Observation Report: 29 February 2008

[goober]

Location: Melbourne
Time: 11pm - 12:45am

A quick and dirty report. Conditions looked really good here in Melbourne tonight - seeing was very steady. Time flew as I went from target to target.

Algieba - at 275x (5mm plus 2.5x Powermate), a lovely, clear split. Beautiful pair of gold colour stars. I was using this as my Sirius meter, as Algieba is listed as 4", so Sirius should be that and around half again.

Saturn - absolutely stunning at 275x. I would never have believed my scope would support it on a planet, but it did. Huge, detail in the rings and on the surface (banding).

Trapezium - very nice at 275x, even right over the roof of the house as it's slipping into the west. The west? Check watch... it's the 1st of March. This season went way too fast.

Sirius - okay, prepare the eggs, but I think I split it. I spent about 15 minutes on it at 275x and didn't see anything. I was concentrating east, especially after it left the field of view. No luck. Then I saw something in the glare with averted vision, but it seemed too far away - perhaps around 8". Not sure. I spent another 10 minutes watching it wink in and out, always in the same place. Not a reflection in the eyepiece. As Sirius slid out of the FOV, this star was exiting slightly below Sirius, so it wasn't directly in the E/W plane where I was expecting it to be (close though).

I sketched the view, and compared it to MSA inside. I can mark the "W" of stars to the west of Sirius, but not the star I saw to the east of it. Who knows? I've posted a photo of a sketch I made at the eyepiece for comment.

Leo Galaxies - bagged M95, M96, M65, M66 - which is good from Melbourne in a 4". Good transparency. Can't wait for a good look from Snake Valley.

M104 - easy to pick out, and hints of the lane could be seen with averted vision.

Centaurus A - could just see the lane with effort.

Omega Centaurii - great, always is. Diamonds sparkling everywhere.

Beta Crucis and it's ruddy carbon star - lovely contrast at 49x.

Did the other favorites between Vela and Crux... everything looked great tonight.

[Dennis]

An enjoyable observing report Doug and congrats on bagging the pup! How do you manage to keep your note/sketch book dry when it is very dewy?

Cheers

Dennis

[goober]

Thanks Dennis - not sure I did bag it. I'll wait for SAB or Les D. to stop by and tell me yay or nay :)

It wasn't that dewy last night - my atlases, eyepieces, scope ... all dry when I packed up.

[§AB]

YAY you got sketches :D Doug, your sketch of Sirius shows the pup at a 90º angle to the arrow marked "west", in other words, north or south of the main star. The pup is actually almost exactly due east of Sirius and one way to conform a sighting is by letting Sirius cross the FOV - if you can see a tiny dot "following" it, that is the pup. I suspect you mave have seen an internal reflection in your EP. These can infact look *very* convincing! Btw, neat handwriting :p

It was a good night of seeing, wasnt it? ;)

[goober]

Thanks for taking a look. I'll take that as "negative" then :thumbsup:

This star (I'm sure it wasn't a reflection) did follow Sirius out of the FOV, but it wasn't directly behind it. If Sirius was exiting due west, and due east was opposite, I'd put this star as ENE. i.e. almost due east, but not quite.

But yes, very steady last night. Sirius was just a big steady glare, not flickering at all. Hence I could spot this candidate and hold it. I'd never have seen it if the seeing was normal.

[§AB]

Interesting, worth further investigation - I'll check for you tonight using that W of stars in the sketch :)

[goober]

Thanks SAB :thumbsup:

I found this image on the whereabouts of the Pup...

[ngcles]

Hi Goober & All,

Excellent report -- a good read as usual.

Re your observation of Sirius and Sirius B.

It is pretty diifficult for me to judge one way or the other, but I am inclined to say it probably wasn't the pup baised on your drawing:

From the drawing, "the pup" is definitely shown in the wrong PA. According to "The sixth catalog of orbits of binary stars: Ephemerides" -- in 2008.1, the seperation is 8.039" in PA 98.1. For 2009.1 it is 8.435" in PA 94.6. So from that, being now March 2008, the PA would be approx 97.2. From your drawing, you have it in about PA 165 odd (assuming N is approx top right in the drawing). Just so you know the same catalog has Algieba in 2006 as 4.609" in PA 125.7 and in 2009 4.612" in PA 125.7 (unchanged).

But then again, maybe the drawing is wrong? I checked this idea on Megastar with an 18 arc-min field and I can't quite match that "W" shaped asterism that you have drawn approximately west of Sirius. Instead the best match for that group of stars on Megastar, is a group almost due E by pretty much the same distance you have drawn it to the West. Maybe the drawing is in error? Maybe it isn't -- hard to tell. You are a naughty boy for not indicating North!

I don't doubt for a moment that you saw some sort of faint mote in close to Sirius, but I can't really say whether it was the pup or not based on the drawing. More likely nay than yea, but really can't say!

To eliminate the possibility of it being an internal reflection, observe it (move it around) in all four quadrants of the field of view of the eyepiece, just marginally away from dead centre of the FOV. If the PA and/or seperation shifts, you have an internal reflection.

Yes, you do have very very neat handwriting!

Best,

Les D
Contributing Editor
AS&T

[goober]

Thanks for your comments, Les. It's great having you on tap!

I quickly went out again, even though it's windy and the seeing is mush, and had another look at Sirius. The drawing is accurate enough - although there is a bit of difference in brightness in the "W" members, and it's slightly more extended than I drew it.

North is, I assume, at around 7pm on the sketch. I was viewing through a refractor with a diagonal; i.e. right side up, left/right flipped. Therefore north "down", south "up". I nudged the scope towards the NCP, and the star would exit "up" (i.e. south). I keep the diagonal in the plane of the OTA.

Sirius was totally boiling, so I couldn't see any little doggies tonight.