Cold observing nights on January 9 and 10, 2024

After a long, wet and very windy autumn and start of the winter, we finally had some clear nights on January 9 and 10, 2024.  

January 9, 2024

The first night, I mostly tested the eFinder, but I had some problems this time:

• The software did not seem to recognize the ServoCat.  This was a stupid mistake as I did not use the servocat setting in the configuration file 

• My settings in SkySafari were not correct, so I could not connect the telescope to SkySafari. 

• The push button of the eFinder handpad did not work anymore, so I needed to fix this.

I tried to use a voice recorder on my phone for the first time to keep track of the notes.  Certainly during this cold night, it was very useful that I didn't need to write everything down.

I started to observe at 20:56.  The SQM value at that moment was 19.7.  After playing around with the eFinder, I first looked at Jupiter.  The best magnification I could use tonight was using the 8mm Tele Vue Ethos, giving a magnification of 296x. Three moons were visible at the west, one moon (Europa) was at the east.  A faint star was also visible close to this moon. The two equatorial bands were very clear.  During moments of better seeing, festoons could be seen in the bands, mostly in the north equatorial belt.  A lot of smaller, colored bands were also visible above and below the equatorial belts.  

At 21:30 (SQM 19.77), I observed M 42, the Orion Nebula.  As alway, the views of M 42 are truly spectacular!  

• 31mm Tele Vue Nagler with CLS filter: Southern part is wonderful, the arms reach up to a star.  6 stars are easily seen in the trapezium.  An enormous amount of detail, mottling everywhere. Dark, straight line visible away from the fish mouth.  M 43 very bright and comma shaped.  UHC filter makes the view even more spectacular, with the nebula that goes a lot further with a lot of details.  M 43 is more difficult with the UHC filter.  O-III filter still shows a lot of details.  The trapezium is more difficult to see.  The arms are almost totally filled with nebulosity.  H-beta filter show less mottling close to the trapezium, much more even brightness.  
• 21mm Tele Vue Ethos with CLS filter:  Even more spectacular.  A lot of details around the trapezium, 3D effect.  Less nebula around the trapezium (darker).  
• 13mm Tele Vue Ethos with CLS filter:  Less sharp, but M 42 is already very low above the horizon, in between some houses.  Inside the fish mouth, a lot of nebulosity can be seen.  
• 8mm Tele Vue Ethos with CLS filter:  Very large, a lot a details, a bit less sharp.

At 21:45 (SQM 19.82), I observed M 1, which is a difficult object in this sky, not so bright, quite large, long, not a lot of details.  

The final object of the night was the eskimo nebula (ngc 2392), which at first looked like a very nice, blue ball.  The central star is easy to see, with brighter circle around the central part.  A fainter circle is visible around this brighter part. 

I started to break everything down around 22:00.  The temperature was -3.9°C at the beginning and went down to -4.8°C.  Humidity was around 70%.

January 10, 2024

The second night was even colder than the first one.  When I started to observe around 21:00, the temperature was -3.8°C.  When I stopped observing, the temperature had already dropped to -8.8°C.  Humidity went from 66% to 75%.  

I started observing at 22:13 with an SQM value of 19.84.  The first object I observed was Jupiter.  The 8mm Tele Vue Ethos gave again the best views.  There were a lot of details visible.  Two moons were visible at the eastern, and two at the western side.  

The next object was M 35:  Field of view was full of stars in 31mm Tele Vue Nagler.  A double curved line of 10 stars stands out, with at the end a brighter star. More difficult to see all stars in the 21mm Tele Vue Ethos, but the stars look more colorful.  NGC 2158 is very easy to see, with the first stars resolved, shape of a triangle.

At 22:37 (with an SQM value of 19.92), I observed M 45: Much too large for the 31mm Tele Vue Nagler.  Reflection nebulae are clearly visible, not only around the stars (which will most of the time point to a too high humidity).

At 22:44,  I switched to M 78.  A nebula was visible around two faint stars.  Best in 21mm Tele Vue Ethos, 13mm Tele Vue Ethos also gave good results.  Dark part close to one of the stars.  Faint object.    

The temperature graph for January 10, 2024.