Telescope Reviews: Looking for Comet Barnard 177P

Comet Barnard 177P was recently "recovered" after a hiatus of over 100 years and had been declared a "binocular object" on several websites with a magnitude of 8-9 being bandied about. I had looked briefly for it a few days ago in my 18x50 Canon binos but saw nothing. So tonight with clear skies unexpectedly appearing after several days of rain, I decided to make it the sole objective for the evening to find this comet with my Saturn III's (39x100) which are ideal for this kind of task. There are reports on some other forums about this comet and the difficulties in finding it, but since it had been declared a binocular object, I thought I should post my observations on this forum.

Humidity was drippingly high at 88%, but the skies were pretty dark, measuring 21.30 on my skymeter which is pretty good even if not the darkest skies I've experienced here at Gorilla Haven (I've seen 21.50 on occasion). I'm very bad at estimating NELM because my naked eye observing is really only done with one eye as my other eye is corrected for near vision so I can get by without having to have reading glasses handy at all times. But these were clearly 6th+ magnitude skies - the milky way was very prominent, and with it being 2 days to last quarter, the moon was not going to interfere in the early part of the evening.

I looked first at Starry Nights to see what it said about this comet. It identified it as an object at magnitude 13.77 with an angular size of 0.062 arc seconds. Well hopefully this was all wrong as otherwise, there would be no point in going out to look for it!

Other websites have listed its magnitude at 8-9 - I've seen 8.4 bandied around, but that struck me as optimistic - at least for this evening's observation. Magnitude 8.4 spread over a 10' region (which would be big for this comet) would be much brighter - I've caught M74 in my 18x50 binos when it was at the Zenith, and that's usually tagged as a 9.8mag object, some 10' in size.

I decided I would try and find it, and if successful, watch it as the moon started to rise to determine the exact point at which it disappeared and make a judgement of the dimmest star still visible as that event occurred as that would at least provide some objective measurement of its apparent brightness.

Starry Nights WAS bang on with the location of Comet Barnard and a quick star hop from Sigma Herculis to HIP82012 and then to HIP82355 put it only 30' away and in the field of view. My eyes were not really dark adapted yet, but I looked around anyway and was pretty sure I saw a fuzzy blob, but decided to wait another 10-15 minutes.

Going back, the comet was now readily visible

, but it was DIM. I estimated the size of the hazy blob to be around 6-8 arc minutes - larger than I was expecting. Because it was so faint, it was hard to discern any shape, but no elongation was apparent. Nearby (less than 12' away) was a trio of stars which Starry Night listed at mag 10.78, 10.93 and 11.43 - all readily visible. Some 15 minutes later, my eyes were close to fully dark-adapted and I decided this was a good time to see what the dimmest star was that I could catch. I drew a quick map of the very faintest stars I could see around the comet and then went back to Starry Nights to identify them. I was quite surprised to see that I had caught TYC3083-1369-1 at mag 12.09 but even more surprised to see that I had caught USNO J1651368+434206 at magnitude 13.05 - the first time I've ever been able to confirm seeing a 13th magnitude star in the Saturn III's (assuming of course that Starry Nights was correct in its information). There was another "star" just 3' 27" away in the direction of the comet but Starry Nights did not identify it even though it showed a hazy blob at that position (sometimes just an uncataloged star or perhaps a very small, faint galaxy?). I've regularly seen stars around 12.5 in the Saturn III's, but never anything this faint.

It was now about 10:45pm and I decided to wait for the moon to start rising and monitor the skies. They started to lighten rapidly - my Skymeter going down to 21.00 and then 20.90. The comet was still visible, but was fading fast into the background. I continued to monitor it as the sky lightened and just before 11:30pm I decided it really had completely disappeared. The milky way was still visible over most of the sky and at that point the faintest star I could see was about 11.5 - the 12th magnitude star had disappeared some 10 minutes earlier and three stars around 11.4 which I had noted earlier were now all at the borderline of visibility. The trio of stars that had been quite easily seen earlier was now very difficult to find.

So my observation was that Barnard is still one difficult object to find and not something I would describe as a "binocular object" due to the very low surface brightness. Maybe in superdark 7th+ mag skies, one could pick it out with 18x50's, but it would not be easy. Unless it brightens unexpectedly, it's really going to take 100mm binos to catch this object (80mm's in very dark skies would probably be the absolute limit). I had originally thought this would be a relatively easy catch, but after seeing how dim it actually was, I was appreciative of having such dark skies this evening for this search.

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