Saturday Night Follow-up - 20 September 2008

[asteria]

We had another reasonable night down in Devon. The skies were clear, but perhaps not as transparent as Friday.

I got the ST120 and MAKCASS out today and gave plenty of time for cool down. Both scopes are pretty hefty and benefit from a long period of chilling. Even the ST120 is better after an hour plus of cooling, with up to two hours being about optimal for both.

I had a range of eyepieces out tonight, including the 26mm Revelation 2” WA (70 deg), a selection of Celestron Plossls (32mm, 25mm and 9mm) and WO WA 20mm (66 deg).

First up, with the ST120, I had another go for:

M13 and M92 – I had a dual set up going with the ST120, using the 2” eyepiece for locating objects and then swapping in 1.25” eyepieces. I took the magnification up to around 66x with the 9mm Plossl. Both globulars looked clear against a dark sky. I wasn’t able to resolve any stars with the higher magnification, and probably the optimum eyepiece was the WO at 30x. The image here was good with the clump of stars nicely framed in the eyepiece.

Moving over to Lyra:

M57 – the Ring Nebula was an easy pick tonight, with the “fuzzy star” very clear at the eyepiece. Taking the magnification up here showed the nebula’s ring shape very nicely.

Back down to Sagitta for another crack at:

M71 – still no joy! Even with a higher magnification I couldn’t pick this up.

Moving up to Vulpecula:

M27 – another easy find tonight, with the planetary taking a little extra magnification well. However, at 66x I thought that the definition had fallen away, with around 30x being optimal.

Albireo provided the reference for another go at:

M56 – a first look at this globular. A little extra magnification helped here, with the dim cloud of stars just showing up. It took a bit of tracking down, but once I had it, the cluster was unmistakable. Nothing as spectacular as the M13/M92 pair but still worthwhile.

At this point I swapped over to the MAKCASS.

The focal length of this scope is 1800mm, 3x that of the ST120, so potential magnification is much higher, but the images are dimmer. These scopes are really designed for work with bright objects – the planets, Moon and double stars. Undeterred I headed off for:

M13 and M92 – I tracked these down with the 32mm Plossl (56x), and then turned up the power with the WO WA (bringing around 90x) and the 9mm (bringing around 200x). FOV can be an issue with a long focal length scope, and after the luxury of around 3 degs TFOV with the ST120, the meagre 1 deg with the 32mm eyepiece can make tracking stuff down a challenge. Both clusters took magnification well, but I had to use averted vision with the high power to see much. A few stars seemed to resolve at the edge of the cluster, but the view wasn’t significantly better than with the refractor.

Back to Lyra for another look at:

M57 – the Ring Nebula always look good in this scope, and at moderate power the structure is clearly discernable. At high power, using averted vision, the ring is very clear.

On the way, I stopped at the:

Double Double (Epsilon Lyrae ) – I was able to split this (just) at 90x with WO, but with the 200x 9mm, the spit was clear, with the ‘right-angle’ offset between the pairs showing.

And:

Albireo – looking good in the MAK, although, I have to say, this pair does look very special in the wide field refractor.

Returning to Vulpecula for a try at:

M27 – this was another nice view. The shape was clear and best at a moderate power.

I then moved up to Gamma Cyg to track down:

M29 – this looked beautiful through the MAK, with low and moderate powers adding some further stars to the view when compared with the ST120. I guess the extra inch of aperture, plus the higher contrast image and some more magnification, is making a difference. I hadn’t expected the MAK to do so well with this type of object, the smaller open cluster.

This was confirmed when I moved over to Cassiopeia for a look at:

M103 – again, a delicate spread of stars, showing more detail than the ST120. I will definitely be trying for some of these smaller open clusters again with the MAK, to see what it can do.

By now it was getting late, so a few other items followed, including:

The Double Cluster – even with low power, it is only possible to see one cluster at a time with the MAK. These large targets really need the rich field experience of the ST120. However, the view was good, with the higher magnification meaning that a more detailed look at each cluster was possible.

On to Algol and from there to:

M34 – another open cluster, although not as pretty as M103 and M29.

Finishing up with a double star:

Gamma Andromedae – a nice coloured double.

Thanks for reading.

Ed

[Andrew*]

Excellent report Ed,

some brilliant targets there and you conveyed them very well.

Thanks for sharing!

Andrew