Most of you know by now that I am a variable star observer. I have a 12-inch telescope in a dome I use to monitor several hundred cataclysmic variables for outbursts visually, and another 12-inch telescope in a roll off roof observatory that has a CCD camera doing photometry, more or less automated.The visual monitoring program is sort of the astronomical version of a Chinese fire drill. I start in the east and work my way west through the night going from one variable star to the next as fast as I can. I make an observation in 60-90 seconds, log it, and move on. The reason for the rush is, it's a numbers game.
Most cataclysmic variables are too faint to be seen at all in a 12-inch scope when they are quiescent, not in outburst. Only when they erupt do they become visible. Most of the stars I follow outburst brighter than 15th magnitude, typically in the 13's or 14's. Some, like SS Cygni, get a lot brighter in outburst, and can be seen with binoculars.
Outbursts can last days or weeks depending on the star, but the thing is, they are totally unpredictable and they do not wait for anyone. If you miss a rare outburst, you may not get another chance for years, or decades. In some cases, never again.
On any given night only a handful of these stars may actually be active, out of the hundreds known. So the only way to be sure to catch them as they go into outburst, and to increase your chances of catching that rare find, is to observe as many of them each clear night as possible. I try to do at least 100 observations per night.
The majority of visual observations I log in a night are negative detections. In other words, I didn't see the star. It's not in outburst, or it's too faint for me to detect yet. When I log the observation I note the name of the star, the time to the nearest minute and the magnitude of the faintest comparison star I can see. For me, the limiting magnitude is usually between 14.8 and 15.2. On moonlit nights or under hazy skies that may drop to 14.5 or less, and on really fine, clear, dry nights I may occasionally glimpse a 15.5 comp star briefly.
When I report the observation it is written as 'less than the magnitude of the faintest comp star' (<14.8). So it's easy to tell the quality of a night by the typical limiting magnitude as you slew from one area of the sky to the next. The fainter you can see, the better the night, basically. In the morning, I type out my report and submit it to the AAVSO and several other email lists that track CV activity.
So, back to my story.
Around 2:30 I start observing in Andromeda, which is just about straight overhead. The star dots have shrunken down to fine points and the seeing has obviously improved a lot. As I examine the field of V402 And I'm stunned to see the 15.8 comp star plain as day. I've seen it on CCD images before, but never in the eyepiece. I move to the next field, LL And and I can see the 15.9 comp star easily with averted vision. I would have to image this field for 60 seconds with a CCD and V filter to measure a 15.9 star, and yet here it is in my Mark I eyeball! The sky has literally opened up for me and I am seeing things in the eyepiece I have not even glimpsed before. I log more than a dozen more record magnitudes over the next 45 minutes and also manage to catch several CVs in outburst.
It's just me, the telescope and the Universe sharing an exceptional night together when suddenly the peace is shattered by -- RING-RING...RING-RING...RING-RING!
My very loud cell phone is ringing at 3:20AM. The obnoxiousness of it startled me so much I nearly fell off my chair. As I fumble to find it in one of my pockets in the dark, terrible thoughts start to run through my head. Did someone fall ill, get rushed to the hospital or die? Is it Mom? Maybe something happened to Dad. I answer the phone with my flashlight still in my mouth.
"Hewowe?"
"Mike, is that you?" It's my brother Doug, and the first thing that pops into my head as I take the flashlight out of my mouth is 'he's in jail and needs me to come get him.'
"Yea" I say rather irritated.
"I'm surprised you answered".
"I'm surprised you called. What's wr..." I never get the rest out because Doug is in full blown talking mode now. It's a one-way street. His mouth opens up and his ears shut down.
"I'm outside looking up at the most incredible sky I've ever seen." (Tell me about it.)"Mars is talking to me, I can see Pluto and that little-dipper-like-thingy" (the Pleiades) "and oh my God, it's just beautiful, Mike."
I try to tell him the name of the cluster and that Pluto can only be seen with a telescope, but he'll never remember. My brother is drunk dialing at 3:20 in the morning and I was stupid enough to answer the cell without looking at the caller ID. Crap!
So after a few more 'I love you, mans' we hang up and its me and the morning sky alone again. I made a note in my log, DOUG CALLED!, and proceeded back to the business at hand. After my nerves calmed down a bit I started to chuckle to myself, because he was right. It was a beautiful sky, he knew I'd be out there at the telescope, and he just wanted to share the moment with me, bless his heart.
I took a little time to get lost in the Orion Nebula in his honor, and debated with myself if it was worth trying to chase down the Horsehead Nebula. I quickly came to my senses and got back with the program. I was rewarded for my efforts with three Orion CVs in outburst in a row, CN Ori, V1159 Ori and BI Ori--the Trifecta! This really was a great night!
I finished up in Auriga and Gemini about an hour before dawn and came in to warm up, eat breakfast and submit my reports. Out of 116 CV observations, 20 were active or in outburst. The rest are hiding away, biding their time, waiting to present themselves on another fine night.
Note to self:
Turn the cell phone on 'vibrate' when out at the telescope.
2 comments:
Great story! Glad you had an exceptional night of seeing.
Dallas area has been under clouds for 2 weeks, so I forgot what stars look like.
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