Quattro 8inch

[Stu Wilson]

Has anyone used one of these to image?

After my other thread. Dont know which scope to go for.

Basically after 20 years of having the 200P thats at the end of its life I'm looking for something new and the quattro has got my attention.

Has anyone got any good pics taken through this OTA so I can be sure its for me.

Thanks

 

Stu

 

[ollypenrice]

From reading a lot of posts my conclusion is that the Quattro is supplied as a ready-made work in progress. What it isn't is 'plug and play.' If you are up for a serious bit of tinkering then it might be for you because it will, when sorted, deliver good, fast imaging. Just have an eye on your chip size when it comes to the flat field it will cover. 'Fast' and 'Cheap' are not natural bedfellows but there are images out there which show that, wth careful marriage counselling, they can become so!

lly

Edited January 14, 2021 by ollypenrice
Typo

[alacant]

On 12/01/2021 at 19:17, Stu Wilson said:

20 years of having the 200P

Hi

When fast reflectors first appeared, many years ago it says here, they earned themselves bad press due mainly to inadequate mirror mounting and bendy metal tubes. These days, the early problems have been addressed, but I'd still recommend some simple modifications: six strong springs for the primary mirror cell, a long wide dovetail plate and a stiff rail along the top of the tube rings. Holds collimation all day. And night

But hey, unless you need the extra FOV, why not replace the f5 you have already with a modern variant? I'd still recommend the same modifications however.

Call out to @laser_jock99 who pioneered the work for the modifications.

Cheers and HTH.

**If you can extend to the Bresser 203mm f3.9 with the aluminium alloy tube and proper focuser... Very much a step up from SW build quality.

 

Edited January 16, 2021 by alacant

[Stu Wilson]

23 hours ago, alacant said:

Hi

When fast reflectors first appeared, many years ago it says here, they earned themselves bad press due mainly to inadequate mirror mounting and bendy metal tubes. These days, the early problems have been addressed, but I'd still recommend some simple modifications: six strong springs for the primary mirror cell, a long wide dovetail plate and a stiff rail along the top of the tube rings. Holds collimation all day. And night

But hey, unless you need the extra FOV, why not replace the f5 you have already with a modern variant? I'd still recommend the same modifications however.

Shout out to @laser_jock99 who pioneered the necessary modifications.

Cheers and HTH.

**If you can extend to the Bresser 203mm f3.9 with the aluminium alloy tube and proper focuser... Very much a step up from SW build quality.

 

Ok heres what I've gone for guys.

On order are TS OPTICS  version of the 8" Quattro (meant to be better optics. It definitely has a much better focuser.It has an addon cooling fan behind primary too) I've also gone for TS OPTICS version of the f4 coma corrector which is probably the same as skywatchers but was the same price.

I'll go for alicante idea of bracing the top of tube rings too. As it happens I'm a steel fabricator so that's no problem.

I'll report back in a week or sos time when hopefully it arrives and I've got a clear sky 🙂

 

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p10259_TS-PHOTON-8--F4-Advanced-Newtonian-Telescope-with-Metal-Tube.html

 

Stu

Edited January 15, 2021 by Stu Wilson

[alacant]

19 minutes ago, Stu Wilson said:

TS OPTICS

Hi

That's the gso. You'll definitely have to change the primary mirror springs!

Cheers

Edited January 15, 2021 by alacant

[Stu Wilson]

In what way? Stiffer springs?

[Stu Wilson]

Not a problem but any idea where to get them?

Ps looking at them some motorbike clutch springs or car brake springs would do.......... without measuring can't be sure.

Well see when it comes.

 

Stu

Edited January 15, 2021 by Stu Wilson

[alacant]

58 minutes ago, Stu Wilson said:

10 minutes ago, Stu Wilson said:

Stiffer springs?

 

Yes.

9 minutes ago, Stu Wilson said:

where to get them

Bobs knobs or ts-service supply 1.3mm wire springs, but rather than pay €silly for still-not-up-to-the-job items, just order from AliExpress. 10 for €3. Any wire you like. I'd recommend at least 1.4mm.

Cheers

[Stu Wilson]

4 hours ago, alacant said:

Yes.

Bobs knobs or ts-service supply 1.3mm wire springs, but rather than pay €silly for still-not-up-to-the-job items, just order from AliExpress. 10 for €3. Any wire you like. I'd recommend at least 1.4mm.

Cheers

Do you have a web link for any?

Cheers

 

Stu

[alacant]

AliExpress. There are dozens of suppliers e.g. this one.

To save time, I extracted the items suitable for telescopes here. Specify your choice in the messages section of your order.

Good luck.

Edited January 16, 2021 by alacant

[Stu Wilson]

Killing time in lockdown today.

Found a pretty good stl file for 3d print of new bahtinov mask. As same size as new scope when it arrives I know it'll fit.

Only took 6 hours on 3d printer lol

[Stu Wilson]

On 15/01/2021 at 22:46, alacant said:

AliExpress. There are dozens of suppliers e.g. this one.

To save time, I extracted the items suitable for telescopes here. Specify your choice in the messages section of your order.

Good luck.

Ordered springs today. Took some doing.

I presume from brexit people have gone nuts lol.

Any I found abroad the delivery charges were up to 115 quid lol.

Found some in redditch which I've bought but again....... minimum order of 12 plus 6 quid delivery and vat lol

Unreal but they'll do the job and I've got 6 to sell to anyone else doing the mod.

Can't wait for new scope to come.

Think if I've got all the bits I'm gonna do the mods before I even try use it.

I've got my eye on some 40mm x 8mm flat bar at work to make the top brace for the tube rings too. 

Only needs to be about 13 inches long so not alot of weight.

 

Stu

Edited January 19, 2021 by Stu Wilson

[alacant]

20 minutes ago, Stu Wilson said:

about 13 inches long

You really need longer. We use a 55cm Losmandy dovetail plate with 4cm X 2cm thick walled aluminium to tie together the rings.

20 minutes ago, Stu Wilson said:

Took some doing

Really? The AliExpress guys have all the springs with free postage. We used 1.4 X 12 X 15. It only takes a week.

Anyway, good luck with the upgrade:)

Edited January 19, 2021 by alacant

[Stu Wilson]

Cheers and yeah never thought about aluminium........

Back to drawing board (stores lol)

[Stu Wilson]

Update......

Scope and new superflat coma corrector definitely arriving tomorrow.

The springs should arrive tomorrow too. I've made the new thumbscrews ready to cut threads to size and hopefully I'll get a length of aluminium tomorrow at work.

The dovetail I use at the moment is 535mm so ill use that if the supplied one is of smaller size. I followed your friend's idea to make the bolts with shear nuts.

When all this is done and dusted ive got all the parts twice over if anyone wants to buy them to do the modification. I had to buy everything twice due to minimum quantity.

Edited January 24, 2021 by Stu Wilson

[alacant]

Well done. 

One final thing: be careful with the length of the new bolts. The mirror cell design is such that if the threaded portion is too long, there is a risk of the bolt bearing directly against the glass of the mirror if tightened clockwise too far (sic). IMHO, a poor design option.

Make certain that when fully tightened, the bolts clear the mirror. There's only about 3mm of cork clearance. Fortunately, you haven't used shear nuts so you can shim with washers rather than having to shorten the bolts.

Fast imaging here we come:)

 

Edited January 24, 2021 by alacant

[Stu Wilson]

Figured out that apart from strengthened springs the idea is to get that mirror 10mm up tube too so if I measure bolts that come with it and add 10mm to them I should be good to go. Got all cutter disks etc at home so a 2 min job.

What I was going to ask you was am assuming correctly that moving it up tube 10mm theoretically makes it f3.95?

[alacant]

?

Why do you want to move the mirror up the tube? It will serve only to move focal plane further from the tube and destabilise the focuser, make your camera more prone to tilt and the main mirror more susceptible to lateral movement. You have ample backfocus as it is:)

If you do do it, it will make no difference to the focal ratio. The mirror remains at the same focal length.

At f4, we need all the help we can get. Don't make life more difficult than it need be!

Cheers

[Stu Wilson]

Ok I must of misunderstood your friends info. So if I make my bolts the same size as originals it will keep everything in correct place but alot more sturdy with a) 6 springs and b)them being longer giving more compressive force to stop movement? 

[Stu Wilson]

8 minutes ago, alacant said:

?

Why do you want to move the mirror up the tube? It will serve only to move focal plane further from the tube and destabilise the focuser, make your camera more prone to tilt and the main mirror more susceptible to lateral movement. You have ample backfocus as it is:)

If you do do it, it will make no difference to the focal ratio. The mirror remains at the same focal length.

At f4, we need all the help we can get. Don't make life more difficult than it need be!

Cheers

Heres the bit thats thrown me.

[alacant]

18 hours ago, Stu Wilson said:

 6 springs and b)them being longer giving more compressive force to stop movement? 

6 springs, yes,  the same length as the originals, BUT in a thicker (more resistant to compression) wire than the originals.

I posted the link here.

Using the nomenclature of the AliExpress outlet I linked to, I used 1.4mm x 12mm x 15mm for my f5 (Gso supply only 1mm wire). For your f4 you may want to go with 1.5mm. Until you've dismantled, you don't know what length you'll need. As the 203mm mirrors have the same mass, my guess would be the same as the f5.

HTH

Edited January 25, 2021 by alacant

[Stu Wilson]

Ok cheers.

Well find out tomorrow

[alacant]

58 minutes ago, Stu Wilson said:

 tomorrow

Good luck:)

Edited January 24, 2021 by alacant

[Spile]

On 12/01/2021 at 18:17, Stu Wilson said:

the 200P thats at the end of its life

Would you mind expanding this bit please?

[Stu Wilson]

22 hours ago, alacant said:

Good luck:)

Ok heres all done and collimated but clouds everywhere so can't test any further 😞