August 19, 2015: Hunting Comet C/2015 F4 Jacques

[michael.h.f.wilkinson]

The skies cleared last night so I had my first bash at Comet Jacques, which is now quite close to Vega and the Double Double. It is an area of the skies I know well, but the rich star fields make the hunt non-trivial. I first tried the 15x70 bins. The comet was listed as magnitude 10.9 fading by .6 magnitudes towards the end of the month, which could be in range of big bins (although "small scopes" was the rating in Comet Chasing). I did see something in roughly the right spot, but I could not be sure I wasn't seeing clumps of unresolved stars. I tested the transparency of the skies by looking at M51 which was low over the neighbours house, but couldn't spot it. Not a good sign. I then got out the APM 80mm F/6 with 22T4 Nagler and Orion 2" Amici prism, which is a great comet hunting tool. The fuzzy patch I spotted earlier with the 15x70s was instantly resolved into several stars. but another hazy patch hinted at something closer to the correct spot (close, but no cigar). I then had a look at nearby M57, and even at 22x I could easily resolve the little disk (egg, really). I have never managed that with bins. The difference between the APM triplet and the Helios Apollo 15x70 binoculars is really striking. There is really no contest between them. I finally decided to use the C8. That resolved the other hazy patch spotted in the APM 80mm as a clump of stars. Using the 31T5 and 22T4 Naglers I got tantalizing hint of something fuzzy, but never enough to be sure. I then switched to the 17T4 Nagler which darkened the background more, and after a lot of moving to and fro I noticed a little patch of haze just south of the earlier offending clump of stars. It's apparent diameter was at least a degree, which is consistent with seeing the centre of a 1' coma at 119x. The position was right on the track in the Comet Chasing chart, and in the right position. Moving the scope consistently showed it (in averted vision only) in the same place. There is no nebula or galaxy in the neighbourhood, so I must have spotted Comet Jacques. I moved briefly to M57 and M13, and although they were nice, the image was a bit lacklustre. The humidity in the air was really high, and as I packed the scope in I noticed some dew on the corrector plate. This must have built up in just 25 minutes even with the dew shield in place. This, plus the low transparency must explain why a mag 11-ish comet was so hard to spot in an 8" scope.

I do consider the comet bagged, but will try to confirm it later.

[cotterless45]

Waiting for this, but cloudy skies are holding up the hunt !

Nick.

[John]

Good hunting Michael !

Like Nick, I'll be looking out for this one when we actually have some sky to look at

On the surface brightness thing, I was looking for a galaxy, NGC 7640 in Andromeda, the other night with my 12" dob. It's billed as mag 11.8 so I thought it would be an easy spot but it was actually really rather difficult and I overlooked it a number of times. It turns out to be a low surface brightness, rather elongated barred spiral which some find challenging with 16" of aperture. Shows how the quoted brightness figures can lead our expecations astray !

[xtreemchaos]

great report mate, yer nick cloudy here iin south wales too.thanks for posting. charl.

[laudropb]

Very interesting report. A pleasure to read it. Hope for a clear sky to try myself. Thanks for sharing.

[YKSE]

Nice hunting Michael, I used the same comet chasing chart and marked on tristar B chart for more precise location, the cheating goto mount made the my persuit trivial in that sense.

[michael.h.f.wilkinson]

Cheers everyone!

Nice hunting Michael, I used the same comet chasing chart and marked on tristar B chart for more precise location, the cheating goto mount made the my persuit trivial in that sense.

No cheating involved. You might just as well say a 14x70 finder is cheating. Once you have found the location by whatever means, conditions must still allow you to spot it.

[michael.h.f.wilkinson]

Just updated the date of the observation (August 19 instead of 16 )

[Paul73]

Good report. I'll be having a go at this one if the forecast for tomorrow night holds true. Hopefully 10" will be enough.

Paul

[paul mc c]

I have been trying for this,and using Comet chasing as a guide still cant find it,using all my scopes,obviously looking in the wrong spot.

[mdstuart]

I saw this one the other night. It's small and faint even in my 16 inch..Lovejoy is still brighter than this one IMHO.

[paul mc c]

I saw this one the other night. It's small and faint even in my 16 inch..Lovejoy is still brighter than this one IMHO.

That does'nt make me feel as bad.

[michael.h.f.wilkinson]

It was much harder than expected. I think the rich star field interferes a lot with it. Tonight might be clear, so I will try again and see if I can confirm the patch I spotted has moved

[Special K]

Sounds promising, Michael, and hope you get another good look soon with a better sky.