Orpington Astronomical Society

Astronomy => Telescopes Etcetera.... => Topic started by: The Thing on Jun 14, 2020, 20:14:40

Title: New Telescope - well it was in 1996!
Post by: The Thing on Jun 14, 2020, 20:14:40
Found this TAL 2 150mm f8 Newtonian in the local depot vente (second hand shop with a twist) for the princely sum of €126.50 with all the extras e.g. the pier, three eyeypieces, 4x Barlow, 5 filters, excellent finder scope etc. It's got an RA drive and is built like it should be on a tank. It needs a good clean, hopefully the coatings reasonable, the mirrors just look dusty. Renovation will take a while.


(http://gallery.orpington-astronomy.org.uk/albums/userpics/10050/normal_IMG_20200614_171712~0.jpg)
Title: Re: New Telescope - well it was in 1996!
Post by: Carole on Jun 15, 2020, 10:47:31
What are your plans for it Duncan?

Visual?
Travel?
Convert for imaging?

Carole   
Title: Re: New Telescope - well it was in 1996!
Post by: The Thing on Jun 15, 2020, 13:12:40
Hi Carole,

I think it will be for visual use though I might have a go at planetary imaging with a guidecam and the TAL 4x barlow which is supposed to be very good. It only has a 1.25" focuser (very smooth) and a small secondary so probably can't do much more than illuminate a tiny sensor.  I have had a look through it at some tree tops and the image looks very nice despite layers of dust all over. I think the first thing I should do is remove as much dust as possible with the hosepipe - it's that dirty! Then find out if the RA drive works.
Title: Re: New Telescope - well it was in 1996!
Post by: Hugh on Jun 15, 2020, 15:32:56
Hi Duncan

Looks Good!  I did a quick bit of Googling and found one for sale a couple of years ago at £195 for just the scope and a few bits ~ so I think you may have a 'find' there.

Some old reviews on the telescope all seem good as well.

Good luck!

Hugh
Title: Re: New Telescope - well it was in 1996!
Post by: The Thing on Jun 19, 2020, 08:28:12
I've been cleaning it up, the mirrors are unblemished which is great news. The collimation screws on the secondary and primary are a bit corroded, been trying to re-collimate the primary and it doesn't move freely. I think I'll have to take the mirror off the mirror cell and dismantle properly - I tried a drop of 3-in-1 on each screw and it only helped a bit. Might need stronger/new springs.

The motor drive works, it's a bizarre AC arrangement with a transformer to produce 12Vac for the motor. Long cables are supplied. No possiblity of RA guiding with this mount!

I've also been glueing some of the supporting wooden block back in the cases. The foam on the contact surfaces has all rotted and sticks to whtever comes into contact with it. I'll have to scrape it off and replace. It appears the while thing fits in the two boxes though I've yet to work out where the column legs go.

It's missing it's solar projection screen, I may knock one up out of plywood. It attached to the counterweight bar. Orienting the eyepiece down toward it projects the sun image. Neat.

I hope to have a look through it Monday or Tuesday night as the skies should be fairly clear here.
Title: Re: New Telescope - well it was in 1996!
Post by: MarkS on Jun 19, 2020, 09:20:49
Quote from: The Thing

It's missing it's solar projection screen, I may knock one up out of plywood. It attached to the counterweight bar. Orienting the eyepiece down toward it projects the sun image. Neat.


Yes, a clever idea!

Mark
Title: Re: New Telescope - well it was in 1996!
Post by: Rick on Jun 19, 2020, 09:46:01
it's a bizarre AC arrangement with a transformer to produce 12Vac for the motor.

A 50 Hz synchronous motor drive, at a guess. They were pretty common until computer controlled stepper motors came along.
Title: Re: New Telescope - well it was in 1996!
Post by: The Thing on Jul 12, 2020, 19:42:40
I've used this scope now and it's excellent. Pin sharp stars. The Dumbbell nebula was really easy to see, great contrast. The tracking works though the axis controls are a bit unusual. I'll be using it more.