Saturday, 11 January 2014

20140110 - Exoplanet Observing Preparation plus some Comet Observations and Images

I had hoped to have been writing up a successful observing run today, but it was not to be. :( However I did manage to put the time to good use and none of the research I carried out for it is wasted. :)

Once the internet was back on I checked the weather for the coming week. It was not looking good at all. It looked as though there was going to be some clear patches last night, then a couple of days of cloud and rain, then a clear night starting at midnight on Saturday and then four days of either cloud, rain or snow!

I checked against my lists of exoplanets to observe to see what transits and secondary eclipses were due to take place last night and created a potential observing list.

Find The Stars

Now the great majority of exoplanet host stars are known by the name of the survey that discovered them, then a number to indicate the order that they were discovered and finally a letter to indicate the planet. The first planet to be discovered orbiting a star is "b", the second "c" and so on. There are exceptions to the rule and when appropriate I will mention them. :)

So the starting point is to identify the star so that I have something to do a "find" or "locate" when using the planetarium programme I use to control the telescope.

The best way to do this is by using an online astronomical database called SIMBAD . It is a fantastic toolset and one that I will mention quite a lot in the future. Today though I will just cover some of the tools.

One of the query options is by identifier and this is the one I start with. It does not have all in them so I will cover a few other options as well. Let us say that the exoplanet I want to know about is CoRoT-1 b. I key in CoRoT-1 - after all it is the star I am interested in. This brings up the correct page. I then scroll down to the Identifier Section where it lists all the other names it is know by. One of the identifiers listed is GSC 04804-02268. This is ideal for my purpose as GSC (Guide Star Catalogue created for the Hubble Space Telescope) is one of the catalogues supported by the SKY programme I use to control the telscope.

If this does not work then I do a simple Google/Yahoo/Bing search on the exoplanet name and GSC and normally that will pull up a paper or a Wiki that will give me the answer.

The last option is again using SIMBAD, but instead of using the Indentifier Query I use the by Coordinates Query and enter the RA and DEC  and this should bring up the star.

This chore is reducing as I have a file that I keep updating each time I observe a different exoplanet.

Location of Star

I know time range that I need to observe (this is in the original observing list) so the next thing I need to do is check which parts of sky these potential options will traverse, (of course it is the Earth that is revolving on its axis and not the sky). I use the SKY programme to help me see where in the sky they will be at different kinds. I eliminate from the list all those that cross the Meridian (imagine a line starting directly to the South, going up overhead, through the Pole and to directly North). This is because the type of telescope mount here is a German Equatorial Mount  which is not capable of tracking across the Meridian.


I then look at what is left in the list. Unless there is any with a special priority I then decide which are the best ones to observe. I take into account altitude, where the Moon is, the brightness of the star, the range in potential magnitude variation during the transit and few other odds and ends LOL `(the odds and ends are actually a blog in their own right as it includes comparison stars and guidestars)

Finder Charts etc

The final thing I can do before the evening is to download any finder-charts I need. Many of the steps taken only have to be done once, so once a you have observed a specific exoplanet, the next time most of the preparation work has been done.

Back to Last Night

On my list I had four options, two rising in the East and two setting in the West. The weather forecast had mentioned a strong wind from the East, so I had a walk up to the observatory to see how strong it was. It was quite strong so I scrubbed the two in the East off the list. I waited a couple of hours for the first in the West, during that time it was clear to the South West, but guess what the cloud came in. The same thing happened at four in the mornings so I packed up and went to bed :(

Hangout about Exoplanets

Talking about exoplanets LOL. On Wednesday evening I attended a google hangout on exoplanets involving Astronomy and Discovery   magazines and chaired by +David Eicher Editor of Astronomy. It was great. No dumbing down, interesting and suitable for all. I look forward to more of them. You can even
ask questions :) so I did :) . I am quite new to this hangout idea, so not sure how long they are kept on line. Here though is the Link to a recording, but how long it will remain live I do not know.Well worth an hour of your time.

While I was waiting around last night

I processed a number of images I had taken a few days ago of some comets. Below is a selection of a few of them. The one good thing about comets is that in a normal exoplanet observing night there is normally time to slot in before, between and after, a few images of comets.  

290P Jager 2014-01-06 20:33 N Mag 13.7
4" Pentax at F4 ST8 clear
The small boxes - viewing left to right show the progress of the comet over 30 minutes covering about 20 arc seconds.

C/2012 X1 Linear 2014-01-07 04:58 N Mag 10.7
4" Pentax at F4 ST8 clear

C/2013 R1 Lovejoy UT 2014-01-07 05:46 N Mag 8.3
4" Pentax at F4 ST8 clear