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.

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).

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.

A very big sun spot from May 2016

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: http://www.astrosell.it/annuncio.php?Id=70007

This was meant to be an improvement to the previous ISS shooting, since I tried to do it with a bigger telescope, but the low altitude and the very bad seeing did actually worsen the quality.

The shape of the Space Station is anyway clearly visible, as it passes in front of the Moon. It is dark, this time, because it already entered in Earth shadow. We could actually see it rising, bright as usual, and then slowly fade until it completely disappeared just a few seconds before crossing the Moon.

Technical details of the shot can be found on the pagina Youtube.

Video on youtube: [url=https://youtu.be/uQ2MAcVAf6A]https://youtu.be/uQ2MAcVAf6A[/url]

This was meant to be an improvement to the previous ISS shooting, since I tried to do it with a bigger telescope, but the low altitude and the very bad seeing did actually worsen the quality.

Last august I had the chance to see the International Space Station passing in front of the moon right from my home.
The ISS is clearly visible many nights, and depending on the user position on Earth, it might align with some object in the sky.

These days I was reorganizing my gallery, and I found the original video.
So, after reprocessing it a while, I decided to republish it.

The ISS is really fast: the video is slightly slowed down. I remember that during the transit I couldn’t see the station, and I waited a few minutes because I couldn’t know if the transit already happened or not: it was still daylight, and in the original frames is barely visible.
Only after watching the video I could finally notice that tiny dot passing right in front of the moon.

ISS transits over the Moon.

Video on youtube: [url=https://youtu.be/Fcwv85l20Xo]https://youtu.be/Fcwv85l20Xo[/url]

I shot this with my 130mm F/5 telescope, to be sure to have a field wide enough to not miss the space station.

It was still daylight, with the moon very low in altitude.

Also, I had to track the moon manually, since this telescope has a dobsonian mount.

For this shot, I used my old Celestron Astromaster 130, in an alt-azimuth mount, and my QHY5L-IIm as shooting camera. I had to try following manually the moon, since I obviously had no motorized tracking.
I had to use the 130mm scope instead of my main 8″ scope because of the shorter focal length: this way I could shoot almost the whole moon, so I could be sure that I didn’t miss the ISS.

Spring is back, and here in Milan we finally had a few days (and nights) of very nice weather.

I also bought a new lightweight battery for my HEQ5 mount, instead of the usual heavy car battery I’ve been using until now, so I took a minimal setup and placed myself in a local park.

Seeing wasn’t perfect, but it was fine enough to shoot a few nice details of an almost full moon.

More importantly, Jupiter was at opposition a few weeks ago, so it’s still in a very favourable position.

Satellites in order, from left: Io, Europa, Ganimede

All these shots were done using my own Planetary Imager.
Image processing was done using Autostakkert (stacking), Registax (wavelets), and GIMP (post processing).

After rediscovering Siril, a nice astronomical images preprocessing tool for GNU/Linux, I wanted to give another try at processing a few test images taken this summer.

It’s surely not a masterpieces, but I’m not too disappointed either by what I could make of them, given that it was just a basic attempt, with no more than half hour total shoot time.

Messier 42 in a first quick test shot

Postrocessing was done using DarkTable.

Another couple of high resolution images, taken on the Appennines, with quite a lucky seeing.
Jupiter is now rising earlier, and it was a welcome preview to the observing night.

Firstly I tried shooting on prime focus, using small magnification, and then I used a 2.5 barlow lens. The prime focus shooting should have been just a test, but it proved to be the better one, as I had troubles focusing with the barlow lens (we were already in “night” mode, and I had to darken a lot my monitor, so focusing was really difficult).

This is the prime focus shooting elaboration.

Red spot visible

Saturn is starting to rise earlier, and around 4am is starting to be fairly hight for a few shots.

Since we already finished observing I could remove my notebook darkening panel, and focus quite better with the 2.5x barlow.

A first glimpse on Saturn, waiiting for the next opposition. Seeing was very good.

It was also a very satisfying deep sky stargazing night (which was actually the main purpouse of our trip to the Appennines).

Spring constellations enable us to go really “deep”, with very far and suggestive galaxy clusters.

Another shooting, much improved in quality compared to the previous ones: Jupiter bands are very well defined, rich of details, much more compared to the images of fifteen days ago: probably both because of the better seeing, and of the removal of the IR-pass filter, replaced with a more classical IR-Block, gathering much more light.

The “guest” of the title is the dark dot almost at the center of the planet: it’s not an image artifact, but it’s the shadow of the Io satellite projected on the planet. Basically, a solar eclipse on Jupiter.

The satellite itself is not visible on the picture, submerged in the planet disk. The other two satellites are, from closest to farthest, Europa e Ganimede.

Notice: this article is currently available in italian only.
I will translate it soon. You may contact me via comments if you want me to “prioritize” this article first.

Per una serie di vicissitudini (e per il maltempo che l’ha fatta da padrone) non ho potuto osservare molto Giove, in opposizione proprio nei prossimi giorni, e quindi nel periodo di migliore osservabilità.

Ieri sera comunque sono riuscito ad effettuare qualche osservazione e qualche ripresa, approfittando di un seeing stranamente non cattivo come solitamente da casa mia: purtroppo non ho balconi o terrazzi, e mi tocca riprendere ed osservare dalla finestra aperta, cosa che alza di parecchio la turbolenza per il continuo passaggio d’aria tra interno ed esterno.

Jupiter shot from home, average/bad seeing conditions (but luckly not so bad), quite low on the horizon (less than 20°).

Infrared filter to block most of the atmospheric turbulence.

In visuale era piuttosto evidente la Grande Macchia Rossa, che nelle riprese invece sembra quasi invisibile. Non è infatti il globulo scuro che si vede nella banda in alto a sinistra. Questo perchè la ripresa è stata effettuata nel vicino infrarosso e non nel visuale, per ridurre l’interferenza atmosferica, quindi i dettagli visibili nella ripresa sono un po’ diversi da quelli che si vedono ad occhio nudo.

Si vedono molto bene anche due dei satelliti galileiani, Io ed Europa.

Ripresa effettuata al fuoco diretto di un Meade ACF 8″, 2000mm di focale, con filtro IR “Planet IR Pro 807“, camera QHY5II-L. Sommati circa 800 frames (di 2000 totali).

Aggiornamento, 02/02/2015
Giusto una manciata di giorni dopo ho potuto ripetere il tentativo, con una messa a fuoco un po’ più fortunata.
Non è visibile la macchia rossa, in questo caso, ma sono riuscito a tenere nel campo tutti e quattro i satelliti galileiani.