Startravel 102T and Dual-Speed 2" Crayford Focuser for Sky-Watcher Refractors

[Richard_B]

Hi all

I am considering the following for my Startravel 102T as I am finding the original focuser very frustrating:-

https://www.firstlightoptics.com/skywatcher-focusers/dual-speed-2-crayford-focuser-for-sky-watcher-refractors.html

I am trying to workout the weight increase when the original is removed. Approx weight of the Dual Speed Crayford is thought to be about 1.25kg. I am a bit concerned about adding too much weight to that end of the OTA as I already use slightly heavier eyepieces than the originals.and am adding a 90 degree 9x50 finderscope.

Has anyone done this upgrade that would be able to either let me know what the new weight of OTA and focuser is or what the weight of the original focuser and might be once removed?

One other question sorry - are there any other available options for the ST102T that might be lighter? I am aware there used to be an upgrade kit from Lacerta (https://www.astromanie.ch/en/systeme-de-mise-au-point/1229-systeme-de-demultiplication-110-messier-hexafoc-bresser.html) that just removes the spindle and a new mechanism is inserted, but it doesn't seem to be available in the UK (and may not actually be compatible with the ST102T). Are there any inline microfocusers available similar to this https://www.365astronomy.com/optical-accessories-1/focusers/365astronomy-1.25-rotating-helical-focuser-with-male-t-thread-connection that might work?

Thanks

Richard

[banjaxed]

I fitted that focuser upgrade to my SW 120 ST and did not notice any difference in the weight at all and it vastly improved the focusing. I would not go back to the standard focuser.

[Stu1smartcookie]

As above ... the dual speed focuser hardly adds any weight as opposed to the original ... what you will find is that its a brilliant addition , quality wise . 

[Richard_B]

Thasnk you both for your replies. Looks like a new purchase is on the cards 🙂

 

[Cosmic Geoff]

I got a Svbony helical focuser for my Startravel ST102.  (cost £30) It screws on the back of the  2"/1.25" adapter (T2 connection).  I have used it a few times - seems an improvement on the standard R+P focuser action.  My feeling about a replacement focuser is that If I needed to spend that much on upgrading a basic achromat I should have bought an ED with a dual speed focuser in the first place.

[Richard_B]

13 hours ago, Cosmic Geoff said:

I got a Svbony helical focuser for my Startravel ST102.  (cost £30) It screws on the back of the  2"/1.25" adapter (T2 connection).  I have used it a few times - seems an improvement on the standard R+P focuser action.  My feeling about a replacement focuser is that If I needed to spend that much on upgrading a basic achromat I should have bought an ED with a dual speed focuser in the first place.

I did think the same to be honest. However I already have the 102T and quite like it. This hobby is a money pit after all :-)

 

[Richard_B]

19 hours ago, banjaxed said:

I fitted that focuser upgrade to my SW 120 ST and did not notice any difference in the weight at all and it vastly improved the focusing. I would not go back to the standard focuser.

Do you happen to know the bolt size to attach a dovetail mounting plate? Can't seem to find reference to it anywhere.

[banjaxed]

Could you be more specific, where are you wanting to attach a dovetail bar ?

[Cosmic Geoff]

31 minutes ago, Richard_B said:

Do you happen to know the bolt size to attach a dovetail mounting plate? Can't seem to find reference to it anywhere.

So far as I recall, the dovetail-to-rings bolts are metric M5 or M6. I reworked my bar a bit so that I could slide the bar into the grip of a SLT mount, which required a countersink bolt, and later moved one of the rings along so that the tube could be shifted forward to counterbalance the weight of a DSLR. Both bolts are now countersunk.

[Richard_B]

45 minutes ago, Cosmic Geoff said:

So far as I recall, the dovetail-to-rings bolts are metric M5 or M6. I reworked my bar a bit so that I could slide the bar into the grip of a SLT mount, which required a countersink bolt, and later moved one of the rings along so that the tube could be shifted forward to counterbalance the weight of a DSLR. Both bolts are now countersunk.

Thanks

[Richard_B]

23 hours ago, Cosmic Geoff said:

So far as I recall, the dovetail-to-rings bolts are metric M5 or M6. I reworked my bar a bit so that I could slide the bar into the grip of a SLT mount, which required a countersink bolt, and later moved one of the rings along so that the tube could be shifted forward to counterbalance the weight of a DSLR. Both bolts are now countersunk.

Managed to find out - they are M4 bolts so have ordered some 10mm countersunk allen bolts from ebay hoping that 10mm is long enough 🙂

[Dave Lloyd]

The Crayford focuser is great but I've found it hard to maintain focus when using a dslr. It can be locked but you can't focus then. I've got a r&p on another scope that I use exclusively for dslr photography. 

Edited April 23, 2021 by Dave Lloyd