Go Back   IceInSpace > Beginners Start Here > Beginners Equipment Discussions
Register FAQ Calendar Today's Posts Search

Reply
 
Thread Tools Rate Thread
  #1  
Old 01-05-2013, 11:29 PM
BruceG's Avatar
BruceG (Bruce)
Registered User

BruceG is offline
 
Join Date: Mar 2013
Location: Blue Mountains, Australia
Posts: 367
Problems focusing WO SWAN 33 mm EP in Megrez 90

Hi all,
I just took delivery of my first EP and was desperate to have first light with it.
So desperate in fact I'm still waiting for my dovetail adapter, I sat on my steps hand holding the thing to take my first look.
Houston... We have a problem.
The scope came with a feather touch 2" focuser which has 2.5" of travel. Whe I placed the 2" 33mm in the diagonal, I still cannot achieve focus with the rack all the way out.
I don't have any other EP's yet- I have a couple on the way.
Any ideas?
Bruce.
Reply With Quote
  #2  
Old 02-05-2013, 12:05 AM
Steffen's Avatar
Steffen
Ebotec Alpeht Sicamb

Steffen is offline
 
Join Date: Feb 2010
Location: Toongabbie, NSW
Posts: 1,976
How far away was your subject? The required extension increases as you move from infinity to close focus. For a telescope something like 20m can be very close (about the closest my Mak does with all the extension tubes I've got).

Cheers
Steffen.
Reply With Quote
  #3  
Old 02-05-2013, 06:29 AM
BruceG's Avatar
BruceG (Bruce)
Registered User

BruceG is offline
 
Join Date: Mar 2013
Location: Blue Mountains, Australia
Posts: 367
I'm afraid to say I was looking at stars.
Reply With Quote
  #4  
Old 02-05-2013, 08:12 AM
The Mekon's Avatar
The Mekon (John Briggs)
Registered User

The Mekon is offline
 
Join Date: Jul 2007
Location: Bowral NSW
Posts: 828
Looks like you another frustrated owner of a modern refractor where the manufacturerers refuse to supply a decent length tube. I have griped about this before on this forum with little support. Their aim must be either to save money on tube length, provide the smallest case possible, keep the astrophoto lobby happy, or make a dollar selling extension tubes. Perhaps all four! My astro-tech 106 will not come to focus using a 1.25" diagonal, and I have to use the 2" to get focus. I am surprised your WO will not focus with a 2" diagonal in. You may have to buy an extension tube. Bintel have good ones at a reasonable price. I bought a 35mm tube.
Reply With Quote
  #5  
Old 02-05-2013, 08:32 AM
Kunama
...

Kunama is offline
 
Join Date: Sep 2012
Posts: 3,588
Bruce it might be due to the Feathertouch focuser causing a shorter lightpath for astrophotography or binoviewer applications so you may indeed need a short extension tube.
Reply With Quote
  #6  
Old 02-05-2013, 10:17 AM
LewisM's Avatar
LewisM
Novichok test rabbit

LewisM is offline
 
Join Date: Aug 2012
Location: Somewhere in the cosmos...
Posts: 10,389
Must admi, it was a B*TCH fight getting the Takahashi FS60 to come to focus visually. Absolute NIGHTMARE. Only issue was it was an IN FOCUS thing - needed somehow to REDUCE the total length of the visual train.

Get some extensions and go from there. I have some 2" diameter GSO extensions (various lengths) I would be willing to sell cheaper than new. Seeing I am ALL Vixen, not much use to me now at all.
Reply With Quote
  #7  
Old 02-05-2013, 10:38 AM
Steffen's Avatar
Steffen
Ebotec Alpeht Sicamb

Steffen is offline
 
Join Date: Feb 2010
Location: Toongabbie, NSW
Posts: 1,976
Quote:
Originally Posted by BruceG View Post
I'm afraid to say I was looking at stars.
Haha, ok, sorry. From reading your post I somehow got the idea you were trying it during daytime

Cheers
Steffen.
Reply With Quote
  #8  
Old 02-05-2013, 10:42 AM
Kunama
...

Kunama is offline
 
Join Date: Sep 2012
Posts: 3,588
Bruce you did take the plastic cap off the end of it didn't you ?????

I have done this a couple of times in the dark, then its a case of

Last edited by Kunama; 02-05-2013 at 11:02 AM.
Reply With Quote
  #9  
Old 02-05-2013, 10:49 AM
BruceG's Avatar
BruceG (Bruce)
Registered User

BruceG is offline
 
Join Date: Mar 2013
Location: Blue Mountains, Australia
Posts: 367
It's a good question. Yes I did.
I received my 12.5 mm illuminated reticule EP today. I will give that a quick test tonight.
Reply With Quote
  #10  
Old 02-05-2013, 11:03 AM
Kunama
...

Kunama is offline
 
Join Date: Sep 2012
Posts: 3,588
Maybe post a picture of your scope setup?
Reply With Quote
  #11  
Old 02-05-2013, 11:06 AM
BruceG's Avatar
BruceG (Bruce)
Registered User

BruceG is offline
 
Join Date: Mar 2013
Location: Blue Mountains, Australia
Posts: 367
Hi LewisM,
Looks like I will need somewhere around the 50mm or 80mm 2" tube.
How much are you talking for yours?
Bruce.
Reply With Quote
  #12  
Old 02-05-2013, 10:08 PM
BruceG's Avatar
BruceG (Bruce)
Registered User

BruceG is offline
 
Join Date: Mar 2013
Location: Blue Mountains, Australia
Posts: 367
OK I have a couple of quick snaps of telescope hopefully showing the focuser and maybe allowing the expert eyes to determine if the Megrez is the earlier or later version. That's if I can work out how to upload the photos
Bruce.
Attached Thumbnails
Click for full-size image (P1090193 (Small).JPG)
109.3 KB14 views
Click for full-size image (P1090194 (Small).JPG)
120.2 KB14 views
Reply With Quote
  #13  
Old 03-05-2013, 09:57 PM
Kunama
...

Kunama is offline
 
Join Date: Sep 2012
Posts: 3,588
Mystery to me Bruce, that adapter does not seem to match either the old FT adapter or the new one for the M90.It looks more like the original WO 'foot' adapter with the Ft focuser screwed directly into it.
If you have a look at this http://www.williamoptics.com/support...d/megrez90.pdf you will note that the adapter that screws onto the telescope tube is the same as yours but the focuser is actually about 30mm shorter overall so unless the drawtube in yours is 30 mm longer than the stock focuser you will need an extension tube. I don't know how the previous owner used it like that unless he had either binoviewers or extn tubes.
Good luck!

Last edited by Kunama; 03-05-2013 at 10:08 PM.
Reply With Quote
  #14  
Old 03-05-2013, 11:29 PM
BruceG's Avatar
BruceG (Bruce)
Registered User

BruceG is offline
 
Join Date: Mar 2013
Location: Blue Mountains, Australia
Posts: 367
Yep, I tried the 1 1/4 EP's that arrived today and you are dead right - I need to raise the EP about 30mm or so before i can get focus. Looks like a 35mm extension tube is needed.
This is probably a silly question but is the extension placed pre or post diagonal?

Last edited by BruceG; 04-05-2013 at 12:27 AM.
Reply With Quote
  #15  
Old 04-05-2013, 07:14 AM
Kunama
...

Kunama is offline
 
Join Date: Sep 2012
Posts: 3,588
Extn tube goes between the diagonal and the focuser.

If you're 35mm shy of the mark now with your focuser fully racked you will need at least 50mm extension tube to give you some flexibility with various eyepieces.
A 35mm extn would only leave you 5mm more out focus and that might not work with some eyepieces. The GSO/Bintel ones have a brass compression ring.

Last edited by Kunama; 04-05-2013 at 07:40 AM.
Reply With Quote
  #16  
Old 04-05-2013, 07:59 AM
BruceG's Avatar
BruceG (Bruce)
Registered User

BruceG is offline
 
Join Date: Mar 2013
Location: Blue Mountains, Australia
Posts: 367
Thanks Matt, you and the rest of the IIS community have been so helpful.
I will grab a 50mm tube next week.
I saw Saturn last night (for the first time),but the optical aberrations were severe with the EP only just in the holder.
Thanks again Matt, much appreciated.
Bruce.
Reply With Quote
  #17  
Old 12-05-2013, 05:57 PM
BruceG's Avatar
BruceG (Bruce)
Registered User

BruceG is offline
 
Join Date: Mar 2013
Location: Blue Mountains, Australia
Posts: 367
Very happy to report I have installed the 2" extension tube and I all of my Ep's focus well.
Friday night I chose Saturn as a first target as it was nice and high. After centring it with my 22mm switched to 6mm and found the view shap as a tack. I the swapped to my 3mm and was astonished to find the magnification was still useful. I could see some banding and shadow of the rings on the plant and the plant shadows on the rings at the back. I couldn't resolve the Cassini division but hey, the view exceeded my expectations of the 90mm aperture.

After that stared looking for fuzzies and I believe I saw M104 Sombrero, Trifid and Lagoon Nebs, as well as several other open and globular clusters. A great start considering I haven't even powered up the mont yet.
Reply With Quote
  #18  
Old 12-05-2013, 07:44 PM
Kunama
...

Kunama is offline
 
Join Date: Sep 2012
Posts: 3,588
Sounds great Bruce. It is certainly a challenge to see some of the more distant or dimmer objects with these smaller refractors but very enjoyable all the same. The same views would be a cinch to see through a big reflector sucking up all the spare photons in the universe but I really enjoy the challenge.

Two nights ago I sat outside in Jindabyne a few hours, mesmerized by the pure white pinholes of light on the velvety background viewing 47Tuc, M42, k Cru, Omega Cent among other things as well as panning to follow satellites zipping by as the frost settled on me and the Tak. In the end the scope was too cold to hold onto with bare hands (it was -5C)

Look forward to reading your observation reports.
Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 02:42 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement