Do I Renovate or Save and Buy New ?

[Did You See Them]

A couple of questions if you dont mind ?

Newbie Alert :withstupid:

1 - I've got an OLD hand made 8 inch reflector on a basic swing it a round eq mount.It seems OK to me - a novice.

The mirror needs recoating but is adequate for my needs for the short time but as I want to have a go at some astrophotography I dont know if its worth recoating or to save money and invest in a new bought "goto" scope - but price IS a BIG consideration.

The focuser is also a problem (no make to identify) It seems it has a piece missing - a collar or something. I have to have the focuser fully extended with the eyepiece/s only inserted so far - leaving them about 1/4 cm from being fully pushed in. If I dont do this It is impossible to focus using what little play I have.

Should I buy a new focuser ? , Can I just "extend" the focuser with some kind of "collar" ?

or do I save the money again and wait for a "real" scope ?

I primilary want to spend my time on lunar and planetary observation but deep space also becons.

any advise trully appreciated.

[GazOC]

I'd renovate it, recoating the mirror will be around (rough guess!!) £50 and the focuser and collar could well be picked up for free in a "wanted" ad.

[darditti]

The telescope itself may well be a useful one with the mirror recoated, but the issue is that if you want to do astrophotography of any type the undriven mount will make it hard. It will restrict you to the Moon and maybe attempts at Jupiter and Venus.[br]

So one possibility would be to re-mount the telescope on a modern mounting. This could be non-straightforward, however. If my experience is anything to go by, old reflectors are often very heavy, and therefore require a bigger and more expensive mount than the equivalent modern optics. There might also be problems actually mating it to a modern mount. It may require some DIY work to achieve.[br]

With the focuser, it may be possible to extend it with a 1.25 inch extension tube (I assume this is the drawtube ID - it is on most old telescopes). Or you could use a cheap Barlow with the lens unscrewed. The main thing is that equipment is held in securely so it doesn't fall out. Old focusers often only had a friction fit - not a setscrew, which is not very good. Again, you could buy another focuser and fit it, but again, this will require some DIY to adapt.[br]

I don't think you should be primarily thinking about GOTO at this stage, you should learn the sky. The telescope as it is may be good enough for that.[br]

David

[scotastro]

If the mirror is hand made it is possibly of much higher quality than a mass produced mirror. Its quality can be checked when it is re-aluminised.

Is the EQ mount old? Motor drives might still be available. If you don't know what you have post a picture someone might be able to identify it.

If your mount cannot be motorised, heavy weight EQ mounts often turn up second hand on astro buy sell or on SGL so worth keeping an eye out for.

Fitting a new focuser is quite easy.

All this is cheaper than the cost of a new 8 inch scope.

Mike

[Did You See Them]

Thanks guys - Ill take some pics to show it and illustrate the points.

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[Did You See Them]

The scope was made in the 80's by an astronomy club apparently.

The mirror IS hand ground and I suspect as has been said of a better than average quality allthough in nead of some tlc.

The base is extremly heavy yet despite this the whole thing moves remarkably well on the nylon washers that seem so crudely clamped in place.

[DanDare]

That looks like an interesting piece of kit and seems that it wouldn't take much to restore it.

I'm sure that you'd get lots of good advice if you do decide to restore it.

[vlebo]

That definately looks like a scope worth restoring and keeping and I agree with dandare that it looks like it would not take much to get it back up to scratch.

[Did You See Them]

Just checked out the Moon through it with a 20mm and a celestron x cell 5mm - seems fine with my eyes however Venus seems blured - but then I'm not sure what to expect at this early hour and low elevation ?

I convinced it needs collimating in so far as to what I've read - but I wish I new how to photograph the mirror to show you.It has a blue,misty tinge to it and just does not want to come clean.I dont want to do much to the mirror cause I don't no what I'm doing and don't want to damage it.

Any ideas ? - vinegar and newspaper ? Windowlene ? lemonjuice ? warm soapy water ?

spit ?

Now you know why I'm leaving it alone !

Lunar and planitary stuff is all I expect I really want to focus on and the lack of a motor mount whilst beneficial seems above both my means and needs for such.

and Yes ! I want to see this scope running at it's best.

Sixty quid on e-bay by the way (plus a drop of juice to pick it up )

So where is a good place for recoatings etc and what level of finish is best for it ( remember money is at a premium ) ?

Do they test the mirror ?

Can they "fix" any scratches if it has them ?

Will they advise if it not worth bothering with ?

I'd like to do it justice

Thx

[GazOC]

Try Galvanoptics for re-coating but you'd be very surprised how bad a mirror can look and still give great views.

[Did You See Them]

Try Galvanoptics for re-coating but you'd be very surprised how bad a mirror can look and still give great views.

Thanks I will - and yes it does ! - With the 5mm I'm "there" and moon surfing !

Too much detail for its flaws to detract from.

[darditti]

Sixty quid on e-bay by the way (plus a drop of juice to pick it up )

That was a bargain. It is a nice and interesting piece of telescope construction, and I think it is worth preserving more or less in its current state, though that will mean reserving it for visual work, and possibly planetary webcam imaging.

I recognise the type of focuser. Looks like an Irving. It is as I suggested - a slotted drawtube type. There is nothing missing so far as I can see. It was made to only give focus with a standard eyepiece slightly out of the drawtube to give it sufficient range for very short eyepieces and also for SLR film cameras to reach focus. One thing I did once with this type of focuser was to put a small "hose clip", that could be tightened with a key, round the slotted drawtube, to clamp eyepieces or cameras more securely in place.

So where is a good place for recoatings etc and what level of finish is best for it ( remember money is at a premium ) ?

Galvoptics in Essex as suggested, or Vacuum Coatings in East London (very cheap), or Orion Optics in Crewe. I would go for the basic service. The "super" coatings are not really noticeably different in my experience.

Do they test the mirror ?

They can test it, but this is expensive, and I don't know why you would want it done really. The proof of whether it is any good is in looking through it (as I discussed a lot recently on another thread). There are also testing methods you can use yourself. A good book on telescope optics will cover it.

Can they "fix" any scratches if it has them ?

The cleaning process they use to remove the old coating does remove small scratches. Larger ones cannot be cured, but might not be very harmful anyway. See how it goes. I would be 99% certain it will turn out well.

Will they advise if it not worth bothering with ?

No, they won't be able to tell without testing, which is costly. But you say the Moon looks good, so it's probably a good mirror. Venus is very tricky - too low at the moment.

It looks as if it would not be beyond human ingenuety to motorise that mount, but it would be a tricky job, so I would leave it as it is probably - as a nice "period-piece"

David

[barkis]

Most ATM's worth their salt would ensure their mirror was figured to a high degree of accuracy.

It is most likely a very fine mirror.

Ron.

[DanDare]

Terry at Vacuum Coatings tested and then re-coated my 10". I'll dig out the bills and let you know. May not be until tomorrow though.

[Did You See Them]

Thanks - Good info guys.

I think the mirror is good enough to spend a few quid on as a personal test.

I am impressed with what I see so it can't be to bad for my needs.

In my opinion ( which is worth nothing really ) It seems OK.

No deep surface scratches - seems like a couple of minor ones caused by wiping but they maybe just light marks - not sure ! - Its the dull bluish misty dirty look overall.My dirty bathroom mirror at least shines !

I'm new to this game but I am aware of coins and so I do inspect things on a fine scale looking for blemishes etc.

On a "coinage" scale I would say the overall the mirror condition is "fair".

It can only be improved can't it!

You don't sit and make things in such clubs to end up with a real pup do you !

As mentioned a motor mount is not out of my cababilities but age/time is and I'm lucky enough to be in that position in life were I can say sod it and eventually just throw hard to come by cash at solving such problems.I just do not have the time or building commitment these days.

(Memo to self - start saving for a major new scope - and don't let the wife know !)

I'm interested in seeing the rough costs of re coatings Dan so please let me know when you have time.

Warming up now after a pre dinner lunar viewing.

Hope it is clear later and not too much colder - I'm going back out later if all is well.

Then a mug of Hot Chocolate and bed !

Thanks

[barkis]

Some mirrors were silvered rather than aluminised. Some also had a chrome base prior to aluminising. I personally had never seen one, but I was given this info by the Late David Sinden, who always lamented about the difficulty of removal when he cam across one that required re aluminising.

Ron.

[DanDare]

Mine was in a bit of state and had that blue tinge to it, not sure what that was. It was in a bit of a state, the 'scope had been sitting in a shed for over twenty years. I had it tested, stripped and a single coating put on, it came to £40.00 not sure what the charge would have been just to test it. Just one or two of the deeper scratches didn't cover, but I don't think this will affect the mirror too much. I'm still working on the truss and mount so haven't actually tried it in anger yet.

You might want to get the focuser & collimation sorted first and then go for the re-coating if you still feel the views aren't up to scratch (sorry for the pun).

Roy

[Did You See Them]

Thanks Dan,

Focuser is sorted - Used a cheap barlow with the lens removed.

It is nice and smooth - no loose wiggles in the thread and seems nice and tight on the finner thread - if that is the correct way to describe it.

Collimation is the next step.

I've been nervy about doing this - the three butterfly nuts that are for it have lashings of paint over them - The original owner obviously never touched them.

I wont either untill I drop a collimater in there.

What would be the easiest newbie route - Cheshire or Laser ?

I need to buy/lend one for the job - better still get someone round here that knows what they are doing !

[Whippy]

What would be the easiest newbie route - Cheshire or Laser ?

Some people like lasers, some people prefer cheshires. Either one would get you close enough to get at least some half decent views, then a star test will nail it. Have a look at this: http://geogdata.csun.edu/~voltaire/tmb/tmb4.html

Tony..