Object of the Week May 1st 2022 - Minkowski 4-17

[obrazell]

M 4-17

PN G079.6+05.8

Planetary Nebula

Constellation: Cygnus

R.A. 20h09m01.9s

Dec. +43°43'44" (2000)

Magnitude: 14.50

Size: 23"



Mink 4-17 was discovered by Rudolf Minkowski in 1948 from objective prism plates taken with a
10" Cooke triplet but does not seem to have been published independently. It was first recorded
in the CGPN in 1967 and what references there are there suggest it was sent as a private
communication to the compilers of the CGPN. It is a ring nebula in the middle of Cygnus and
the HASH database records it as a true planetary nebula. Perhaps unsurpingly there has been
very little research done on this object, even its central star is not certain although
there is an object with a GAIA DR 2 g mag of 20 that has been identified as it. Its parallax however
is not obvious so a distance to the nebula cannot be calculated from that. Distance estimates from
other methods place it at around 2kpc. This maybe a bit early in the season for this object,
especially from northern latitudes but it is worth going after anyway. The notes in HASH suggest
it is a high excitation bipolar nebula. There are also strong detections in the IR which would
suggest the presence of warm dust as well.

m4-17pan.jpg

Perhaps surprisingly there are a number of observations of this nebula. In the NSOG Vol4 it is
suggested as a target for 16/18” telescopes at high power when it shows a pale disk.
Kent Wallace in his mammoth compendium on Visual PObservations of Planetary Nebula also
has an observation of it with an 8”, although this sounds rather odd to me.
He also suggests it is better seen at low power and responds to an OIII filter. He suggests
the first known visual sighting of this object was by Jack Marling in 1985. My only
attempt so far was with a 37cm (15”) when Cygnus was not that high and I skunked
out. The spectra show very strong OIII lines compared to H-Alpha so that suggests the OIII
filter will be the best for viewing it. I note that there is a drawing of this in the Interstellarum
Deep Sky Guide for chart 17. There is also some interesting information at
https://www.deepskycorner.ch/m4-17/m4-17.en.php.


Its location is shown here :-

https://stellarium-web.org/skysource...g=-1.58&elev=0

As always give it a go and let us know.

[Raul Leon]

Hi, here's my observation from 10/12/2012 ; Minkowski 4-17 planetary nebula in Cygnus ; magnitude: 14.5 ; size: 23" x 21" ; small and very faint round glow; one of the faintest planetary nebula that I have observed. No central star was seen. I did not use a filter. I used a 6mm Ethos at 304x with my 14.5 Starstructure f/4.3mink 4-17 cropped.jpg

[Steve Gottlieb]

My single observation also goes back 37 years to 1985 using an early blue sonotube 13.1" Odyssey I dob. It was logged two months after Marling, who used a 24" f/15 Cassegrain on Mauna Kea summit.

According to my notes, it was faint but visible unfiltered at 166x. Using a Deep Sky filter (not sure why I didn't use a UHC filter) it was easily seen as a small, round disc. Situated in a rich field 6.9' ESE of mag 8.7 SAO 49228 and collinear with two mag 12/13 stars about 2' W.

[Clear Skies]

Three observations in my log for this planetary. As Raul and Steve noted, it's a faint one. The second time around, using a 12" SCT, the nebula appeared just a tad brighter on the southern side. Every time filters made it slightly clearer, with an OIII filter outperforming the UHC. Upping the magnification did not help and I was never able to discern the ring shape.

1.jpg 2.jpg

Click here to download the observing guide.

[Uwe Glahn]

Found one entry of M 4-17, 27 years after Steve.
I noted a faint ring, which responded very well to the [OIII]. Details stands out not better with filter, so I decided to observe and sketch the PN without any filter. I did see some brighter ring sections, but no CS.

sketch: 27", 586x, NELM 586x, Seeing II-III
M4-17.jpg
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