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STOG

PostPosted: Sun Jun 30, 2013 6:54 pm
by DaveMcC
In this and subsequent “Small Telescope Observer Group” (STOG) guides the ‘standard’ star-hop unit of measurement is a 5 degree finder, North up, West on the viewers left of view. You will need to translate my ‘up’, ‘down’ etc. to whatever type of finder you are using. For reference I am using either the Cambridge Star Atlas or Norton’s Star Atlas and the draughtsman’s multi-hole stencil I described on the course, to plan my star hops.

So, keeping it simple to see members reaction and uptake, lets look at Lyra. Here is the July STOG target list: Remember the main Lyra shape is a sort of squashed box below the bright star Vega.

(1) Epsilon – double, double
(2) Zeta - double
(3) Delta – double, double
(4) Beta - variable
(5) M57 – Planetary Nebulae
(6) M56 – Globular Cluster

Vega is the bright magnitude 0 star at top right of summer triangle, almost overhead (depending on time of night) . When the finder is on Vega there should have two other fairly bright stars forming a triangle with Vega. The northern one should be Epsilon(1). Move this to centre of view. Swap to main ‘scope and it should resolve into four stars. Go back to finder, move ‘down’ to centre the other star which should be zeta(2).

Back to the finder and on the edge of view (on your left when not looking through ‘scope) is Delta(3). Strictly it is delta1 and delta2 .

Now using the finder again move South (down) to the ‘bottom’ two stars of the squashed box. The right one is the variable Beta (4), it varies between about 3.4 and 4.3 over roughly 13 days. The nearby Gamma, the ‘left’ corner of the ‘box’ is 3.2. Is Beta about the same or dimmer when you look ?

Half way between these two stars, perhaps a bit closer to Beta, is M57(5), the Ring Nebulae. Can you see a faint ring ? Dark skies will make this one easier.

Finally, look for the ‘cross’ of Cygnus, and the bottom of the cross is Albireo (Beta Cygnus) – worth a look in passing as it’s a coloured double. So once the finder is on it move Albireo to about 7 o’clock position. M56(6) should be at diagonally opposite at about the 2 o’clock position in the finder, within he field of view on a line towards Vega so gently move the scope along that mental line.

Dust the cobwebs of that scope/ unpack it . Happy hunting.

Dave McC

Re: STOG

PostPosted: Sun Jun 30, 2013 10:18 pm
by Glyn
This is a great idea Dave, keep up the good work.

Re: STOG

PostPosted: Sat Aug 03, 2013 11:06 am
by DaveMcC
Friday 2nd August 23:30 BST. Clear sky now and it’s been a warm day.

Using my small 80mm refractor on a lightweight unguided equatorial mount. No finder fitted as this is an f5 ‘wide angle’ instrument. I noted however that the 18mm eyepiece gives about a 5 degree field of view – about the same as a finder. I can get Vega , (1) Epsilon, (2) Zeta all in same field.

(1) Epsilon – double, double. The wide double is easy but cant split them. In theory at 2” I should just be able to – but not tonight even with x3 Barlow and 7mm giving x170.

(2) Zeta – double. Found and easily split with 18mm (x22)
(3) Delta – double, double. Found. Very wide – if I have right target, one looks red/orange to me.
(4) Beta – variable – Looks dimmer than Gamma to me , estimate at magnitude 4
(5) M57 – Planetary Nebulae – just visible as faint smudge in 9.5mm (x42) and x7mm (x57). Wont focus to a point so is not a star. Can’t resolve into a ‘ring’.

Albireo (Beta Cygnus) – crick in neck now. Used basic mechanical setting circles on mount so I don’t have to peer up side of tube to get a basic alignment. Can see the colours of the pair. This confirms I am in right area to get to (6)

(6) M56 – Globular Cluster – well I am sure I was looking right at it but I can’t pick it out from background stars so I’ll record a negative for this one.