Plato craterlet and double stars with 4 inches

[Victor Boesen]

I'm very late to post this, but busy times have been upon me lately

Due to the bright sky even at midnight I decided I'd bring out my 4" Tecnosky refractor for some lunar observing and a couple of double stars. My main attention, however, would lie in Plato where I wanted to give the craterlets a go, since I've never actually done so before.

Plato

The seeing wasn't the best but I spent quite a while teasing out detail around the Plato area, and I even tried sketching a lunar feature for the first time (see below). I was aware that 4 inches of aperture would be right on the limit for observing the craterlets, but at 152X and brief moments of steady seeing, I began to spot a slightly bright dot/mark approximately right in the center of the Plato floor. At first I was very sceptical, but on purpose I didn't take a look at a picture of Plato to compare with. Instead I continued observing Plato until I repeatedly was able to glimpse the bright mark, and I also spotted the feature at 106X. I later confirmed that this was infact craterlet "A", the largest of the craterlets.

Double stars

Epsilon böotes, 3 arcsec sep.
This double looked beautiful in the 4" of aperture. Is was split perfectly at higher magnifications and both stars were pin point sharp!

Gamma Virginis, 2.5 arsec sep.
Same went for this double, was comfortably split but a little more difficult than Epsilon böotes.

Double double
The lowest magnification I was able to split these doubles with was 81X where the faint pair, however, was nodged the majority of the time and not split completely. At 106X both pairs were split most of the time but faint pair nodged for some moments.

It was a very enjoyable session as I ended it and I went to bed. I never really observe double stars much but I always find the interesting to observe and a challenge to split certain pairs or try splitting at lower magnifications and etc.
Thanks for reading!

Victor

[John]

Nice report and sketch !

I think there are 4 Plato craterlets that can be seen with a 100mm scope but two of them are close together and appear as one and the lunar phase does need to be right to get effective illumination. These are known as the "Big Four" or A, B, C and D

Nice guide to these little craters here:

https://www.cloudynights.com/topic/34841-guide-to-plato-craterlets/

 

 

 

 

[Victor Boesen]

23 minutes ago, John said:

Nice report and sketch !

Thanks John! As hard as a I tried I couldn't spot anymore, but I will certainly be revisiting these at some point! I think the pair of craterlets (C & D) would be doably with good seeing and the moon closer to Earth at perigee. Fun challenge with four inches!!

Victor

[callisto]

Nice report, thanks for sharing 👍

 

Mark

[Starwatcher2001]

Nice one Victor. I was looking at Plato and Sinus Iridum (my favourite lunar feature) a few days ago during daylight, but couldn't spot any craterlets with my 80mm. I'll have to have a go with the 925 when the evenings are dark enough to warrant setting it up.

@John, great link on CN, thanks very much.

Victor, if you've not come across it, this is a great interactive site for looking at the moon in detail (posted here on SGL by some kind person, I forget whom):

https://quickmap.lroc.asu.edu/layers?extent=-13.3059512,49.8523329,-6.032996,53.4861116&proj=10&layers=NrBsFYBoAZIRnpEoAsjYIHYFcA2vIBvAXwF1Siylw4oNEQBmOORxBLPAk8y8oA

 

[Mr Spock]

My 120mm achro picks up 4 craterlets, so your 100mm apo should too.

[Victor Boesen]

1 hour ago, callisto said:

Nice report, thanks for sharing 👍

Thanks Mark! Thanks for reading;)

1 hour ago, Starwatcher2001 said:

Victor, if you've not come across it, this is a great interactive site for looking at the moon in detail (posted here on SGL by some kind person, I forget whom):

Wow thanks! I've been looking for something like this for a while so thanks for sharing. Will be very useful!

52 minutes ago, Mr Spock said:

My 120mm achro picks up 4 craterlets, so your 100mm apo should too.

Perhaps, but I'll need some clear skies first

[RobertI]

Nice report Victor, doubles to indeed look superb through a nice 4" apo.

[chiltonstar]

The craterlets are certainly a test of eye, scope and seeing! Nice report.

Chris

[wookie1965]

Great report a 4" Refractor is a great scope for doubles and multiple star's even in these light night summer evenings. 

[Mr Spock]

I'm hoping to get my new 250mm Newt on this. The last one I had, an old blue tube Skywatcher, was excellent on planets. It picked out a number of Plato craterlets as well as the rille in Vallis Alpes. I'm hoping for some good seeing this lunation so I can confirm the new scope is just as good.

[Victor Boesen]

1 hour ago, Mr Spock said:

I'm hoping to get my new 250mm Newt on this. The last one I had, an old blue tube Skywatcher, was excellent on planets. It picked out a number of Plato craterlets as well as the rille in Vallis Alpes. I'm hoping for some good seeing this lunation so I can confirm the new scope is just as good.

Wish I had tried Plato with my old 250PX before I sold it. Frankly I just didn't have the time and surplus to use such a large scope. Hope your new one will perform great!

1 hour ago, wookie1965 said:

Great report a 4" Refractor is a great scope for doubles and multiple star's even in these light night summer evenings. 

Indeed! It's good to have something that motivates you to get out the scope despite the lack of darkness

[John]

The best I've managed was 11 craterlets on a great night a couple of years back with my 12 inch dob. The Pentax XW 5mm is a super lunar eyepiece as I discovered that night. The illumination was very favourable showing the craterlets as tiny but distinct pits with illuminated rims and darkened floors.

 

[Victor Boesen]

20 minutes ago, John said:

The best I've managed was 11 craterlets on a great night a couple of years back with my 12 inch dob

Very impressive John. I sometimes miss the large aperture from my 10 inch dob I sold in exchange for my 4" apo, but the amount I use the apo makes up for every inch considering my current point in life

[chiltonstar]

On 09/07/2021 at 19:35, John said:

The best I've managed was 11 craterlets on a great night a couple of years back with my 12 inch dob. The Pentax XW 5mm is a super lunar eyepiece as I discovered that night. The illumination was very favourable showing the craterlets as tiny but distinct pits with illuminated rims and darkened floors.

 

Interesting how the number of craterlets increases with aperture! With my 4" frac, I see 4 clearly, with the two close craters seen as one. With my 180 Mak using a 15mm Vixen SLV (superb ep) I can see about 6 - 7 visually. If I connect a camera and display the output on a screen, I can add a few more. Imaging it with a fast frame rate (10 ms or so frames) and stacking adds more, for example earlier this image earlier this year. Craters below the resolution limit of the scope just appear as white marks.

Chris

Edited July 13, 2021 by chiltonstar