A new way of sending ISS alerts

Dear follower of Twisst,

We just put online a new version of the notification system. We hope you will like it!

ISS over Kathmandu, by bigyanMany of you asked for a couple of changes to the way Twisst works. The most important was the alerts for morning passes. Twisst always sent out an alert about three hours before the actual pass, even if that pass was at 6 in the morning. Many felt there is no sense to get an alert for a morning pass of ISS after they went to bed.

Another thing that was not too practical, was the fact that Twisst sent out alerts for every single pass. Sometimes that made people feel they were spammed with alerts. ISS circles the earth every 90 minutes, so sometimes it will fly over a certain location multiple times a night, and some of those may be very low above the horizon and not very bright.

New and improved

Michel SchepMichel Schep (@michelschep) and I have been working hard to build a new version of the part of Twisst that sends out the alerts. It will now send out alerts that summarize the night. So a better service with less alerts. Don't worry, you will still get alerted to passes that may be a little less bright - but if there is another one that is better that night, we will mention that one in the alert. For morning passes, you will receive an alert during the evening and will be something like this: "Two extremely bright ISS passes in the morning! First one at 06:15 in the East." If you want to see what all the times are that ISS will cross your sky that night, you can click the link to your page on twisst.nl.

We would very much like to know what you think of these changes. Let us know if this works for you and what other improvements you would like to see.

More improvements

This new system is more stable, and is also the basis for other developments. There are many more improvements and developments we can think of. We will be working to implement a few every now and then. We would also like to invite followers of @twisst to work with us to get more improvements done. I will try to set up a forum where developers, designers, astronomers and other enthusiasts can submit and discuss code for new improvements.

A few examples of features that are needed:

  • an environment for group translations (wiki-style, I was thinking Drupal), to translate the alerts into French, Russian, Hindi, Portugese and other languages
  • code to recognize coordinates in Twitter profiles in this formats like this: "49°30'00"N, 123°30'00"W"
  • nice visualisations on our websites to show where ISS is and to point you in the right direction to look for ISS
  • enable Oauth as a way to have users log in and set preferences, such as their language and which passes they want to get alerts for

Anyway, that's just a small part of our wish list. But more on that soon. For now, let's see how our new system for sending alerts works out!

Thanks for your support!

Jaap Meijers (@tjaap)
Michel Schep (@michelschep)



Hi Ed, we soon will be able to let you set some preferences for our service. Choosing an account to get your alerts from will be possible once that works, but I can't tell you when yet. However, we plan to announce a new service this coming week which may solve your problem. So stay tuned ;-)

You wrote "You should receive alerts from many different sender accounts, like twisst42 and twisst13. Tweets from those accounts should show up in your replies-list:

Thats exactly my point. Whenever I think 'Lets see if there is an ISS passing by' and I check my @replies ISS has passed just before. I only remember to check when I have time and wether permits a view The only passes I'v seen since @twISSt isn't sending the alerts where those announced by Govert.

I understand you can only send a set amount of tweets on each twitter account. But is it possible to have me sent my alerts by one sender account only so I can follow and get the announces in my timeline?

Hi Yamuis,

You should receive alerts from many different sender accounts, like twisst42 and twisst13. Tweets from those accounts should show up in your replies-list:

If you have more questions, please contact me on @twisst or @tjaap. When I see your Twitter username, I can see what we have been sending out for you.


I don't get any alerts anymore while following @twisst, but instead I can find them under twisst57. How come?


Yeah, I'm with Anoniem; an iPhone and/or Android app would be terrific!
Love the updates. Keep up the great work!

Hi, thanks for your question.

We're not changing username at all. What we do have, is a host of accounts which we use to send the alerts. We need this as a workaround for limits Twitter has set. Twisst sends about 11,000 tweets every day, and it's not possible to send them with just one account, because of those limits.

If you want the ISS alerts, just follow @twisst - not the other accounts with a number.

If you tell us your username, either here or through Twitter, I can check if you have been missing out on alerts.

In the early days of twisst I followed @twisst an got alerts right on time. Soon after the alerts stoped and according to the twisst.nl that meant there where no visible passes for a time.

But then, weeks later I noticed on twisst.nl I missed some passes, and a search on twitter revealed an alert was sent by @twisst15. As one only receive @replys of followed users in ones timeline, I started to follow @twisst15. But soon I discovered @twisst changed username again, so I was stuck from getting alerts (or getting it to late when I did a search for it on twitter [or as I discovered lately check @replies] manualy)

Why is twisst changing username so often? And can you tell what username you will be using next in an alert, so I can start following to get the next alert in time?

Do you guys recommend a Twitter Iphone client that would push an alert for a bright passage? It would be neat to set some parameters so that a push message would pop up an hour or two before an observable passage.

As for cloudiness a pie in the sky dream would be to factor in satellite cloudiness for one's location. See http://goo.gl/xO5G for the "Clear Sky Clock."

I'm from Brazil aaand...
I can help translating to Portuguese!
E-mail me at diogo@diogobernini.com

See you later!


The change sounds really good!

The new alert scheme sounds helpful, although I have yet to receive one to see for myself. But.... the real problem is all those clouds up there! Got any solutions for that?


A lot off good changes on the way, fine.
My favorite: Switching off the morning alerts.

Sounds great!

Thanks for changing the alert times.

Best wishes for 2010!