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Hi fellow astrophotographers, I know the ISS is not a deep sky object nor a planet.... but it seems to be really a fun project to capture it ! That being said, my skills are really limited, and I am just starting to get descent images of deep sky objects and some solar system objects, but never tried satellites. I use Stellarium to plan my sessions of imaging, and I now have a CEM70 to play with. So, if there are people with experience in that : - what is the best instrument and focal length ? Too much FL may kill any possibility to aim ? Too large field of view makes it just a few blurry pixels.... - how to shoot the ISS ? : lucky imaging ? (I doubt you use AS3! though you may film it for sure), what exposure time ? (Seems to be bright) - what software to prep the sesssion ? Is Stellarium precise enough ? - how do you prep the mount ? Any tips like aligning the mount differently than the North to follow the ISS in only one rotation axis ? Do you « aim » manually ? Or do a 3 star alignment and then just enter coordinates into your mount ? (And then how to track that ? This is definitely not sidereal speed....) - how to check the slewing speed of my mount is sufficient to track the ISS ? Where can I find the angular speed of the ISS (i can google it and even calculate it, but sure it’s been done before...) - maybe it requires specific software to aim and then track ? Maybe you don’t track and just let it croos the field of view ? - last but not least, do you have a software that easily helps calculating « transit » (ISS in front of the sun, or the moon, but also to plan transit of mercury - i know i have time... - or venus in front of teh sun) Thanks for any help on that ! |
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A lot of questions!Jérémie: You may take a look at https://transit-finder.com/. It is possible to record the passage of ISS in front of the Moon by just using a DSLR in video mode and a telephoto lens:  International Space Station Lunar Transit |
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| @Die Launische Diva fantastic site ! Already found 2 dates in February where transits will be visible from home - sun and moon - unfortunately i won’t be there :-) Anyway, i have seen that the ISS will have a 30ish arcseconds size, so indeed, with my refractor and a Barlow that will make it ! I will have a resolution of between 1,4 arcsec / px and 0,35 arcsec / px, depending on the Barlow i will use, wich will make it distinguishable ! Just have to wait for the next opportunities... Thanks ! |
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Hello ! I have been monitoring Transit Finder website extensively until I found a window to shoot the ISS in front of the moon (this week). But... my son and I were ready to record that transit and we started recording a few seconds before it. With my ASI183MM Pro, connected through USB3 on the computer, the framerate on screen was around 5,5 FPS. Which is OK to see the transit as it last below the second. My son saw it on screen (I was stupidely watching at the moon - the ISS was in shadow, no way to see it before it crosses the moon). I was expecting to see it when looking at the SER file, but nothing... I was using ASIAIR Studio, and looking at the SER file, it seems it could only record 1 frame per second in average... and the ISS went through between frames 😭 So, my question is : how do you capture such brief events ? First of, next time I will record RAW 8bit and not higher, that should help, but is there better way to capture it ? With a DSLR that can record up to 15 frames per seconds ? I don’t want to record in full HD : I want a nice resolution on the ISS with my 1620mm focal length. Thanks for your suggestions ! |
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I never did that but, from what I've heard, is a matter of tracking manually with the loose axis while keeping the ISS at the center of the finderscope. For what concern the capture it should be just like planetary imaging with Firecapture on similar and the exposure settings should be prepared before the transit since it's such a brief moment. The ISS has a magnitude of -6 and there's nothing with the same magnitude to use as reference to set the camera... so this is also gonna be tricky. I would probably use a Red or and IR Pass filter, to improve contrast and to minimize the risk of overexposure. Then you'll have to select the best frame (or frames? I don't know if due to its proximity the perspective will change, rendering the stacking useless), calibrate it with darks and flats and process it. And about the scope aperture and FL, it should be just like planetary... the more the better, taking into account seeing and the narrow field of view. Clear Skies, Andrea |
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If you aren't trying to manually track the ISS it every time it goes overhead at -2.8 or brighter magnitude, then you don't know what fun is regarding a telescope. Sure, you can get software but getting that dialed in correctly before you experience the pure rush of chasing the space station through your guide scope, you most likely won't deal with downloading, calibrating and dealing with the 4-5 new programs you'll need. But once you start trying to catch it by tracking it by hand, you will be hooked. You will NEVER experience a more exhilarating, stimulating or adrenaline pumping onslaught that looking through a telescope has to offer then the 2-3 minutes you'll spend trying to get ISS every time you're luck to get a good pass. You get ready, you align your scope to it's orbit, you do a practice run, and you hit record and hope all it good, because no time to adjust or even look at the screen. You are just hoping to get ISS to pass in the middle of your finder scope and I mean the MIDDLE. you can try to track it, but it's better I think to lead it and have the scope be still as it passes, then leap frog again, hope it hits center, repeat. What I have learned, You want to align your scope 180 degrees opposite Az of the HIGHEST Alt and (90 degrees minus highest Atl) (ex. highest alt is 47Az/76Alt you would align your scope North 227 degrees and 14 degrees Alt. You can use Heavens Above App to set up very close and only have to move move RA axis and nudge DEC a hair or two and get the images you need. (Shown on an old CG4 mount as my AVX is now on a new pier, but still have the AVX tripod so I trust it.) ISS Tracker Snip.mp4 That's all you get from me, the fun is figuring out everything else out, and you won't curse me for too long, you'll thank me for turning you on to the most fun you can have with your telescope, even if you do end up with 25 gigs of black frames a couple of times. But 1 more thing, get a correct image finder scope. The SV208 will be your friend. |
