The new Cherenkov Telescope on La Palma

End of 2018 I visited the new Cherenkov Telescope on La Palma. Actually I planned to write a long article about this visit - but as it happens sometimes, other things are more important... I decided to skip this article since now there is sufficient information out there about this telescope. However, I think the images I took for this article are still worth to see and give an impression from the observation site on the Roque de Los Muchachos on La Palma. The following two links provide more information about the CTA on La Palma:

https://www.cta-observatory.org/lst-1_inauguration/
https://www.cta-observatory.org/project/technology/lst/

Clear skies!

An article from lost-infinity.com in the "Dark Sky Travels Magazine"!

Recently Dark Sky Travels Magazine contacted me and asked if they could publish one of my blog articles in their magazine. The article describes how one can use DeepSkyStacker to stack conventional DSLR camera RGB frames. Of course I didn't say no and in the end it just happened and I saw my article on page 42/43 in Issue 4 of the DarkSkyTravels magazine!

I am very happy about that opportunity and the chance to share my experience this way.

Thanks and clear skies!

Easy 2D Signal-to-Noise Ratio (SNR) calculation for images to find potential stars without extracting the background noise (C++)

Long story short - I was looking for a way to detect more or less reliably if a user selected a region which contains a star. I wanted to be able to clearly distinguish between the following two images:

After a long journey I finally ended up with the following working solution based on the CImg library:

For the two images above the code gives the following results:

For many people this is where the journey ends. But for some of you it may just begin 🙂 Follow me into the rabbit hole and find out why the solution shown above actually works…

Continue reading →

NGC2175 from La Palma

Date2019/01/09
LocationLa Palma / Spain
ObjectOpen cluster NGC2175
CameraAtik383L+
Guidingyes, QHY5-II Mono via OAG
Telescope8
Barlow lensnone
MountEQ6 Syntrek
Cooling-10°C
Luminance8x 600s, bin: 1x1
Red7x 150s, bin: 2x2
Green7x 150s, bin: 2x2
Blue7x 150s, bin: 2x2
Dark2x
Flat10x
Total exposure~2h13m

On Wednesday, 9th January I imaged the open cluster NGC2175 the first time from La Palma. The seeing tonight again was very good - around 1.5~2"!

For post-processing I used the free software DeepSkyStacker and GIMP.

The full resolution images is available here.

Clear skies!

Milky Way - A longer exposure image

Date2019/02/01
LocationLa Palma / Spain
ObjectMilky Way
CameraEOS6D + Samyang 2.8/14mm
Guidingno
Telescope-
Barlow lensnone
MountEQ6 Syntrek
Cooling-
Luminance6x
Red-
Green-
Blue-
Dark3x
Flat-
Total exposure~15min.

Once more back on La Palma / Spain. I imaged the Milky Way a few times before from this beautiful location. However, up to now I was always bound to a maximum exposure time of about 20 seconds due to the earth rotation. This time I decided to put the camera - an EOS6D with a Samyang 2.8/14mm lens - on top of an EQ6 mount. This way much longer exposure times with a lower ISO value (i.e. less noise in the image) were possible without getting any star trails. I took 6 frames with ISO 1600 á 148 seconds each. The total exposure time is therefore about 15 minutes.

The frames were then post-processed with rawtherapee and averaged using the ImageMagick "convert" tool. In addition 4 frames of the foreground (the house) were taken and also averaged (of course with disabled EQ6 mount). Finally the two pictures were overlaid and merged with the help of a mask using gimp.

To me it is amazing to see the Andromeda Galaxy (M31), the California Nebula (NGC1499), the Orion Nebula (M42), the Pleiades (M45) and the Horsehead Nebula (B33) clearly on this photo. This overview picture gives a good idea of the brightness, size and exact location of the objects compared to each other.

A full resolution image of the result can be found here. Another image without object descriptions can be found here. I am curious to repeat this procedure in summer when the bright part of the Milky Way will be visible again 🙂