Sharpstar 150mm f/2.8 HNT collimation

[Davey-T]

31 minutes ago, Adam J said:

Seriously dont mess with it just send it back its not right. You dont pay that much to have to fix it yourself.

Adam

Just testing it again now.

Dave

[Adam J]

On 06/07/2020 at 00:34, Davey-T said:

Just testing it again now.

Dave

So did this have a happy ending?

[Davey-T]

59 minutes ago, Adam J said:

So did this have a happy ending?

Not yet, just got it mounted on the Rainbow RST-135 today.

Dave

[The Admiral]

44 minutes ago, Davey-T said:

Not yet, just got it mounted on the Rainbow RST-135 today.

Dave

Ah, then will you be writing up a review of the RT-135? ☺

Ian

[Davey-T]

1 hour ago, The Admiral said:

Ah, then will you be writing up a review of the RT-135? ☺

Ian

Took a video of it on phone but it's sideways and can't get any software  to upright it, PIPP tries but falls over.

Dave

[The Admiral]

58 minutes ago, Davey-T said:

can't get any software  to upright it,

I only have access to my tablet, so I can't check it out, but I think the free ShotCut video editor might be able to do it.

From what little I've read, the strain wave kit doesn't respond well to guiding, so it would be worth hearing any thoughts.

Ian

[Davey-T]

22 minutes ago, The Admiral said:

I only have access to my tablet, so I can't check it out, but I think the free ShotCut video editor might be able to do it.

Redone it with phone round the other way but lost the sound now 😂

Dave

[Davey-T]

Not an expert on collimation but watched and read a lot about it and beginning to think this scope has a serious flaw, still trying to collimate it but the only way to get it centred on the primary is by rotating the secondary so it no longer lines up with the focuser.

There is tilt adjustment on the focuser but don't want to start messing with that

Dave

[Highburymark]

Have been following this thread with interest Dave. Very frustrating - only positive is that you know much more about collimation than you did before. I’ve been so lucky with my F/3.3 Epsilon 130 that it arrived well collimated and hasn’t budged during 18 months of use. But sounds like you are running out of options and the scope needs to go back.

[Davey-T]

1 minute ago, Highburymark said:

I’ve been so lucky with my F/3.3 Epsilon 130 that it arrived well collimated and hasn’t budged during 18 months of use.

Should have bought the Epsilon. that'll teach me to try and save money 😂

 It appears to me either the spider or the focuser are drilled in the wrong place so can't line them up without rotating the secondary so its no longer aligned with the focuser.

Wouldn't surprise me seeing how the finder bracket was fitted.

Dave

[Davey-T]

Just to illustrate the problem, replaced primary with white card with centre hole to avoid confusing reflections.

The only way I can get the secondary to line up with the centre of the primary is by rotating it, no amount of twiddling with adjusters gets it aligned with the primary when fitted.

Bought expensive HG collimating laser which is perfectly collimated itself.

Any help appreciated as if I read / watch one more collimation tutorial telling me how easy it is I might say a removed word or two 😂

Secondary aligned with focuser in Catseye I think ?

 

Laser pointer in focuser misses primary centre by a lot

t

 

Laser pointer in focuser aligned with primary centre by rotating secondary.

 

Secondary no longer aligned with focuser through Catseye or is it ?

 

 

 

[Gonzo]

On 24/06/2020 at 00:02, Davey-T said:

Still messing around trying to collimate the SharpStar 150HNT.

Lined up secondary and focuser but can't adjust primary to centre it.

If I carry the scope by the handle I can hear the primary mirror flopping back and forth so how can one collimate the thing, various howtos say have it level on a bench but there's no telling how the primary has ended up.

It's sitting on three small domes behind the mirror, visible as rusty looking thing in the video.

Dave

What a faff uploading a YT video is now, haven't done it for years, sure it wasn't that much messing around last time I did it, gave up and got son in law to do it 😂

 

 

I'm also interested in this scope, I've found the following Japanese blog (Google chrome translate works fine) where the user fixed that issue.

http://asterism5592.blog.fc2.com/blog-entry-598.html

http://asterism5592.blog.fc2.com/blog-entry-569.html?q=15028HNT

[Gonzo]

Dave, have you had much luck with this telescope yet please? Would you recommend it or would you say: stay away from it...

I'm currently contemplating upgrading my current observatory telescope (Megrez 72 f6.0) for something seriously faster and this scope is interesting.

I have read all the threads here and on CN about it, from what I can see the quality control isn't on par with a Tak (I have no experience with a Tak, so it's based on what I read).

[Davey-T]

48 minutes ago, Gonzo said:

I'm also interested in this scope, I've found the following Japanese blog (Google chrome translate works fine) where the user fixed that issue.

I did look at doing something like that but the top part of my mirror cell appears to be glued on so not just a question of unscrewing it.

Be good if those supporting rivets were changed for adjustable nylon screws as the top plate of the cell has a felt backing and with a bit of adjustment could be made a perfect fit without any tension applied to the mirror.

I squeezed some small self adhesive bits of Velcro between the front of the mirror and the front ring  of the cell, seems to be working so far.

If you do decide to buy one then I'd recommend getting it from TS as they claim to thoroughly  check and collimate them before despatch, don't know how thoroughly though as mine had a few faults that required disassembly to locate and fix  and folk on CN report loose screws falling out of theirs.

Dave

[Davey-T]

38 minutes ago, Gonzo said:

Dave, have you had much luck with this telescope yet please? Would you recommend it or would you say: stay away from it...

If you're into DIY I'd recommend it although if I'd realised how much trouble it was to sort I'd have bought a Tak' Epsilon instead.

Had it for months and only just got around to getting some sort of image out of it a couple of nights ago.

Dave

 

[Gonzo]

57 minutes ago, Davey-T said:

If you're into DIY I'd recommend it although if I'd realised how much trouble it was to sort I'd have bought a Tak' Epsilon instead.

Had it for months and only just got around to getting some sort of image out of it a couple of nights ago.

Dave

 

DIY isn't something I'm scared off

But I'm more thinking about the price of the scope itself vs the work that you have to put into it... 

[Davey-T]

1 minute ago, Gonzo said:

DIY isn't something I'm scared off

But I'm more thinking about the price of the scope itself vs the work that you have to put into it... 

Half the price of an Epsilon and no reason that it can't produce similar images, hopefully TS will look at them closely before they despatch them.

Dave

[The Admiral]

5 hours ago, Davey-T said:

If you're into DIY I'd recommend it although if I'd realised how much trouble it was to sort I'd have bought a Tak' Epsilon instead.

Had it for months and only just got around to getting some sort of image out of it a couple of nights ago.

Dave

 

Personally there is no way I would expect to fettle to such an extent, on a 'scope costing nearly 2 grand, whether I liked DIY or not! It would have been returned, end of. What else can compel the manufacturer to up its game? Each to their own I suppose, and I if you end up with something approaching the optical quality of the Tak, and its ruggedness, then it may be money well spent. Somehow, purse and sows ear come to mind

I admire your tenacity though!

Ian

Edited September 20, 2020 by The Admiral

[Gonzo]

5 hours ago, Davey-T said:

I did look at doing something like that but the top part of my mirror cell appears to be glued on so not just a question of unscrewing it.

This one has managed to separate it https://www.cloudynights.com/topic/663055-new-sharpstar-15028hnt-initial-impression-with-pics/page-4#entry9578548

[Davey-T]

Yes saw that, took all the screws out of it but ring is glued on with some sort of black adhesive, thought about hammering a Stanley knife blade into the join to see if it would unstick.

Also makes it hard to clean the mirror when it's trapped in the cell.

Set my mirror up square to the tube and it's definitely not central as mentioned on CN.

Dave

Edited September 20, 2020 by Davey-T

[Gonzo]

On 13/09/2020 at 14:56, Davey-T said:

Should have bought the Epsilon. that'll teach me to try and save money 😂

Dave

 

 

Are you still thinking the same now, or is it ok?

[Davey-T]

1 minute ago, Gonzo said:

 

Are you still thinking the same now, or is it ok?

Still working on it, got it all back together waiting for the rain to stop.

Dave

[Gonzo]

I want to believe this scope is worth the price tag, lately our clear nights are getting rarer and rarer. And I hate looking at the forecast now... it's just cloud cloud cloud.

Hence I'm ready to step into the complicated world of super fast scopes, oh look 1 hour clear night. booom... target acquired !!! 😂

[CCD-Freak]

I had to work on mine a bit to secure the primary mirror but everything else has been OK. 

There is an old saying (origin unknown)..."Every telescope is built twice....once by the maker and again by the astronomer"   This seems to apply here.  I have never had any telescope that did not require some tweaks to get it to do I wanted it.   It does bother me that after paying almost "2 Kilo Bucks" I had to work on it but I think I will be happy with it now I have tuned it up.

Test image of NGC6992  30 x 2 minutes (1 hour total) Gain = 100 at -5°C Bortle 4 skies with smoke and haze.  

 

John Love
CCD-Freak
WD5IKX

[Gonzo]

From what I read, the collimation is a bit fiddly at this f/rate, not quite an issue, I guess you just need to be patient and accurate.

What I'd like to know is how often do you really have to redo it? If I get such scope, it will be for my remote observatory which is very remote (I'm talking at least 8 hours drive via several countries...) I would hate having to re-collimate "at every use" really...