M91 or Why It’s Important to Keep an Observing Log
I was quite worried about grabbing the dim galaxy M91 in my quest to see all 110 Messier objects with my Canon 15×50IS binoculars. And this was with good reason, you M91 had alreday eluded me a short while ago, twice actually but the second attempt was pretty short.
So you can imagine my surprise, when I was writing my previous blog entry, when I opened my Messier “seen” spreadsheet and found a checkmark next to M91!
I immediately deleted it and went about writing the entry. Later on, that evening, I was thinking about it. How could that be there and then I remembered. I actually had seen it! It was the same week as the previous blog entry, perhaps even the same night. I couldn’t remember. Everyone in the house was asleep, except for me of course, so all the lights were out and I just bundled up and went outside and kept on trying. It was about 45 minutes to an hour later than I first glimpsed it. And glimpse indeed, it was dim, perhaps the dimmest object I had ever observed, I could only get it with averted vision and even then it would come and go. It was clearly non-stellar and actually a tiny bit larger than I expected.
As with any dim sighting, I needed to confirm it. So I would look away, actually put the binoculars down, and star hop back to it. I probably did this 4 or 5 times until I was able to convince myself that I had actually found it.
So this is great news, I now only have 7 left and this was one of the two difficult objects left.1 But what went wrong? How did I make this mistake? How could I make an “important” observation and not even know what day I made it on?
I don’t keep a written observing log.
I know, I should, but I tried it once and I found it hard to both write in the cold and hard to keep the paper free of dew. I have a voice recorder that Jeannette would sometimes use for work but I don’t use that either.
This whole episode shook me a little. (Just a little, really, I’m not crazy.) So I promise now to always keep an observing log. I’ll read up on it and ask my club members and the folks at CloudyNights.com for help.
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1 M76 is the other object that I’ve worried about. I had a very difficult time with it at the WSP but two highly respected binocular astronomers on CloudyNights have told me not to worry about it. So I won’t.