Go Back   IceInSpace > Equipment > Equipment Discussions

Reply
 
Thread Tools Rate Thread
  #41  
Old 01-09-2019, 07:09 PM
Slawomir's Avatar
Slawomir (Suavi)
Amateur Photon Collector

Slawomir is offline
 
Join Date: Sep 2014
Location: Proserpine
Posts: 2,989
Great to hear that Greg - looking forward to seeing the results of the first light

I hope you don't mind - in another thread Nick has shared an interesting graph of 128 scopes from a Russian lab showing PV and RMS vs Strehl with some approaching Strehl of 1.

I approximately positioned the values from your certificate on the graph - blue line for PV and red for RMS - both are better than 128 scopes in this sample Clearly, none of these scopes, with some approaching Strehl of 1, are better than PV 1/8 wavelength - maybe Russians got it wrong too
Attached Thumbnails
Click for full-size image (strehl of 128 Russian Scopes and Greg's CFF.jpg)
112.9 KB24 views
Reply With Quote
  #42  
Old 01-09-2019, 08:13 PM
Wavytone (Nick)
BigBanger

Wavytone is offline
 
Join Date: Jul 2008
Location: Killara, Sydney
Posts: 3,997
Try the updated graph - a least squares quadratic fit is more appropriate as itís a a square law relationship in theory. Hence the problem with the intercept with a linear fit.
Attached Thumbnails
Click for full-size image (C8AE3B07-1766-4607-B588-62A7F4A23634.jpeg)
159.1 KB34 views
Reply With Quote
  #43  
Old 02-09-2019, 03:54 PM
gregbradley's Avatar
gregbradley
Registered User

gregbradley is offline
 
Join Date: Feb 2006
Location: Sydney
Posts: 15,410
Quote:
Originally Posted by Slawomir View Post
Great to hear that Greg - looking forward to seeing the results of the first light

I hope you don't mind - in another thread Nick has shared an interesting graph of 128 scopes from a Russian lab showing PV and RMS vs Strehl with some approaching Strehl of 1.

I approximately positioned the values from your certificate on the graph - blue line for PV and red for RMS - both are better than 128 scopes in this sample Clearly, none of these scopes, with some approaching Strehl of 1, are better than PV 1/8 wavelength - maybe Russians got it wrong too
Quote:
Originally Posted by Wavytone View Post
Try the updated graph - a least squares quadratic fit is more appropriate as itís a a square law relationship in theory. Hence the problem with the intercept with a linear fit.
Thanks for the graphs. Impressive indeed.

Any statistical measure will be useless if it does not take enough samples. That is basic statistics. So it would not surprise me, as some have mentioned, that the formula used by most companies would be the one that gives the best marketing spin not the most accurate.

Greg.
Reply With Quote
  #44  
Old 03-09-2019, 08:13 AM
gregbradley's Avatar
gregbradley
Registered User

gregbradley is offline
 
Join Date: Feb 2006
Location: Sydney
Posts: 15,410
I mounted the CFF 105 on top of the AP Honders last night. Luckily the counterweights just make it in balancing it with a bit left over. I was able to image with round stars with the Honders and Proline last night.

The CFF has a lovely slightly sparkly pearl finish. Its not a solid white. The rotating Feathertouch focuser is simply superb. Fabulous fine control.

I used the scope visually last night. My eyepiece collection is not that extensive but it gave pleasant views. A bit dim as 4 inch scope don't collect a lot of light. But the planets looked good. I have a collection of Meade Plossls so I'll look again tonight if its clear and use the shortest focal length I can. I have a TV barlow as well so I'll get that out.

I plan to mount the Microline 16 on it which should give a wider field than the Honders and perhaps it can be collecting colour when the Honders is collecting luminance if I can get them to see much the same spot. Its close now and I haven't really tried.

Visually though an SCT or a larger refractor are hard to beat.

I plan to spend a night or two with the Honders visually. It just means removing the imaging train and refitting the focuser which isn't a big deal but enough of a job to put it off! I think I'll do the same with the CDK again. It really needs good seeing otherwise its horrible visually.

Greg.Attachment 248813
Attached Thumbnails
Click for full-size image (CFF and RHA.jpg)
195.9 KB41 views
Reply With Quote
  #45  
Old 03-09-2019, 11:48 AM
Slawomir's Avatar
Slawomir (Suavi)
Amateur Photon Collector

Slawomir is offline
 
Join Date: Sep 2014
Location: Proserpine
Posts: 2,989
Great news with the visual test Greg.

The setup looks very impressive - so I was correct stating that I take images with a guidescope!
Reply With Quote
  #46  
Old 03-09-2019, 12:47 PM
gregbradley's Avatar
gregbradley
Registered User

gregbradley is offline
 
Join Date: Feb 2006
Location: Sydney
Posts: 15,410
Quote:
Originally Posted by Slawomir View Post
Great news with the visual test Greg.

The setup looks very impressive - so I was correct stating that I take images with a guidescope!
Hehehe
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 09:53 AM.

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