ISS Transit of the Sun

[ejwwest]

Just taken from my back garden with my EdgeHD 925 scope and Canon 40D DSLR. Presence of cloud but got a couple of reasonable shots. Another tip: if shooting in RAW leave a while to let the buffer write to the CF card! I took the card out too early and was lucky to get two shots on the card!

International Space Station Transiting the Sun by ejwwest, on Flickr

International Space Station Transiting the Sun by ejwwest, on Flickr

ISS transiting the sun by ejwwest, on Flickr

[spaceboy]

I have wanted to do this myself but could never figure out when it will happen where I am. Great shot BTW!!

[ejwwest]

I have wanted to do this myself but could never figure out when it will happen where I am. Great shot BTW!!

calsky.org is the best site. It'll tell you when solar and lunar transits occur near you. It seems to be about once per year from my own site. If it's nearby but can't take my scope to, then I'll use my 800mm lens setup on the 40D. There's one a few miles away tomorrow morning so will see about that one.

[spaceboy]

Thanks EJ

[MikeD]

Great stuff:headbang:

Mike.

[Viv]

Nice captures !

Love the sun spot, near as well.

[Dave]

Great capture.

And a good sunspot group as a bonus.

[RogerTheDodger]

Very nicely done.

Ooh just checked on calsky and I get two transits of the ISS over the sun from my location on Sunday... I'll see if I can give it a go

[jgs001]

Nicely done

[ejwwest]

Very nicely done.

Ooh just checked on calsky and I get two transits of the ISS over the sun from my location on Sunday... I'll see if I can give it a go

I've put some hints and tips here: http://stargazerslounge.com/blog.php?b=1159

Hope they help but I'm still a long way behind the quality Thierry Legault gets!

[RogerTheDodger]

Thanks for that, I might try the Canon on the first pass and my QHY5 on the second but in avi mode. I'll have a little experimentation tomorrow.

[ejwwest]

Thanks for that, I might try the Canon on the first pass and my QHY5 on the second but in avi mode. I'll have a little experimentation tomorrow.

I used a laptop to help focus the Canon today (on the big sunspot group) rather than using Liveview (which is always difficult to focus the sun with as it's too bright). Whilst I'm sure it could be tweaked a bit better, the seeing and air turbulence (as well as cloud) looked to be the limiting factors today.

[stonemonkeylives]

Great shots.

sent from Gherkin Muncher mk .III (commonly known as a Galaxy S2)

[spaceboy]

Very nicely done.

Ooh just checked on calsky and I get two transits of the ISS over the sun from my location on Sunday... I'll see if I can give it a go

From what I can make out you would need to be here to see the transit. Is that correct ? as it so happens to have a nice open space to set up. Not far from us either RTD.

[Freddie]

Good job, nice pic

[RogerTheDodger]

From what I can make out you would need to be here to see the transit. Is that correct ? as it so happens to have a nice open space to set up. Not far from us either RTD.

Calsky says I'm on the centerline for the transit, so I'll see how it goes from home... too much kit to move for a 0.8 second transit

[ejwwest]

Calsky says I'm on the centerline for the transit, so I'll see how it goes from home... too much kit to move for a 0.8 second transit

Being on or near the centreline is best as you have more margin for error. In locations where two sightings are predicted on consecutive passes, it is likely one or both are very short transits close to the limb of the sun, making it much harder to be sure you'll get them (at least with a DSLR) unless you have a very high frame rate.

Good luck. Just about to process the shots I got this morning with my 800mm lens on the 40D.

[ejwwest]

and here it is:

ISS Transit Across the Sun by ejwwest, on Flickr

[Astrokev]

I've put some hints and tips here: http://stargazerslounge.com/blog.php?b=1159

Hope they help but I'm still a long way behind the quality Thierry Legault gets!

Just checked your tips. A good starting point, but folks should bare in mind that exposure, frame rate and jpeg vs raw will obviously depend on the camera used, not to mention thye scope or lens. With my Nikon D300 the buffer allows about 100 RAW shots at 7 fps without too much of a problem.

It's probably worth adding that it's best to have noise reduction turned off as this will definitely slow the processing speed.

For anyone brave enough to try and capture the ISS at night, I'd recommend looking up Dave's thread (formerly known as Eagleseye). He's managed some stunning shots and explains how he does it with manually tracking.

[ejwwest]

Yes, this will depend on those factors. On my Canon 40D you have to turn OFF the noise reduction to get more than about 12 frames in the buffer (RAW or JPEG) so that limits me. 1/1000s is about the slowest one can go when the ISS is that high in the sky without motion starting to show, which means a high ISO (1600). At that speed the ISO noise probably isn't a concern, especially as the focus and air turbulence are the more important factors. There are a lot of variables one needs to get just right and it's very easy to screw one up and mess up an entire shoot!

There's another predicted pass from my garden on Tuesday morning with the Sun low down and it'll take nearly 3 seconds to cross the sun. I can probably go to a slower shutter speed (say 1/500) and reduce the ISO to 800. However, I'll need to use JPEG as I'll fill up the buffer with RAW in less than the transit time (not even taking account that one needs to start the burst a second before).

I have done a number of ISS shots at night but with the telescope aligned on a fixed point the ISS is predicted to pass through. I usually get about 3-4 frames with the ISS in depending on orientation and timing etc.

International Space Station by ejwwest, on Flickr

I have not tried manually tracking the ISS and using a video camera and then stacking to get a better image. Maybe one day!

[MidnightSun]

Thx for the tip and great shot. Since Venus was a bust due to weather, maybe I'll have to try the ISS...

[ejwwest]

Thx for the tip and great shot. Since Venus was a bust due to weather, maybe I'll have to try the ISS...

Transits of the Sun by the ISS are reasonably common (3 times in the past year from my back garden and lots of opportunities within 10-20 miles every couple of months) but they're over in less than a second.