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(IAAC) Re: (ATMoB:Discuss) Obj: NGC 6309 (Box, Exclamation Mark nebula) - Inst: 25" f/3.5 dob

Lew,

Great observation of the Box. I have observed it with the 13" from both 
Westford and Myles Standish. It does live up to its name of the Exclamation 
nebula moreso than the Box nebula in which it is better known. I found the 
"rectangular" shape to be just barely visible with my 5mm Radian giving me 
about 300X. Every time I observed NGC 6309 I saw the 9th mag star.

David Aucoin



Climb high,
Climb far,
Your aim the sky,
Your goal the stars

Waltham, MA.
42n32 North Latitude,
71w14 West Longitude





>From: "Lew Gramer" <lew@upstream.net>
>To: <netastrocatalog@visualdeepsky.org>
>CC: "Lew Gramer" <lgramer@upstream.net>,"atmob-discuss" 
><atmob-discuss@atmob.org>
>Subject: (ATMoB:Discuss) Obj: NGC 6309 (Box, Exclamation Mark nebula) - 
>Inst: 25" f/3.5 dob
>Date: Fri, 6 Jun 2003 17:25:27 -0400
>
>IAAC Deep-Sky Observing Log Entry
>
>Name of observer: Lew Gramer
>Your observing skills then:  Advanced (many years)
>Date/time of observation:  02/03 June 2003, 0500 UT
>
>Site type:  Exurban
>Location: Westford MA USA (Latitude 42 Elevation 86m)
>Sky darkness: 5.3 (Limiting magnitude)
>Seeing: 8 (1-10 Seeing Scale (10 best))
>Moon presence: None - moon not in sky
>
>Instrument: 25" f/3.5 dob
>Powers: 110x, 245x, 460x
>Filters: None, UHC, OIII
>
>Deep Sky Object: NGC 6309 (PK 9+14.1, Box, Exclamation Mark nebula)
>Object category:  Planetary nebula.
>Object class: III+II
>
>Constellation: Oph
>Position: RA 17:14, DEC -12:54
>
>Object data: mag 11.8, SurfBt 8.9, size 19"x11"
>
>Description:
>Tonight the conditions were less than perfect at
>ATMs of Boston's Britton Clubhouse and Milon Obser-
>ving Field... A fairly even covering of very light
>cirrus or haze, forced us to focus on just "high
>or bright" objects with Steve Mock's resident 25".
>--
>The common name for this object is the "Box Nebula".
>This is an example of how deceiving a name can be!
>In many longer-exposure astrophotographs, and even
>visually from a very dark sky if a nebula filter is
>in use, n6309 might indeed look like a little box.
>(See Yann Pothier's logs on www.visualdeepsky.org!)
>--
>--
>However, under most conditions, a visual observer
>will perceive this strange object, together with
>the mag 9(?) star < 1' N, as bearing a striking
>resemblance to a certain punctuation mark(!) And
>so that is just how we refer to it up here. :)
>--
>This stunning little object lies just inside the SE
>"fist" of the Serpentholder, forming an obtuse tri-
>angle with mag 2 Eta Oph and mag 4 Nu Ser, roughly
>3o N of Eta Oph. It is quite near Oph's border with
>Serpens Cauda, in fact. With a finder or very wide
>field epc, n6309 is found by moving from Eta Oph 1o
>N past mag 7 star HD155413, and then about the same
>distance further NNW, to a pretty group of 6 stars,
>mags 8-10. These stars form two opposing isosceles
>triangles. The NW of the two triangles contains the
>brightest star in the grouping at its N-most vertex,
>mag 8 yellowish HD 155612, which is itself a neat,
>low-power pair (45") with a little mag 11 star.
>--
>The PN was a barely noticeable blue-green "blip" in
>the 80mm finder (probably not visible in a smaller
>finder), about 15' due E of the "center of gravity"
>of this brighter, NW triangle of stars. I FAILED to
>notice the mag 9 star right next to it, although I
>did not think to look for it at that point. (As it
>was visible in the finder tonight, I'm leads to be-
>lieve that even under mediocre conditions, this PN
>may be a good target for much smaller scopes, too.)
>--
>At lowest power, the Exclamation lived up to its
>(local) name admirably, appearing at first glance
>very much like a highly elongated rectangle aimed
>NW toward the mag 9 star that is the "dot". How-
>ever, increasing power to 245x (9mm Nagler), the
>bizarre shape of this planetary started to become
>conspicuous in tonight's steady seeing! At this
>power with the UHC, the NW half of the nebula was
>clearly somewhat brighter and larger than it was
>to the SE. This impression was stronger with UHC.
>--
>Finally, I got first light with a 4.8 mm Nagler I
>had recently bought from Gardner, a fellow amateur
>who is in the New Hampshire Astronomical Society.
>At this high power (460x), in this unusually good
>seeing (for this area), the Exclamation Mark sudden-
>ly presented a whole new wealth of detail! What had
>looked like a very thin rectangle, now resolved in
>to successive lobes or "pulses" of nebulosity, THREE
>of them in fact! This impression of three successive
>"bubbles" emanating from the nearby mag 9 star was
>best seen unfiltered, but was also apparent though
>less prominent, with the UHC and OIII.
>--
>Even more intriguing, fainter wisps of nebulosity
>could be seen stretching out from the NW lobe of
>the PN, arcing S-ward to a point maybe 5" due W of
>the midpoint of the main nebula. These were (again)
>strongest with the UHC, though also apparent with
>an OIII, and even hinted at with no filter at all.
>--
>A faint spark (mag 13 or 14) was seen with direct
>vision, glimmering off center in the middle lobe.
>This (I assume) central star was equally prominent
>both unfiltered, and with the UHC. As expected, it
>was harder to see with the OIII in place. In add-
>ition, though, we got the impression with averted
>vision of one or more OTHER stars involved in the
>length of the nebula, and just outside its W edge.
>--
>All in all, the Exclamation is eminently worth your
>time to find, while Ophiuchus is still riding high!
>--
>Any Web URL related to log:
>  http://archive.stsci.edu/cgi-bin/mastpreview?mission=hst&dataid=U2SA2702T 
>,
>  http://www.fortunecity.com/greenfield/twyford/637/ngc6309.htm
>
>

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