Sunspot 12804 plus prominences and filaments

After a brief break early February, the Sun is still showing activity. Here are the nice but small sun spot 12804 as well as 2 filaments and a detatched prominence.

Image data:
Date: 2021-02-26 13:30 – 14:00 UTC
Location: Graz, Austria
Telescope: 102mm f/7 APO with 4x Tele-Centric
Camera: QHY183C @ -10C
Filters: SolarSpectrum 0.5A @ 60.5C

High-Res Moon

Yesterday evening, during our astronomy club chat, I had my scope active to observe the moon. Fortunately, there have been quite stable air conditions. So I could record several craters, mostly located near the terminator for best shadows in the crater valleys 🙂

Image data:
Date: 2021-02-24 19:00 – 21:30 UTC
Location: Graz, Austria
Telescope: 256mm f/5 Newton with 2.5x Barlow
Camera: QHY462C
Moon: Phase: 32d / 92%
Moon-Diameter: 31m41s
Imaging scale: 0.19″/pixel – 1 pixel = approx. 350m on the surface of Moon
Filters: UV-IR Cut, 850nm IR Pass

Sahara dust – or did we wake up on Mars?

Last night, during quite clear conditions, the majority of the stars vanished in a haze. The bright moon did the rest to let me cease imaging. The haze was not actually a haze, but rather the dust carried from the Sahara desert to central Europe.
In the morning, the rising Sun appeared rather soft and set in a diffuse sky. If there were no buildings, but red sandy flats, one could be tempted to be viewing new images from Mars 😉

NGC2264 – The Cone Nebula and Christmas Tree Cluster

Here is another result from last weekend of fine weather. This is the Cone Nebula and Christmas Tree Cluster in NGC 2264, a beautiful H-alpha region.
The image is a 2 1/2 hours pure H-alpha recording. Therefore presented in black and white.

Image data:
Date: 2021-02-12 – 2021-02-14
Location: Graz, Austria
Telescope: 102mm f/7 APO with 0.79x flattener (equals to 564mm focal length)
Camera: QHY183C @ -30C
Filters: Narrow band H-alpha filter
Guiding: MGEN-II with off-axis guider
Exposures: 15x600s Ha

Virgo Galaxies around M86

This is the next image captured last weekend. I recorded 114 individual exposures of 120s, from which I could use 43 due to clouds crossing in the night.
I annotated the image with the galaxies visible. Among them are:
M86 (mag 8.8)
NGC 4438 (mag 10.0)
NGC 4388 (mag 10.9)
NGC 4440 (mag 11.8)
NGC 4402 (mag 11.9)
and the faintest ones visible are
IC 3386 (mag 16.0)
IC 3349 (mag 17.7)
IC 3363 (mag 17.7)
PGC 40723 (mag 17.7)

Image data:
Date: 2021-02-11
Location: Graz, Austria
Telescope: 102mm f/7 APO with 0.79x flattener (equals to 564mm focal length)
Camera: QHY183C @ -30C
Filters: Baader UV-IR Cut + IDAS LPS-D2
Guiding: MGEN-II with off-axis guider
Exposures: 43x100s RGB

Leo Triplet with H-alpha and O-iii enhanced

During the last few days there were really promising clear nights. I recorded several data sets from my urban location (under these conditions, going up the mountains would have been a treat!). Now, as there are clouds again, I am processing the captured data. Here is the first result from the Leo Triplet (M65, M66 and NGC 3628).
I still have not yet received my color filters. So here I have a combination of luminance (UV-IR-Cut), H-alpha and O-iii data.

Image data:
Date: 2021-02-12 – 2021-02-14
Location: Graz, Austria
Telescope: 102mm f/7 APO with 0.79x flattener (equals to 564mm focal length)
Camera: QHY183M @ -30C
Filters: Baader UV-IR Cut + IDAS LPS-D2, narrow band Ha, Oiii
Guiding: MGEN-II with off-axis guider
Exposures: 41x100s Luminance, 20x300s O-iii (2x binning), 30x300s H-alpha (2x binning)
Sky-Quality: 19.4-19.6 mpss

M42 (Orion nebula) in narrow band – Hubble palette

Finally, the clouds did break! After more than 2 months, this is the first chance to do some astro photography. It would have been a great opportunity to go up on one of my mountain observing spots. But with clear skies and a northern wind, temperatures dropped to -10C and below. So I stayed in the comfy warmth of home with urban light. Even though, narrow band images are still possible with quite long exposure times.

With the great Orion nebula, imaging is not too hard to accomplish, as the nebula is really bright. So a set of 110 exposures of 100s revealed the following image. Unfortunately, I could not completely remove the amp-noise from the camera as well as the uneven background. I have to improve my skills in post processing 😉

Image data:
Date: 2021-02-11
Location: Graz, Austria
Telescope: 102mm f/7 APO with 0.79x flattener (equals to 564mm focal length)
Camera: QHY183M @ -20C
Filters: Baader narrow band Ha, Oiii, Sii
Guiding: MGEN-II with off-axis guider
Exposures: 42x100s H-alpha, 42x100s O-iii, 26x100s S-ii

Effect of temperature tuning a Fabry-Perot Etalon solar H-alpha filter

Since the first days I could observe the sun through a narrow band solar H-alpha filter, I was wondering what the tuning effect of such a filter would be. It does not matter whether the filter is pressure, tilt or temperature tuned. The effect of slightly shifting the filter central line is the same. With the temperature tuned filter, I have at hands, a comparable test series is easy to achieve.

I know from previous observations that the filter performs best at 58.0C. Therefore I set the test points at 5 degrees steps across the range of possible temperatures. Only close to the 58C I added 2.5C halve interval steps.
Each individual image was recorded with a set of 100 frames, from which the 20 best frames were stacked. At each temperature I recorded 2 sets at different exposure settings: one for the surface (granulation, … – unfortunately no sunspots were active) and the other for prominences (only minor activity here as well).

As is obvious from the result, the low temperature settings yield close to no interesting view. Between 55.5C and 63.0C the filter delivers good contrast. Beginning at 63.0C contrast degrades again.

Imaging setup:
Telescope: 102mm refractor
Camera: QHY183M @ -20C
Filter: Solar Spectrum – Solar Observer Series 1.5, 0.5A solar H-alpha filter