iObserve: An Observer’s Perspective

It is time to look at iObserve again; since Cédric told us about it in September, I have used the App for three separate observing runs. So here is what I found out about iObserve as an end-user. In a few words, iObserve is a must-have for any observational astronomer. I would even recommend it for people who have been observing for years. iObserve is worth its $11.99 price tag (Free Demo) many times over.

My favorite part about iObserve was that it provided a platform aggregates (almost) all the information I  wanted about my targets. There was no need to open separate windows for my IDL-based airmass charts, for a webpage with SDSS finding charts, or for a webpage with my target list(s). All of them, and many other functionalities, were right there in the iObserve window. Obviously, all of this was well organized and easy to access.

Here’s a list of what I liked:

  • Most major observatories are already built into the App, so you have access to not only the LST, UT, sunrise/sunset times but also to the observatories’ website from within the App.
  • The airmass charts had twilight times and moon tracks clearly marked. If you turn tracking on, you can see the exact airmass and altitude of your target for any time in the night.
  • SDSS (gri composite), 2MASS (J, H, or K), or  DSS (blue, red, or infrared) images can be easily downloaded with a click to be used as finding charts.
  • You can upload any number of targets and plot their airmass tracks simultaneously. This makes it really easy to plan the next few targets you are going to observe.
  • If needed you have access to the SIMBAD or the NED pages for your target (if they exist). For well-known objects (like standard stars), iObserve will automatically fetch aliases, magnitudes, and references from SIMBAD.

What this meant for me was a very smooth observing experience. With very little prior planning, I was able to sort through and select optimal targets during the night. I was able to easily pull SDSS or 2MASS finding charts to locate fainter objects that were barely visible on telescope camera.

There were a couple things that would make the iObserve experience even better. The ability to store target lists in folders, upload additional fields (e.g., mag, colors), and to view them in sortable tables would mean iObserve would be the only App I need for observing. Fortunately, Cédric is already working on these and many more features (including Observation Simulator, Time/Flux converters, and eventually night logs).

Cédric said in his post that iObserve is the App that he wished he had when he was working as an astronomer at  La Silla Observatory in Chile. I heartily agree. After a few years of fumbling around with my own scripts, I am delighted to have an App that works seamlessly. Plus, the iPad version is coming soon.

19 comments… add one
  • Cédric May 23, 2012 @ 8:32

    Saurav, when I will say that your post has not been sponsored by me at all, who will believe me?! Thanks a big bunch for the review. It is the occasion for me to inform the users of a few things, since I have been a lot silent these past weeks. One good reason though: preparation of iObserve 1.1 and iObserve touch (on iPad). The latter one, I promise it since more than a year I think. I am getting closer, and it starts to look pretty good! I will post screenshots in the Facebook page of iObserve (

    Now, a few random remarks about little things in iObserve.
    – Twilights are pure geometrical, don’t account for local altitude, and use the sun’s center. The reason for that is that I never imagined to have a user who wanted to plan a robotic telescope based on iObserve values! I wanted to provide estimates. Now that I have such user, I will improve this point.
    – Are missing the exact moonrise and moonset times. I am working on it.
    – There are way too few standard stars catalogues included. Version 1.1 will have at least 7 or 8.
    – You cannot yet drag & drop your own custom find charts. It will also be possible (hopefully with FITS support)
    – The handling of standard stars (and all objects for that matter) is file-based and not database-based. It is inefficient and a bit unstable. Version 1.1 uses databases.
    – I am working on adding comets and asteroids using JPL’s Horizons service. It works pretty well. I was thinking about releasing a simple app doing just that: an interface to JPL’s Horizons. Leave a comment if it is interesting for you.
    – I have also added a quick and easy way to add stars with exoplanets, based on the latest exoplanets catalogues.
    – The informations to the right (aliases, magnitudes etc) are obviously incomplete compared to what SIMBAD provides. Version 1.1 will have all values that SIMBAD provide.

    There will also be some nice new features I can’t talk about right now… But just to be clear, the Observation Simulator and Night Logs Saurav is talking about are the graal of iObserve. It will be reached once all the parts of the puzzle will be in place.

    Version 1.1 will be OS X 10.7 and up, and iOS 5 and up. The goal for iObserve touch is a feature’s match with desktop version, with iCloud support. If it takes too much time, I’ll include iCloud support a bit later.

    I think that’s it. Thanks again Saurav.

  • Eilat May 23, 2012 @ 10:15

    The thing I need most in any observing software is the ability to compute offsets to my target from nearby stars. This is important because I do a lot of blind offsetting to faint spectroscopic targets. Does iObserve have this capability? Ideally it would be awesome to pull up a finding chart, click on a star in the field near my target and have the program return the DeltaRA and DeltaDec in arc seconds from the star to my target (i.e., 14.6″ E and 22.7″ S). If this capability exists (or something similar) then I will gladly shell out the $12.

    • Cédric May 23, 2012 @ 10:36

      Hi Eilat. iObserve does what you request. Not in a perfect way, though. Let me just explain. The normal scientific way of doing it would have finding charts as FITS files, with WCS coordinates inside. Unfortunately, the finding charts that iObserve retrieve from the web are images (jpegs most of the time), and thus the coordinates information is provided in a separate way. In fact, they are specified in the finding chart options (in iObserve chart tab), and the “tracking” I make on top of that is based on these options (after verification with the webservice). But I noticed that in some services, when you request a 2’x2′ image, you don’t necessarily get the same number of pixels on each dimension. Hence it is difficult to make a perfect tracking. The other possibility, and a very serious one, is obviously Aladin: But it’s web/applet-based.
      Last note: iObserve provides only estimated distance from its central target. Not distances between targets accross the field (something I could do indeed…).

    • Thomas May 24, 2012 @ 10:59

      Hi. I am one of the Aladin developer.
      Thank you for mentioning our software. I just wanted to specify that Aladin is available both as an applet and as a standalone application. For Mac users, we provide with a standard DMG installer downloadable from

    • Cédric May 24, 2012 @ 16:33

      Thanks Thomas for the precision. I remember having used the Aladin app on OS X, already quite some time ago. That’s also a must have for observers.

  • Tigran Khanzadyan May 24, 2012 @ 2:51

    Great App as I have numerously mentioned here and pretty much elsewhere. The things that this App can do are amazing. Here I was reading the post and thought came to me …

    Would it be possible to implement some sort of PLASTIC or similar hub support? I’m sure you know where I’m going with this.

    • Cédric May 24, 2012 @ 8:04

      Hi Tigran. Thanks for the post. I knew about PLASTIC at some point, but right now, I couldn’t figure it out again. And searching for PLASTIC in the web even with ‘astro’ and ‘software’ didn’t really end up with meaningful results. Can you help a bit?

    • Thomas May 24, 2012 @ 11:05

      PLASTIC has been deprecated in favor of an IVOA-endorsed standard called SAMP (Simple Application Messaging Protocol).
      SAMP allows astronomy applications to interoperate and communicate. For more details, look at
      This standard is already supported by DS9, Aladin, Topcat, JSky, GAIA, etc

    • Tigran Khanzadyan May 24, 2012 @ 13:37

      Oh, didn’t make on time with my answer. SAMP support would be just perfect. You could get the object list from say Aladin or VO Desktop App. You could also temporarily get the fits files with communicating back to Aladin. All sorts of possibilities can be explored like this.

  • Cédric May 24, 2012 @ 16:35

    I will have a look. If we can plug iObserve to other services, it would be nice.

    • Abhi Jun 12, 2012 @ 10:19

      Hi Cedric, I was wondering if there is a clean way in which to export parameters (folders, objects, etc) from the application? There are two reasons for me to ask this – 1) My colleague and I are observing and one of our machines has the observing details prepared in a meticulous manner and we would like to replicate it on the other machine. 2) I am moving to a new machine and would like to carry the information over to the new machine.

      Also thanks for the excellent software – it really simplifies the organizational aspect of each observing run.

    • Cédric Jun 12, 2012 @ 11:08

      Hi Abhi,

      Version 1.1 and touch will have iCloud support. But it won’t solve the need to share data with a friend. So I make a note, and will try to add it to 1.1. I am busy with converters these days (Times, Distances, Coordinates and Fluxes lately…).


    • Abhi Jun 12, 2012 @ 11:25

      Hi Cedric,

      I look forward to the update. I hope you are able to implement some form of export feature – I think it would make sharing information easy and possibly increase the visibility of the software even more :).


      p.s: is there a backdoor/ugly method of copying parameters – at this point we are even willing to rewrite what is present on the other machines. Though I guess it would be a one time thing.

    • Cédric Jun 12, 2012 @ 13:29

      You may try the following:
      – Quit iObserve
      – Copy the entire folder ~/Library/Containers/iObserve from the source computer.
      – Restart iObserve


    • Abhi Jun 13, 2012 @ 1:18

      Thanks Cedric that worked perfectly.

  • Gwanjeong Kim Nov 26, 2012 @ 20:24

    iObserve program is very useful for preparing observation.
    I’d like to suggest three functions for iObserve.
    First, I hope that iObserve has the category of the observation schedule like pdf file or webpage. It makes user convenience to take a observational schedule.
    Second, I hope that iObserve has the modify function for the property of the observatory. After user adds new observatory manually, user sometimes wants to update it.
    Third, I hope that iObserve has the menu for linking the developer homepage.
    That’s all.

    • Cédric Dec 2, 2012 @ 12:29

      Hi Kim,
      Thanks for your comment. However, I am not sure to understand very well. Just a few remarks: the observation schedule and night logs is a big feature that willl come in one next big update (not the next one, but another one). It takes time because it will be linked to other “sections” of the app such as Objects and Observatories (i.e. it will be easy to schedule objects for observation in a given observatory…). As for the observatory update, it’s not yet possible to change its properties, except for a few properties in custom observatories (builtin ones are not updatable). Again, a lot is coming for Observatories in next versions. As for the developer home page, I’ll make sure it is included.
      Thanks again!

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