Seas on two worlds: Lunar and Martian Mare

[John]

Clear skies and quite steady currently here.

Got the Tak 100mm out and targeted the Moon. Lots of interest but the Mare Crisium stood out as it was bisected by the terminator and it's dorsa (fine ridges) were well displayed. I also observed at 200x - 300x the two promontories, Lavinium and Olivium that reach out towards each other across a bay on the western rim of the Mare. This was the site of the famous giant bridge spotted in 1953 by amateur astronomer John J O'Neill. He was of course mistaken but it makes an interesting story nevertheless and was used by Arthur C Clarke in his novel "A Fall of Moondust" as explained here by Stephen James O'Meara:

  https://astronomy.com/magazine/stephen-omeara/2010/05/stephen-james-omearas-secret-sky-oneills-illusion

I could see how the small crater between the promontories might, under specific lighting, be mistaken for something else. It is a very interesting area of the lunar surface to explore at high powers under tonight's illumination.

Mars is nearby and had risen out of the unstable air. It was showing steadily and sharply at 225x - 300x with the 100mm refractor. The southern half of the martian disk was where the darker detail showed clearly in the form of two distinct bands tonight. These areas include the Mare Sirenum, Mare Cimmerium and Mare Tyrrhenum. The southern polar cap was clearly defined as well.

I used some PC editing packages to produce this representation of the view of Mars tonight. Probably the nicest of the opposition so far for me:

[Les Ewan]

I really envy people with drawing abilities like this it must be very satifying. My twin sister is a great artist but non rubbed off on me.

Seeing here was not so good for Mars as yesterday morning but still managed to use my 9mm kellner for a descent view at 200X. I find the polar cap a bit difficult now.

[Ships and Stars]

Nice one John. I viewed Mars through a scope for the first time last night - used the 10mm BCO and 2x powermate. I didn't do much research beforehand, so didn't look out for the polar caps or the seas, but could make out some detail. I did note the three seas you mention.

I viewed around 12:45am, wanted to wait until it was a bit higher in the night sky for better seeing here, but had to get some rest as the kids keep us on our toes in the daytime.

I think we still had a bit of jetstream up here last night, but seeing was ok. Not brilliant, not terrible.

Thanks for the report and the information 👍

 

[Paz]

Nice drawing. I still haven't observed Mars this time around as getting up early or staying up really late has been beyond my levels of motivation but I looked out of the window at 4 in the morning and thought crikey it's really high up.  I am going to have to try a dawn patrol!

[jock1958]

Thanks @John I was out at 5am and had a similar experience as yourself through my Tak 100DL & TV 3-6 zoom at 225x - 300x.

Even though Mars was high in the sky and atmosphere calm the seeing wasn’t consistent with only occasional detailed glimpses of the darker areas and SPC, am I hoping for too much with my ageing eyes? 
 

[Nyctimene]

Another one here attracted by the bisected Mare Crisium. Observed with the 5.1" Heritage under almost clear skies; average seeing. Found the Dorsae quite prominent; attractive was the crater trio Atwood, Bilharz and Naobonu, the first two displaying as well lit rings under the low sun. Gutenberg; Goclenius (the Rimae not visible); Colombo; Montes Pyrenaeus. Nice crater pairs of Colombo/C. A, Magelhaens/M. A. and McClure/Mc C. Slightly N of McClure C, I stumbled, pointed by LunarMap HD, over the concentric crater Crozier H. With mags of about 150x (Seben Zoom+ 2.25x Barlow), I could make out it's oval-pointed outer crater, but not the concentricity. Seems of similar difficulty as the concentric crater Marth; Hesiodus A is way easier. A nice detection; should be doable with the 8". - Mars with the small polar cap, and the darker "band" John mentioned. 45 minutes of pleasure in the early morning hours, ending 05.20 CEST.

A comprehensive introduction to concentric craters here:

https://skyandtelescope.org/observing/celestial-objects-to-watch/crazy-about-concentric-craters02252015/

Stephan

 

Edited September 5, 2020 by Nyctimene