Wednesday 25th April 2018 – 22:04-23:10
I’d recently come across an interesting sounding asterism known as Kemble’s Cascade and decided that it warranted some telescope time. It is a chain of stars, situated in the far northern constellation of Camelopardalis – the Giraffe. This constellation is quite faint and does not have many objects of interest, so it was a pleasant surprise to find something within it that intrigued me. Located at one end of the cascade lies NGC 1502 – a small open cluster, which makes locating it much easier.
Unfortunately for me, my observing site has a tree to the north, and as such this part of the sky is always difficult to observe. I opted to set up the telescope on the front patio by the house, which I seldom do. After aligning on Arcturus and Regulus, I slewed to the cascade, and discovered it was now behind the house! The telescope batteries had not been changed for quite some time, and it was running dangerously low on power. As such I decided to take the telescope back inside, replace the batteries, and set up once more in the usual spot, hoping that the tree would not be in the way.
Luckily for me, the tree did not impede my observation, and I found the open cluster (NGC 1502) at one end of the asterism (after realigning, this time on Arcturus and Spica). The cluster itself was quite compact and small, and had two bright stars that looked a little like eyes. It was very nice, and a good signpost for Kemble’s Cascade.
The cascade itself is quite large, so to observe it all I had to slew the telescope. However it was nice to see, and well worth the challenging set up (although it wouldn’t fit in the eyepiece all at once, so a focal reducer and/or imaging it as a mosaic would make it more spectacular).
NGC 1502 and Kemble’s Cascade (outlined in grey) – screenshot from Starry Night Pro
Once I had spent some time observing this, the next target was Jupiter, which was just rising.
I had a good view of the planet, and all four of the Galilean moons were visible. I found it quite difficult to get it in focus with the 9.7mm eyepiece, but it looked good after a while. There were cloud belts visible, although I couldn’t see the Great Red Spot (but that may have been because it was on the side of the planet facing away from Earth).
One issue with the Great Red Spot is that it drifts around the planet and is not in a fixed position. As such its position as simulated in Starry Night is almost certainly incorrect. Fortunately this has been thought of by the developers, and its position can easily be changed by altering a number in a text file. Since this observing session, I have found a website that tracks the GRS’ longitude, and it appears to drift fairly predictably, making regular updates to the position in Starry Night fairly straightforward (and therefore enabling me to predict when I ought to be able to see it)! There is also a good website that tells you when the GRS should be transiting the face of Jupiter.
After I’d spent some time observing Jupiter, I decided to have a look at the moon before heading indoors. The wind was starting to pick up at this point, and I didn’t want to risk the telescope blowing over. The moon was very bright, even though it is still waxing. I have now finally ordered a moon filter, so the brightness of the moon will be less of a problem in the future!
I saw a couple of interesting looking craters along the terminator, which I later identified as Hainzel and Mee. I also saw Clavius. I took a few photos with my phone through the eyepiece, and although the quality isn’t great, you can clearly see Clavius, and the other two craters too.
Clavius is visible towards the bottom left of the image, while Hainzel and Mee are located about halfway up along the terminator
Having had a long and successful session (in spite of the issues at the beginning), I went inside and ended the session.