First Light!

[Davesellars]

Well, my Skywatcher 120ST finally saw the light of some stars after sulking for a quite a few days while it rained and rained and rained...  Summer seems to have arrived, finally and along with it clear skies of some sort.

Family stuff meant getting out was just an impossibility and cursory glances out there was a good mix of clouds and haze added to the bargain at about 10:30pm when at least one of my daughters was tucked up in bed. So I fired up the NEQ6 agains the open window and aligned against Deneb - First:  A little bit of extra colour against this mag 1.3 star for sure but not distracting...  so far so good.

I started with my 36mm Baader Aspheric EP for alignment and noticed that the view on the last 10% a touch distorted. I would hardly use this combination though as it yields 16.7x and 4.3 degrees FOV I think it's too much FOV for the scope to handle and most likely over the limit (but haven't worked this out yet). Dropping down to my 22mm EP for 27x and 2.6 degrees (much more useful), the scope & EP reacted perfectly and sharp stars pretty much the edge of the FOV. Attempting a star test against a mag 2.5 star Epsilon Cygni provided a really nice true colour with no CA noticable however the star test was pretty much impossible. De-focusing showed how bad the seeing actually was with a high level of haze causing a rather chaotic image. Still.... on the face of it, collimation looks to be fine at a higher magnification yielded a round image at least I won't be able to check this properly until another day with excellent seeing.

On to M39...   This bright open cluster showed gorgeously in the middle of a large field of view really putting the cluster in to context. Then, before I could really get on to another target some high clouds bombed in so I closed down...

It stayed cloudy for a good while so I went to do some other stuff and just before calling it a night at 2am and hitting the sack I looked out and it had cleared again. Still reasonably dark but not for much longer...

Now, Cassiopeia was perfectly positioned. It seems the high level haze had not really gone so no chance for really faint stuff so I went for some of the clusters around there.

The Double Cluster. This is always a pleasure to see. The 120mm at f5 delivers the same FOV as my 80mm f7.5 and the Double Cluster is one of my favourites with a large FOV. The 120 ST delivered a wonderful view at 27x with both clusters well encompassed in the FOV and I worked up my EPs:- 35x (17mm), 46x (13mm) and 75x (8mm). Only the 8mm not being able to encompass entirely the two clusters in the same FOV. Also at this magnification the seeing you could tell was decidedly bad however in between the wafts of haze blinking in and out stars - the stars were still pin-point so this was very much encouraging as this is perhaps the maximum magnification I will use with this scope

On to a few other clusters: M103 and NGC663 both of which showed very well at the higher magnifications. A quick look for giggles at M31 - Well, the core was visible which I kind of half expected not to be able to see it with the conditions being so bad - low down and well in the haze however there was nothing else to see. M32 could not even be seen. It was late then so I packed up.

OK so a little review or first impressions of this short fat frac:

So it seems the optics in this scope very much punch above its price bracket. Apart from very bright stars, colour reproduction of the star I thought was spot on and pin-point up to higher magnifications. There is obviously some field curvature which is slightly noticeable at this speed as the focus shifts slightly towards the end of the FOV at lower magnifications but this is very very slight and does not distract from the view.

However, you can see where the money goes (this optics) and where it doesn't... OK, the tube is nice and its sparkly but I think Synta spend $5 (or less) on the focuser. Using it before just to check some stuff out in the daylight I thought it was passable but really this thing is a real pain to use. There's a slight gritty nature to it while doesn't detract from its functionality is just not nice to use (I guess this is the synta grease or lack of finishing at work...).

The thumb-screws to hold the diagonal are pretty much useless for anything heavier than the standard 1.25" diagonal and 1.25" EPs as supplied so under the weight of a 2" setup the diagonal sags down slightly so it's not true... OK, this has a relatively expensive fix in added a Baader Click-Lock like I've done with my other scopes...

There's a further problem which is difficult to look past though and this is the image shift as focus is changed. Now, this could be to do with the fact that the focuser is quite stiff (even with the thumb screw fully out) and you need to apply imho rather a little too much force to change the focus however I don't believe slacking it off will change the image shift. It's not even though the image shift is that small I just think that these focusers are pretty much junk. The Crayford focusers that come with the ED scope get quite a lot of criticism because they are not strong enough however I've found them to be perfectly suitable once they are adjusted and hold quite well a heavy 2" setup - they just need maintaining from time to time however I don't ever have any image shift while focusing.

So what to do? There is a replacement Skywatcher Crayford focuser (https://www.firstlightoptics.com/sky...efractors.html) available which looks quite nice but doesn't have any fitting (nor seems any way of fitting) a finder.  I need my RACI

The other option is a Moonlite focuser... At least these come with 2 finder clamps so I could fit a RACI and the red-dot finder. Rather more expensive though even just going for the single speed option (which I think I would since it's only for observation at low magnification) and more expensive than the scope itself! However, it does sort out all the issues in one go.  er.... I'll have to mull this one over... 

Or... I just put up with the Synta junk...