Personal Experience -- My First Month with Rent-A-Scope

Personal Experience -- My First Month with Rent-A-Scope

My name is Andrew Lowe. I'm a 46-year-old geophysicist and amateur astronomer from Calgary, Alberta, Canada. I've been interested in astronomy since a very early age. Unfortunately, the combination of cold winters and short summer nights doesn't allow me to observe as much as I would like to. Also, I live in a large city, so there's a long drive to get to dark skies.

Over the years, my main interest has been the computational aspect of astronomy, particularly celestial mechanics. When I got my first personal computer in 1984, I programmed it for orbital calculations. From 1985 until 1994, I did a lot of work on linking two-night asteroids from different years and proving that they were the same object. For this work, in 1990 I was honoured by the IAU with the naming of (4091) Lowe.

By 2000, thousands of sky survey plates had been digitized and made available to the public on the Internet. I started to download portions of these surveys and used the measuring software Astrometrica to report astrometry of asteroids to the Minor Planet Center (MPC). In the last five years, I've measured thousands of positions of asteorids.

In 2002, I realized that some of the sky survey plates could be used to discover new asteroids. I made 54 discoveries from this database. Then in 2003, I made another 86 discoveries from NEAT CCD scans before discovery rights for amateurs ended.

When I first heard of Rent-A-Scope in 2004, I thought that it might be an interesting way to follow-up some of my old discoveries and get their orbits refined, and to discover new asteroids. Arnie Rosner was very helpful with my questions, and he suggested that the Takahashi Epsilon E250 Astrograph, a 0.25-m f/3.4 telescope with a 56' x 37' field-of-view, would be most appropriate for chasing asteroids. My wife bought me a few hours of Rent-A-Scope time for Christmas, and I was ready to try out the system in early January when we returned home from Christmas vacation.

On the evening of Jan. 2, 2005, I logged on to the Epsilon scope and tried a few exposures of my 1991 TR15 asteroid. I typed in the R.A. and Dec. coordinates and photographed the object for a series of two-minute exposures. By stacking the images at the speed of the asteroid (in other words, tracking the asteroid and not the stars), I got a clear view of 1991 TR15 and seven other known asteroids in the area. Two nights later, I acquired more astrometry and sent the batch to the MPC. MPEC 2005-A11 was published the next day with the results of my work.

By this time, the moon was leaving the evening sky, and I was keen to try to find some new asteroids on the evening of Jan. 7. Where to shoot? One thing I didn't want to do was prove up a lot of recently-discovered objects, so I used the MPC's Sky Coverage plot to avoid areas where the big surveys had been active. I shot three discovery fields, north to south, about 10 south of Saturn. I shot field #1, then field #2, then field #3, then repeated the whole process two more times. I ended up with three images of each field over an interval of about 80 minutes. When I loaded the southern field into Astrometrica, I could see a number of known asteroids. In the lower-left corner, however, there was an unknown object. I wasn't sure that it was real, because it was only visible on the second and third frames. On the first frame, it would have been next to a bright star. I figured there was only one way to find out if the object was real or not, so I logged back on to the Epsilon and reshot the field about three hours later in the evening. I was thrilled when I found the object at the expected location.

I didn't find anything else new on the other two discovery fields. I reshot and found the new object the following night on Jan. 8. I also shot two new discovery fields, but nothing came out of those fields. I sent my astrometry for the two nights to the MPC, and a little later they informed me that I was getting discovery credit for my unknown object. It was now officially 2005 AC11!

Jan. 9 was cloudy, but I reshot 2005 AC11 the following night to improve its orbit, as well as three new discovery fields about 20 north of Saturn. No unknowns came out of the discovery fields, but I got a third night on 2005 AC11 and for the first time a general orbit could be computed.

Jan. 11 was cloudy, but on the following night I wanted to get some astrometry on 2002 QC58, one of my NEAT discoveries. So I shot a discovery field centered on 2002 QC58 and two more fields to the north. Sky conditions were very good that night, and I not only found my target but eight unknown asteroids! Two of these unknowns turned out to be previously-observed asteroids with poor orbits, and two others had been observed on a couple of nights in the previous month, but I got credit for the other four: 2005 AQ26, 2005 AR26, 2005 AS26, and 2005 AR36.

I ended up shooting for another seven nights to acquire extra astrometry for my new asteroids. On Jan. 15, I found another unknown object in the field for 2005 AC11. Initially, I was surprised I hadn't discovered found it before, but I subsequently determined that it had been close to stars and difficult to see. I sent the astrometry to the MPC, and they informed me that I was getting discovery credit, with the designation 2005 BA.

I continued to shoot my new discoveries until Jan. 19, when the moon moved into the evening sky. The orbits are now good enough that I'll be able to observe them in early Feb. 2005 when the moon leaves the evening sky. If I can observe them for over a month, it should be possible to recover them in upcoming years to further refine their orbits.

On Jan. 26, the MPC announced in MPEC 2005-B53 that 2005 AC11 had been linked to an object observed on two nights in April of 2002, and I retained discovery rights. The orbit is now well-known. Upcoming oppositions for 2005 AC11 are in May 2006 and Aug. 2007.

Looking back over the month, it was an exciting time to learn the potential of the Epsilon scope and to make the six asteroid discoveries. I experimented with the telescope and found that stacks of five exposures of ninety seconds gave me the best results. Arnie is great with attending to the needs of the observers, and their data is quickly available for download via a high-speed FTP server. Rent-A-Scope now offers a script-based telescope control for observers who would prefer to let the telescope execute a series of point-and-shoot commands. I've tried this approach on some comet discovery fields over the past few nights while the moon is too bright for asteroid work, and it's worked very well. I'm looking forward to finding more new asteroids with this automated approach.

For observers without access to research-quality equipment and a dark site, Rent-A-Scope offers the opportunity to experience the thrill of making your own discoveries!