NOVA CYGNI 2001 No. 2 (August 18, 2001 Discovery Date)

Nope, I didn't discover the nova, to be described.  However, by sheer coincidence I took a picture of the region containing the nova when it was close to maximum brightness, 1.6 days after it's discovery.  I didn't learn about the Cygnus nova until two months later, when it occurred to me that I had been taking lots of pictures of that region in order to create a zoom sequence for the North America Nebula (in Cygnus).  Sometimes "dumb luck" pays off, as in this case when I took one of the earliest color pictures of the nova.

So, do you see anything unusual about the following image?

Figure 1.  Cygnus region with the North American Nebula (red) in the center.  The bright star just upper-right of center is Deneb, the brightest star in Cygnus.  [2001.08.19, 9:51 PM, PDST; Nikon F3, 105 mm FL, f/3.5, mounted to Meade ETX125 telescope for sidereal tracking; average of two 9-minute exposures; Fujifilm Superia X-tra 800; observing site Santa Barbara residence, 200 feet ASL.]

When I looked at it I saw only the North American Nebula, which was my goal for that evening.  It didn't occur to me to look for any stars that "didn't belong" in the image.  Let's look at an earlier photo of the same region, taken 3 months before.

Figure 2.  This image has a slightly different scale, but it is was taken with the same camera and lens combination and it is possible to compare it with the previous image to locate a missing star.  Don't try doing it because below I present relevant portions of these two images side-by-side.  [2001.05.23, 00:40 AM, PDST; Nikon F3, 105 mm f/4.5 lens, mounted to a Meade LX-200 10-inch telescope for tracking and hand guiding adjustments; average of two 6-minute exposures; Fujicolor Professional 400 NPH film pushed to ISO 800; observing site along the East Camino Cielo Road, 3200 foot altitude, near Santa Barbara.]

Figure 3a (left).  Detail of the previous image, taken before the nova appeared.
Figure 3b (right).  Detail of the August 19 image, taken during the nova's eruption.

Can you locate the nova in Fig. 3b?  Hint: it's in the upper 1/4.  The upper portions are blown-up in the next "blink image":


Figure 4a (left).  This is an example of a "blink movie," illustrating a common method for discovering nova and asteroids.  (The planet Pluto was discovered in this manner.)   There are only two frames in the movie, and they repeat forever in the movie.  The two images were taken from the top portion of the previous two images, one from the evening of May 22 and the other from the evening of August 19. The blink movie displayed here is a 1/2-scale (smaller than the stills in the previous figure); if you have a wide-band internet connection you may want to click this blinking image to see a full scale version blinking movie (430 KB in size).

Figure 4b.  Two months before the nova outburst, on June 15, 2001, I obtained this image of the same region, with slightly better resolution under a slightly darker sky.  Inside the circle there is no star brighter than magnitude 10.5.  [2001.08.15, 01:45 AM, PDST; average of three 5.5-minute exposures, 105 mm FL, f/5.6, mounted to Meade LX-200 10-inch telescope for guiding; Fujicolor Superia X-tra 800; observing site San Marcos Pass, 2200 feet ASL.]

The nova appears to be yellowish, and is at magnitude 7.02 +/- 0.05 (according to several Hubble Comparison Stars in the Meade Epoch 2000 Sky Software).  It was discovered in Japan 1.6 days earlier, but I didn't learn about it until a month later.  The discovery image was taken August 18.599, when the nova was at magnitude 8.8.  The nova image on this web page was taken August 20.202.  Many observers, more alert to notices e-mailed by the AAVSO (American Association of Variable Star Observers) made measurements starting a day after discovery, and these allow a "light curve" (intensity versus date) to be constructed.  The nova brightened to magnitude 6.6 about one day after discovery, then dimmed about one magnitude per day for several days (i.e., dimmed about 40% each day).

Figure 7.  Light curve for the nova.  The black square at day 52141.70 is my magnitude estimate of 7.02 +/- 0.05.

My magnitude estimate agrees well with other reports.


This site opened:  October 19, 2001 Last Update:  October 26, 2001