This weekend weather in London was quite amazing: sunny, a bit too windy, but sky almost perfect. Seeing forecast was also encouraging, so on Friday evening I took a chance to shoot at Jupiter.

It was a bit of an unlucky evening: firstly I discovered that I forgot my red dot finder on, so the battery was totally drained. After struggling for a while trying to align my GoTo mount without it, I decided it was worth to leave the telescope alone for a few minutes (my garden is easly visible from the street... I didn't want to do it unless absolutely necessary) and got back inside to find new batteries.

After everything was aligned, and I was ready to observe and record my images, I noticed that the image wasn't exactly satisfying at the eyepiece. When I replaced the eyepiece with the camera, the very unfocused image revealed me why: some tree branches were in the way, and of course the image was deteriorated from the interference!

I looked around me to see if I could find a better spot to place my scope, but with no luck. I decided to try anyway, taking multiple shots, so maybe in some of them I might get an almost clear picture.

This is the best result I could get:

Jupiter, 25/03/2017

Of course, the difference with my previous shots taken with a bigger 200mm SC is pretty visible, but I think with better conditions this new telescope can do much more.

Since I made four sets of images, spanning a bit more than 40 minutes, I was also able to an animation showing Jupiter rotation: Jupiter rotation animation

Shots data:

  • Celestron Nexstar SLT 127 Maksutov
  • ZWO ASI 178mm with LRGB filters
  • Software: my Planetary Imager for shooting, Autostakkert!2, Registax, Siril and GIMP for image processing.

Luminance channel: 4500 frames, best 20% used. R/G/B channels: 1000 frames, best 40% used.

I'm currently living in a house with a very nice backyard, right outside London. Still a lot of light pollution, but it can be manageable, and useful for testing my equipment before running to darker locations.

This was meant to be a (L)RGB shot, but light pollution and humidity made the blue and green channels pretty useless, while red channel produced quite good results

Last friday night the sky was finally very clear, so I made a few shots.

M 42, HorseHead, Flame Nebula

The brilliant Orion Nebula (M42) is very well defined, but also the Flame nebula (NGC 2024) is quite conspicuous on the left. And very close to the Flame nebula, a tiny Horsehead nebula can be spotted too.

For being just a test shot, I must say I'm very happy with the result, and can't wait for better conditions to try RGB.

I recently bought a new smartphone, a OnePlus 3, since my Nexus 6 was pretty much dead, turning off pretty much everytime I did something else than keeping it in my pocket.

I was particularly interested in the "manual controls" feature of the OnePlus, including the ability to shoot up to 30 seconds, particularly convenient if you want to use it for astronomy.

It turned out this really works out well!

I just did a few tests, but the results are very promising.

Taurus, Aries
Lira, Delphinus, Aquila
Orion and neighborhood
Flying over france

The phone can also save images in RAW format, which means that if I'll also be able to program a sequence of shots, I could be able to stack pictures, to produce even better results.

It's been a while since my last updates. I recently moved to London, changed work, and.. changed astronomical instruments too. I'm planning to buy an ultra portable 300mm dobsonian soon, probably the best choice since I would like to travel as much as possible with it - back to Italy, or maybe to the southern skies.

But I also wanted a "quick" telescope, lightweight and simple, something that I could bring out in the garden in a very few minutes, and even better, ready for planetary imaging, so in the meantime I also bought a small Maksutov-Cassegrain telescope, a Celestron Nexstar SLT 127. I also got a new camera, USB3, with very high resolution and wider field than my previous one, a ZWO ASI 178mm, still a monochrome camera, but this time with RGB filter set.

Given the smaller aperture, I'm not expecting really great shots, but my previous setup much heavier, so I spent very little time observing and shooting, which in turn means I didn't really got it to its maximum potential.

My first shooting with the new setup is a very difficult one: Saturn, in an unfavourable time, quite far away from its opposition, and very low in the UK skies.

Tiny Saturn

Given the small aperture, and the difficult target, I can say I'm really satisfied about it. I also tried a few new softwares for image processing, particularly ImPPG, with a very handy lucy-richardson deconvolution filter, which greatly improved the image over my first processing attempt.

A very convenient tecnique in c++ programming is the one known with many names: "d-pointer" (found in Qt/KDE contexts), shadow pointer, "pimpl", opaque pointer. Basically the idea is to hide all the private details of a class in a forward declared private pointer, which will be the only real private member of the class. Since this member will never change, this will guarantee binary compatibility among different versions of a library.

But there are other advantages in using d-pointers: one is compilation speedup during development (usually if you change a private member of a class, the header changes, and you have to recomplile all units using that header, while with d-pointer you change only the .cpp file), and another is code cleanup: you will have very compact header files, describing your class public interface without private stuff pollution. Also, sometimes you may want to add your d-pointer definition in a separate header file, ending up with three well defined files:

  • myclass.h: class declaration, only public stuff, without private stuff
  • myclass_p.hpp: private class declaration: only private stuff, no implementations
  • myclass.cpp: only implementations

The classical approach is to create a plain raw pointer to a forward declared class, initialize it in the constructor, and delete it on the destructor. A nice addition is to have the private class be a nested type, so that you can avoid polluting your IDE class list.

Continua a leggere...

It has happened in a few occasions, to launch a command in a shell only after a command in another shell has successfully finished (for instance, after a long task like source code compilation, i want to launch tests on another shell).

Continua a leggere...

This sunspot was particularly big, so I waited for the best moment to try and catch it.
Seeing wasn’t great, and my solar filter was a bit damaged, but the final image doesn’t look too bad anyway.

Sunspot 2546

Unfortunately, this will be the last image for a while.
Just a few hours later, someone opened my car, and took away my HEQ5 mount, together with all my eyepieces and the camera I used for all my planetary shots.

I’ll also be relocating in a while, so I’ll wait a few months before buying a new setup.
If someone is interested, I’m selling my current main optical tube here:

Questa ripresa doveva essere un miglioramento rispetto alla precedente, dato che ho usato questa volta il mio telescopio più grande, ma la bassa altezza e il pessimo seeing hanno in effetti peggiorato la qualità.

La forma della Stazione Spaziale è però chiaramente visibile, mentre passa davanti alla Luna.
È scura, questa volta, perchè era già entrata nel cono d’ombra della terra. La abbiamo in effetti vista salire nel cielo, luminosa come sempre, e quindi sbiadire lentamente fino a scomparire del tutto pochi secondi prima di incrociare la Luna.

Un simpatico gracidio di rane ci ha tenuto compagnia nell’attesa dell’evento.

Dettagli tecnici della ripresa sulla pagina Youtube.

ISS transit over the Moon - April 2016

Marte si sta avvicinando velocemente all’opposizione del 2016, la migliore dell’ultimo decennio, essendo molto vicino alla terra.
Il meteo a milano non è stato clemente in questi giorni a Milano, quindi io ed Alessia abbiamo cercato di approfittare della prima serata che offrisse un cielo sereno, possibilmente con un buon seeing.

Siamo stati abbastanza fortunati: il seeing non era il massimo, sopratutto con marte così basso sull’orizzonte, ma era sufficientemente buono per avere un primo sguardo e distinguere alcune caratteristiche evidenti, sopratutto dopo che si è alzato di poco sopra i 20°.
Ho anche effettuato alcune riprese, questo è il miglior risultato, mostrato qui di fianco a una simulazione di Stellarium per quella data e ora.

Mars, first 2016 shot
Mars, first 2016 shot

simulazione Stellarium, per confronto

Abbiamo anche osservato Saturno, che si avvicina anch’esso alla sua opposizione, anche se ancora più basso di Marte, e Giove, ancora molto brillante ed alto nel cielo.
All’oculare era davvero impressionante: la Grande Macchia Rossa era evidentissima, ed un satellite (successivamente lo abbiamo identificato come Europa) si avvicinava al disco del pianeta.
Quando ho iniziato le riprese con la mia camera aveva già cominciato a transitare sopra Giove, ed è ancora ben visibile come un punto chiaro sulla parte destra del pianeta.

Jupiter with Europa transiting

Anche se le riprese non sono buone come avessi sperato è stata una bella serata, abbiamo finalmente potuto goderci un buon paio d’ore di astronomia fatta bene, ed è stato un sollievo dopo così tanto tempo di inattività a causa del maltempo.

Lo scorso agosto ho avuto l’occasione di poter osservare la Stazione Spaziale Internazionale passare di fronte alla luna direttamente da casa mia. La ISS è spesso ben visibile, ed a seconda della propria posizione sulla terra, potrebbe risultare allineata con qualche oggetto celeste.

In questi giorni, riorganizzando la mia gallery, ho trovato il video originale, quindi, dopo un po’ di riprocessamento, ho deciso di ripubblicarlo.

La ISS è davvero veloce: infatti il video è leggermente rallentato. Ricordo di non aver visto la stazione durante il transito, ed ho dovuto attendere qualche minuto perchè non potevo sapere se era già avvenuto o meno, anche perchè era ancora giorno, e nei frames originali la stazione è a malapena visibile. Solo dopo aver riguardato il video ho potuto finalmente intravedere quel piccolo punto bianco passare di fronte alla luna.

ISS transits over the Moon

Per questa ripresa ho usato il mio vecchio Celestron Astromaster 130, su montatura altazimutale, e la mia QHY5L-IIm come camera di ripresa. Ho dovuto inseguire manualmente la luna, dato che ovviamente non avevo tracking automatico. Ho scelto di usare il 130mm invece del mio solito 8″ proprio per la lunghezza focale più corta: in questo modo ho potuto assicurarmi di non mancare la ISS, potendo riprendere la luna quasi per intero.