I had the chance to borrow a Hydrogen alpha filter for solar observation. As the weather was just perfect, I set up my 80/600 refractor with the filter and a camera attached. Every 15 seconds I captured 400 frames for later processing. After 4 hours, my hard disk was loaded with 850GB of data…
Now, more than 2 days of stacking, aligning, optimizing, … are over. The resulting image sequence is simply fascinating and beautiful:
As the nights are really short right now, I set up my scope at home and took a look at the moon. Seeing was not too good, but in moderate magnification, the moon still was pleasant to look at. So I thought, I did not shoot the Moon or the planets for a while. Why not give it a shot? I took my my planetary camera which was stored in their box for more than 2 years and set up for imaging…
For the “first” results, I am really pleased. Now I think I have to optimize and go for it again soon 🙂
102mm f7 APO, ASI120MM-S, RGB+IR Filters
Copernicus: 10% of approximately 5000 frames
Plato: 10% of approximately 11000 frames
Last night I spent near my home town – a short 25 minutes drive – to a place I frequently used years back for astronomy. It is a quite dark spot, though the light pollution is still obvious. Nevertheless I tried to go for some deep sky objects, getting as much observation / camera time as possible in the short nights of June.
My list of objects was not too short. All of them were well placed in the sky and really nice to see :-). So here you go: 1) Hercules cluster M13 (Sony A99ii, 800mm f4, 2xTC, 27x120s, ISO3200) 2) Virgo galaxies M60, M87, M90, M100 (Sony A6000mod, 70-200mmf2.8 @ 200mm f4.5, 22x300s, ISO3200) 3) Virgo galaxy M90 – though I intended M87 😉 4) Whirlpool galaxy M51 (Sony A99ii, 800mm f4, 2xTC, 6x360s, ISO3200) 5) Andromeda galaxy M31 (Sony A6000mod, 70-200mm f2.8 @ 200mm f4.5, 5x30s, ISO3200) – I made an error in exposure time, so instead of 5×300 I ended up with 5x30s 🙁 6) Jupiter (I did not pack my planetary imaging camera – so I used the same setup with Sony A99ii and 800mm scope at 1600mm) 7) Saturn (same as Jupiter)
And far too late (at 01:30) I set up my timelapse camera for a night-to-day movie. The milkyway was beautifully placed just above the pasture. The resulting video clip is below.
Finally a couple of cloud free evenings are here! So lets see, what is to see from the city…
From a balcony facing south across a city, there usually is not too much to expect. This time, I chose the star cluster M5, which is quite bright an was not too hard to see in the scope. Sure, it does not hold to a darker spot away from light polluted city skies. But hey, there is still a lot to see:
Image properties: 75x 40s, 800mm f/4, Sony A99ii @ ISO 1600
After the completely washed away telescope meeting in the beginning of May, I tried to meet up with a few enthusiasts with quite promising weather prospects. Unfortunately the cloud cover did not vanish all the way. Even though there was quite a lot of clouds passing over, I could manage to snap some light frames from M51 – the Whirlpool Galaxy.
A few times in the past I have seen charts of the dark sky quality for astronomical use. Especially during a visit of the University astronomy department I had the chance to talk with one of the facilities operators. This made me curious about how they quantify the night sky quality.
Upon further research I found the widely used Sky Quality Meter by Unihedron. It is a small box measuring the sky brightness by means of a light sensor with corresponding frequency output. When I could find a distributor selling these sensors for a good price, I was up to building my own one. My concept was to use a arduino style micro controller and build a sky quality meter together with weather data (temperature, pressure, humidity) recording device. The device should save every 10-30 seconds the data collected. And it should last for at least one whole night running on a small(er) battery like AA or 18650 lithium type.
The hardware part was quite easy to accomplish. I simply had to connect a couple of wires from the micro controller to the sensors and other components. The harder part was to create a proper software, fulfilling all my needs. I had to find a way to 1) cope with the frequency range of 0.01Hz to 1MHz 2) fit all the code within the small memory 3) calculate sky quality and calibrate device to a reference device
Luckily, apart from a reasonably well described device on the Unihedron web-site, I could borrow one Sky Quality Meter from a fellow astronomy club member. So I had a reference device to compare and calibrate my device.
Here is the test setup. The readings are already very close to the original device!
It is always frustrating to see good weather pass without the opportunity to do some photography – especially astro-photography. So even if time does not permit a trip to the darker spots in reasonable distance from my home, it is worth a try to setup the telescope on the balcony.
This time, clouds cleared throughout the day (and happend to reappear before midnight). So I had to take the chance to spot Comet C/2018 Y1 Iwamoto. Unfortunately, I was unable to spot the comet through the eyepiece. The sky was far too bright (approximately 18mpss) watching straight over the citys light dome and having a 60% illuminated moon shining bright. Fortunately, through the camera I could make out a smudge, being brighter than the sky.
Processing the 180s subs with 1 hour total exposure time, I could achieve this result (compare to the unprocessed image!):
Image is a composite of 2 stacks (one aligned on stars, second aligned on comet). The comet moved more than 1.5 degrees during the 1 hour capturing time! Above the comet: NGC 2903 (mag 9 galaxy) At left: NGC 2916 (mag 12.1 galaxy)
Imaging setup: 800mm f/4.0 Newton, Sony A6000 full spectrum modified, UV/IR block filter, UHC filter, coma corrector (at wrong distance). 20x 180s @ ISO800, darks and flats Conditions: +2°C, 60% moon, 18-18.5mpss sky in suburban location (with ample street light)
I had a bit of time to experiment with an H-alpha filter at home. Conditions are limiting astro-imaging as my balcony faces south. Living in the northern outskirts of a city, all the sky visible is significantly affected by city lights. This night, the sky was somewhat OK, reaching up to 18.7 to 19.5 mag/arcsec².
Using narrow band filters, like an H-alpha filter, the majority of the city lights may be cut away. This image (not perfectly focussed) shows, what is possible. It is a result of 12x240s, captured at ISO800 with my modified Sony A6000…
After 2 weeks of thick cloud coverage, I had the chance to spend the evening at the observatory. Actually I jumped in to hold the guided tour this evening… As there was almost full moon and some cloud coverage (which got steadily thinner) I played a bit around with the setup. I thought – deep sky at full moon is a waste of time. But how about the comets 46/P Wirtanen and 38/P Stephan-Oterma? How brigth are the comets still? Would they shine through the moon lit sky? Well… I could not make out Stephen-Oterma. But Wirtanen was barely (in)visible. I had some other tasks to do, so I attached the camera to the scope and let it run to see, what may be gathered under these conditions. Despite of the Moon and the corona of Moon, a little bit of the comets was still possible to process from 90 minutes of total exposure time each:
In the night of the 2018 Perseid meteor shower maximum I was out to the mountains for a fantastic view of the stars. I also setup my slider to capture the milkyway moving across the sky… Well I did not expect that amount of humidity. The camera got completely covered in dew and I forgot to bring my dew heater. So the video only lasts for 3 hours time, until all was soaking wet…
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