Three supernova discoveries in a month for Ron Arbour

2015 July 20

Callum Potter & Roger Pickard

In June this year, using his 35cm f/6 SCT with  SXVR H9 CCD, longstanding BAA member Ron Arbour discovered two supernovae in a week, and a third followed soon after in July.
On the night of 2015 June 10 Ron identified PSN J14372160+3634018 in the galaxy NGC 5695 in Boötes at magnitude 17.0. Spectral follow-up by the Padova-Asiago Supernova Group classified it as type II.
Next on June 16 Ron discovered PSN J15044078+1237436 in the galaxy NGC 5837, also in Boötes, at magnitude 17.5. Spectral follow-up by Leonard (San Diego State University) et al. reported in ATel 7690 classifies it as type IIn.
Finally on July 9, Ron found PSN J17292918 +7542390 in NGC 6412 in Draco at mag 16.7. A follow-up observation by the Asiago group on ATel 7787 confirmed it as an ‘early’ type II object.
In a message to Roger Pickard in June, Ron commented: ‘The UK mid-summer skies never get really dark enough and the limiting magnitude with very short patrol images suffers very noticeably. To get beyond 200 images when starting so late becomes somewhat difficult! With this very low number of images the chances of discovery are dramatically reduced compared to the winter when 500 to 1000 images per night are reasonable expectations.
‘Statistics show the interval between discoveries by dates and number of images; to me this means ‘You never can tell’:
2014 Nov 2 to May 10 – 19,437 images to discovery of SN in NGC 2770;
2015 May 18 to June 10 – 681 images to discovery of SN in NGC 5695;
2015 June 13 to June 16 – 153 images to discovery of SN in NGC 5837.’
Our congratulations to Ron whose tally of supernova discoveries is now 35.
Callum Potter & Roger Pickard