May's meeting was well attended and saw the return of Pat Clough, society member, to talk about DSLR Photography part 2.
Jackie Harris opened the evening by welcoming all, in particular new members, and running through a few notices.
Sandy Giles, who runs our practical evenings, discussed the next practical evening in July. It will run the format of an “astronomers question time” with four panellists and Sandy put out a request for questions to be asked on the evening.
Morton then went on to discuss the roof of the observatory and asked if anyone had experience of fibreglass resins, of which we plan to
re-roof the observatory with.
Pat’s second lecture was informative and generated lots of questions from the audience. He went through a variety of aspects of digital SLR photography including focusing, the exposure triangle, histograms, white balance, mirror lock up and file formats.
Pat uses a Bahtinov Mask which has transformed his focusing. These masks fit on the front of the telescope to aid focusing and can be easily made at home. There is a link on our website to print out a template for making a mask to fit your scope if you are interested.
The exposure triangle is a combination of the ISO, which controls the amount of light, the Shutter speed, to control movement and the aperture which controls depth of field which, when used together correctly will produce the ideal exposure.
Several pictures of histograms were shown and Pat described the ideal histogram to try and achieve and Pat told the audience that it was essential to look at the histogram in order to get a good astro-photograph exposure. He explained that the left start of the histogram reading needed to be away from the left hand edge of the screen.
For astro-photography Pat uses Day Light white balance. Custom white balance can also be used and this can be achieved by taking a picture of the night sky and then asking the camera to set it.
Pat then showed us a variety of pictures and discussed his process for taking them. He recommended that at least 15 frames be taken which can then be stacked, the noise reduction should be turned off and for deep sky he would use an ISO of 800 and for the moon an ISO of 200.
All in all this was another informative and interesting lecture that Pat gave us and it was well received by the audience.
The next meeting will be the Astronomers Question Time on Thursday 4th June – please do come along to ask your questions.....its looking as though this is going to be another good evening.