. The best visibility is early in the month as seen from the southern hemisphere.

64P/Swift-Gehrels in Andromeda will next reach perihelion in early November, when it will also pass within 0.4 AU of the earth. It also is predicted to reach maximum brightness of magnitude 9.7 in early November. An evening comet visible in small telescopes This comet begins the month in Andromeda at magnitude 11.6. Look for a 1.5' coma. It should brighten by about 0.7 magnitudes by month's end.
29P/Schwassmann-Wachmann in Aquarius is reported to have had a ~3 magnitude outburst on September 21, and has now faded. Typically, it has primary outbursts, resulting in a brightening of 0.5 - 1.0 magnitudes, which occur roughly every 59 days, typically taking 5-10 days to subside. But up to three subsequent outbursts may occur 5-10 days afterward, each typically smaller than the last, although on some occasions they can be even brighter than the first. These outbursts make 29P one of the most interesting comets to follow, both visually and scientifically. 29P/Schwassmann-Wachmann has a 14.8-year orbital period, and will next reach perihelion in early March 2019. But it varies in its distance from the Sun from 5.8 AU (at perihelion) to 6.3 AU (at aphelion), which is an unusually small variation for a comet, and remains quite far from the sun at all times.  An evening comet visible in a 6-inch (15 cm) telescope This comet begins the month in Pisces at magnitude 11.4. Look for a 1.5' coma. It should fade slowly, moving into Aquarius by month's end.

C/2016 N6 (PANSTARRS) in Hydra passed perihelion in mid July. A morning comet visible in an 8-inch (20 cm) telescope This comet begins the month in Cancer at magnitude 12.3. Look for a 1' coma. It should brighten slowly, moving into Hydra by month's end.

- Compiled by Hannes Pieterse, ASSA Bloemfontein

Monday, 20 August 2018

Clean your eyepieces for comet 21P/Giacobini-Zinner - September 2018

astronomy, telescope, astro photography, amateur
21P/Giacobini-Zinner - Motion Trace 5 - 15 September 2018
Click on image to enlarge

Comet 21P/Giacobini-Zinner

astronomy, telescope, astro photography, amateur, comet

Visual Synopsis comet 21P/Giacobini-Zinner (Skytools 3)

On this night (10 September 2018) 21P/Giacobini-Zinner is best visible between 03:28 and 05:26, with the optimum view at 05:03. Look for it in Auriga, fairly high in the northeastern sky during morning twilight. It is obvious visually in the Celestron NexStar 11 SCT. Use the Plössl 6mm for optimum visual detection. It is magnitude 7 with a diameter of 8.5'.

In the following 30 days this object is obvious visually on September 11-22, and again from October 3-6, with the best view coming on September 22. During this period it will fade by about 1 magnitudes and rapidly move higher in the sky.

21P/Giacobini-Zinner will next reach perihelion in late March 2025. It also is predicted to reach maximum brightness of magnitude 10.5 in late March. It will be undetectable visually in the Celestron NexStar 11 SCT from Bloemfontein, South Africa near maximum brightness. At that time it will be in Pisces, high in the sky in daylight. The previous perihelion was early September 2018. Note that the magnitude and visibility of a comet can be very unpredictable.

Monday, 30 July 2018

Total Lunar Eclipse: 27 July 2018 (Occultation)

Animation of the occultation during the total Lunar Eclipse: 27 July 2018. SAO163626 and SAO163625. (Photo: Hannes Pieterse)

Tuesday, 24 July 2018

Open Evening at Boyden Observatory - Lunar Eclipse, Friday 22 July 2018

Open Evening at Boyden Observatory!
 ● Friday 22 July 2018
The Friends of Boyden cordially invite the public to their Open Evening on Friday 27 July 2018 at the Boyden Observatory (next to Maselspoort).
The programme begins at 18:00 for 18:30.  Entrance is R50 per vehicle.

Booking is not necessary.

A total lunar eclipse takes place that night – and mars is in opposition.

Lunar Eclipse – Mars at its closes
Refreshments will be on sale.

Entrance:  R50 per car – no booking

Enqueries : Office hours (weekdays):  Yolande Fick, tel. 051 401 9751 (or )
After hours:  Prof. Matie Hoffman, tel. 083 625 7154

Monday, 23 July 2018

Sunday, 22 April 2018

5th Free State Star Party - 8,9 & 10 June 2018

 Photo: Hannes Pieterse (ASSA Bloemfontein)

A Star Party in the warm heart of Central South Africa
8,9 &10 June 2018 (Friday - Sunday)

 On the farm Gansvlei close to Brandfort (13km)
GPS Coordinates:  28°47'48.63"S   26°28'25.66"E

Booking via Shaun Staats  -

GPS Coordinates  28°47'48.63"S   26°28'25.66"E
 Google Earth - Gansvlei - FS Star Party

Prepairing for the FS Star Party

To dew or not to dew

Observation site - In short
Storage room close to observing site during night/day.
Separate astro photography site available not to disturb serious observers.
Electricity available for telescope and electronic equipment (No kettles or heaters).
Observers must bring their own leads to get power from a central point in the veld.
Bring covers if you want to leave your equipment in the veld during the day.

- Have respect for your fellow observers. Use your headlight sparingly. You are blinding someone next to you. No bright white/red lights when observing starts. 

Deep-sky Marathon
ASSA Bloemfontein did the  first Deep-sky Marathon on Gansvlei in 2014 . (ASSA Top-100 Observing List). It is based on the very popular Messier Marathon. It was customized for deep sky objects visible in Southern-Africa.

 Visit the ASSA Marathon web page Sections > Deep-sky Section > Nebulae >  Clusters>
 Deep-Sky Marathons

 Download Observing lists for the Free State and Karoo Starparties

 - Scroll down to Observing Lists  for the Southern Hemisphere
( ASSA Deepsky 100, Lacaille and Messier)

The FS Star Party is not about marathons alone. It is also an event where astro friends will do some serious observing, astro photography and relax with hot coffee and serious braaiing. 

 2017 -7°C (00:00) and with a light wind from the East pestering us. It was 2.8 °C at 01:00 (Friday night)
2016 2°C (23:00 Friday); 10°C (00:00 Saturday; with wind and clouds moved over late in the evening. Clear early morning, with wind)
2015 dew caused havoc. Bring your dew heaters. Come prepared!
2014 Extreme –  We measured -7°C during the first night. Prepare with warm clothing and bedding.

Bring your own food according to your dietary preferences.
Hot beverages will be available during the night at a Coffee point close to the observing point.
Central braai area available. We braai early to be ready for the nights observing.
Brandfort - 13 km
- Branfort Slaghuis/Butchery is the place to buy your meat   (
14 Voortrekker St, Brandfort)

Bloemfontein 52 km

Provisional Programme

Friday  –  8 June 2018
Afternoon: Arriving and setting up at observing point
Evening - Early Morning:  Observing

–  9 June 2018
Morning: Visit Brandfort or sleep late; (No official programme). 

Afternoon - 11:00 till Before observing time: Advice and discussing Astronomy
Evening - Early Morning:  Observing

Sunday –  10 June 2018
Breakfast and we all leave! 

Other accommodation - Brandfort and surrounding
Ou Pastorie 
Lekkeslaap – Near Brandfort

June is Deepsky Marathon Month at the Free State Star Party - Helpful links