July 2020 – IMT3b Observatory

Exoplanet WASP-74b (30-31/7/2020) – IMT3

Started around 21:15, Guiding by 22:02, Capture started 22:22, Finished at 03:31.

Dave and I are part of the amateur exoplanet monitoring effort for the ESA Ariel mission. We decided that we would allocate some time to try and provide observing data towards the project whenever we could.

Part of this requires some forward planning such as looking at the upcoming transit visible and their associated time. This is due to the altitude of the object, the ingress and the egress times of the projected transit.

Prior to this we had discussed in advance which object to target for the chosen evening. All the hard work of choosing objects is done by the Exospies project website as they list the candidates they need data for via a schedule. So it’s a simple task for use to go through the list and work out what fits best for us.

Unfortunately whilst opening the dome to cool down I decided to review the schedule but I was hit with a server 500 error from the website. In a panic that I might miss the start of the event I scoured the internet for alternate exoplanet transit time websites and found the excellent Exoplanet Transit Database of the Czech Astronomical Society.

Later on I found https://www.exoworldsspies.com/en/scheduler/ as well which will be useful in the future, especially for looking at past events.

I had issues with focus drift all night due to the temperature fluctuations but at a recent Zoom session it was discussed that images can be out of focus with no detrimental effect on the measurements :

I was unable to auto focus successfully maybe due to the low altitude and seeing. I also discovered that temperature compensation was enabled so we probably need to remeasure the temperature compensation coefficients so the focus deltas are better between the par focal filters.

The object was at a relative low altitude, the outside temperature was warm and although the skies appeared clear our AAG CloudWatcher sensors via the Grafana dashboard told a different story. For us a truly clear sky is anything equal or lower than -18℃.

Sky Temperature – it was clear but it wasn’t !

After performing a meridian flip, resumed the guiding I started to feel tired so I set my alarm for 3am and went to bed. Unfortunately there appeared to be a guiding issue at some point shortly I went to bed.

Guiding issues shortly after meridian flip

This was investigated using the phdLogViewer and shown to be a loss of guide star and didn’t recover for around 18 minutes.

The guiding issue also caused the image to shift so the target and reference stars moved. We need this in frame in order to run the frames through the provided HOPs data analysis program which hopefully won’t have a problem in reading them. That’s an exercise for this weekend and hopefully we will have enough data to yield a decent light curve that we can submit.

Viewing Report 25th July 2020 – IMT3

21:47 – 00:23

GingerGeek and I were out imaging tonight. The sky unexpectedly cleared and we thought given the impending move of IMT3 to another site that we would try to gather some more data on M57, specifically LRGB and some additional Ha on the 12″.

We ran Autofocus on Luminance which gave 60,671 at 20.64℃ and HFR 6.5. We then started to image and after a few frames the temperature started to drop. In the main this is because we opened the dome last minute rather than a minimum of 2 hours before we used it so the dome was warm and now cooling down the optical train shifts.

We refocused to 62,712 on luminance at 19.10 with an of HFR 5.15. We then ran the image acquisition and below is a screenshot of the guiding, which looked like it was going to cause an issue but it was ok. If it had then it would have been the local fog rather than anything on the mount. At midnight we performed a Meridian flip nice and early which afforded us to leave the observatory running and go to bed. Notice the graph below, the yellow line drops as we performed the meridian flip, this is due to the dome now shielding against next doors light !!!!!!!

Guiding ok, notice the drop in the graph

The neighbours light continue to be a pain as can be seen here, I really cannot wait to move the observatory to it’s new dark site.

Finally managed to capture LRGB and Ha, below the RGB and Ha frames can be seen in PI. Note the central star is not visible in the Ha frame,

Finally I stacked 1 of each colour without calibration to see what it would look like.

So we left the observatory imaging, I had a quick peek outside around 12:30am and there was water running off the dome and the outside windows of the orangery! The Observatory ran until the dome shut at 3:58am (it woke me up) when the light levels started to rise.

Viewing Report 22nd July 2020 – IMT3

21:28 – 23:24

I opened the dome at 8:30pm and then went off to do some more work. A few calls later and it was time to come back and see if I could grab comet C/2020 F3 NEOWISE which had now moved further West and further in altitude over the past week, meaning it should be visible from the dome. Below is Arcturus as I performed a quick sync.

Below you can see Arcturus on The Sky X with the dome slit showing and the obstructions from the horizon also present.

Comet NEOWISE can be seen just above next doors tree.

A quick peek with the camera and I could just make out the comet.

Clearly more clouds rolled in which is typical

Looking at the cameras in the dome I could see the cloud bank of cloud (picture top right)

Fortunately the comet could be seen at the back of the cloud bank.

45 second exposure of Comet C/2020 F3 NEOWISE

So I set about quickly taking some images before the comet disappeared behind the tree.

90 second exposure of Comet C/2020 F3 NEOWISE

The other useful thing tonight was using the monitoring GingerGeek put together. Below are a selection of shots from the website.

The chart below shows the light cloud cover and the sky temperature is representative of the sky clarity and relates to cloud coverage too. The scale is inverted to -18℃ is a cloudless beautifully clear night sky, which tonight was not!

IMT Conditions Summary – Fisherprice style 🙂

At least there was no rain 🙂

This image below shows the cloud bank just North West of Reading that was a problem.

This next chart is from the data produced by the AAG CloudWatcher weather station. Note the sky temperature is nowhere near the -18℃ to be clear.

And finally the all sky cam just as I packed up showing the clouds clearing

Viewing Report 17th July 2020 – IMT3

22:05 – 02:00

Tonight I thought I would take some more images of M57 through the 12″ in OIII and then Ha. I first got the OIII filter focused at position 62,500 with a temperature of 22.42℃, I took 10 more images at 600 seconds.

Guiding was good even though there was high level cloud, seeing was good

Ha was then started at 00:44 after meridian flip. I spent some time looking at comet C/2020 F3 NEOWISE through 100mm binoculars with Helen, Ezri and her boyfriend Luke. Then we took some photos with the 50mm lens on the 6D.

I went to bed at 2am and left it running. In the morning I noticed I had 10 good images then the image moved due to guiding problems due to cloud.

Viewing Report 11th July 2020 – IMT3

21:00 – 01:55

GingerGeek and I decided to go after M57 the planetary nebula in Lyra. I had seen a lovely photo on Flickr with the outer Ha/OIII halo showing which resembled a splat of paint, taken with 9 x 1200 seconds Ha, 3 x 1200 seconds OIII and 9 x 600 seconds luminance. So we decided to go try. It would also add to my ongoing collection of Messier objects.

The resulting image of M57 was rather small as can be seen above. We initially set an autofocus run on Ha which came in at 67,213. We then focused on OIII at 67,178. After a few frames we noticed that the focus point had shifted ever-so, thus we refocused at 23:33 for OIII and to a position of 63,610.

The OIII focus exposure length was 20 seconds on a magnitude 4 star which completed very nicely. By the time we had gathered OIII for 9 x 600 seconds the clouds rolled in. We took Flats. GingerGeek ran the whole session remotely whilst I directed 🙂