Looking at the sun using a Celestron Astromaster 70 and a solar filter

Couple of months ago i got the idea of observing the sun using a solar filter. I ordered a cheap solar filter from Israel and placed it front of the telescope. Note that you have to adjust the filter in front of the the telescope not between the body and the eyepiece because high temperature can be developed inside the telescope's tube.

The next step was to point to the sun. Compared with the night sky it is really hard to target the sun, as you can't look (or you shouldn't) directly to the sun. The easiest trick is to align the body of the telescope with the sun to minimize the shadow created as shown in the next two pictures:

Aligning the telescope to the sun using its shadow.

Finally, we align as perfect we can the telescope. I aligned the telescope without the eyepiece because it was easiest to move it.

The final result, note the sunspot on the right. Not perfect aligned and not the best quality, but for the 20$ price tag of the sun filter is a good opportunity to explore the sunspots.

Photo of the Sun using the celestron travelscope and the sun filter.

Processing Milky Way in RawTherapee

This text is an analysis of a video I did some months ago how to process photos of our Milky Way in RawTherapee. You can find the picture here . The photo was taken by wiegemalt. This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Editing: Step 1: Fixing lighting The first thing someone notices when opening the picture is the extreme noise due to high ISO used (1600 - check the picture on the right). The first thought is to de-noise the picture, however, if you do that you are going to loose the details of the night sky. The main reason for the high noise is the additional exposure Rawtherapee adds when the 'Auto' button is pressed. In particular, the RT adds +2.4 EV to equalize the picture. This is Wrong! What we want is to keep the noise down and at the same time bring the stars up. That's why we are going to play with the Tone Curve of the RT. To adjust the light properly we increase the cont

Static linking with gcc and g++

In this tutorial, we will explain what the static linking is, how this affect the size of final binary, and why statically linking with g++ sometimes is pain. By definition, a statically compiled binary is a group of programmer ‘s routines, external functions, and variables which are packed into the final binary executable. The compiler or the linker produces the final object and embeds all the functions and variables and the linking phase. There are two reasons of using dynamic linking and shared libraries: 1) Avoid creating a huge binary, if all the programs use a standard set of libraries why not having the operating system providing to them 2) Compatibility on operating system and machine dependant characteristics: sometimes the libraries must be implemented based on the architecture or the operating system and using dynamic linking is an easy way to avoid this catch. On the other hand, static linking is the ideal way of distributing one software product, paying

Homemade NAS after two and half years

Few years ago, I created a NAS system using my old PC. The old pc is powerful enough to do the basic NAS operation except real time transcoding of 4K or more than one 1080 streams. The setup was setup as follows: 1 SSD 128 GB for boot device 2x 4 TBs for the main storage configured as RAID 1 The hard disks were from different manufacturers (WD red plus and Segate) to avoid catastrophic situations: disks are part of a bad batch and you will have a second failed disk during the build of the RAID array. Here is a list of my mistakes: My first mistake was CentOS. I wanted a stable machine without surprises, unexpected behavior, as much less bugs affecting my setup. I had three free/open source options: Open Media Vault: Debian based Linux with many configuration options. The main downside is that you don't have support for ZFS and you have to very often use the command line to fix things. Moreover, there are a plethora of open issues/bugs that can make your life harder than expected

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