One Fantastic Hour

[Roy Challen]

Got the Tal RS out last evening for a lunar session. Oh wow, what a session!

For starters the seeing was the best it has ever been in my garden. I pushed the magnification to x375 (6mm + 2.25x barlow = f/22.5, CA? What CA?) and the view wasn’t just acceptable - it was sharp. Not as sharp as without the barlow, but not mushy or blurred or in any way soft. I’ve never had the mag so high, in any telescope I’ve ever used, and it felt like it could take more. However, that was as high as my eyepiece selection would go. I don't think any smaller details were being resolved, but what was resolved was bigger, therefore easier to see. I was actually impressed with the Skywatcher 66⁰ 6mm. This series of budget wide angles doesn’t have a great reputation in fast scopes, but in the Tal, they are genuinely good eyepieces. I need to use them more, I think. There was a little bit of kidney-beaning with the barlow, but it wasn’t bad, and I quickly got used to the correct eye placement.

At this magnification, it’s a bit pointless trying to take a tour so I concentrated on the Lacus Mortis region, located between Mare Frigoris and Lacus Somniorum. Lacus Mortis is a small lunar lake dominated by a central crater, Burg, with a cleft (that's how it appeared to me) central peak. Burg is nicely terraced, and this was very obvious due to the angle of sunlight. On the plain, there are two very obvious rilles and a couple of much fainter ones. Small craters dot the smooth areas. The ejecta surrounding Burg gives a nice texture. Surrounding the lake are low hills to the west, north and south. The southern rim is broken by several craters of different sizes, the two largest of these are called Plana and Mason. The level of detail was astounding.

I spent about an hour in this area. It was made considerably easier by the fact that, for the first time since I’ve owned this mount, I was using the motor drive for the RA axis. It’s really easy, just plug it in and turn it on. All it does is track, although you can speed it up or down for centring. It is silent in operation, and seems to be accurate, certainly good enough for visual use. It is a bit more faff to get the extension cable, plug it in in the bathroom, pass it through the window and run it up the garden, but it really is worth it. I don’t know why I’ve never used it before…

I had a quick look at Mars, but there were no details visible, even at x375. Maybe the nearby moon washed out any details. I also had a go at resolving the E and F stars of the Trapezium in M42. This was at a lower altitude than the moon and the seeing wasn’t as good here so couldn’t see those elusive stars. It felt as though the subtlest hints were being made of their presence though, so if the seeing were better, there may have been a chance. Watching A-D dance around was quite hypnotic 🤩.

What a great session! 
 

Edited March 20, 2021 by Roy Challen

[Epick Crom]

Nice report Roy! The Moon is a beautiful and rewarding target👍

[Stu]

What a fabulous session Roy, really beautifully described. Lacus Mortis is not a feature in familiar with so I had a look at the Lunar Quickmap app on my phone to follow your descriptions; they match very well 👍. Burg does indeed look to have a cleft in it.

I’ve posted a few screenshots here, this link below may also take you to a map. The illumination is set for 10pm last night so should be roughly right for your observation.

https://bit.ly/3r6ckPK

[Roy Challen]

Cheers Stu, I take it that's an iPhone app? I'm using Moon Atlas 3D for Android, it's a bit basic but does the job.