Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
Get a Cloudy Nights T-Shirt Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu uh, User

Equipment Discussions >> Reflectors

Pages: << 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | (show all)
Sarkikos
Postmaster
*****

Reged: 12/18/07

Loc: Suburban Maryland, USA
Re: Thermal Issues and Fans Successes new [Re: Starman1]
      #5664947 - 02/06/13 10:37 AM

I've never seen fan-induced vibration from the fan behind/below the primary in my two Dobs even at higher power, no matter if the defocused image be of a star or a planet. I'm not saying it doesn't happen in other scopes, but I've never experienced it in mine.

Mike


Post Extras: Print Post   Remind Me!   Notify Moderator  
SteveG
Post Laureate
*****

Reged: 09/27/06

Loc: Seattle, WA
Re: Thermal Issues and Fans Successes new [Re: johnnyha]
      #5665386 - 02/06/13 02:24 PM

Quote:

Update: Last night using my new exhaust system on my mirror box, I had the best views of Jupiter ever in my lifetime. So it certainly isn't hurting to switch to the exhaust fan. I was able to go over 250X for the first time in months and months, with a perfectly stable, sharp image. I have never seen such detail on the disc, it was simply amazing. I was truly gobsmacked, I did not think my scope was capable of such incredible views from my backyard in Los Angeles. I recently switched to a thinner 14.5" Zambuto mirror and Protostar quartz secondary, and that combined with this new exhaust fan system has delivered the goods - finally - a beautiful, thermally stable image.

This is a simple 3 speed exhaust fan with a closed back, I don't have a di Lio baffle or any boundary fans installed at this point. I also had my 12V box fan about 8 feet from the scope creating a light breeze blowing my body heat away.




Can you clarify; is the fan blowing on the back of the mirror or sucking?


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pinbout
Postmaster
*****

Reged: 02/22/10

Loc: nj
Re: Thermal Issues and Fans Successes new [Re: SteveG]
      #5665951 - 02/06/13 08:13 PM

His fan sucks


Post Extras: Print Post   Remind Me!   Notify Moderator  
johnnyha
Postmaster
*****

Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: Thermal Issues and Fans Successes new [Re: Pinbout]
      #5665993 - 02/06/13 08:52 PM

Yes it is sucking or exhausting air out the bottom, not blowing air onto the back of the mirror.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Mark Peterman
super member


Reged: 08/07/12

Loc: Texas
Re: Thermal Issues and Fans Successes new [Re: Mark Peterman]
      #5678122 - 02/13/13 06:19 PM

I just finished adding the temperature readouts to my fan baffle assembly.

The kit I referenced earlier uses digital temp probes instead of resistance based probes. As a result, it updates fast and can be connected with up to a six foot wire without affecting the accuracy. It came with a blue LCD readout which I replaced with a red on black version.

The first picture is the temp probe attached to the back of the mirror using Bryan Greer's instructions on his website.

The second picture is with everything hooked up and running. You can see the outside probe at about the 2 o'clock position. I added a thick wire inside heat shrink so that it is bendable and stays put.





Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: Thermal Issues and Fans Successes new [Re: Mark Peterman]
      #5678137 - 02/13/13 06:29 PM

If using dual readout thermometers, maky sure your "outside" thermometer is not exposed to the sky. The sky is very cold and heat from the thermometer will radiate away faster, yielding falsely-colder readings.
A good place to put the second thermometer is near the azimuth bolt of the scope--it is never exposed to the sky directly (it's under the shadow of the scope).


Post Extras: Print Post   Remind Me!   Notify Moderator  
Project Galileo
scholastic sledgehammer
*****

Reged: 11/14/07

Loc: Jefferson County, Colorado
Re: Thermal Issues and Fans Successes new [Re: Mark Peterman]
      #5678160 - 02/13/13 06:44 PM

Nice install!

Post Extras: Print Post   Remind Me!   Notify Moderator  
Bob S.
Carpal Tunnel
*****

Reged: 07/14/05

Re: Thermal Issues and Fans Successes new [Re: Project Galileo]
      #5678204 - 02/13/13 07:12 PM

Mark, Very nice install. Bob

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: Thermal Issues and Fans Successes new [Re: Bob S.]
      #5678261 - 02/13/13 07:58 PM

Since the greatest thermal inertia is in the outer section of the mirror, I might have attached my "inside" thermometer to an outer segment of the mirror.
Additionally, that would get it out from directly under the fan, where it might read the ambient temperature instead of the glass.

Edited by Starman1 (02/13/13 08:00 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: Thermal Issues and Fans Successes new [Re: Starman1]
      #5678374 - 02/13/13 09:17 PM

Mark!!!!

Look at that clean work of yours!!! Dang it - excellent job. Don makes really good points - till now I've used the out of focus star test to see thermal shadows and such but the better system has the sensors - and again, the exacting clean finish is well done.

Pete


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mark Peterman
super member


Reged: 08/07/12

Loc: Texas
Re: Thermal Issues and Fans Successes new [Re: azure1961p]
      #5678527 - 02/13/13 10:52 PM

Thank you for the compliments.

Thanks for the tips Don. The fan exhausts out the rear so the temp probe does not get a direct blast on it and it is pretty well insulated.


Post Extras: Print Post   Remind Me!   Notify Moderator  
De Lorme
professor emeritus
*****

Reged: 12/30/08

Re: Thermal Issues and Fans Successes new [Re: Mark Peterman]
      #5678688 - 02/14/13 01:15 AM

Hi Mark, Where did you get the temperture kit?
Thanks De Lorme


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mark Peterman
super member


Reged: 08/07/12

Loc: Texas
Re: Thermal Issues and Fans Successes new [Re: De Lorme]
      #5679211 - 02/14/13 11:15 AM

Quote:

Hi Mark, Where did you get the temperture kit?
Thanks De Lorme




I found the kit to make the temperature meter here:

http://electronics-diy.com/pic_temperature_meter.php $39.95

It is rather simple to build if you are okay at soldering. The kit comes with a blue backlight LCD display. I wanted a red on black display for night vision purposes and I located one here:

http://www.adafruit.com/products/399 $13.95

The red on black LCD is plug and play, there are no modifications needed to have it work with the temperature meter kit.

Mark


Post Extras: Print Post   Remind Me!   Notify Moderator  
Sebastian Quirk
member


Reged: 01/04/12

Re: Thermal Issues and Fans Successes new [Re: Mark Peterman]
      #5679493 - 02/14/13 01:33 PM

Does anyone have any data or experience with the startup voltage for the Noiseblocker, or Sunon Maglev fans? I had some very nice fans years back but they wouldn't get rolling at less than 10 volts. Once rolling, they could be dialed down to 6 volts okay.

And the specs listed for the fans by the manufacturer are not terribly reliable in terms of start up voltage...I was looking for direct experience.

thx
Q

Edited by Sebastian Quirk (02/14/13 01:35 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Project Galileo
scholastic sledgehammer
*****

Reged: 11/14/07

Loc: Jefferson County, Colorado
Re: Thermal Issues and Fans Successes new [Re: Sebastian Quirk]
      #5680149 - 02/14/13 08:12 PM

My noise blocker needs 4.5 volts to get running and cuts out at 4.5 on the way down.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Sebastian Quirk
member


Reged: 01/04/12

Re: Thermal Issues and Fans Successes new [Re: Project Galileo]
      #5680512 - 02/15/13 12:57 AM

Thank you!

Q


Post Extras: Print Post   Remind Me!   Notify Moderator  
De Lorme
professor emeritus
*****

Reged: 12/30/08

Re: Thermal Issues and Fans Successes new [Re: Mark Peterman]
      #5680519 - 02/15/13 01:04 AM

Thanks Mark, De Lorme

Post Extras: Print Post   Remind Me!   Notify Moderator  
De Lorme
professor emeritus
*****

Reged: 12/30/08

Re: Thermal Issues and Fans Successes new [Re: De Lorme]
      #5680555 - 02/15/13 01:37 AM

I got my 3 39cfm fans and low to high speed controllers from Digi-Keys. Although the controllers won't turn off they do get pretty low. I plan on putting a toggle switch in. There pretty cheap,$2.70ea for the fans and $6.50ea for the controllers. De Lorme

Post Extras: Print Post   Remind Me!   Notify Moderator  
MDavid
super member


Reged: 11/15/11

Loc: 29N (Texas)
Re: Thermal Issues and Fans Successes new [Re: Mark Peterman]
      #5681579 - 02/15/13 01:58 PM

Quote:

Quote:

Hi Mark, Where did you get the temperture kit?
Thanks De Lorme




I found the kit to make the temperature meter here:

http://electronics-diy.com/pic_temperature_meter.php $39.95

It is rather simple to build if you are okay at soldering. The kit comes with a blue backlight LCD display. I wanted a red on black display for night vision purposes and I located one here:

http://www.adafruit.com/products/399 $13.95

The red on black LCD is plug and play, there are no modifications needed to have it work with the temperature meter kit.

Mark




Mark,

That looks awesome...What are you using for power?

Thanks for the links.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mark Peterman
super member


Reged: 08/07/12

Loc: Texas
Re: Thermal Issues and Fans Successes new [Re: MDavid]
      #5682021 - 02/15/13 05:29 PM

Thank you Mike.

To power my secondary heater, telrad heater, fan, and temp display, I use this battery:

http://www.ebay.com/itm/BESTEK-12000mAh-USB-Power-Bank-external-battery-charg...

and run it through a Thousand Oaks Dew Controller:

http://www.thousandoaksoptical.com/dew.html

The temperature display is always on when I have the battery on as it draws next to nothing and I want the ability to see the temp when the fan is off. The fan only is controlled through the switch that you can see on the baffle.

The Thousand Oaks controller has a direct 12V out jack that connects to the jack on the baffle. Take a look around page 21 of this thread, post ##5656751 for some pics.

Mark


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: << 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | (show all)


Extra information
13 registered and 20 anonymous users are browsing this forum.

Moderator:  ausastronomer, Phillip Creed, JayinUT, okieav8r 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 19861

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics