Observing with Dob-Mounted SW250PDS

Wednesday night (3rd February 2021) was the first opportunity for 4 weeks that the sky has been clear enough for long enough at a reasonable time (I am fussy) to get in some observing. It was due to cloud over later so decided on the 10″ SW on the Dob. My target in January had been globular cluster M15, but it’s now too low in the murky West towards Burton on Trent. Orion was well placed so I focussed on multi-star system sigma Orionis, about 45 arcminutes south of zeta Ori, Alnitak, at the eastern end of Orion’s belt.

This is a 5 star system but I learned later only 4 are visible in amateur telescopes, that’s a lesson in planning that could have saved me a few eyepiece changes! The bonus with this target is that you get a triple star system in the same view, Struve 761. The image below was obtained using a Canon 60D 1/8s @ iso3200.

Auriga was high above, so I had a go at finding 1 of its 3 open clusters and found M37, the most impressive of the 3, suprisingly quickly, as I last observed it over a year ago using a GoTo mount. I do like star clusters and this was a real jewel, that was best at magnification of 100X. My image from 2020 below does not do it justice, of course.

Just time to slew over to Perseus to check out Mirfak and the Alpha Persei Cluster, using the 9×50 finder to view it all before the inevitable high clouds rolled in. Overall, I was pleased with what I had seen in just over an hour during only my 2nd session of 2021.

3 Responses

    1. Both were taken with the Canon 60D at prime focus attached by T ring. Sigma ori was taken with 250pds on the Dob, hence the short exposure. M37 was 15s @ iso800 through my SW 200P tracking on an HEQ5 Pro mount in January 2020. I usually do very simple single frame astro photos purely as a record of what I observed. But I have had some success with stacking using the Camera Control function on the SW handset, with it connected directly to the camera.

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