Focuser upgrade for 150PDS Newtonian

[masjstovel]

Hi, 

I'm  1 year+ into astrophotography now and i need some guidance regarding focusers for newtonians.
I have a ASI1600mm with filterwheel, and an EAF attached to the stock focuser, and that is too much as the focus-tube travels a bit sometimes especially in positions with its pointing downwards.

I have very limited knowledge regarding focusers and was wondering if someone could help me on the way. 

Preferably links to specific focusers would be much appreciated! 

[banjaxed]

This should work fine for you, it is available from FLO.

[masjstovel]

Thanks! It looks identic to the stock version, but do you have a name/link?

[johninderby]

It is the same focuser but is sold as an upgrade to other OTAs that come with the cheap r&p focuser. 

There are ones like the Moonlite or Baader that will fit.With the Baader think you will have to drill new mounting holes though but that’s a simple job.

https://www.firstlightoptics.com/moonlite-focusers/moonlite-cr-dual-rate-tri-knob-crayford-focuser-for-newtonians.html

https://www.firstlightoptics.com/baader-diamond-steeltrack-focusers/baader-steeltrack-diamond-nt-for-newtonians.html

Edited August 8, 2020 by johninderby

[masjstovel]

Thanks alot. See from the FLO-feedbacks that it fits nicely on 150PDS. Heard alot good about Moonlite focusers, even if theyre a bit pricey. 

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p12256_Artesky-2--Ultra-Light-Focuser-for-Skywatcher-Newtonians.html

 

How about this one? "Found it" just now. Anyone know anything about the focuser or the Artesky brand in general? I like that the product description mentions ZWO EAF, which i have. 

 

I read here and there about the draw tube travel. Is it important that the new one matches the old? 

Edited August 8, 2020 by masjstovel

[barkis]

I bought the Steeltrack, for my 190 Mak.Newt. and added the Lakeside Focuser to it.
Both Great  pieces of kit I had a bit of a fiddle initially, but all's well now.
Not cheap by any means, but I'm very pleased  I bit the bullet..
Ron.

[johninderby]

The Artesky is a new focuser so not been around long enough to establish any track record but does look pretty good. Only thing that concerns me is that it only has 22mm travel so I can see maybe needing to use extentions tf there isn’t enogh focus travel.

A possability though? 

Here’s the link to the Artesky website.

https://www.telescopi-artesky.it/en/artesky/focuser/3425-focheggiatore-newton-2-ultra-light-8055517131169.html

Edited August 8, 2020 by johninderby

[masjstovel]

@johninderby I see. I see some brag that their focusers are CNC produced and very stable with no tilting etc. There are no such info on the Artesky one as far as i can see. You cant see stuff like that out from photos i presume? The artesky site didnt explain much about the focuser, but 5 italians have rated it 5/5 stars

About the travel distance - i can measure the stock focuser i have now, but i believe its alot more that 22mm. 
As i mentioned earlier - i dont know much about focusers, but my eaf gets the stock one in focus at ~5000 steps every time So why the extra travel distance? Depends on whats attatched and in what distance backfokus or? 

[johninderby]

Yes it all depends on what’s attached to it and if it’s being used for visual or imaging. I see from the TS website that the overall height of the focuser is 98mm including the base so perhaps ypu could measure the height of the stock focuser to see how that compares. 

The focuser on my Bresser has 40mm travel plus you can fit a 50mm extension as well.

[masjstovel]

@johninderby I see, thanx for your reply. So logically (for me at least), shorter tubetravel with camera is ok because of distance to the chip or backfocus-requirements?

 

 

I measured 73mm (+/- 4mm) from the top of the collar with the 2 locking screws to the bottom of the bended plate.
Does this mean the Artesky focuser is too high built for my setup, or in the limit zone? I mean ~73mm + ~10mm (from memory of the visual position when in focus) = 83mm which is shorter than 98mm so this is a no-go? 

Edited August 8, 2020 by masjstovel

[johninderby]

I wonder if the height given by TS is with the drawtube fully extended or with it retracted. Might be worth asking TS. If ot is the retracted height might be a problem. 🤔

[masjstovel]

Or....  I would have to add up the height of the base plate on the artesky also when i think twice (?)  The 98mm is just the focuser with no base plate. The height of the 150PDS focuser with no plate is 63mm.

The picture from artesky on TS website shown underneath, there it looks like the same baseplate/adaptor i have now (picture in post above). If thats the case then i will still be too high with the artesky - or am i thinking of this wrongly now? 
s

 

What catches my attention in the product description on TS is this:

"The focuser already contains an adapter flange for Skywatcher Newtonian which is suitable for the models 150 F5, 200 F4, 200 F5, 250 F4 and 300 F4."

What so you think? .

[johninderby]

I think you need more information about the Artesky focuser and maybe someone who has imaged with the 150PDS could give some info onwatbthey fpund worked?

[masjstovel]

So, i contacted TS and they saw the problem that its to high and therefore wont fint 150PDS, so they will change the product description.

 

I ended up buying the Baader Diamond 2" SteelTrack NT instead:)

[johninderby]

The Baader is a great focuser. You won’t be disapointed with it.

Some useful drawings.

https://www.baader-planetarium.com/en/downloads/dl/file/id/30/product/2859/bds_nt_dimensions_technical_drawing.pdf

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

 

Edited August 11, 2020 by johninderby

[masjstovel]

Oh nice! Thank you @johninderby, those will indeed come in handy. Been doing the math on length in my head until now, but i love having it visually. Screw hole distances too  is nice too have. 

Bought that clamp adaptor too. Excited to see if its in the focus area (85ish mm) or if it will get me in trouble from time to time.

I saw a user giving feedback on FLO saying he didnt have enough shims in the package to fit his 150PDS. And i can only find extra shims at Baader website, but for some reason they dont ship to Norway (?) 

[johninderby]

Pity Artesky dodn’t have the technical drawings like Baader. 🙁

Found the shims on eBay.

https://www.ebay.co.uk/itm/Baader-1-5mm-Strip-Shims-BDS-NT-Focuser-2957235-UK-Stock/333580514398?hash=item4daaf2b45e:g:zIwAAOSwoNpeno6Y#shpCntId

[masjstovel]

Nice! I feel 80 years old now, not finding stuff on "the internet"😅. It doesnt say how many shims it is. 11bucks versus baader 3, but to be fair baader doesnt say how many shims is in their either.

[masjstovel]

FYI: TS took some tests it seems like, and contacted Artesky which also took som tests or at least confirmed that its too high for 150 P/PDS). TS has removed  the 150 P from their compitabilty list now. 
I cant understand it though, because the pic i posted above here is from the manufacturer (Artesky) on a 150 P or PDS. 😟

[johninderby]

Found this on a French website.

This is a 1.5mm thick spacer to fit the Baader SteelTrack NT for Newton on small diameter tubes.This spacer allows you to adapt the Newton plate supplied with the BDS-NT to your optical tube if its small diameter does not allow it.It measures 110 x 12 x 1.5 mm (length x width x height). It is only suitable for the BDS-NT Diamond Steeltrack focuser for Newton telescope.

It is normally included (four pieces) in the scope of delivery of the BDS-NT.

Characteristics

Thickness (mm): 1.5

Sold individually!

Adaptable for Baader Diamond SteelTrack BDS-NT

https://translate.google.co.uk/translate?hl=en&sl=fr&u=https://www.pierro-astro.com/materiel-astronomique/accessoires-astronomie/mise-au-point-focus/spacer-%C3%A9paisseur-1-5mm-pour-porte-oculaires-baader-diamond-steeltrack-bds-nt_detail&prev=search&pto=aue

[masjstovel]

Thanks again for the help @johninderby!
Ordered 4 of them, and i dont know how many from ebay (11EUR, but no quantity mentioned).  I hate the waiting game so had to order more :D.

[masjstovel]

Just to be on the safe side:
When the base-plate screw-holes are different placing from old to new focuser, what do you do with the old holes?

[Davey-T]

3 minutes ago, masjstovel said:

Just to be on the safe side:
When the base-plate screw-holes are different placing from old to new focuser, what do you do with the old holes?

Throw them in the bin 😂

Sorry

Dave

[masjstovel]

No, but I'm serious - Havent changed focuser before. I suspect the old holes has to be covered up some how? Anyone has inputs on ways to do this? 

[johninderby]

Just use some black electrical tape on top of the holes assuing they will be hidden under the new base.

Edited August 15, 2020 by johninderby