The Herschel 400
By Luca Vanzella
By August 2015 at Saskatchewan Summer Star Party (SSSP), I had observed all but six objects in the RASC Finest NGC list. Following what I thought was a natural progression for deep sky observing after the Messier Catalogue (already completed) and the RASC Finest NGC List, I decided that my next observing project would be the Herschel 400 (and I would pick up the remaining Finest NGC’s along the way).
The Herschel 400 is a list of 400 galaxies, nebulae, and star clusters selected from the Catalogue of Nebulae and Clusters of Stars published by William Herschel and his sister Caroline. The objects were selected by members of the Ancient City Astronomy Club in St. Augustine, Florida circa 1980 to provide amateur astronomers with an observing project beyond the Messier Catalogue. The Herschel 400 forms the basis of the Astronomical League’s Herschel 400 Observing Program1. The objects range in brightness from 4th to 13th magnitude, with the vast majority (321 objects) from 9th to 12th magnitude.
The Herschel 400 contains 17 objects that are also in the Messier Catalogue2 and 83 objects that are also in the RASC Finest NGC List3. Since the latter two lists have no overlap, by August 2015, although I didn’t realize it at the time, I had in fact already observed about one quarter of the Herschel 400. My plan was to observe all 400 objects even if I had previously observed them (although in the end it didn’t work out quite that way).
By this time, I was using SkySafari for planning and tracking my observing projects. The SkySafari website contains a repository of observing lists crowd-contributed by users (but not necessarily vetted by anyone)4. The website has two offerings for the Herschel 400: by constellation and by season5. I decided to download and use the four SkySafari skylist files for the Herschel 400 by season since that’s how I had worked on the Finest NGC’s. At this point, unbeknownst to me, Murphy joined my observing project and would make three appearances.
On the particularly nice evening of New Year’s Day January 2016 at the future home of the Black Nugget Lake Observatory (BNLO), I started on the Herschel 400 with the first four objects in the winter group. In May 2016 at BNLO, I really got going on the list by observing 90 objects in the spring group. In August 2016 at SSSP, I picked up another 35 objects. In March 2017 (after an aborted Bimarathon in Maui7), I observed 75 objects in three nights. Another 27 objects were identified at BNLO one particularly nice night in December 2017. I scooped up another 21 objects over two nights in March 2018 at BNLO. In May 2018, I was able to get 42 objects at a family camping location in Alberta. Another 24 objects were logged in three nights across September, November and December 2018 at BNLO.
The Saga of the 400th H400 (Enter MURPHY)
By March 2019, I thought all I had left to do was one object in the winter group, 31 in the spring group and 29 in the summer group. I figured I could get them that month, which I did in three great all-nighters in Maui. I thought I was done, but then I noticed that somehow I had MISSED getting one of the fall group objects (NGC 613) along the way. I tried in vain to get NGC 613 in the very early evening in Maui but the sky was just too bright before the object set. Oh well I thought, I will get the 400th object back in Alberta.
As I prepared to observe the 400th object in October 2019, I reviewed my observations in SkySafari and realized that I had also MISSED getting one of the spring group objects (NGC 4752) along the way. OK I thought, I will observe NGC 613 in October and NGC 4752 in the spring of 2020. In October 2019 in Arizona, while working on the Astronomical League’s Multiple Star observing program8, I got NGC 613. The 399th object down, one to go.
On March 20, 2020 at BNLO, I swung the 18″ Barry Arnold Memorial Telescope (BAMT) to NGC 4752 in Coma Berenices and tried to observe the 400th object. It was then that I noticed NGC 4752 is a 15th mag spiral galaxy. I should be able to get it with an 18″ scope, I thought. Hah! I nailed the field, but I could not see it. I asked uber experienced, deep sky observer Alister Ling to come have a look. He thought he teased it out, but I could not honestly say that I had seen it. Perhaps the snow covered landscape contributed to too much sky brightness? Maybe next New Moon window with no snow on the ground, I thought.
Since I was close to completing the project, I decided to compile my observing log from the observations I had tracked in SkySafari. SkySafari includes a cloud storage option called LiveSky to backup and manage observations on the web. I downloaded all of the Herschel 400 observations from LiveSky in CSV format to create a spreadsheet, but the data did not download cleanly. This made for quite a job getting the data into shape – but that’s another story. To my surprise, the downloaded data included an observation for NGC 4752 back in March 2017! I don’t know why the observation was in the LiveSky cloud storage but not in SkySafari on my tablet (I guess some sync error had occurred – yet another story). My comment on the March 2017 observation of NGC 4752 said “Vfff”. I wondered why I saw it in a 10″ scope, albeit “Vfff”, but not in the 18″ BAMT. It didn’t occur to me to ask why was a 15th mag galaxy in the Herschel 400? Oh well, I had bagged the 400th object and the project’s complete – time to write it up.
I decided to do a final comparison of the objects listed in my Herschel 400 list (based on the four SkySafari skylist files for the Herschel 400 by season) against the list published on the Astronomical League website. Turns out that the skylist file for the spring group contains NGC 4752 whereas the Astronomical League lists NGC 4725 (a 9th mag galaxy). Someone had apparently TRANSPOSED two digits. Talk about an error that’s hard to notice9: Both 4752 and 4725 are in galaxies Coma Berenices, fairly near each other in the constellation and to boot, both objects appear in the same position in the Herschel 400 if included.
So I was back to needing one more object to complete the Herschel 400. Or was I? I checked in SkySafari to see if I had recorded any observations for NGC 4725. Boom, an observation appeared from February 2013. Turns out I had observed NGC 4725 when doing the RASC Finest NGC list! In my excitement, even though the observation was from a prior observing list, I decided to count it. Whew, my Herschel 400 project was complete!
Overall, the project has been rewarding and fun. Over the last few years, whenever I found myself under clear nighttime skies equipped with a telescope, whether or not I had an observing plan, I always had the Herschel 400 list to provide targets. Of the four telescopes I used, two were GoTo and two were manual. Sometimes the GoTo worked well and other times not so much (I’m looking at you SkyWatcher). With the manual telescopes, the star hops to acquire the targets were fun since there was always something interesting to see along the hop. If you are an aficionado of faint fuzzies, the Herschel 400 should be in your observing plans.
Elapsed time to complete project: 6 years, 8 months, 15 days
- Started: Feb 6, 2013 (NGC 4725)
- Ended: October 20, 2019 (NGC 613)
- The bulk of the observations (393 objects) were made in about 3 years from May 2016 to March 20196.
Most Productive Sessions: 4 (268 objects)
- 90 May 2,3,4, 2016 at BNLO (Alberta)
- 75 March 25,27,29, 2017at La Perouse Bay and Kihei (Maui)
- 42 May 19,20,21, 2018 at Bumsted (Alberta)
- 61 March 2,4,5, 2019 at Ahihi Bay (Maui)
Number of observing sites: 8
- 3 in Alberta
- 3 in Maui
- 1 in Saskatchewan
- 1 in Arizona
Number of Telescopes Used: 4
- My 10″ Genstar (Newtonian Reflector)
- A friend’s 11″ Celestron CPC (Schmidt-Cassegrain) (thanks Sheldon and Kelly!)
- My 12″ SkyWatcher (Newtonian Reflector)
- RASC Edmonton Centre’s 18″ BAMT (Newtonian Reflector)
Most Used Eyepiece: 10mm Televue Delos (360 objects)
- 127x (10″ Genstar)
- 150x (12″ SkyWatcher)
- 280x (11″ Celestron CPC)
5 The Astronomical League website states “there is an object on the list on the website that is different from an object that appears on the list in the manual.” The website lists NGC 7814 whereas the manual lists NGC 1750. Evidently the SkySafari skylist files by season are based on the manual since they include NGC 1750, whereas the skylist files by constellation include NGC 7814. The Astronomical League accepts either object.
6 In May 2016 at BNLO, I somehow missed getting two of the remaining six Finest NGC’s. In August 2016 at SSSP, I got four of the remaining six Finest NGC’s). I bagged the final two Finest NGC’s in March 2017.
9 As of March 2020, the skylist files “3_Herschel The Spring Group” and “H400_All” still contain the erroneous NGC 4752. This has been reported in the support forums10. As it turns out, on the SkySafari website, the SkySafari skylist files for the Herschel 400 by constellation contain the correct object NGC 4725.
© 2020 Luca Vanzella