#1  
Old 10-10-2007, 10:42 AM
DougAdams
Lord Lissie

DougAdams is offline
 
Join Date: Dec 2004
Posts: 233
Observation Report - 9th October 2007

Oakleigh, Melbourne
4" Refractor
11pm - 12:30am.
Seeing: 2 (good)
Transparency: 3.5 (haze, some high cloud)

A cool evening in Melbourne, with high cloud scudding over. It seemed to be moving quickly so after 10 minutes outside with the binoculars, I bit the bullet and set up the scope. I wanted to test out the new 5mm Nagler, and it may be another week before I got the chance.

M31 - low, low down in the north. I found it easily enough, an obvious large, round glow. I couldn't see any sign of definition or elongation, just a large blob. I tried to spy M32, but couldn't see it. The light pollution, low elevation, and possible haze defeated me. Still, the Andromeda galaxy from suburban Melbourne is good enough!

NGC253 - the Silver Coin. I've never viewed this, but star hopped my way from Deneb Kaitos. It's quite easy from there - you immediately come across an asterism of 3 stars in an equilateral triangle, then continue on through a trapezium of equally bright stars (7th Mag.?). Turn to the east from there and you have it. Wow, I wasn't expecting much, but this is a lovely object. A large, long glow slashing its way through an extended isosceles triangle of 8-9 magnitude stars. I estimated the length at about 20'. This object looked great at various magnifications, from 23x to 154x (my maximum). I could resolve three stars on the galaxy itself - I assume these must be field stars. The galaxy seemed to be only slightly brighter in the centre, compared to the rest of the disk. Nice - it must look marvelous from dark skies.

NGC288 - this was in the same field of view as the Silver Coin at 23x, so I centered it and had a long look. Very faint globular cluster, really barely more than a smudge at the eyepiece. I increased the magnification and resolved 3 stars, but that was it. From Melbourne, if I didn't know it was there, I doubt I'd have spotted it.

47 Tuc - this really has to be the king of globulars. Amazingly bright, condensed core, surrounded by hundreds of sparkling stars. I spent 25 minutes gazing at this object, with the best view being at 77x - the cluster was framed nicely against the background sky, with stars resolved everywhere - even across the bright core. This reminded me of my only dark sky telescope view of this object at Heathcoate, years ago.

M45 - Subaru was rising (and I drive a Honda), so I couldn't resist a look. At 23x and nearly 3 degrees field of view, the entire cluster was framed. I couldn't see any nebula, but didn't expect to. Just for fun I began counting stars, but got lost at around 40.

M42 - Orion was half up over my neighbours house. I moved the scope and had a look at the Trapezium. I used to bag six stars all the time with my 8" Starhopper, but could only manage five stars with my 12" GSO (go figure). I wasn't expecting much here, with M42 so low. Five stars, straight away! I could see the E star clearly, which is magnitude 11 from memory. I struggled for the F star, but no luck. Given how easy E was, low down, I'm sure F will be within reach over summer. The other weird thing was seeing a steady Airy disk over the A star at 154x.

The sky and seeing was getting clearer and steadier. I wrestled with inner demons as to wait for Mars or get some sleep and be a zombie in the office tomorrow. I defeated the demons and went to bed.

Last edited by DougAdams; 10-10-2007 at 01:45 PM.
Reply With Quote
  #2  
Old 10-10-2007, 04:01 PM
NQLD_Newby's Avatar
NQLD_Newby
Clear Skys and Open Road

NQLD_Newby is offline
 
Join Date: Jul 2007
Location: Townsville
Posts: 207
Nicely done Doug. The feeling you get when you find an object for the first time can't be replaced. When it turns out that it is a fantastic object even in small scopes like ours it is even better. Well done, keep it up.
Reply With Quote
  #3  
Old 10-10-2007, 04:30 PM
DougAdams
Lord Lissie

DougAdams is offline
 
Join Date: Dec 2004
Posts: 233
Thanks Rex. This tiny scope is my 5th, but by far the one I'm having the most fun with.
Reply With Quote
  #4  
Old 11-10-2007, 07:33 AM
你B
Its only a column of dust

你B is offline
 
Join Date: Aug 2007
Location: New Iceland
Posts: 761
Enjoyable read Doug, thanks I started with a 4.5" reflector aswell, had fun with it for 7 years and saw alot!

I was toying with the idea of waiting for Mars aswell, but on acount of the seeing Iwas experiencing, I figured why sit around until 4:30 to see probably nothing when I could catch some much needed sleep

Interesting how you saw only 5 stars in your 12" - if your 8" can pick the six and my 10" at only 104x, maybe your 12" suffers from a pinched primary/secondary (or miscollimation or a defective mirror or...) or just happened to have horrible seeing?

Keep 'em coming (if its possible living with our horrible cold and gloomy climate)!
Reply With Quote
  #5  
Old 11-10-2007, 10:21 AM
DougAdams
Lord Lissie

DougAdams is offline
 
Join Date: Dec 2004
Posts: 233
Quote:
Originally Posted by 你B View Post
Interesting how you saw only 5 stars in your 12" - if your 8" can pick the six and my 10" at only 104x, maybe your 12" suffers from a pinched primary/secondary (or miscollimation or a defective mirror or...) or just happened to have horrible seeing?
Cheers SAB. Yes, it's weird, but I pointed the 12" at Orion all last summer and never saw more than 5 stars. Having now looked through half a dozen different scopes, I can appreciate the 8" Starhopper had a great mirror. Saw some amazing stuff with it.
Reply With Quote
  #6  
Old 11-10-2007, 12:04 PM
你B
Its only a column of dust

你B is offline
 
Join Date: Aug 2007
Location: New Iceland
Posts: 761
That's very strange. I think something must've been amiss with your 12". I saw all six components with my 10" GSO at 104x with direct vision. They literally jumped out at me they were that obvious. That fact that you saw em with the 8" re-inforces the theory that your 12" must have something wrong.

Try this: remove the primary mirror and check if the rubber clips holding it are too tight. If so, place the aluminimum plate thats ontop iof the clips under them and leave a tiny gap, enough to fit a piece of paper between the clip and the mirror face. I did this with my 10" and it seemed to improve the view.
Reply With Quote
  #7  
Old 11-10-2007, 12:22 PM
DougAdams
Lord Lissie

DougAdams is offline
 
Join Date: Dec 2004
Posts: 233
Quote:
Originally Posted by 你B View Post
That's very strange. I think something must've been amiss with your 12". I saw all six components with my 10" GSO at 104x with direct vision. They literally jumped out at me they were that obvious. That fact that you saw em with the 8" re-inforces the theory that your 12" must have something wrong.
I fully agree - I always saw 6 with direct vision, and it was very easy to see 5 with the 4" low down in the east a couple of days ago.

The 12" was fine on axis, but there was something amiss as the object I viewed moved across towards the exit of the field of view. The object would get slightly blurred.

Quote:
Try this: remove the primary mirror and check if the rubber clips holding it are too tight. If so, place the aluminimum plate thats ontop iof the clips under them and leave a tiny gap, enough to fit a piece of paper between the clip and the mirror face. I did this with my 10" and it seemed to improve the view.
I don't have the scope anymore (sold it about five months ago), but I did do that. I took everything out and loosened the clips. Got it all back together and collimated to knife edge perfection. It was okay, but the blur on the right hand side of the FOV was still there.

I feel a song coming on. To all the scopes I've owned before ....
Reply With Quote
  #8  
Old 11-10-2007, 01:26 PM
astro_south's Avatar
astro_south (Andrew)
No GOTO..I enjoy the hunt

astro_south is offline
 
Join Date: Jan 2005
Location: Brisbane
Posts: 1,094
Nice report Doug - NGC253 is a real stunner.

What type of eyepieces were you using when you viewed Orion? When you described objects getting blurry as they left the FOV, what eyepiece were you using and did you try rotating the eyepiece to see if the blurring also rotated?
Reply With Quote
  #9  
Old 11-10-2007, 01:40 PM
DougAdams
Lord Lissie

DougAdams is offline
 
Join Date: Dec 2004
Posts: 233
Quote:
Originally Posted by astro_south View Post
What type of eyepieces were you using when you viewed Orion? When you described objects getting blurry as they left the FOV, what eyepiece were you using and did you try rotating the eyepiece to see if the blurring also rotated?
8mm and 12mm Radians (187x and 125x). I don't recall rotating eyepieces, but they must have been rotating from session to session.
Reply With Quote
  #10  
Old 11-10-2007, 01:51 PM
astro_south's Avatar
astro_south (Andrew)
No GOTO..I enjoy the hunt

astro_south is offline
 
Join Date: Jan 2005
Location: Brisbane
Posts: 1,094
Your eyepieces are not likely to be the issue.

Have you checked that the focuser is square? When you collimate to knife edge perfection do you rack the focuser in and out to see if there is any miss-alignment? I am just asking as the blurriness could be that the cone of light might be at an angle to the eyepiece and when focused on axis, the focal plane is at an angle. Are the objects entering the field of view also blurry? <--probably the first question I should have asked!
Reply With Quote
  #11  
Old 11-10-2007, 01:54 PM
DougAdams
Lord Lissie

DougAdams is offline
 
Join Date: Dec 2004
Posts: 233
Quote:
Originally Posted by astro_south View Post
Your eyepieces are not likely to be the issue.

Have you checked that the focuser is square? When you collimate to knife edge perfection do you rack the focuser in and out to see if there is any miss-alignment? I am just asking as the blurriness could be that the cone of light might be at an angle to the eyepiece and when focused on axis, the focal plane is at an angle. Are the objects entering the field of view also blurry? <--probably the first question I should have asked!
I don't have the scope any more so it's all a bit hard to check now

But no, objects entering were not blurry, it was just as they tracked past the centre of the FOV and moved towards the exit did it blur.
Reply With Quote
  #12  
Old 11-10-2007, 02:04 PM
astro_south's Avatar
astro_south (Andrew)
No GOTO..I enjoy the hunt

astro_south is offline
 
Join Date: Jan 2005
Location: Brisbane
Posts: 1,094
Oops - didn't realise the report above was with a 4" refractor. Should read all posts before replying ... especially the original post
Reply With Quote
  #13  
Old 11-10-2007, 09:45 PM
Rob_K
Registered User

Rob_K is offline
 
Join Date: Oct 2006
Location: Bright, Vic, Australia
Posts: 2,101
Very nice report Doug! Always good to hear small-aperture adventures!

Cheers -
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

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 04:26 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Advertisement
SkyWatcher Australia
Advertisement
Celestron Australia
Advertisement
Bintel
Advertisement
OzScopes Authorised Dealer
Advertisement
Astromechanics
Advertisement
Meade Australia
Advertisement
Lunatico Astronomical
Advertisement
Astronomy and Electronics Centre
Advertisement