Small, Carbon, f5, 600mm Newt, is there such a thing ?

[Spaced Out]

Does anyone know if this exists ? I would like to find a small f5 newtonian with a 600mm(ish) focal length, carbon tube and a decent focuser (or ability to add a decent focuser) ?

 

I’ve seen the TS optics scopes, they look good but the smallest f5 version is 750mm FL, I’d prefer a little less. I would consider the f4 600mm version but the internet is littered with stories about collimation woes below f5.

[TerryMcK]

The Skywatcher Explorer 130p is 650mm and F5 but not carbon fibre. It is still lightweight though prob a steel tube.

[Spaced Out]

1 hour ago, TerryMcK said:

The Skywatcher Explorer 130p is 650mm and F5 but not carbon fibre. It is still lightweight though prob a steel tube.

Thanks, I am coming from a SW 130 PDS. It's a nice scope but its weak point is the focuser, it works OK with my DSLR but it doesn't like my heavy camera + filter wheel + OAG + MPCC combo, this is why I'd like to upgrade to a carbon tube and better focuser if possible.

[wimvb]

I think that with any 600 mm fl f/5 system, you will have the same focuser problems you are experiencing already: finding one that fits the tube. I haven't seen any carbon fibre scope smaller than 6" yet. Is f/4 so much harder to collimate? Most scopes keep collimation very well. So once you have them collimated, they pretty much stay that way. 

[Adam J]

12 hours ago, Spaced Out said:

Does anyone know if this exists ? I would like to find a small f5 newtonian with a 600mm(ish) focal length, carbon tube and a decent focuser (or ability to add a decent focuser) ?

 

I’ve seen the TS optics scopes, they look good but the smallest f5 version is 750mm FL, I’d prefer a little less. I would consider the f4 600mm version but the internet is littered with stories about collimation woes below f5.

Well you could take the optics out of a 130PDS and then make your own "tube" out of high quality ply wood. That would leave you with a flat surface to mount any focuser you want to mount to it. 

https://hantsastro.org.uk/resources/telescope/index.php

Adam

[Spaced Out]

6 minutes ago, Adam J said:

Well you could take the optics out of a 130PDS and then make your own "tube" out of high quality ply wood. That would leave you with a flat surface to mount any focuser you want to mount to it. 

https://hantsastro.org.uk/resources/telescope/index.php

Adam

Thanks, I'm looking for an off the shelf solution really that I can use for imaging. Also I've just ply lined my little shed for a warm room and I'm sick of ply ! 

[Spaced Out]

4 hours ago, wimvb said:

I think that with any 600 mm fl f/5 system, you will have the same focuser problems you are experiencing already: finding one that fits the tube. I haven't seen any carbon fibre scope smaller than 6" yet. Is f/4 so much harder to collimate? Most scopes keep collimation very well. So once you have them collimated, they pretty much stay that way. 

All my research so far has been online. While some people suggest collimation of f4 is no harder than f5, a lot of folk seem to suggest it is more demanding and also f4 telescopes don't maintain collimation very well compared to f5. My concern is that the telescope won't be permanently mounted in an obs, it will be moved by hand indoors after every session, I might spend more time worrying about collimation and less time using it !

Collimation is the only thing putting me off an f4 scope tbh.

[Adam J]

17 minutes ago, Spaced Out said:

Thanks, I'm looking for an off the shelf solution really that I can use for imaging. Also I've just ply lined my little shed for a warm room and I'm sick of ply ! 

Nothing to say it would not do well for imaging. Clearly don't make it as a dob though attach a dove tail. As you say though you would need to have the inclination. 

Adam 

[johninderby]

Telescope Express do a carbon fibre tube upgrade for the Skywatcher 150mm f/5.

Not cheap though. 🙀🙀🙀

https://www.teleskop-express.de/shop/product_info.php/info/p8328_TS-Optics-Carbon-Fiber-Tube-Upgrade-for-Skywatcher-6--f-5-newtonian.html

Edited March 13, 2020 by johninderby

[Captain Scarlet]

or here http://klaushelmi.de/en/ , which where the TS ones may well be sourced...

(I'm planning to order a custom tube from here for my 200p, slightly longer than normal to allow my secondary to get fully illuminatedm which it isn't at the moment).

M

[wimvb]

16 hours ago, Spaced Out said:

My concern is that the telescope won't be permanently mounted in an obs, it will be moved by hand indoors after every session

An f/5 seems a safer bet in your case. But the sw 130pds doesn't have much competition. 

[TerryMcK]

Is there any reason why you wouldn’t consider a comparable refractor?

[Skyline]

Anything lower then f/5 the mechanical aspects need to be more critical, mirror cell, spider vanes, collimation, focuser mountings, flexture etc.

The 130PDS has a rigid steel tube, hardly any flexture, or if at all very little. Just fit a longer dovetail to the ota.

The only downside is the focuser, but the cheapest solution  commercially is a moonlight for now.

From a long time never bothered using a laser collimation, just use a 2" concenter eyepiece and a Cheshire. 

Edited March 14, 2020 by Skyline

[Spaced Out]

5 hours ago, TerryMcK said:

Is there any reason why you wouldn’t consider a comparable refractor?

I'm used to the 130PDS newt which I really like when the focuser isn't sagging. I also like diffraction spikes !

I did look at the SW Esprit 100 ED for a little while. It's a lot of ££££ for me and looking online my camera (ASI 1600) seems to have more noticeable micro-lensing issues with refractors and bright stars, which puts me off a bit too.

Edited March 14, 2020 by Spaced Out

[Spaced Out]

6 hours ago, wimvb said:

An f/5 seems a safer bet in your case. 

This is my thinking too. Moving it about after every session is surely going to be a pain in the neck with an f4 ?

So long as I handle it gently the 130PDS is quite forgiving, I can just remove the scope with camera still attached then bring it back a few days later and it holds collimation well.

[Spaced Out]

33 minutes ago, Skyline said:

Anything lower then f/5 the mechanical aspects need to be more critical, mirror cell, spider vanes, collimation, focuser mountings, flexture etc.

Yep this is my concern, I want an easy life ! I'd rather spend my time imaging than faffing on with collimation all the time.

[CraigT82]

Sounds like your easiest course of action is to replace the focuser in your 130pds. If you feel that there is tube flex around the focuser you could always buy an extra pair of tube rings and clamp one or both around the focuser to stiffen up the tube. The scope would be very front heavy though! 

[Spaced Out]

5 minutes ago, CraigT82 said:

Sounds like your easiest course of action is to replace the focuser in your 130pds. If you feel that there is tube flex around the focuser you could always buy an extra pair of tube rings and clamp one or both around the focuser to stiffen up the tube. The scope would be very front heavy though! 

Thanks, I've looked into fitting Baader SteelTrack etc. The only focuser that will fit the tube diameter EASILY is a Moonlite (it has a specific 130PDS fitting kit), they're expensive and I've seen mixed reviews so I am little nervous of taking that route. Seems all other focusers will require some amount of bodging !

[Skyline]

I'm thinking about ordering the 130PDS mounting kit from FLO. You can always pick up a s/h dual speed moonlite focuser later on.

I do not think I be getting rid of scope anytime soon due to my recent disability. I find the 130PDS very manageable compared to my 150mm newt I used to have.

Also I might have to pass on the 100ED I have due the length and bulkiness - I really hope not as it is a very versatile scope and it took me ages to find that particular model.

What I have found using the skywatcher cc, the focuser tube is racked in more, so it reduces any tilt on focuser tube if instead racked out when using something like a baader.

[Spaced Out]

2 hours ago, Skyline said:

Anything lower then f/5 the mechanical aspects need to be more critical, mirror cell, spider vanes, collimation, focuser mountings, flexture etc.

The 130PDS has a rigid steel tube, hardly any flexture, or if at all very little. Just fit a longer dovetail to the ota.

The only downside is the focuser, but the cheapest solution  commercially is a moonlight for now.

From a long time never bothered using a laser collimation, just use a 2" concenter eyepiece and a Cheshire. 

Thanks. I already have a long dovetail fitted.

The focuser + flaky SW autofucuser seems to be the issue for me, it doesn't like it when I hang heavy gear off it. I’m still not sure about the Moonlite, lots of people rave about them but at least a couple on here have said they’re not great. It’s a lot of money to spend so I’d like a little reassurance that it will help solve my issues. 🤔

[CraigT82]

12 minutes ago, Spaced Out said:

lots of people rave about them but at least a couple on here have said they’re not great

You could say that about literally any product you might want to buy! 

[johninderby]

The baader Steeltrack is more durable than the Moonlite and carries a heavier load but the supplied base is for 200mm dia. and over OTAs.

 

Edited March 14, 2020 by johninderby

[CraigT82]

5 minutes ago, johninderby said:

The baader Steeltrack is more durable than the Moonlite and carries a heavier load but both are similar in smoothnes although the Moonlite may be a tiny bit smoother if anything. .Easy to install as well using the suppied Baader Versabase.

https://www.baader-planetarium.com/en/downloads/dl/file/id/31/product/2859/bds_nt_versabase_dimensions_technical_drawing.pdf

https://www.baader-planetarium.com/en/downloads/dl/file/id/175/product/2859/instruction_manual_for_all_baader_diamond_steeltrack_bds.pdf

 

According to that diagram the minimum tube diameter for the versabase is 200mm. Will need some bodging to get it to fit the 130pds tube

[Spaced Out]

2 hours ago, CraigT82 said:

You could say that about literally any product you might want to buy! 

Yeah, I guess but when one person says they are complete rubbish and another says they're not much better than stock focusers for tilt issues/holding heavy gear it makes me wonder if it is suitable for my needs.

Of course, I could be being overcautious and they might be great !

[Skyline]

I have had moonlites in the past, the one I liked was the shaft lock versions. I have used them with heavy equipment, Reducer+Filterwheel+Spacers+Atik 383L+, I could say it was once one the best setups I had in the past - without slippage.