The past months I had trouble with my 10 inch scope. I was not able to image with nice round stars. So i kept imaging with my smaller refractor, as stars were rendered round. After some investigation and chat with fellow astronomy club members, I could nail down the cause of the elongated and triangular stars: the auto-guider as well as a too short settle time after dithering were messing up. So, to achieve the round stars everyone is after, I had to increase the settle time after dithering (otherwise, I got double-images due to the offset) as well as the guiding parameters in MGEN. My settings for off-axis guiding on 1250mm focal length are: Threshold: 0.1, Aggressivness: 100% in RA and 80% in DEC and 2×2 binning.
The first test target was M48 with 50% aggressiveness. Stars were not yet fine. The second target was M65 together with M66. Stars are fine!
Image data: Date: 2021-03-31 Location: Graz, Austria Telescope: 10″ f/5 Newtonian with GPU corrector (1250mm focal length) Camera: QHY183M @ -20C Filters: Optolong RGB Guiding: MGEN-II with off-axis guider Exposures: M48: 83x10s L, 46x20s R, 30x20s G, 30x20s B M65+M66: 48x60s L, 39x60s R, 32x60s G, 20x60s B
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
The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.