TAL Alkor - 65mm Light Thimble

[Stu]

Well, it's not a light bucket is it

This could quite possibly be one of the smallest Newtonians around at 65mm. Bought for less than the price of an Ortho off eBay, I was delighted to find out that the seller was none other than Dave T (f15Rules). It took me some weeks to manage to get some time to drive up to collect it, but when I eventually did, it was great to finally meet Dave and have a nice Astro natter .

The TAL Alkor is built like a tank! It comes in a very nicely constructed wooden case, with a secure place for everything. The components screw together quickly and firmly to give a very simple to use, and rugged little scope.

The mounting is AltAz, with the ability to set a coarse position, then have an amount of slow mo control once clamped in position. The 'finder' is just a couple of sighting holes front and back, enough to get you on target at the lowest power. The focuser is a simple single speed, very smooth but possibly needs a tighten up if I can find out how. There is a little bit of image shift which may tune out with a bit of fettling.

The system of eyepieces is beautifully simple and easy to use. I say eyepieces, there is only one, a 15mm I believe. There is also a Barlow and an extension. On its own the eyepiece gives x33, with the Barlow it gives x88 and with the Barlow and extension you get x133, all you need really. There are no locking screws or compression rings, just simple, precise engineering so the components slide easily into each other with no slop.

The engineering is beautiful but simple. There is a tiny secondary mirror on a single stalk and the little primary is in a fully adjustable cell. The adjustment bolts are covered on my scope, but a quick star test showed that the collimation is off so at some point I will dig out the putty and have a tweak.

I do like trying to see just what you can achieve with very small scopes, which is partly what attracted me to the Alkor. So, the views?

I tried the scope fairly quickly last night before it was fully dark. I picked up Saturn first at x33. Lovely crisp view with the rings clear. At x133 the separation between rings and planet was clear. I could also see the difference in shade between the A & B ring and a band on the planet's surface. Quite amazing for such a small scope. With better collimation who knows, the Cassini division may be possible on a good night.

Moving on to Mars, the views were less impressive as you might expect. I could detect the phase, but otherwise it was a washed out pale orange colour with no surface markings at all.

Mizar was next. At x33, which was all I used on this target, the split between Mizar A and B was clear and the whole system, including Alcor (appropriately given the scope name) and Sidus Ludoviciana the eighth magnitude star between them, looked lovely. A fabulous view.

I had a peek at Izar, and would class this as a definitely probable split . The miscollimation showed here, the diffraction rings not symmetrical around the primary, but there was a fairly clear view of the blue gray secondary amongst the rings which were jumping around in the poorer seeing.

Finally, I was trying to find Vega (doh!) which should be trivial but it was in the 'dob hole' which affects AltAz mounts too, so I ended up somewhat fortuitously on the Double Double by accident. At x33 they were a fine pair, but at x133 I was delighted to see a clear split in both pairs. Each star was beautifully resolved with a lovely diffraction ring around it. The more difficult of the two pairs was still resolved, with clear black space between the stars.

Overall I'm delighted with this little scope. Hopefully it should be fun to use on the moon with Lorna (my 2 year old) as she gets older, and it is rugged enough to stand up to a bit of rough and tumble. I will also enjoy using it for fun quick sessions to see what I can see with it. It will sit on the EQ platform too which will make planetary and lunar observing much easier.

A few pictures of my new 'Light Thimble'  

[RobertI]

What a lovely little piece of equipment, so nice to see something different to the norm and so capable for its diminuitive size. Should be even better collimated!  

[nightfisher]

lovely little scope, and ideal for  your young one to get to learn with, i think maybe i should have got the TAL 1 instead of the AS 150

[Stu]

1 hour ago, nightfisher said:

lovely little scope, and ideal for  your young one to get to learn with, i think maybe i should have got the TAL 1 instead of the AS 150

Thanks Jules. Thought the optics would be better in the AS150?

[Stu]

23 hours ago, RobertI said:

What a lovely little piece of equipment, so nice to see something different to the norm and so capable for its diminuitive size. Should be even better collimated!  

Thanks Robert. I do like different scopes, and ones which are nicely engineered. It's certainly not lightweight! The box feels like it weighs a ton!

[laudropb]

That's a lovely looking wee scope Stu.

[Alien 13]

I am not a newt fan but I do like the Tal what a little beauty, it reminds me of a little military sighting scope I had with a one inch objective it gave stunning views.

Alan

[Stu]

Some more pics of this little gem. Having found the collimation to be out, I am keen to sort it so decided to dig out the rather hard putty which was covering the screw heads. Amazed to see a proper push-pull mechanism so I should be able to get it spot on; at f7.7 it shouldn't be too sensitive though. I might even go the whole hog and flock it at some point. Fitting a finder shoe should also be possible and will make life easier than grubbing on the floor trying to sight through the front and back holes!

The date in the book say 1992! That's about the same age as the old Vixen 150ED I used to have.

[Stu]

I managed to spend some time tweaking the collimation on the Alkor this evening. First off I used an artificial star and got it pretty good, but found it needed more adjustment when I did a proper star test in the dark. It wasn't totally trivial, the adjustment was very sensitive and I managed to make it worse before getting it right. I'd say it's pretty good now, perhaps just needs a tiny tweak at high power.

The stars in this scope are totally refractor like. I suppose the small aperture means there is just not enough brightness to generate visible diffraction spikes, just a hint of them off Vega for example, but anything dimmer that this and you just get a beautiful airy disk and first diffraction ring.

Alberio was beautiful tonight, very strong colours, again perhaps the lower light level stops the colour washing out. Izar was as before, a probable split.

The Double Double is gorgeous at x133, cleanly split and beautiful stars. I tried it at x88 and am pretty convinced I split both again so I think the collimation has definitely improved.

Polaris' secondary just about showed as a faint point of light, very tight shape again though.

I could only view the moon early on in daylight, the scope stand is quite low so I was unable to view it, or Saturn and Mars later on, will have to try another location.

The only pain of the scope is the finder, involving grubbing around on the floor and even then not being very easy, I'll have to find an alternative which doesn't involved modifying the scope from its original condition.

A lovely little scope, great fun to see what it can do.

[swamp thing]

Always loved these little scopes. Congrats matey  

[RobertI]

Sounds like it performs really well. It's seems a strange configuration to have the eyepiece pointing towards the mount - i guess it works ok in practice?

[Stu]

9 hours ago, RobertI said:

Sounds like it performs really well. It's seems a strange configuration to have the eyepiece pointing towards the mount - i guess it works ok in practice?

You are right, it is slightly strange but it actually works ok in practice. I tried it in shortened mode last night which was much more comfortable, I just sat on the ground and everything was easy to reach.

The seeing was pretty wobbly last night, but I still managed some very nice views of the moon. I pulled the eyepiece and spacer out of the Barlow a bit and was probably getting over x150! Impressive for 65mm!

[iPeace]

Your pictures in the second set are priceless. What a great thing to have and enjoy! Excellent job on putty removal as well.

[Stu]

Thanks all!

Too much?

Wont make any permanent changes to the scope as I want it in original condition but this should make life easier.......except it now won't fit in the case. Hmmmm, a large supply of cable ties and some scissors required me thinks  

[oldfella]

Hi, Stu, using this type of finder, it would have to be removed every time it went into its box, or, would a couple of pencil Mark's be made on the telescope so it fastened back in the same position each time bring it back to its initial position work ?