ISS capture failed with Celestron NexStar 4SE and ZWO ASI662MC , exposure and gain advice

Hello! Last evening, I tried to capture the ISS with my Celestron NexStar 4SE telescope and ZWO ASI662MC camera. I carefully positioned my telescope along the predicted path of the station, but I couldn’t see anything in the recorded video. I think that the exposure and gain settings might have been wrong. I set the exposure to about 0.18 ms and the gain to 420 in SharpCap. What do you think? Could you recommend the correct settings for this setup to capture the shape of the station without overexposing it or making it too dark? I am under Bortle 5/6 skies. Thank you!

You know you need to track it, right?

andrea tasselli · Jan 21, 2026 at 02:39 PM
You know you need to track it, right?

Exactly! I tried manual tracking using the NexStar hand controller, but nothing was visible, and the red dot finder was properly aligned and clearly pointed at the moving station. I also pointed the telescope at the position where the ISS was predicted to pass, and according to Stellarium, it passed through my field of view.

Astropartament · Jan 21, 2026 at 03:04 PM
andrea tasselli · Jan 21, 2026 at 02:39 PM
You know you need to track it, right?
Exactly! I tried manual tracking using the NexStar hand controller, but nothing was visible, and the red dot finder was properly aligned and clearly pointed at the moving station. I also pointed the telescope at the position where the ISS was predicted to pass, and according to Stellarium, it passed through my field of view.

Maybe my methods are not correct, and they are simply not effective or don’t work at all. Thanks for every reply!

There’s basically two ways to do this, easy and hard. The hard way is to use a Dobsonian. Start your camera running and manually track the station while looking through a finder scope. The easy way would be to use a program like SkyTrack that will drive your mount to follow the satellite of choice. I know which one I would pick!

Tony Gondola · Jan 21, 2026 at 03:15 PM
There’s basically two ways to do this, easy and hard. The hard way is to use a Dobsonian. Start your camera running and manually track the station while looking through a finder scope. The easy way would be to use a program like SkyTrack that will drive your mount to follow the satellite of choice. I know which one I would pick!

Thank you! Do you think it would be possible to try the first method with my 4-inch Maksutov-Cassegrain? Of course, the second method is much easier, but I’d like to try capturing something with the first one first, just to see what I can get with this type of telescope. 🙂

You could try but it will be difficult. because of the way dobs work there’s always a certain amount of friction and if you let go, it just stays there. You can freely move on any direction you want except at the zenith. That would be hard to replicate with your mount. The best you could do would be to put enough drag on the locks to emulate that behavior. That said, give it a try. Even a single fleeting glimpse would be progress and you’d appreciate more the difficulty involved.

Tony Gondola · Jan 21, 2026 at 04:33 PM
You could try but it will be difficult. because of the way dobs work there’s always a certain amount of friction and if you let go, it just stays there. You can freely move on any direction you want except at the zenith. That would be hard to replicate with your mount. The best you could do would be to put enough drag on the locks to emulate that behavior. That said, give it a try. Even a single fleeting glimpse would be progress and you’d appreciate more the difficulty involved.

You’re right, it’s going to be difficult, but I’ll give it a try! It’ll be interesting to see what can I get. 😉

When one of (maybe the last) Planetary alignments took place, I setup my DSLR and big telephoto lens to shoot where the planets were supposed to align. Turned out the Planetary imaging was a complete bust, but something bright flew through the FOV.

At first, I was disgusted. Thought is was a plane or something. Then I looked it up in Stellarium. It was the ISS flying over.

So instead of dropping them in the delete file, I studied them and put them together as a You Tube slide show. I had tried and tried to catch the ISS in a fly over, but then this night I caught it quite accidentally. January 22 2016

Satellites never have any marker lights going winky-blinky. Stellarium proved it out.

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