Resurrecting an old Meade SCT

[Jimbo75]

Hi all,

I own a Meade LX-10. For those who aren't familiar with this type of scope, it's a '90s era 8 inch Schmidt Cassegrain mounted on a basic wedge and field tripod. Motors are fitted and functioning but sometimes need the odd 'nudge'. The OTA is a good starting point but if I'm being honest the rest could do with a bit of a make over!!

I'm not a fan of the wedge (well, this type at least!) and so I'm looking to defork the OTA and purchase an equatorial mount. I'm keen to future proof and would like the option of GoTo, either immediately or later via an upgrade. From what I'm reading Skywatcher seems to be the way to go. Any views on whether an EQ5 would suffice or should I hold out for an HEQ5? In terms of mounting the OTA, what's likely to be better in this case, a dovetail bar or tube rings? ?

I should also mention that at some point in the future I'd like to invest in a faster scope - I was initially thinking Newtonian but I can see lots of advice on here for APO refractors. Again, the name Skywatcher keeps popping up. Further down the line I would also like to try imaging. 

At present I have 9.7mm and 26mm Meade 4000 series Super Plossl eyepieces and a x2 Orion 'Shorty' Barlow lens. It seems the Meade eyepieces have a sound and steady enough reputation but I understand I may need to upgrade if I go significantly faster than F10 with my next scope. Are there brands and eyepiece focal lengths that I should be looking out for? At the moment I'm uncertain whether I should look out for something in-between the above or something longer? 

In summary - I'm thinking of upgrading my mount first, then investing in other / 'better' eyepieces but I'd appreciate views on any of the above!

Thanks!

Jim

[RT65CB-SWL]

1. I would be inclined to go with the HEQ5.
2. If attaching a dovetail bar directly to the OTA, make a mark somewhere on the corrector plate for when you re-assemble it too. There are videos on YouTube for how to strip-down/re-assemble SCT's - tube rings maybe the easier option. I have a de-forked Meade ETX105, (see below), and attached a dovetail bar using two Jubilee rings, (I have lined them with some strips of sef-adhesive felt and neoprene). I would not recommend Jubilee rings for your LX-10.
3. What do you intend to image? - Have look for a f6.3 focal reducer/field flattener... (avoid f3.3 ones).

 

Image of my de-forked 're-modded' ETX105 alongside my C6/SCT on a dual-mounting bar... it's a bit on the heavy side for the Vixen GP!

Two more images of my 're-modded' ETX on a Tele-Optic Giro mount.

[Jimbo75]

Thanks for the reply @Philip R - that's an impressive looking set up! Makes me want to get an ETX to partner with the 8"!

I've read that an HEQ5 may be the more stable option. The potential to get one with SyncScan - or retrofit later is a big draw. I used to have a C8 on a Vixen SP mount and I'm aware that the Skywatcher mounts are clones based on it. The GP is a really well engineered mount and I've read that SyncScan can be retrofitted onto those mounts - so a good second hand GP / GP-DX may also be an option. 

I'm not sure I fully understand your comment regarding making a mark on the corrector plate for when I reassemble. I can't imagine it'll go back on the LX10 wedge - is that what you meant by reassemble? I've seen a few videos on YouTube about deforking SCTs but none seem to cover the LX10, although I suppose the principle remains the same for most wedge based SCTs. I'm going to do some more reading up on the subject as I don't want to scratch the OTA. 

I'd love to get to a point where I could image deep space objects - although I realise I need to walk before I can run so will focus on getting more proficient on the optical side first. I also need to take into account my location (partial light pollution) so I may need to make sure things stay relatively portable. 

Edited May 9, 2019 by Jimbo75
Added missing info.

[michael8554]

I don't think PhilipR is aware that there are circumferential screws at both ends of the LX ota that can be used to attach a dovetail.

Michael 

[RT65CB-SWL]

@Jimbo75 - When you said '...makeover...' I assumed you meant inside, (i.e. cleaning the primary mirror & corrector plate, flocking, etc.), as well as the outside.

@michael8554 - No, I was not aware... especially the older Meade's - thank you for clarifying that.

I apologise to both of you in advance. 

Edited May 9, 2019 by Philip R

[Merlin66]

An 8" SCT sits and plays nicely with the HEQ5Pro. I used the wider Losmandy dovetail to mount mine.

My write up on the deforking of an LX200 attached.

No issues, no drama.

 

Lx200_defork.doc

[Jimbo75]

9 hours ago, michael8554 said:

I don't think PhilipR is aware that there are circumferential screws at both ends of the LX ota that can be used to attach a dovetail.

Michael 

Thanks for your insight on this Michael - that should make life a little easier.. I wasn't keen on the idea of drilling the OTA!

7 hours ago, Philip R said:

@Jimbo75 - When you said '...makeover...' I assumed you meant inside, (i.e. cleaning the primary mirror & corrector plate, flocking, etc.), as well as the outside.

No problem at all Philip! In that context your comment makes perfect sense. To be honest this is a top tip which I'll bear in mind in case of the need for future cleaning. 

2 hours ago, Merlin66 said:

An 8" SCT sits and plays nicely with the HEQ5Pro. I used the wider Losmandy dovetail to mount mine.

My write up on the deforking of an LX200 attached.

No issues, no drama.

 

Lx200_defork.doc 27.5 kB · 0 downloads

@Merlin66 Huge thanks for this! The write up covers most of the things they seem to skip over in the YouTube Videos - it's really going to be useful!

[Cosmic Geoff]

An EQ-5 would be adequate for visual use, or planetary imaging - I tried mounting my C8 on my EQ-5 and it worked okay, the OTA weight being well within the mount limits.  I did not pursue this route as dismantling the C8 SE rig and then doing polar alignment each time seemed too much of a faff.

If you have deep-space imaging in mind it may be advisable to go for a heavier equatorial mount. 

A sidenote - it is highly advisable to provide your SCT tube with a grab handle at the back end, or on the other side of the tube from the dovetail, to reduce the risk of dropping it.

[Jimbo75]

1 hour ago, Cosmic Geoff said:

An EQ-5 would be adequate for visual use, or planetary imaging - I tried mounting my C8 on my EQ-5 and it worked okay, the OTA weight being well within the mount limits.  I did not pursue this route as dismantling the C8 SE rig and then doing polar alignment each time seemed too much of a faff.

If you have deep-space imaging in mind it may be advisable to go for a heavier equatorial mount. 

A sidenote - it is highly advisable to provide your SCT tube with a grab handle at the back end, or on the other side of the tube from the dovetail, to reduce the risk of dropping it.

@Cosmic Geoff - thanks for your insight on this. It looks like an HEQ5 is probably the minimum I should aim for to keep imaging as an option for the future - I've seen mention that an EQ6 would be better still, but I need to strike a sensible balance between cost, practicality and portability. Good point regarding a handle - there won't be much to grab onto once it's deforked!

[KEJ]

On 10/05/2019 at 06:03, Merlin66 said:

An 8" SCT sits and plays nicely with the HEQ5Pro. I used the wider Losmandy dovetail to mount mine.

My write up on the deforking of an LX200 attached.

No issues, no drama.

 

Lx200_defork.doc 27.5 kB · 221 downloads

Funny, I was just doing a search to see if anyone had created any documents as I had just completed one today after changing my Meade LX10 8" onto a EQ6-R Pro yesterday and your process like very similar - great minds, although  Ron pointed me in the right direction.

Deforking a Meade LX10 8inch to SW EQ6-R Pro PDF.pdf