Observing the Herschels:
An Astronomical Perspective
It started in the late summer of 1977 and it ended nearly 18 years later in the early morning hours of 21 May, 1995. The hunt opened in Jacksonville, moved to West Palm Beach and Atlanta and carried on from Murphy, North Carolina to the Florida Keys. Finally, the Herschel List was complete!
One of the most interesting observational challenges for the amateur astronomer equipped with a modest sized telescope are the 400 objects that comprise the Astronomical Leaguesí Herschel List. Most amateurs are familiar with the Messier list and are aware that the Astronomical League awards a certificate and pin to those who observe these bright deepsky objects. Once you have developed your observing eye on the Messier List, the Herschel List can further increase your knowledge of the sky and your observing prowess.
I would like to reminisce a bit about my own hunt for the Herschels over that 18 year period.
My own quest for the List started on the night of 5 August, 1977 from the front lawn of an apartment building in Jacksonville, Florida. I had not owned a telescope for several years after selling my home-built 6 inch reflector in 1970. My situation at the time was pretty good and those Celestron ads in "Sky and Telescope" kept catching my eye. Celestron was announcing a substantial price increase sometime in the summer and it looked like the perfect time to buy a new telescope. I called the Celestron dealer in Orlando and took delivery of a brand new C-8 in the middle of July, 1977.
As anyone who has bought a new telescope can attest, new telescopes attract rain and my C-8 was no different. Along with the telescope, I brought home 3 weeks of rain and first light did not take place until the night of 5/6 August, 1977. My observing log starts with Epsilon Lyrae being observed at 2050 hours and shows the famous Double-Double to be an easy object at 80x.
That first night was a wild tour of the sky as double stars, nebulae, clusters and galaxies were explored. Just before midnight on that first night a "very bright planetary with a central star viewed at 160x and bluish in color" was observed - NGC 6826. The first of the Herschel objects had been observed.
I am not sure when the Astronomical League first started awarding observing certificates. I know that the AL was awarding the Messier Certificate in 1977, but I donít think the Herschel List was yet in existence. NGC 6826 was just another deepsky object and would not become a "Herschel" until my hunt started in earnest many years later. As circumstance would have it, I actually observed 3 Herschels that first night - 6826, NGC 7008 and 7662.
We left Jacksonville in early 1978 and moved back to West Palm Beach. My first observing session in West Palm took place on the night of 6 February, 1978 and included another Herschel, NGC 2362, the beautiful cluster centered around Tau Canis Majoris.
These were my double star days. The observing log is filled with interesting pairs, but I was also hunting down some deep-sky objects. Our observing is, to a large extent, dictated by circumstances. I was living in West Palm Beach and had typical suburban skies that grew dark late at night, but were brightly lit during the early, easily accessible hours of the evening. These skies did not hamper double star observing and observe doubles I did.
Reading back though an observing log can be a wonderful experience if you keep it in the form of a diary. Finish up your notes with some general information about what is going on in your life and you can relate particular observing sessions with those events. One such night was that of 28/29 January, 1979. I see from the log that my daughter was going to have her first doctor appointment in the morning (she had been born 12 days earlier) and I also managed to nail 10 Herschels, the best night of the hunt before I knew that there was such a hunt!
The observing log ends abruptly on the night of 31 March, 1981. I had discovered computers and ended up selling the C-8 in order to finance my new hobby. The last night was spent taking photographs and no Herschels were recorded. My last Herschel with the old Celestron was NGC 2194, a small open cluster in Orion observed at 0100 on 30 Nov., 1980.
The log opens again on 24 July, 1989 when I purchased my second Celestron-8 from a gentleman who had bought the telescope originally to observe Comet Halley. In the interim I had moved from West Palm Beach to Atlanta and the telescope bug bit again.
I had been talking about astronomy to some people on a local computer bulletin board and we decided to put together a small group for some impromptu observing. Our first gathering was at Arabia Mountain Park off I-20, but the light pollution was terrible. One of the guys suggested heading east to Hard Labor Creek State Park and we met out there several times without knowing anything about the Astronomical Society of the Atlantic. We set up our telescopes in a small cemetery inside the Park less than half a mile from the Akinís Field Observing site.
The first Herschel observed with the new scope was the planetary nebula NGC 6543 in Draco on the night of 23 September, 1989 from that cemetary at Hard Labor Creek. It is listed in my log as being very bright, small, but an easy object at 100x with the central star visible at higher magnifications.
I first became acquainted with the Astronomical Society when I saw a brief blurb for the first Georgia Star Party to be held on the last weekend in September, 1989 at Rock Eagle State Park outside Eatonton. Packed my kids and telescope in the old brown van and drove out to spend part of Saturday, 30 September, at the Georgia Rain Party. It rained for the entire weekend and no observing was possible It was at this event that I was signed up with the Society as the Observing Coordinator and met several of the folks involved with the Society. I actually joined the Society at the November, 1989 meeting at Fernbank. It was at the Georgia Star Party that a couple of us learned of the observing site at Akinís Field and our first observing session there was held on 20 October, 1989. No Herschels were observed.
A couple of us from this original observing crew headed up to the Blue Ridge Parkway Regional Star Gaze near Boone, North Carolina on the last weekend of October, 1988. We about froze our tails off with ice forming on the telescopes before midnight, but the night was clear and the skies very dark and I was able to pick up 2 more Herschels - NGC 253 in Sculptor and NGC 7000, the North American Nebula.
The second Georgia Star Party was held at Camp Danial Morgan in Hard Labor Creek starting on 11 October, 1990. The weather didnít look promising with 2 tropical disturbances moving over Georgia, but it cleared up Friday night, 12 October, and I was able to pick up NGC 7008, a planetary nebula in Cygnus.
The next Georgia Star Party took place at Camp Rutledge in Hard Labor Creek on the weekend of 3-6 October, 1991. We had clear skies on Thursday and Friday nights, but were clouded on on Saturday. Several Herschels were seen over that weekend. In fact, so many were seen and they were listed in my observing log in the same order as they are in the listing from the Astronomical League, that it becomes obvious that the hunt for the Herschels had actually begun!
And so it went through the Winter Star Parties in 1992, 1994 and 1995 as well as the Georgia Star Parties in 1992 through 1994. A quick look through the logbook shows that I had observed around 150 Herschels prior to the 1991 Georgia Star Party and needed to observe another 250 to complete the list. The vast majority of my observing time from October 1991 until May 1995 was spent in finding and observing those 250 objects.
Finally we come to the morning of 21 May, 1995 at 0120 hours and NGC 6540. I went to Akinís Field with only 10 objects left to view and just a few hours to do so since the moon was at the last quarter and would be rising at about 0155. The night started well with NGC 5694 (a globular) being observed at 2150, but then I had to wait for more than an hour while NGC 6426 got high enough to see. By 0105 I was on the penultimate Herschel, the globular cluster NGC 6544. It was time for the last Herschel.
I checked my printouts from the New General Program (see below for more information about observing helpers) and noted that 6540 was an open cluster with a listed magnitude of 14.5! It is a small cluster of about 10 stars stretching across only 48 arc seconds of sky; a very small and VERY faint object and I wasnít sure I could pick it up in the skies around Hard Labor Creek. My other favorite reference, Skiff and Luginbuhlís "Observing Handbook," shows it as being "just visible as a tiny, faint patch" with a 25cm scope. A twenty five centimeter scope is a 10 incher and I only had 8 inches of aperture... had I come so far only to be defeated by the last object? Using NGC 6544, I tweaked the right ascension setting circle to show the precise RA and checked the declination circle to make sure everything was set dead on and then moved the scope to where 6540 should be. Since it is a small object I needed a bit more magnification than I usually use for hunting, so slipped a Meade 18mm Superwide Angle into the diagonal holder (about 110x) and took a peek. It was there!! A small, faint patch but easily visible at 110x; the hunt was over.
I am writing this article as a form of closure to a project that extended over a considerable percentage of my life. During the course of observing the Herschel list I have had a child born, gone through a divorce and planning another marriage, as well as making a move from one state to another. As with any major undertaking, the successful completion calls for a bit of reflection and contemplation on what has taken place during that undertaking and I hope you donít mind my sharing some of this with you, the reader.
Would I do the whole thing again? Well, letís say that I already have the numbers of the NEXT Herschel 400 and checking over my observing logs it appears that I have already observed 29 of them!
The Mechanics of the Hunt
As most of the observers in the Society know, I am a firm believer in setting circles. Nothing digital, but I successfully use the analog circles found on the Celestron-8. I know that some people have done the Herschel list by star-hopping, but star hopping is the technique required for the Messier list and after completing that list I was not about to try it for the Herschels!
Star hopping or setting circles, the decision is yours. You should be able to complete the list with nothing more than a basic star chart and a list of the NGC numbers for the objects. However, I have found other observing aids that are almost essential for the successful completion of this project.
As I mentioned before, the NGP (New General Program) is the best database software around for MS-DOS computers. Written by Dean Williams, this free program is an excellent observing guide to the entire New General Catalog. Included for each object are the:
The program allows the inclusion of your own observing notes and, best of all, an easy means of exporting your notes and importing the notes of other observers. When you first run the program you start out with an empty database that you can fill with observing notes from such well known deep-sky observers as Steve Coe and Barbara Wilson. It is great fun to compare your observations of these objects with those of such observers using other telescopes.
NGP has a facility to enter a text file with the numbers of objects you wish to observe and it will show only those objects. For instance, a text file exists that lists the 400 Herschels. Using this, you can set the software up to only display those 400 objects.
The several print options allow printing out your observing lists for each night in different formats including one that leaves you room for writing your notes on the printout.
This software is free and available for download from the Deep-Sky BBS along with observing notes from several amateur astronomers and some notes from professional catalogs. My copy with all the data takes up about 3.5 megabytes of disk space and is well worth it!
Since I am a setting circle observer, I donít have much use for the small scale charts like Sky Atlas 2000.0 My old copy of the Skalnate Pleso serves almost as well even if it is Epoch 1950. Star charts are very necessary when you get into some of the tighter areas of the sky like Virgo and Coma. It becomes difficult to pick out which galaxy is the one you are looking for when 5 or 6 are visible in the same field of view! For these times you need either Uranometria or one of the CD-ROM based programs like Megastar. I probably used Uranometria on 15-20% of the objects viewed to make certain I was looking at the right one.
The best observing handbook for the Herschel list is Skiff and Luginbuhlís "Observing Handbook and Catalogue of Deep-Sky Objects." The only major fault with this book is that right ascension and declination for objects is not listed with the notes about the objects, but in tables in the back. You will also find some wonderful, large scale charts of the more densely packed areas of the sky that make identification in these areas much easier. The highly detailed descriptions found in the Handbook are also a major aid to indentification. This is a must have for any serious deep-sky observer!
How big a scope is needed to complete the Herschel list? The brightness of the objects in the list varies widely and an occasional Messier object is thrown in (why, I am not sure!) and will surprise you if you donít know what you are looking for. On my last night I went looking for NGC 6514 and went scrambling back to the observing list and charts when M20 - The Trifid Nebula - was centered in the field of view! Other very bright objects include the Double Cluster in Perseus, M106, M109, M33 and a few other, well known objects.
Of course there are the faint objects as well. Many of the galaxies required careful searching even after the scope was centered on the field. Some of the more difficult objects were open clusters like NGC 1750. Located in rich areas of the sky, it was very difficult to pick out the actual cluster from the background stars. 1750 is actually a cluster of just a few stars located as part of another cluster. You end up trying to guess where one cluster starts and the other ends.
The bottom line? I would not attempt the Herschel List with anything smaller than a 6 inch reflector or a 5 inch refractor under the light pollution conditions found at Hard Labor Creek.
Ideal magnification for hunting is a personal choice. My preference with the 8 inch Celestron is to use a fairly wide field eyepiece of about 100x. When I started the hunt, my favorite was a Meade 20mm Erfle, but this has now been replaced with the 18mm Superwide Angle which gives about 110x. The 18mm has a little wider field than the old Erfle and the higher power makes picking out small objects easier. I know a lot of people like to use low power for hunting, but many of the smaller objects would be easily overlooked with a 40-60 power eyepiece. Even at 110x objects like NGC 5631 can look like a star surrounded by a faint halo. At lower magnification the object almost disappears.
I donít normally use filters to hunt for objects. I will use a UHC or OIII filter only after the object has been found just to see if the filter improves the view on nebulae. I donít believe any sort of filters are needed to successfully observe the Herschel List.
Well, there you have it. It is my hope that this article will get a few of you fired up enough to give this observing challenge a try. Itís not easy, but it is a lot of fun. Those of you with LX200ís and digital setting circles should be able to find the necessary fields easily, but actually spotting the deep-sky objects still requires a practiced eye. Digging out the details will require liberal applications of averted vision and lots of patience.
And remember my philosophy about observing:
If you don't log it, you didnít see it!