Kevdog
sage
Reged: 07/11/12
Loc: Desert Hills, AZ
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ISS Magnification and viewing?
#5353812 - 08/05/12 09:18 PM
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If it's even possible, what magnification do you need to resolve some of the shape on the ISS?
I have a Meade LT8 and a Williams Optic 7-22.5mm zoom eyepiece. I know the Meade is supposed to track the ISS and was hoping to try it tonight.
Any hints for best viewing? It's supposed to be a bright pass in Phoenix tonight and I want to try my best to do it properly.
Thanks!
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RussD
member
Reged: 04/20/06
Loc: Minnesota
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Re: ISS Magnification and viewing?
[Re: Kevdog]
#5354358 - 08/06/12 07:58 AM
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It does not take all that much power to resolve shape on the ISS. But to really knock your socks off, try 100x plus.
I have always done this on a dob mount. The first and most crucial step is to perfectly align your finder. Try to catch the ISS as it is rising out of the horizon when it is moving slowly, follow it in the finder and place the scope just ahead of it. Then quickly jump to the eyepiece and try to follow it as it passes through the view.
My most memorable view was at about 250x and managed to follow it off and on for a minute or so. At that magnification I would only be able to get it momentarily. The view though was stunning, I could see details on the solar panels. It was amazing.
Russ
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FordGalaxy
member
Reged: 07/06/11
Loc: Virginia, USA
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Re: ISS Magnification and viewing?
[Re: RussD]
#5354747 - 08/06/12 12:25 PM
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I've only caught it at 40x with my 30mm widefield and my dob. It was too fast to track otherwise, but a cross shape was definitely visible. Using a well sighted laser helps in acquiring it very quickly. I never needed my finderscope. The zoom also seems to be a good idea, provided APFOV isn't compromised too much.
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Ptarmigan
Lagopus lagopus
Reged: 09/23/04
Loc: Arctic
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Re: ISS Magnification and viewing?
[Re: Kevdog]
#5355699 - 08/06/12 11:17 PM
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It moves really fast through the telescope for me, even at low power. It looks slow when you see it through your eyes.
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TechPan6415
member
Reged: 07/29/12
Loc: Aspen, Co
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Re: ISS Magnification and viewing?
[Re: RussD]
#5355878 - 08/07/12 02:25 AM
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Quote:
My most memorable view was at about 250x and managed to follow it off and on for a minute or so. At that magnification I would only be able to get it momentarily. The view though was stunning, I could see details on the solar panels. It was amazing.
..............................that's pretty incredible!
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David Knisely
Postmaster
Reged: 04/19/04
Loc: southeastern Nebraska
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Re: ISS Magnification and viewing?
[Re: Kevdog]
#5356920 - 08/07/12 06:48 PM
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Quote:
If it's even possible, what magnification do you need to resolve some of the shape on the ISS?
I have a Meade LT8 and a Williams Optic 7-22.5mm zoom eyepiece. I know the Meade is supposed to track the ISS and was hoping to try it tonight.
Any hints for best viewing? It's supposed to be a bright pass in Phoenix tonight and I want to try my best to do it properly.
Thanks!
With seeing the way it is, I quickly determined that there was little need for large aperture when viewing ISS, so I used my 4 inch f/6 refractor. I had my 5-8mm Speers Waler with its 78 degree apparent field, giving me about 75x and a full degree true field of view which helps a lot with keeping the station in the field of view for at least a few brief moments. It is hard to track manually at anything but low powers, but I found that 75x was enough to allow detail to be seen without making the station too hard to track with the scope. As the pass began and the station cleared the western horizon, I could see a sort or gold letter "H" formation quite easily. As the station got higher, the solar panels got harder to see due to the changing aspect ratio, but detail on the station itself became easier. I could easily see several lumpy white modules in a line, and as the station passed to the east, the entire station including the detailed solar panels was well shown. I could see the station's radiators, the main truss line, and many of the attached modules that you see in some videos taken of the station from Earth-based amateur telescopes. I had trouble doing all this by myself, so it is good to have a friend act as the "drive", keeping the station on the crosshairs of your finderscope while you view through the eyepiece. Good luck and clear skies to you.
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bassplayer142
professor emeritus
Reged: 10/03/11
Loc: Michigan
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Re: ISS Magnification and viewing?
[Re: David Knisely]
#5357066 - 08/07/12 08:24 PM
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I've done around 200x and it is pretty hard! That sucker moves fast at those mags. Yesterday I got my first low power 25x view with the st120. It was actually pretty neat at low power too even though it suffered severe chromatic abberation...
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RussD
member
Reged: 04/20/06
Loc: Minnesota
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Re: ISS Magnification and viewing?
[Re: TechPan6415]
#5366465 - 08/13/12 01:25 PM
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I was viewing it through a long refractor on a dob mount which moved very smoothly , and I could not really believe the detail. It was a whole lot easier to catch it as it was receding but as I said I was getting views only now and then as I tried to track it. Oh, I have to say I have not been able to repeat it. But it is not too hard to do at lower mags if you are careful.
Russ
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steveward53
professor emeritus
Reged: 05/14/12
Loc: Newmarket,UK
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Re: ISS Magnification and viewing?
[Re: RussD]
#5366614 - 08/13/12 02:48 PM
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The elevation of the pass makes a lot of difference to the distance it is from you ,
A high level pass directly overhead puts it about 225 miles away ,whereas a low level , say 20 degree , will put it 700+ miles from you.
If you check out the relavent details for the pass you're aiming for on "Heavens Above" site it will give you exact distances at Max. elevation.
http://www.heavens-above.com/?lat=52.29961&lng=0.49275&loc=Unspecified&alt=0&tz=GMT
Eg.81 degree = 412Km / 256 Miles.
22 degree = 947Km / 588 Miles.
Happy hunting..... 
Steve.
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GatorStarGazer
sage
Reged: 05/26/09
Loc: Schertz, TX
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Re: ISS Magnification and viewing?
[Re: steveward53]
#5387625 - 08/26/12 09:51 AM
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Kevdog,
Not sure if you can use the same technique with your Meade that I use with my Dob, but here's how I track the ISS with my son.
Tracking is best accomplished as a two-person operation. My son and I do it with great success all of the time. As Steve mentioned, find a good pass using HeavensAbove.com. Although the bright passes are spectacular (mag -3, -3.5, etc.) you can see better detail when its magnitude is less, like -1. One person can easily spot and track the ISS in the Telrad while the other looks through the EP. As long as the person looking through the Telrad can slew the scope smoothly you'll have no problem observing the station for how ever long the pass lasts. Using the Telrad makes it easy to reacquire if someone has to reposition themselves on a long pass. We've gotten so good at it that we can sometimes observe it at 240x. People are just blown away by the sight they see when we show them the ISS like this.
Of course, this technique works well other large orbiting objects like the Hubble or airplanes/helicopters too!
Cheers...Eric
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panhard
It's All Good
Reged: 01/20/08
Loc: Markham Ontario Canada
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Re: ISS Magnification and viewing?
[Re: GatorStarGazer]
#5387959 - 08/26/12 01:18 PM
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That is a good method.
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Jeremy Perez
Carpal Tunnel
Reged: 08/12/04
Loc: Flagstaff, Arizona, USA
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Re: ISS Magnification and viewing?
[Re: panhard]
#5393232 - 08/29/12 01:30 PM Attachment (93 downloads)
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These are some great descriptions with the different magnifications and methods everyone is using. The two-person approach really does sound like a great plan. I've been doing it solo though, and it's definitely an exhilarating challenge. I'm using my 8-inch Dob and quickly discovered how unmaintained my azimuth bearings had gotten. Jerky nudging is really frustrating with the ISS.
So far, my Pentax XW10 at 120X has given the best view, with a wide-enough field to keep the station visible well enough for some of the basic structures. I still haven't achieved the level of detail that you've seen, David, but with each pass, it seems to get a bit more familiar. I think with enough passes, and if I'm having a good evening with better-than-normal fine muscle control, I could eventually manage to pick out some additional detail in the modules.
Here is a sketch series from last night's pass over the western US--it shot off a nice flare as it receded. I was rattling off details into the voice recorder on my phone, and had a post-it note stuck to the side of the tube to work up diagrams. I used those to create the digital sketches.
Full report
Large sketch
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