Urban Astrophotography

After a winter full of clouds and even more clouds, last Saturday night was a clear enough one to do some astronomy. Mars was waiting us there in their oposition (although not one of its bests) and so we could miss the chance to take some photos of it.

In this occasion we have slightly change our usual observation site in La Azotea (in the middle of Granada city) to a quite near village, Armilla.

After some months without taking out the 25 Obsession Telescope, we go up to the observation place called “Dornajo” in order to take some shot of Jupiter trough the webcam. The operation began at 5 in the afternoon picking up the whole necessary material distributed in several places. 

After several hours, we had the 25 inches telescope mounted above the equatorial platform and polar aligned. It began what seemed a fantastic, windless and clear night. Some time later Javier Algarra arrived and also mounted their impressive Taka. While we spoke about the new astronomical gadget a bank of fog didn't allow us to see anything in the sky. The humidity also at this time overtook the saturation level soaking the whole material. After a half hour, the sky cleared up and we could begin with the planet Jupiter. 

The seeing was not bad but the wind blew in gusts that made very difficult to maintain the planet inside the small ccd of the webcam. Some hours later the moon rose over the horizon and we waited to a better position close to the zenith to tray a mosaic of its surface. In order to get that we used the QHY5 CCD, but once again, the wind hinders us vastly and prevents us taking some quality videos and it didn't give us time to cover the whole surface. In spite of it, a good frame selection, the use of the appropriate software (including our new ManualFrameAlignment) and many processing hours, allowed us to obtain these results:

Remark: Even though we could have incremented the contrast in the Jupiter image, we have tried to obtain a result as close as what we really saw that night through the telescope's eyepiece.

ManualFrameAlignment is a small utility that allows and initial manual alignment (but not very precise one) of the frames of a video. This manual alignment helps other programas like Registax to be able to obtain a much better frame alignment, avoiding in many cases the typical artifacts in very bad aligned videos.

The program is specially prepared to process Moon videos in which weather conditions (wind, bad seeing) makes the frames to be greatly moved one from another, thus not allowing precise automatic aligment. ManualFrameAlignment does not pretend to e a big application but just fulfill its original goal.

Its inner working its quite simple. The frames to be aligned must be in a certain directory (PNG, TIF and JPG formats are allowed) and an output directory must be specified. Then the program present a window in which the user has to select a feature (a creater, for example)from the first frame. Then the program starts showing each one of the frames of the video and the user must follow the feature in each of the frames moving the mouse. Once all the frames have been presented the application will align all the frames according to the movements of the mouse that the user has made.

Some additional of Jupiter and Moon takes from last Sunday. Seeing was much better than in previous attempts and we tried to use two barlow lenses (3x and 2x) together. Click them to watch them at full resolution:

Last Friday, after the S.A.G. meeting we tried to photograph Jupiter from La Azotea. Sky conditions were terrible. The results can be improved, but it is a good start. In the first photograph we didn't obtain good enough focus. In the second one focus is better, but some artifacts appear due to some spots and dirt on the CCD. The third one is a new attempt to reprocess the image using the last version of Registax and using supersampling. We think we have improved it a lot removing almost all the previous noise.

We have added a video to show a small clip of the original raw video that we used. It can be noticed that seeing was quite bad. The original video had around 4700 frames of which 2700 had to be discarded due to bad quality (and a cloud that passed by). In the video you can see some of the GOOD frames that we used. Note that Youtube has added some compression artifacts (squares) that are not visible in the original video.

After several bad weather days, and what it is much worse, loads and loads of work (congresses, end of the academic year...) the Friday evening look promising to go out and enjoy the sky. Both Antonio and myself wanted to go for a visual observation session in Sierra Nevada for a long time. La Azotea is a great place to learn astrophotography, but for visual observations it has lots of drawbacks.

The evening was quite complicated because I had to go to Cullar Vega to finish the preparations for the photography exposition Cosmos: Vistas desde la Nave Tierra of the S.A.G.. It took more time that we initially planned and we finished it  at 8PM. After that I went to Armilla where we loaded Antonio's Pequeñín in the van. Around 10PM we went to Granada to pick up more gadgets, supplies and, of course, some additional winter clothes. Finally, we began our trip to Sierra Nevada around 11PM.

One of the drawbacks of our hobby is the large amount of instruments that we have to carry with us in each observing session: lenses, scope finders, cameras, cables, laptops, laser, filters and so on. And the problem is that it is not unusual to forget one of those objects at home, or even worse, at our observation site and then loose it.

To avoid this kind of situations many of us have created some suitcases in which we organize every astronomical gadget we have. In particular we have bought some good quality suitcases at  Berwall (german online shop).

Once we got our suitcase we have to accomodate every instrument on it. There are several way to do that, but one of the best that we have found is to cut a high density foam and thus adapt every single gadget on it:

But... how do we cut that foam with the shapes of our instruments? That is what we are going to explain in the following.

The night of May 18 to May 19 was a fantastic occasion to go up to La Azotea and continue with our astrophotography learning sessions.

In fact, we were almost using for the first time our new "observatory wardrobe" where we are storing the heaviest items of our equipment (counterweights and tripods) and from which we directly have a power point and an Internet cable, which is quite useful to watch weather predictions from  Meteosat, to watch a film during the photo series or even to inform in real time about what we are doing there.

The night of Saturday March 14th, was again very good for astronomy. After the set up of all the devices, and done a precise alignment to the Polar star, the main goal for this night was the Orion nebula through the refrigerated QHY6 CCD, besides other type of objects as galaxies. The humidity oscillated in the whole night around 50 - 60% and the temperature was about 10 grades which was very bearable.

On Friday, after a spectacular SAG (Sociedad Astronómica Granadina) meeting, we continued to cut our suitcases foam to store the last equipment that we have acquired. The technique to cut the foam is quite easy to implement and the results are also quite good. It is done by using a hot wire that cuts the foam following a paper pattern. In the photograph you can see an example of the cutting of a 2" prism shape. In the future we will publish a tutorial on how to cut foam.