Search found 389 matches

by JohnM
Sat Apr 27, 2019 8:18 am
Forum: General chat
Topic: Finally a Black Hole
Replies: 10
Views: 2365

Re: Finally a Black Hole

You have to be careful when you say this is an image. The U-V plane coverage is sparse as can be seen from the on-line papers about the observation. As a result information is only available about part or the image. It is a bit like being given 10 to 20% of the pieces of a jigsaw and being told wher...
by JohnM
Thu Apr 18, 2019 6:50 pm
Forum: Light pollution
Topic: A cosmic census
Replies: 3
Views: 3633

Re: A cosmic census

I would agree with Stella, I have had experiance of a young person who was able to observe 12+ stars in the Seven Sisters when the older people could resolve 6. The person concerned drew a diagram of the stars she could see which agreed pretty well with images. The other variable that is not control...
by JohnM
Wed Apr 10, 2019 5:52 pm
Forum: Forthcoming meetings and events
Topic: First results from the Event Horizon Telescope
Replies: 2
Views: 3970

Re: First results from the Event Horizon Telescope - BBC TV

The BBC are broadcasting a special programme tonight on BBC4 at 21:00 BST covering the discovery. Details at https://www.bbc.co.uk/programmes/m00042l4. It should be available on iplayer (for those in the UK) for a few weeks after it is broadcast.

John
by JohnM
Wed Apr 10, 2019 5:06 pm
Forum: Forthcoming meetings and events
Topic: First results from the Event Horizon Telescope
Replies: 2
Views: 3970

Re: First results from the Event Horizon Telescope - M87

It turns out the rumours were wrong - the image released today is of the Super Massive black hole in M87. But still 'cool' even though it is very hot ! A popular article is at http://www.astronomy.com/news/2019/04/event-horizon-telescope-releases-first-ever-black-hole-image?utm_source=Yesmail&utm_me...
by JohnM
Mon Apr 08, 2019 9:31 pm
Forum: Forthcoming meetings and events
Topic: First results from the Event Horizon Telescope
Replies: 2
Views: 3970

First results from the Event Horizon Telescope

There is a press conference on 10th April 2019 at 14:00 BST to announce the ground breaking results from The Event Horizon Telescope. This is rumoured to be an image of the event horizon of the super massive black hole at the centre of the Milky Way, Sagiterrius A*. I have also seen suggestions that...
by JohnM
Wed Apr 03, 2019 4:25 pm
Forum: Observing
Topic: Meteor/Fireball
Replies: 7
Views: 2977

Re: Meteor/Fireball

Hello Nigel, One interesting point that Monica made was that one of the reasons that a lot of samples were recovered and investigated was that there were a lot of planetary geologists with a receiving laboratory not that far away in Texas waiting for the Lunar Rock samples. They just drove down to M...
by JohnM
Tue Apr 02, 2019 5:52 pm
Forum: Observing
Topic: Meteor/Fireball
Replies: 7
Views: 2977

Re: Meteor/Fireball

Nigel, The way to find out where a Meteor might have landed is to install a sky camera and join one of the networks that monitor Meteors. The combination of the data from your camera with others enables a prediction to be made of where any debris falls though the vast majority burn up in the atmosph...
by JohnM
Tue Apr 02, 2019 5:47 pm
Forum: Imaging techniques
Topic: Spectroscopy Workshop
Replies: 0
Views: 1633

Spectroscopy Workshop

I would have posted this in the Spectroscopy section but there is not one. If you are interested in Spectroscopy to determine the properties of stars and novae there has recently been a workshop in New Mexico. The presentations are available here : https://www.shelyak.com/whorkshop-spectro-smsw-2/?l...
by JohnM
Sat Mar 23, 2019 7:08 pm
Forum: General chat
Topic: So You Thought Y2K was Bad? Here Comes WNRO
Replies: 10
Views: 2216

Re: So You Thought Y2K was Bad? Here Comes WNRO

David, It is a sextant rather than a compass. From a bit of the manual that is online I think it uses 3V for the internal illumination and 28V for the heater for the top window that is outside the aircraft. Earlier versions used an internal bubble for level but I beleive this version uses a damped p...
by JohnM
Fri Mar 22, 2019 6:09 pm
Forum: General chat
Topic: So You Thought Y2K was Bad? Here Comes WNRO
Replies: 10
Views: 2216

Re: So You Thought Y2K was Bad? Here Comes WNRO

David, Attached is an image of the Aerial Sextant in a Vulcan I took last year. The ones for sale are at https://www.trinitymarine.co.uk/shop/periscope-sextant-mk-2a-calibrated-by-fenns-of-farnborough/ (other suppliers are available !) They look similar except the one in the Vulcan is missing the la...
by JohnM
Fri Mar 22, 2019 8:25 am
Forum: General chat
Topic: So You Thought Y2K was Bad? Here Comes WNRO
Replies: 10
Views: 2216

Re: So You Thought Y2K was Bad? Here Comes WNRO

Brian, Not sure you can navigate modern aircraft by the stars - early 747's still had a sextant port in the top of the cockpit but no longer. I doubt if military aircraft are fitted now - the air sextants from the V Bomber era are all for sale on a surplus site in Devon. GPS does a lot more includin...
by JohnM
Wed Mar 20, 2019 10:10 pm
Forum: General chat
Topic: So You Thought Y2K was Bad? Here Comes WNRO
Replies: 10
Views: 2216

Re: So You Thought Y2K was Bad? Here Comes WNRO

I checked my Garmin 35 GPS receiver that I use for occultation timings and one of the NMEA sentances is reporting the date as 1999 ! However some of the software appears to ignore this and must use the computer clock to get the correct date. LLooking at the output with GPSMON this reports the date t...
by JohnM
Fri Mar 01, 2019 10:25 am
Forum: Forthcoming meetings and events
Topic: SPA London Meeting - How we will leave the Planet
Replies: 1
Views: 1121

SPA London Meeting - How we will leave the Planet

As a preview to the London Meeting on the 27th April 2019 there is an article in the economist that describes some of the problems of inter planetary travel. See https://medium.com/@the_economist/the-problems-of-flying-to-mars-f38a4414fe8a Mekes interesting reading also a good primer for some questi...
by JohnM
Tue Feb 26, 2019 9:27 pm
Forum: Gallery
Topic: Mercury Observation tonight
Replies: 17
Views: 3438

Re: Mercury Observation tonight

I looked out of my window tonight at the place I though Mercury should be - just above the chimney and thought Mercury is bright tonight - it looks as bright as Venus. I picked my binoculars up for a better look and discovered that what I could see was the landing light on an aircraft !! Mercury was...
by JohnM
Mon Feb 25, 2019 8:49 pm
Forum: Gallery
Topic: Mercury Observation tonight
Replies: 17
Views: 3438

Re: Mercury Observation tonight

I found it quite difficult to see visually tonight - it was very close to the chimney of the house opposite and my eyes seemed to want to focus on that rather than Mercury. I had to 'force' them to focus on infinity and then Mercury popped into view. It might have been due to the clear sky with no c...