The cone effect

Cosmic Charlie · February 12th, 2008, 12:13 PM

Hey all,

I searched and searched for an answer on this but to now avail, so thought maybe someone here would know. When I look at stars, the light coming off of them makes it look like a cone, but when I look at planets, there is no cone effect. They are just round. Saturn has a tiny little blur below it, but I'm hoping that's the atmosphere and not just my eyepiece or something (first time I've seen it was last night :).

Anyway, this cone shape of stars. Is it my telescope (reflector) or eyes pieces that are causing this? Is this really how they look magnified or is this an optical illusion of some sort? Just curious. Thanks in advanced for any response.

Cosmic Charlie

slotdrag · February 12th, 2008, 07:07 PM

Have you aligned the mirrors?

sgcullen · February 12th, 2008, 09:34 PM

I'm not all that familiar with your particular scope but being a reflector, it is susceptible to the mirrors going out of alignment. What you describe is certainly an indication of this. You need to collimate your mirrors. It is generally a fairly easy process of loosening/tightening some screws on your secondary mirror while watching an out of focus star. The goal is to get more-or-less a bullseye pattern.

You can also download the 114EQ manual here. They describe the collimation process on pages 23-25. Celestron sells a collimation tool to aid the process. B&H Photo carries it...you can find it here.

Good luck with it and let us know how it turns out.

Cosmic Charlie · February 13th, 2008, 12:02 PM

You guys rock!

I haven't done this before. I'm going to try this tonight and I'll be sure to let you know how it goes.

Cosmic Charlie

slotdrag · February 15th, 2008, 05:14 PM

Good luck. Im sure itll help.

Cosmic Charlie · March 25th, 2008, 12:23 PM

Lessons Learned for a noob to fellow noobs:

* If you are a newbie, don't try to culminate your telescope by the star method alone.

* Learn what the primary and secondary mirrors do and understand what the circles mean when you look through the eyepiece.

* Buy a culmination tool. At $30, a laser culminator is well worth it.

* Don't assume your reflector is perfectly culminated out of the box. You will be very surprised at how much better the image quality is when your telescope is perfectly culminated.

*Finally, be patient. It'll most likely take you an hour or more (in my case about 3), to get the hang of it. But once you do, it's just like riding a bike.

Happy star gazing!!!

Cosmic Charlie

February 12th, 2008, 12:13 PM	#1 (permalink)
Cosmic Charlie Junior Member Join Date: Jan 2008 Posts: 13 Status: Offline	The cone effect Hey all, I searched and searched for an answer on this but to now avail, so thought maybe someone here would know. When I look at stars, the light coming off of them makes it look like a cone, but when I look at planets, there is no cone effect. They are just round. Saturn has a tiny little blur below it, but I'm hoping that's the atmosphere and not just my eyepiece or something (first time I've seen it was last night :). Anyway, this cone shape of stars. Is it my telescope (reflector) or eyes pieces that are causing this? Is this really how they look magnified or is this an optical illusion of some sort? Just curious. Thanks in advanced for any response. Cosmic Charlie

February 12th, 2008, 09:34 PM	#3 (permalink)
sgcullen Administrator [View SpaceSpot Album] Join Date: May 2007 Location: Oro Valley, AZ Posts: 157 Status: Offline	I'm not all that familiar with your particular scope but being a reflector, it is susceptible to the mirrors going out of alignment. What you describe is certainly an indication of this. You need to collimate your mirrors. It is generally a fairly easy process of loosening/tightening some screws on your secondary mirror while watching an out of focus star. The goal is to get more-or-less a bullseye pattern. You can also download the 114EQ manual here. They describe the collimation process on pages 23-25. Celestron sells a collimation tool to aid the process. B&H Photo carries it...you can find it here. Good luck with it and let us know how it turns out. __________________ Mondo brings you the ultimate enthusiast communities on the web.

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February 12th, 2008, 07:07 PM	#2 (permalink)
slotdrag Member Join Date: Jun 2007 Location: Wichita Ks. Posts: 45 Status: Offline	Have you aligned the mirrors?

February 13th, 2008, 12:02 PM	#4 (permalink)
Cosmic Charlie Junior Member Join Date: Jan 2008 Posts: 13 Status: Offline	You guys rock! I haven't done this before. I'm going to try this tonight and I'll be sure to let you know how it goes. Cosmic Charlie

February 15th, 2008, 05:14 PM	#5 (permalink)
slotdrag Member Join Date: Jun 2007 Location: Wichita Ks. Posts: 45 Status: Offline	Good luck. Im sure itll help.

March 25th, 2008, 12:23 PM	#6 (permalink)
Cosmic Charlie Junior Member Join Date: Jan 2008 Posts: 13 Status: Offline	Lessons Learned for a noob to fellow noobs: * If you are a newbie, don't try to culminate your telescope by the star method alone. * Learn what the primary and secondary mirrors do and understand what the circles mean when you look through the eyepiece. * Buy a culmination tool. At $30, a laser culminator is well worth it. * Don't assume your reflector is perfectly culminated out of the box. You will be very surprised at how much better the image quality is when your telescope is perfectly culminated. *Finally, be patient. It'll most likely take you an hour or more (in my case about 3), to get the hang of it. But once you do, it's just like riding a bike. Happy star gazing!!! Cosmic Charlie

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