Fitting a Crayford to my Soligor MT 750/6"E

[Maltese Falcon]

Hi guys.

As promised here is the account of fitting the Astronomica Crayford to my 6" Soligor newt.

Firstly a bit about my scope and why I decided to upgrade it.

I brought it on Flee-bay. £136 all in with 3 EPs a X2 barlow and motor drive. I recolmenated it, because it was way out, and the first thing I saw was Jupiter. Well that was it I was completely hooked

I got eyes on Saturn, Venus and of course the good old moon. Then wifey brought me a DSLR and an adapter. That was when I hit trouble.

There was so much backlash on the rack and pinnion focuser I just couldn't get a reliable focus on anything and with the camera attached it was so bad as to be unworkable. The only way I could use it was to get rough focus with the actual focuser and then fine tune it using a zoom EP as a helical focuser. Not an ideal situation I think you will all agree.

So after doing a spot of reading and considering going down the big fat tele lens and piggybacking the whole kit and caboodel on the top of the scope route. I decided I needed to get myself a crayford. First thing I had to do was figure out which one.

Now one of the main factors was cost. I'm disabeled and whilst I do have a little part time gig in my local pharmacy, I have to stay within very rigid rules as to what I can earn. Contary to what the govenment would have you belive, people in my situation do not have a life of Riley raking in the benifits. In fact because my wife has a well paid job as a PA to a GP we get no help at all with rent or council tax and have to pay full whack. Not only that but I have to pay full price for my medication. Of which there is a lot. So cost was a major factor. With this in mind and having a few surplus model kits in the cupboard I put them on E-bay and 1 week later I was able to order the Crayford and extention tube from the awefully nice chaps at Astronomica.co.uk. The goodies arrived a few days later and of course I missed the postie So after a bit of unarmed combat down the sorting office I finaly got my hands on it. I have to say its lovely. A very well made bit of black anodised ally and a very smooth, positive action, £69.99 very well spent

So there we were, I stared at the focuser and the focuser stared right back. Then I stared at the scope for a bit and the scope and focuser nodded to each other and laughed at me. This went on for about 24 hrs and then I cracked and went and got the tools out.

First thing I did was make a thin card template by the old tried and perfected method of fixing the card to the base plate with a bit of sticky stuff and gently taping around the edges and across the holes with a spanner. I felt I could get away with this because the base plate is detachable and would not damage the focuser in any way.

I then turned my attention to the scope. Fully expecting to have to drill a lot of holes and saw and file to make the draw tube hole larger, I started to strip down the OTA. I removed the front cell and secondry mirror and stuffed a towel into the tube to keep from having to remove the primary. I then removed the offending hunk of junk that passed for a focuser and offered up the template I had spent 20 minuets making and to my complete and joyfull suprise found I had completly wasted those 20 mins :iamwithstupid:Not only was the drawtube an exact fit in the drawtube hole but the fixing holes were EXACTLY 1mm horisontaly out from the corners of the old focuser. So I marked up the new holes with a pencil and with my automatic center punch on its lowest setting and a block of wood inside the OTA, to prevent it from deforming, marked the new holes for drilling. I drilled a 2mm pilot hole first and them opened them up with first a 5mm then a 5.5mm drill to take the new 10mm M5 countersunk allen key bolts from the local modelshop and then test fitted the base plate to the OTA. A perfect fit first time. The base plate did not match the diamiter of the tube but wasn't that far out. I made a "gasket" out of two layers of 3mm low density foam that I had laying around and refited the focuser with two washers between the base plate and tube, to make up the difference between the tube and base plate without distorting the tube, held in place by the gasket, and fitted nylock nuts. Removing the towel, I then took the opotunity to clean the primary and secondry mirrors with first a damp and then a dry microfiber cloth. This done I refitted the front cell. fitted the focuser to the base plate and recollmanated the beastie and I am now awaiting first light. Total time 40 minuets, not including the 20 mins wasted making the template. In fact it took me longer to go and get the nuts, washers and bolts than it took to fit the focuser.

JOB DONE:icon_salut:

[step_hen]

Nice upgrade. I used to have one of these scopes, my first 6". Believe Hugh (The Thing) has one too. Looks like that tube could do with flocking inside- maybe your next project!?

Stephen

PS. Like the Dalek!

[sbooder]

I laughed when I saw the towels down the tube, mainly because that is exactly what I did when I fitted my new Crayford a couple of weeks ago...Astrominds think alike.

[yesyes]

hehehe, yeah, I used some old towels and cloths as well...