It is currently Tue Feb 20, 2018 11:09 pm

All times are UTC




Post new topic Reply to topic  [ 15 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: ISS transits
PostPosted: Wed Feb 17, 2016 5:32 pm 
Offline
Member
User avatar

Joined: Mon Oct 12, 2009 6:47 pm
Posts: 1248
Location: Bolton
I heard from a friend in Bolton that he'd been watching the ISS pass from Bolton just before 6pm on Monday, and was startled to see it transit in front of the Moon!
We looked to see if there would be any similar events in the near future, and it seems that there could be a couple of transits of the ISS in front of the Sun visible from this area on Sunday (21st) and Thursday (25th).
The weather forecast is not good for Sunday, so let's hope for better conditions later in the week. If it looks like there will be a chance of seeing it, I'll post more details here nearer the time.


Top
 Profile  
 
 Post subject: Re: ISS transits
PostPosted: Sat Feb 20, 2016 10:26 pm 
Offline
Member
User avatar

Joined: Mon Oct 12, 2009 6:47 pm
Posts: 1248
Location: Bolton
Here's the path for tomorrow's ISS transit, at 12:40 UTC:
Attachment:
File comment: Track for the ISS transit of the Sun on Sunday 21-Feb-2016.
iss_21feb.png
iss_21feb.png [ 587.25 KiB | Viewed 3313 times ]
This shows the centre-line (where the transit will cross the Sun's equator), but the event would be still visible from a few kilometres on either side. However the transit will last less than a second - so don't blink or you'll miss it!

The weather forecast isn't good (cloudy & very windy), but if we miss this one then there will be another on Thursday morning.


Top
 Profile  
 
 Post subject: Re: ISS transits
PostPosted: Sun Feb 21, 2016 9:18 pm 
Offline
Member

Joined: Tue Apr 22, 2014 5:11 pm
Posts: 14
Hi Ross,
what a brilliant challenge!
I was all revved up with nowhere to go at 1240 today. damn those clouds. Looking forward to Thursday though.. It took a bit of head scratching to work out the Calsky web site but I think I've got the basics sorted.
BTW I've been studying Roger Clark's website (clarkvision.com) for the past few days and apart from giving me brain ache it's got some unexpected conclusions. Such as that with modern DSLRs the read current is very low and not relevant if each exposure has the skyglow at around 25% and modern DSLRs also have onchip dark current suppression which means no need for darks. I've been experimenting with various 'lights' I've taken over the months (both good and bad) and I've got to say that from my standpoint the Canon 600D and 60D fall into the 'modern' category. I've certainly found that darks don't improve anything and flats aren't needed with Photoshop's ability to remove vignetting. He also reckons that a modified DSLR (7D) is not required; but he does live in a dark zone of the USA. Steep learning curve or what??
I'd be interested in your thoughts and comments.
Cheers for now,
Eb


Top
 Profile  
 
 Post subject: Re: ISS transits
PostPosted: Mon Feb 22, 2016 3:59 pm 
Offline
Member
User avatar

Joined: Mon Oct 12, 2009 6:47 pm
Posts: 1248
Location: Bolton
Here's an update of the transit details for Thursday morning:
Attachment:
File comment: ISS solar transit on 25-Feb-2016
25feb.png
25feb.png [ 403.46 KiB | Viewed 3270 times ]

If you're on the blue line then the Space Station will cross the Sun's equator (and so you'll get the maximum duration of one second or so).
The two red lines show the extent of visibility, but if you're close to them then the ISS will only appear briefly, close to the solar limb.


Top
 Profile  
 
 Post subject: Re: ISS transits
PostPosted: Thu Feb 25, 2016 8:15 am 
Offline
Member
User avatar

Joined: Mon Oct 12, 2009 6:47 pm
Posts: 1248
Location: Bolton
The forecast is good for this morning:
http://www.metoffice.gov.uk/public/weather/forecast/gcw2b5mx1
but the IR satellite images show a cloud-belt approaching rapidly from the West:
http://en.sat24.com/en/gb/infraPolair

According to the latest prediction, the event should occur at 10:48 (and 47 seconds in the centre of Bolton) this morning:
Attachment:
25feb.png
25feb.png [ 396.87 KiB | Viewed 3248 times ]
If you are planning to observe it, take all the usual precautions when observing the Sun.
I'll be using solar filters over the front of my 'scope (and finder), but you can of course use projection methods instead. But the ISS is probably too small to see by eye through eclipse glasses.


Top
 Profile  
 
 Post subject: Re: ISS transit on 25th Feb
PostPosted: Thu Feb 25, 2016 11:40 am 
Offline
Member
User avatar

Joined: Mon Oct 12, 2009 6:47 pm
Posts: 1248
Location: Bolton
Got it! :D

I was watching my it on laptop (with my head in the traditional cardboard box!), whilst Colin was following it on his camera' s tiny flip-out screen, and neither of us actually saw it "live". In fact we thought that the ISS must have made a very recent orbit adjustment, and were going to write to NASA to complain. ;)

But on reviewing our video footage, we had indeed captured the transit at the prescribed time.
Just need to work out how to process it now...


Top
 Profile  
 
 Post subject: Re: ISS transit on 25th Feb
PostPosted: Thu Feb 25, 2016 12:59 pm 
Offline
Member
User avatar

Joined: Mon Oct 12, 2009 6:47 pm
Posts: 1248
Location: Bolton
Here's the transit from my webcam (nominally running at 10fps, but looks like it dropped a frame):
Attachment:
File comment: 10-frame clip from SPC800 webcam on 70ED at f/4.3
iss_25feb16.gif
iss_25feb16.gif [ 1.09 MiB | Viewed 3247 times ]
I'd not got the RAW mode set up properly, but I've managed to salvage enough of the data to make up this sequence.


Top
 Profile  
 
 Post subject: Re: ISS transits
PostPosted: Thu Feb 25, 2016 2:47 pm 
Offline
Member
User avatar

Joined: Mon Oct 12, 2009 8:27 pm
Posts: 370
Location: Adlington
Well done Ross - looks like you were almost on the centreline. Adlington was too far north.


Top
 Profile  
 
 Post subject: Re: ISS transits
PostPosted: Thu Feb 25, 2016 3:33 pm 
Offline
Member

Joined: Tue Apr 22, 2014 5:11 pm
Posts: 14
]Hi,
I went up to the Lord Raglan pub at Nangreaves with all my gear EXCEPT the mount controller handset! Doh! Anyway I did have an ordinary emergency lightweight tripod, my 60D and a 500mm cat lens. I didn't know if anything was recorded but it sure was and here are a couple of frames....
Attachment:
ISS transits sun 25th Feb 2016 10h48m43s.jpg
ISS transits sun 25th Feb 2016 10h48m43s.jpg [ 75.02 KiB | Viewed 3237 times ]

Attachment:
ISS transits sun 10h48m44s.jpg
ISS transits sun 10h48m44s.jpg [ 68.74 KiB | Viewed 3237 times ]

BTW if you know to extract frames from a Canon MOV file then please tell; these are screen grabs. Canon software crashes.
Cheers for now,
Eb


Top
 Profile  
 
 Post subject: Re: ISS transit, Thursday 5th May
PostPosted: Tue May 03, 2016 8:23 pm 
Offline
Member
User avatar

Joined: Mon Oct 12, 2009 6:47 pm
Posts: 1248
Location: Bolton
This is the event which I mentioned in my presentation this evening.
According to the latest data, it will take place at 10:50:38 BST, and will only be visible from the area between the two red lines on this map:
Attachment:
File comment: ISS solar transit prediction for 5-May-2016
5may.png
5may.png [ 306.28 KiB | Viewed 2963 times ]

The closer you can get to the blue line, the nearer the path will be to the centre of the Sun, and the longer the event will last (but even then it will be under 1 second!).


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 15 posts ]  Go to page 1, 2  Next

All times are UTC


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group