Go Back   IceInSpace > Equipment > ATM and DIY Projects

Reply
 
Thread Tools Rate Thread
  #261  
Old 23-06-2019, 01:04 PM
Stefan Buda
Registered User

Stefan Buda is offline
 
Join Date: Jul 2013
Location: Melbourne, VIC
Posts: 636
Quote:
Originally Posted by multiweb View Post
Hi Stefan, good to see you again up and about.
You have a heating pad for the secondary and fans only for the primary, correct?
Heating pad for the secondary and also heaters in the air stream for the primary, but only about 6 Watts, just enough to provide dry air in the morning. See earlier pictures.
Quote:
Originally Posted by gregbradley View Post
I am curious. What does overcooling the secondary do? I thought the cooler the better when it came to mirrors or is it more the cooler the better so long as the secondary and primary are in sync with regards to ambient?

Does it make the secondary shift shape slightly compared to the primary?

Greg.
Greg,
By overcooling I mean getting bellow ambient or very close to it. It happens because the secondary assembly is radiating away its heat to a very cold sky and can easily drop below ambient. The same reason you get ice on top of your car when the ambient is still a few degrees above zero. The secondary itself is only 14mm thick in the center and will not develop much of a thermal gradient that would cause shape shifting. If there is a small change in focal length, the auto focus should deal with it. I will set the controller to maintain the secondary at about 1.5 degrees above ambient. That may not be worm enough to prevent dew in some conditions but it will not produce a heat plume either. A humidity sensor would allow the calculation of the dew point, but at this stage I want to avoid using one.
Reply With Quote
  #262  
Old 07-09-2019, 07:11 AM
Stefan Buda
Registered User

Stefan Buda is offline
 
Join Date: Jul 2013
Location: Melbourne, VIC
Posts: 636
Made my own dovetail base, to fit the slots in the mounting bar.
Attached Thumbnails
Click for full-size image (FinderDovetailBase.JPG)
161.2 KB99 views
Reply With Quote
  #263  
Old 02-11-2019, 06:37 AM
Stefan Buda
Registered User

Stefan Buda is offline
 
Join Date: Jul 2013
Location: Melbourne, VIC
Posts: 636
Serial Number 001 is now installed in an automated observatory in country Victoria.
Attached Thumbnails
Click for full-size image (TT5.JPG)
169.5 KB262 views
Reply With Quote
  #264  
Old 02-11-2019, 08:17 AM
sharpiel
Registered User

sharpiel is offline
 
Join Date: Jun 2010
Posts: 670
Looks as good as, if not better, than top end commercial units.

That AP mount looks right at place underneath. An exquisite job as usual from a master builder.
Reply With Quote
  #265  
Old 02-11-2019, 08:50 AM
Atmos's Avatar
Atmos (Colin)
Ultimate Noob

Atmos is online now
 
Join Date: Aug 2011
Location: Melbourne
Posts: 6,871
Incredible build Stefan, it’s come up very nice!
Reply With Quote
  #266  
Old 03-11-2019, 07:12 AM
Stefan Buda
Registered User

Stefan Buda is offline
 
Join Date: Jul 2013
Location: Melbourne, VIC
Posts: 636
Thanks guys.

Quote:
Originally Posted by sharpiel View Post
Looks as good as, if not better, than top end commercial units.
I hope so, as I designed it from the start to be a commercial product if there is demand for it. But I won't start advertising it as such until serial number 002 is completed. That will not happen until mid next year because of other work commitments. Meanwhile I also want to bring up the prototype (SN 000) to the same standard with the electronics as SN 001.
Reply With Quote
  #267  
Old 03-11-2019, 07:33 AM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Hinchinbrook
Posts: 19,829
Awesome product.
Reply With Quote
  #268  
Old 03-11-2019, 09:21 AM
strongmanmike's Avatar
strongmanmike (Michael)
Woohoo it's clear

strongmanmike is offline
 
Join Date: May 2006
Location: Canberra
Posts: 15,267
Beautiful looking (and performing) bits of kit there Mr Buda
Mike
Reply With Quote
  #269  
Old 07-11-2019, 10:05 AM
TWF (Tom)
Registered User

TWF is offline
 
Join Date: May 2015
Location: Melbourne
Posts: 2
CDK250#001 First Light

First light image from BeamTech CDK250 #001.

This image is a calibrated stack of 77 x 240 sec Lum exposures. No further processing applied.

The scope is exceeding all expectations, particularly the time honored ability for new equipment to generate cloud!
Reply With Quote
  #270  
Old 07-11-2019, 02:20 PM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Hinchinbrook
Posts: 19,829
Quote:
Originally Posted by TWF View Post
First light image from BeamTech CDK250 #001.

This image is a calibrated stack of 77 x 240 sec Lum exposures. No further processing applied.

The scope is exceeding all expectations, particularly the time honored ability for new equipment to generate cloud!
Beautiful!
Reply With Quote
  #271  
Old 07-11-2019, 07:49 PM
Stefan Buda
Registered User

Stefan Buda is offline
 
Join Date: Jul 2013
Location: Melbourne, VIC
Posts: 636
Quote:
Originally Posted by TWF View Post
First light image from BeamTech CDK250 #001.

This image is a calibrated stack of 77 x 240 sec Lum exposures. No further processing applied.

The scope is exceeding all expectations, particularly the time honored ability for new equipment to generate cloud!
Thanks Tom for the feedback, and welcome to IIS.
I'm sure you will also get good feedback regarding processing if you post future images in the deep sky section.
This Lum image looks like a promising start, but I don't know how you managed to accumulate 5 hours worth of clear sky. I had to abandon all my attempts of travel to Haethcote because of predicted high level haze.
Reply With Quote
  #272  
Old 09-11-2019, 01:21 PM
Troy's Avatar
Troy
Mars 2010

Troy is offline
 
Join Date: Feb 2008
Location: Hunter Valley
Posts: 943
What everyone else said looks good
Reply With Quote
  #273  
Old 15-07-2020, 05:24 PM
g__day's Avatar
g__day (Matthew)
Tech Guru

g__day is offline
 
Join Date: Dec 2005
Location: Sydney
Posts: 2,606
Longest thread I have read through in its entirety and I am simply amazed at the talent, dedication, perseverance and skill display. I am simply in awe of what you've achieved with your skills; wow falls way short. Stunningly grand work!
Reply With Quote
  #274  
Old 06-10-2020, 02:33 PM
jahnpahwa (JP)
Registered User

jahnpahwa is offline
 
Join Date: Apr 2020
Location: Canberra, AUS
Posts: 412
I've also just read the thread. So happy that this is happening in Australia.

I tried to follow Tom's link to astrobin but got a 404 error. Is #001 still pumping out images that we can take a look at? or #000 for that matter?! (edit: found it. threw beamtech into the astrobin search bar... its there https://www.astrobin.com/search/?q=beamtech )

Thanks for the write up and answering the questions, too, Stefan. A massive achievement.
Reply With Quote
  #275  
Old 06-10-2020, 04:05 PM
Stefan Buda
Registered User

Stefan Buda is offline
 
Join Date: Jul 2013
Location: Melbourne, VIC
Posts: 636
Thanks Troy, Matthew and JP for the encouragement.

At the moment #000 is being used as a development test bed, so it is not producing any images. However #002 and #003 are coming along nicely, although I'm having some difficulties with purchasing materials and parts because of the lock down. Took almost two months for some temperature sensors bought on eBay to arrive, for example.

Last edited by Stefan Buda; 06-10-2020 at 04:26 PM.
Reply With Quote
  #276  
Old 18-10-2020, 03:52 PM
TrevorW
Registered User

TrevorW is offline
 
Join Date: Aug 2006
Location: Western Australia
Posts: 7,122
HI Stefan


Great work on the scope, can I ask where did you get your glass from and how much did the primary and secondary mirrors cost - thanks
Reply With Quote
  #277  
Old 18-10-2020, 08:33 PM
Stefan Buda
Registered User

Stefan Buda is offline
 
Join Date: Jul 2013
Location: Melbourne, VIC
Posts: 636
Quote:
Originally Posted by TrevorW View Post
HI Stefan


Great work on the scope, can I ask where did you get your glass from and how much did the primary and secondary mirrors cost - thanks
Thanks Trevor,

For the prototype primary I used a Pyrex blank that I thinned down and for SN001 I used Borofloat from Schott. Both secondaries were Borofloat.

I'm not very happy with Borofloat, so I've gone back to Pyrex for primaries and borosilicate glass for the secondaries.

I have to slice the old school blanks that I acquire from various sources as they tend to be over 40mm thick.
Reply With Quote
  #278  
Old 18-10-2020, 11:59 PM
TrevorW
Registered User

TrevorW is offline
 
Join Date: Aug 2006
Location: Western Australia
Posts: 7,122
Thanks did you have to cut the hole in the primary ?? and who was the supplier if you don't mind me asking
Reply With Quote
  #279  
Old 19-10-2020, 08:02 AM
Stefan Buda
Registered User

Stefan Buda is offline
 
Join Date: Jul 2013
Location: Melbourne, VIC
Posts: 636
I used a "biscuit cutter" to a depth of 25mm and then I came in from the side with a 9" diamond disc.
I haven't got a supplier for primary blanks yet. What I accumulated so far, is from the second hand market.
Reply With Quote
  #280  
Old 19-10-2020, 08:49 AM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Hinchinbrook
Posts: 19,829
Quote:
Originally Posted by Stefan Buda View Post
I used a "biscuit cutter" to a depth of 25mm and then I came in from the side with a 9" diamond disc.
I haven't got a supplier for primary blanks yet. What I accumulated so far, is from the second hand market.
Diamond crown for the front? (biscuit cutter) How do you use a disc? Very carefully I assume? Got any pics? I'm asking coz this stuff fascinates me. The methodology I mean.
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 08:21 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Advertisement
NexDome Observatories
Advertisement
Bintel
Advertisement
Testar
Advertisement
Limpet Controller
Advertisement
Astronomy and Electronics Centre
Advertisement