John

I've been reading through a CN forum thread on this topic from 2010. This post:

https://www.cloudynights.com/topic/281631-barkers-quadrangle-location/?p=3600170

includes an extract from Sir Patrick Moore's book "Survey of the Moon" and an image similar to @Stu's which seems to suggest what and where this mysterious feature might be.

I'm going to pack in tonight I think but it's been an interesting "quest"

2 minutes ago, John said:

I'll have another look Mike

I got distracted by Petavius and Langrenus both of which are spectacular tonight. The shadows of the central peaks in Langrenus and the shadows on it's ramparts remind me of a Chesley Bonestell painting

Ahh - I see the "kite" shape and it's tail now.

Trouble is, as you start to look hard, the illuminated wrinkle ridges across the mare floor can start to look like all sorts of things

I'll have another look Mike

I got distracted by Petavius and Langrenus both of which are spectacular tonight. The shadows of the central peaks in Langrenus and the shadows on it's ramparts remind me of a Chesley Bonestell painting

18 minutes ago, Stu said:

Success here I believe. I certainly saw a rectangular shape with four corners. Managed to take a picture which I think shows it. Clearer visually of course.

Thanks @paulastrofor the heads up. Gave me a reason to get out with the Heritage 150P 👍

I'm just observing that very feature now with my Tak FC100 at 257x. Not quite a perfect rectangle, slightly rhomboid on one of the shorter sides but it is pretty clearly defined. Now whether that is because of Paul's "heads up" and / or Stu's image and I'm looking for it, I'm not sure 

The "lines" between the corners are pretty fine - probably just a small change in illumination will impact them.

Nice image Stu and thanks for the tip to watch out for this Paul

I'll probably pop the Tak 100 out at some point. It doesn't need much cooling time though

It will be a while until the Moon gets above the conifers here so there is no particular hurry.

6 minutes ago, Adam J said:

I used the terms: "for me", "I would be comfortable with" and "so to me". 

Not sure how you read that as me talking about anything other than my own experiences. 

For me it would make little difference to own a 4 inch scope capable of 400x over one capable of 250x unless I want to see nothing but floaters. So to me the distinction in quality is meaningless.

I never said anything about anyone else but it's something everyone should consider against their expectations of performance for a low aperture premium refractor. Just because it is capable of 400x doesn't mean your eyes are. 

I am knocking no one, infact if you have the eyes for it i am quite envious. 

This seems to refer to "anyone else":

"....to me it is a complete nothing statement when people make claims like that...."

By all means think what you like about what others posts but perhaps best to keep it to yourself ?

Altair Astro introduced these in 2015 I think.

I've tried filters of various types but without success. While the glare from Sirius A subsides, Sirius B seems to get dimmed to the point where it just drops below visibility. Plus the filter itself adds a little more scatter to Sirius A. It seems to be a fine balancing act 

Last night was the first time in a few years of trying that I've split Sirius with my ED120. The next challenge is to try to get it with the Tak FC100.

2 minutes ago, callisto said:

Just ordered a copy Mark 😀

That's my main guide along with the Virtual Moon Atlas on the laptop and Lunar Map HD on my Android mobile.

I observed that area (your first arrow) as well last night. I had it down in my mind as the Mare Anguis as well. I didn't feel that I could see far enough "around" the limb to get the Mare Marginis.

Not sure about the other features

20 minutes ago, Adam J said:

For me its more that the size of the exit pupil to get 300-400x mag on a 4inch scope is not something I would be comfortable with technically possible or not so to me it is a complete nothing statement when people make claims like that.

Just because you are not comfortable with it, does not make it a "nothing statement". By all means use the magnification that works well for you and your eyes but don't knock others who find that they enjoy something else when the conditions allow.

I think people report what has worked for them honestly and with enthusiasm on here and it would be a shame to dampen that.

Lovely images and report Paul

2 more clear nights forecast here. Can't recall when I last observed 5 nights in a row - probably around the time of the comet last year

Excellent Nik

Your "cunning plan" worked a treat

Light scatter from Sirius A is the big issue with this challenge. Last night I noticed that this was quite variable. There were times when the Sirius glare would suddenly inflate for a while masking the Pup star entirely. I assume that this is due to an unstable air mass of some sort ?. I have also found that sometimes "looking too hard" can cause the eye to become moist and that creates it's own very local Sirius scatter as well.

Great report again !

"See the Universe for under 100 quid"

This could be quite interesting.

Not a particularly wide range (7.7mm - 15.4mm) but a 75 degree constant apparent field of view:

https://www.cloudynights.com/topic/758189-new-apm-zoom-eyepiece-77mm-154mm-75°-constant-fov/?p=10915903

Combined with a fine quality barlow / telextender maybe ?

I've been observing the moon tonight, like many of us I expect.

The craters Messier and Messier A, with the distinctive comet-type rays extending from the latter, are nicely on show in the Mare Fecunditatis and will be for the next couple of days, clouds allowing. Well worth a look though any telescope.

While finding out more about this interesting pair of craters I came across this fascinating photo in the Internet Archive. It shows the Apollo 16 Lunar Module "Orion" in lunar orbit while it is being inspected from the Command Service Module "Casper", the photo being taken from the latter craft of course. And in the background, on the lunar surface are the craters Messier A and Messier. Not an image that I've seen before.

You can click on the image to see it at a much larger scale and very impressive it is

https://archive.org/details/as16-122-19533

Interesting views of the Mare Orientale area tonight compared with last night.

It's fully illuminated to the limb tonight. The full length of the darker Lacus Veris can be seen whereas I could only see a small part of it last night. I think I can just make out the crater Kopff very close to the limb just as a highly elongated darker sliver of tone. 

On the opposite limb, the Mare Crisium is showing well with the "cape" of the  Promontorium Agarum extending across the mare on the western side nicely illuminated. 

My other half is watching old "Star Trek" episodes at the moment so I had to have a look at the crater Picard of course

6 minutes ago, Dark Vader said:

Pretty sure I got it tonight with the 200p. Barlowed the Hyperion IV zoom at 8mm with the dedicated 2.25x at (I think) 337x. A very faint speck of light  trailing Sirius A at around the 4 o clock position Dob view.

It came and went with the seeing but I went back to it after a look around Orion and it was in the same position. 

Got the best views yet of Trapezium E&F tonight at 150x as well. 😎

Excellent - well done DV

Very interesting report on the ED150 Mark

I reckon it's got more to give under the right conditions.

10 hours ago, John said:

I'll try the ED120 tonight I think - working my way down the apertures !

Got the little blighter !

First time I've managed it with the ED120. Quite hard and I repeated the observation about 10 times with 2 different eyepieces to make sure. The "Pup" star was not consistently visible but was positively there during periods of the steadiest seeing.

I was motivated to sketch the view with the 3.5mm Pentax XW eyepiece at 257x (refractor plus mirror diagonal view):

I've just been having a quick amble around the double stars in Orion now that my ED120 refractor has cooled down.

The seeing seems to be absolutely top notch here currently 

Text book high power star images. A real pleasure to observe Rigel, Alnitak, E & F Trapezium, etc, etc.

Really clean split of 52 Orionis at 360x !!!! - 2.5mm setting with the 2mm-4mm Nagler zoom. Steady as well - wafer thin dark thread between the airy disks.

Dawes limit for the scope is .97 arc second and I believe 52 Orionis is around 1 arc second in separation so no complaints at all here

A 4 inch refractor of this quality for under £500 is an outstanding buy IMHO.

And thanks to your review, we know that it is a good one too

It does beg the question of what we actually get when we pay 4x-5x more for a similar spec scope from a premium brand with a different type of glass in it

I suspect "not a lot" is the answer for many !

Thanks for compiling and posting your thoughts on this scope. Having done similar stuff in the past, mostly on eyepieces, I fully appreciate that it takes time and thought to do this and it can also be quite a nerve racking process "sticking your head above the parapet", so to speak

Great stuff Paul - very useful info and images as well

I'll be out again later, with the ED120 this time.

Lovely Stu !

"OK-4 fest" does not sound as enticing as a "Fluorite Fest" 

Hi,

Good stuff so far !

How much have you used the scope and mount so far ?

A few sessions with it will start to inform your choices as to what might benefit your visual observing.

How much astro budget do you have left for further purchases ?