As you can also see in the shot above, I've been using the supplied SkyWatcher wedge (thought I may as well persevere with it seeing as I've paid for it). To be honest it's not all that bad as cheap wedges go. It didn't seem to solid when I was adjusting it but to give it its due there was no detectable slack or wobble when it was locked off and in use. I'm still undecided as to whether or not to keep it or revert to using my Manfrotto 410 geared tripod head. The huge advantage of a geared head is that you can just plonk the tripod down in any spot and then level and orientate the head very easily afterwards. Polar aligning is also a doddle with the fine adjustment knobs. The SkyWatcher wedge on the other hand obviously needs you to get your tripod properly leveled and oriented before you start. Like most wedges you only have a small amount of leeway to adjust and there's no facility for leveling other than altering the tripod legs. The wedge is, however, far more lightweight than my geared head and looks pretty cool :)
Above is the image I took of Cygnus and the Milkyway. Not amazing as it was only a handful of 30s subs (19mins total) and the sky was still fairly light, not to mention misty. Did actually leave it going for about an hour only to return and find it all fogged up and covered with dew :( The subs are ISO1600 f/8. I took a few darks and flats also. Something went horrendously wrong with the flats. Apart from an annoying dust spot on the sensor moving position between lights and darks (must remember to disable the cameras sensor clean), DSS overcompensated for the vignetting - turning a minor dark vignette into a major white halo. On the whole I'm fairly pleased with the shot as apart from the bright stars in Cygnus the rest is totally invisible to the naked eye from my light-polluted back garden. At some stage I must look into CLS filters - I'm reliable informed that you can get slot-in filter plates that fit over the end of the lens (no one seems to make neat clip-on sensor filters for Nikons).
Before I move on to mention the pretty impressive built-in polar scope, above is a shot of my setup in daylight so that you can see the bits. Starting at the bottom, you can just about make out the top of my Manfrotto 055XPROB tripod. This is a very sturdy rock-solid tripod that is still light enough to be easily portable. The top of the pole as a proper mounting plate - just about visible under the black mounting plate at the bottom of the wedge. This means that the wedge has a nice flat secure surface to sit on. I've seen pictures of people with the wedge fixed to a cheap pan-and-tilt tripod head but it looks very unstable to me. Far better if possible to fix the wedge directly to the top of the tripod pole.
Working upwards, the next bit is obviously the wedge. The two screws on the right rotate the wedge using the usual push-pull method. This doesn't allow very much adjustment, however. The large lever sticking out to the left is the clamp for the elevation adjustment. I did expect it to lock things off fully when tightened up but found that it was still quite easy to alter the elevation - that's not to say that the mount was in anyway loose. The big knob on the left adjusts the elevation of the mount. As the load on the wedge is never going to be that much (unlike a full sized scope mount) they've gone for a single screw adjuster rather than a pair of push-pull screws. This makes life much easier. The rectangular block with the SkyWatcher logo is the saddle upon which the actual mount sits.
Above is a view of the various buttons and connections on the side of the mount. The 'snap' socket is for connecting a shutter release cable. From what I can gather this triggers once every 100 seconds. Seems like a solution waiting for a problem to me. Like most people I suspect I have an interval timer already and failing that the camera itself has one built in also - both of which are far more flexible. The small USB socket is essentially an external power socket if you don't want to use batteries. It also allows the firmware to be upgraded (not that there is much to upgrade I suspect). It seems to run OK on rechargeable batteries but I'd have preferred to have had a more conventional power lead supplied (E.g. one that would connect to my 12v powertank). As you can see it also has a standard auto-guider port. It's only going to be able to make RA adjustments as that's the only axis the mount moves in. As I've already found out it tracks very nicely for 2min wide field shots so I suspect I won't be needing to attach a guider.
Before I move on, above is the polar scope illuminating device that was supplied. It pokes in the end of the PS and has pretty much the same effect as traditional approach of shining a red torch at the end. I have to say that I found this gizmo to be a bit poor and ended up using my torch to better effect. My main complaint is that the min-max dial does not have an 'off' position. Turning on/off is achieved by unscrewing the battery cover (at the back) to a point where it is just about to spill the battery on the floor. To be fair, the AstroTrac also has a cheap and nasty PS light but at least that lights the actual reticle directly. A big advantage of a torch is that you don't tend to leave it switched on a a fortnight :)
Above is a view through the polar scope. This was taken in daylight but I found it to be just a readable at night. As can be seen, it's got a nice clean reticle with fairly recent calibrations. I much prefer this approach as (assuming you're in the northern hemisphere) all you've got to do is drop Polaris into the appropriate bit of the ring (as indicated on your app) rather than line up star with circles etc. The year calibrations are in theory useful but with my eyesight I can only just about make out the ring :)
On the other side of the mount is the 'speed' dial which controls the tracking rate. This is fairly self-explanatory and the standard speeds have pictures on them. The one with the star on is of most use as this puts the mount into the regular 1X tracking rate. The numbered speeds are intended for 'timelapse' photography I suspect (mount has a timelapse mode).
And finally, there's the battery compartment. Not the easiest of things to get into but it is what it is (I suspect that a few years down the line this may be held on by tape). It takes four AA cells. I've been using NiMH rechargeable cells and found they work well enough - certainly good for several hours of use. The cover also has a handy guide for the hard of thinking printed on the top (which you can't see in the dark without a torch). As you can see the built-in shutter release makes more sense when the mount is used in timelapse mode. Quite why you're want one shot every two seconds whilst spinning it at 12x sidereal I'm not sure unless I've missed something.
Anyway, I'm very pleased with my new toy so far. Looking forward to using it later on in the year when the darker nights return.
No comments:
Post a Comment