Upgrading (mending!) my Startravel ST102

[Macavity]

Finally got round to upgrading / modding my very first scope - A trusty Startravel ST102!

Although perhaps overkill for a budget fast achromat, I have found the added MONORAIL

focusser a positive boon - It anyway now matches my other scopes, so I can share stuff...

http://www.teleskop-express.de/shop/product_info.php/info/p3945_MONORAIL-2--Refractor-focuser---e-g--for-Skywatcher-96mm-flange.html

In my naivety ethusiasm I did drill quite a lot of HOLES in the ST102 OTA to mount stuff!

But I have found the (obvious) ideal solution to these in the form of a car body repair kit!

I should add I'm not a petrol-head car enthusiast, so this is all very new to me...

First I added a layer of David's "Fast Glas" fibre inside the OTA - I liberally coated strips

of the fibre glass with adhesive/hardener. A bit tricky, but not as difficult as I had feared!  

http://www.amazon.co.uk/UPOL-Fastglas-Glass-Fibre-Large/dp/B002HMXSZ8/ref=sr_1_2?ie=UTF8&qid=1448097043&sr=8-2&keywords=david%27s+fast+glass

The result after 24h setting (and a little time spent sitting on top of the lounge gas fire!)

So far so good! I am pleased that the (rather itchy!) glass fibre seems to be well sealed.

I sense it will provide a good "keying" for the next stage - Filling the holes in the OTA.

For this I have bought some (fairly generic) "P38" body filler. (A voyage of discovery...)

http://www.amazon.co.uk/U-POL-100ml-Body-Filler-Blister/dp/B002HMTYEW/ref=sr_1_4?ie=UTF8&qid=1448098657&sr=8-4&keywords=p38+body+filler

Don't expect rocket science? But "To be continued"... 

P.S. Continuing the theme, I don't intend to spray paint the OTA, but rather to try some 

go-faster (pretend!) sticky-back Carbon Fibre covering, once I've smoothed the above... 

[Knighty2112]

Looks like some major DIY! Hehe! Hope it all comes off OK and looks good again.

Just got its big brother OTA the other week, the Startravel 120ST. Does the new focuser you fitted to your ST102 make it better to achieve focus any better than the stock one fitted?

[Dave Lloyd]

What a venerable ota.

[Peter Drew]

Interesting, I have a couple of experimental OTA's just like that currently rigged up as a binoscope. Might just encourage me to fill up some of the added holes. 

[Macavity]

Well, here's the current state of the art... 

I duly filled in all the holes with the body filler and sanded it down.

Were I a more patient man, I would have used increasingly fine

grades of sandpaper... but basically it did the job OK. I might coat

the OTA with metal primer just to make it look better / smoother. 

(It could now either be spray painted or coated with sticky back)

In parallel, I have flocked the interior of the OTA with FLO's black

velour. My "Top Tip" (Hello VIZ readers!) to avoid a *sticky mess*

is to prepare the velour sheets as per lower right in the above...

Leave an initial part of the sticky-back surface exposed to "get

things going in the right direction". But tear off strips of backing 

(use a straight edge etc.) and re-attach to the rest of the velour.

That way you can expose the sticky bit only as / when needed!

RANDOM thought: Of course, now I have added a thin layer of

fibre glass to the tube interior, I have had to omit a couple of

internal baffles. I hope this will be compensated by flocking?

P.S. Interesting to note that (I hear) some high-end refractor

manufacturers may prefer "blackened sandpaper" flocking 

to a plethora of internal baffles... But Hey, don't quote me?

[Macavity]

Just got its big brother OTA the other week, the Startravel 120ST. Does the new focuser you

fitted to your ST102 make it better to achieve focus any better than the stock one fitted?

I would hardly suggest that such things were necessary! I did once put a laser

collimator in my as-purchased ST102 and notted that the dot was "way off" the

centre of the objective. There was a visible "tube droop" within the focusser.

But there are (as ever) many things one can do with the basic system? I found

the focusser benefited from a general strip down, lubrication, and "tightening"!

The FIT of the focusser in the OTA was improved by padding with DYMO strip.

The scope is never going to be an "Astro Physics" (lol) but with a little TLC?

[Starlight 1]

Only just seen this post, couple of questions.

Is the telescope tube made of steel or aluminium.

Steel rust aluminium turn into white powder.

Two types of p38 and P40 for successful bonding the right material must be used.

If aluminium also acetone primer must be applied before primer to get any paint to stick.

Hope this is helpful to anyone carrying out any repairs.

Les

[Macavity]

I am assuming the OTA is aluminium? The filler worked anyway.

I decided to "Neaten Up" the OTA with Hammerite Metal primer:

At this point it could doubtless be spray painted  properly...

But I decided to continue with the Carbon Fibre covering:

The scope is intended as a "Grab and Go" for (unlikely)

clear nights at the local Astro Soc "Observing Evenings".

Thanks Stu (BigSumorian) for the gift of the CF "Offcut"!

[Dave Lloyd]

Totally transformed the little beastie.

[Knighty2112]

Well done. Nice bit of telescope DIY!

[Merlin]

Curious to know what those two rods on the front of the AZ-3 are for? I have a counterweight on mine.

[happy-kat]

Post not required, I just remembered what they are.

[happy-kat]

Great rebuild :-)

[Merlin]

The rods can't be that big a secret. Go on, tell us what they are for. Are they a mount strengthening feature?

[Stu]

The rods can't be that big a secret. Go on, tell us what they are for. Are they a mount strengthening feature?

Not rods, they are springs....

See post 5 in here

http://stargazerslounge.com/topic/248532-az3-not-up-to-it/

[Macavity]

Heheh - Indeed so. Ta Stu - Apologies if anyone felt ignored!

For Grab & Go, I pack the modded AZ-3 into a GITZO tripod bag.

The scope, eyepieces etc. fit in typical DIY shop ABS tool box.

I had to cut down the *metal* dew shield (as you can see!) to fit...

But, I then slide (and tie!) on a longer "camping mat" extension.

P.S. I did get use from the red sticky back! I used the sawn off

bit of the dew shield as basis for a (Baader Film) Solar Filter...

It seemed somehow appropriate that it be covered in RED.

[Merlin]

Thanks for the info. The counterweight I added to my AZ-3 has, of course, the same effect of preventing the 'scope from lurching backwards, but imposes a greater weight penalty than springs. Mind you, the weight is only 1kg, so it doesn't impair the AZ-3's portability. I glued a small piece of rubber as a shock absorber on the top of the mounting base casting, where the bottom of the azimuth axis casting makes contact with it.

I was surprised  how light the AZ-3 and its tripod are, although the screws in the tripod struts have a tendency to come loose over time. Don't know about you, but I reckon that my CELESTRON 102mm/f.5 refractor is about the limit for this particular mounting.