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ISS, up close and personal

Vega

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Vega

Vega

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how are you guiding matt? had a go myself.. trying to point the scope by hand and failed dismally ..lol

It can only really be done with a dobsonian. As it rises in the East, I completely loosen the tightening handle and swivel the scope in azm so it lines up pretty well with it's track. Then I manually lift the tube in alt while looking through the finderscope (not good for the back when it reaches the zenith!). Then when it reaches the zenith I quickly swing the dob around and follow it down to the West. If anything you, want to get it right on the crosshairs when it is at it's highest (which as it happens is the hardest time to be accurate!). The reason being, this is the point at which the space station is closest and will look the largest. Travelling at 17,000 odd mph it sure does get smaller as it gets lower/further away.

I am usually only successful on the passes that are right overhead (over 80deg in height). These passes are almost dead straight across the sky. If the pass has an arc in it's track then it's very hard as I have to move the dobsonian in both axis.... with a barlow it's nothing short of comical trying to keep it in the crosshairs when it's not moving straight!

As an afterthought, it could be done on an EQ mount. You would have to point the N side of the mount to the West and then move the tube in RA until the scope and counterweights are parallel to the ground. Then you can move the tube in DEC with the scope moving straight upwards without any sideways movement. The only problem being the mount would have to be placed quite accurately in the Westerly direction where the ISS rises. It's not like you can suddenly lift an EQ mounted scope up and plonk it down again if it's way out when the ISS rises.

It never goes smoothly, my worst two problems are..

-fogging up of finderscope due to heat from my face being on it for like over 2 minutes solid.

-Can't see crosshairs for the above reason or if the sky is very dark (simply stuffed without a view if the crosshairs)

A last word of advice is, nomatter how badly you think you did ALWAYS play back the FULL movie to see if you caught it in a frame. With the above image, I thought I did terrible until I played the avi file back to realise at one point I jolted the scope so the ISS went right in frame. Just two frames with nothing else either side... I almost missed it while watching the movie it was that quick.

Matt

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Vega

Vega

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Perhaps, using Heavens Above, you could put the scope in the ISS's path, and fire when the ISS crossed the FOV. How long is your exposure?

My shutter speed on the Toucam for this one was 1/1000 but that was using a barlow. It sounds like a fast shutter speed but I remember when I first tried this malarky at 1/250 and all I got was a totally over-exposed blob.

Without barlow I usually do 1/2000 or 1/2500

Shutter speeds, brightness, gain will vary from scope to scope. I was using a 10" so 1/2500 might be a little too fast for say a 6" in order to bring out the solar panels. Strangely enough, the solar panels are much dimmer than the main structure of the station.

Matt

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Starflyer

Starflyer

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Great capture Matt :shock: 2 frames out of 2000 I'm lost for words :D

Matt

Given the effort taken to get these amazing pics. :D

may be you can write up a short piece on the process from start to finish so other can have a go at this.

Cheers

ian

I agree with Ian, an ISS imaging primer would be a great :notworthy:

Cheers,

Ian

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Vega

Vega

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"Stick webcam thingie in the scope hole thing.. Lift the big tube doobry up and follow the bright thing in the sky using cross hair numero dumero jobby. mess about with webcam settings and stuff...." :D

Oh ok. Will work on a primer and post as a seperate thread... just don't expect a video presentation complete with powerpoint presentation. :D

Matt

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trevboyd

trevboyd

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A primer would be great, Matt. I'm intrigued as to how you get the exposure/gain right on the webcam. Is it just experience or do you have some clever way like poiting at something else with a similar magnitude (not that there are many things at mag -2.5)?

:scratch:

Trev

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