Object of the Week December 20, 2015 Jonckheere 320

[Jimi Lowrey]

Jonckheere 320

Orion

RA
05 05 34
DEC
+10 42 23

MAG 12.9(p)

Size 26"x14"

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Jonckheere 320 is a small planetary nebula that you do not hear much about. It was found by the Belgium astronomer Robert Jonckheere on January 22, 1906. He thought it was a double star until he looked at it with a larger telescope and could see it was a nebula. I have viewed this small gem several time over the years and suggest that you have a good finder chart to help you locate this small PN. I found a observation from Sue French that I thought was noteworthy. "This planetary is easily visible in my 105mm refractor even at 28x,but it looks like a star. it begins to appear nonstellar at 87x and shows a very small disk at 127x"This is very impressive to me that Sue was able to see this PN at 28X with a 105mm refractor.

1927

Be sure to use all the power that the conditions will stand on this one. I have gotten good responses with a O III and NPB filters on this planetary also be sure to try it without filters. I have also the last few years started to always try low power view with a filter. This I have found helps to bring out the faint outer halos of PN. I am looking forward to hearing if you will be able to see the bi-polar lobes on this small gem.

1928

There are two challenges that I would like to point out. If you would look at the above image approximately 45" North East of the PN is a small faint face on galaxy with a brighter core.. It is in the 2MASS catalog and I am not sure of its MAG, also near the center of the PN on either side at the 9 o'clock and 3 o'clock axis you can just see some faint nebulosity. I hope a filter will help to bring this out.

Next time out try this small gem in Orion and

"GIVE IT A GO "

[Uwe Glahn]

Very nice obscure but bright PN Jimi.

Unfortunately no positive report of the both background galaxies. Halo was visible as faint plobs N and S of the main body. The bar was visible with its two bright spots at the end. I could not resolve the inner N-S elongated ring. Perhaps to small to resolve under good to normal seeing conditions?

27", 586x-837x, no filter, NELM 6m5+, Seeing II
1930

[Howard B]

Here's my most recent observation, from 2009:

"This is a small, bright, oblong PN with one edge considerably brighter than the other. It took 654x to show this clearly and filters didn't help at all. A narrow and much fainter outer halo jumps out with averted vision, but no central star. Seeing is excellent, 21.12 SQM (transparency was also excellent)."

1931 1932

[Uwe Glahn]

Hi Howard,

"no central star" let me brood about my observation. Just checked my original notes.

I had at all two different observations from two following nights because night one was unsatisfying with the seeing. I wrote:

bright, barely laminar at 110x, good response with [OIII], observation of the details better with no filter, no color detected, CS steadily with averted vision (checked it with CS filter to prevent mistake with bright knot), bright elongated bar with the brighter spot at the SE, very faint extensions to the N and S (they don't react to filter) which ends in faint knots, N knot brighter with a peak in it, S very faint, uncertain if I saw a knot at the end or the extension itself to the S

At the night with not so good seeing I could not see the knots of the Halo but also the CS which was popping in and out of view.

[Howard B]

Hi Uwe, perhaps I didn't see the central star because the sky was brighter than the one you were looking through , and I was at low altitude - only about 200 meters!