Observing in June and July

June and July tend to be a bust for astronomy. At least for visual observing and astrophotography with a DSLR. The skies don’t get really dark at the observatory until a little after 11pm or even 11:30pm and the warm nights make imaging with an uncooled camera challenging.

With darkness well after 11pm, its hard to get motivated to go out to the observatory when its really time for bed. In the winter, its quite possible to observe at 6pm and put in a good 4hrs at the scope before its bedtime. In June, it’s bedtime before it even gets dark.

Then there are the bugs – mosquitoes in particular. In Ontario, June and July are terrible for mosquitoes. The new pyrethrin based repellents are great though. So it’s just a matter of getting the Thermocell started and then comiing back in half an hour. You just have to accept a few (or many) bites setting things up and them waiting for the bugs to disperse.

The camera is another matter though. With evening temperatures in the high teens the camera sensor temp can approach 30c. At that temperature, there is a considerable dark current random noise component. The only way to increase the S/R is to take more subs. However, with only 2-3hrs of dark skies, it means taking images over several nights. The chances of getting two clear nights during a dark moon phase in Ottawa is very slim.