We have had a request from Dr Richard Miles for close-up images of Comet 29P/S-W1. On September 25, amateurs spotted this comet starting a series multiple eruptions causing its brightness to increase dramatically by up to 400 times. These are caused by strange ‘cold’ volcanoes on its surface, which usually lie dormant for months or years. But in this case a very rare event has happened where one volcano eruption triggers another, etc. This is the first time this has been seen as usually we only see ONE other eruption triggered by the first one.  

What do I need to do?

If you can help then it is best to take exposures of 60 seconds duration using all three filters (red, green and blue), in a sequential manner on the 2m telescopes. If you can take 10 frames then that should be sufficient.  

On the 1m telescopes, please take single 120 s exposures with g’ and i’ and then a series of 120 s exposures through r’ to go deep into the outburst coma. 

Anything else?

If you have time afterwards then please repoint the telescope to Comet 17P/Holmes and take as many 120 seconds duration exposures again using all 3 filters. Comet 17P is famous for an outburst that happened in 2007 when it became 400,000 times brighter than normal. Maybe it will have another outburst whilst you are observing! It’s last one was this August.  

Where is Comet 29P/S-W1?

The daily positions for Comet 29P can be found on our monthly targets page.

Step-by-step instructions

1. For the target, use the name ” 29P ” (or ” 17P ” see below)  

2. Enter the RA position. For September 30 and 29P this would be ” 04 57 45 ”  

3. Enter the Dec position. For September 30 and 29P this would be ” +31 52 53 ”  

N.B. You will need to look at the URL to select the actual RA and Dec positions for the day you wish to observe the comet.  

4. Now tick the box for ALL three filters and in the exposure time line , enter ” 60 ” for each of them  

5. When the ‘Go’ button lights up bright green then click on it and wait.   In the top right of your screen you will see what the telescope is doing as well as the countdown clocks.   When the image(s) have been taken and saved, the ‘Go’ button will light up green again so just click on it and repeat the series for a total of 10 exposures.

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If you have time, please repoint the telescope and repeat the exercise but this time looking at Comet 17P and using the name ” 17P ”  

N.B. You can be filling in the new name, positions and exposure times even whilst the telescope is taking an exposure  

Use exposure times of ” 120 ” seconds for each filter.  

The positions of Comet 17P to point the telescope at are given in the table below (depending on which day you are observing):

  Date          RA               Dec
Sep 30   05 50 51      +45 09 04
Oct 1     05 51 38      +45 15 11
Oct 2     05 52 23      +45 21 17
Oct 3     05 53 06      +45 27 22
Oct 4     05 53 47      +45 33 27
Oct 5     05 54 26      +45 39 31
Oct 6     05 55 03      +45 45 35
Oct 7     05 55 38      +45 51 37
Oct 8     05 56 11      +45 57 39
Oct 9     05 56 42      +46 03 39
Oct 10   05 57 11      +46 09 39
Oct 11   05 57 38      +46 15 37