Manual Celestron AstroMaster 90 EQ (page 28 of 32) (English)

580482

Zoom out

Zoom in

1/32

Aligning the Primary Mirror

Now adjust the primary mirror screws to re-center the reflection of the small secondary mirror, so it’s silhouetted

against the view of the primary. As you look into the focuser, silhouettes of the mirrors should look concentric.

Repeat steps one and two until you have achieved this.

Remove the collimating cap and look into the focuser, where you should see the reflection of your eye in the

secondary mirror.

Newtonian collimation views as seen through the focuser using the collimation cap

Secondary mirror needs adjustment.

Primary mirror needs adjustment.

Both mirrors aligned with the collimating

cap in the focuser.

Both mirrors aligned with your eye

looking into the focuser.

Figure 7-1

Night Time Star Collimating

After successfully completing daytime collimation, night time star collimation can be done by closely

adjusting the primary mirror while the telescope tube is on its mount and pointing at a bright star. The

telescope should be set up at night and a star's image should be studied at medium to high power (30-60

power per inch of aperture). If a non-symmetrical focus pattern is present, then it may be possible to

correct this by re-collimating only the primary mirror.

Procedure (Please read this section completely before beginning):

To star collimate in the Northern Hemisphere, point at a stationary star like the North Star (Polaris). It can

be found in the north sky, at a distance above the horizon equal to your latitude. It’s also the end star in the

handle of the Little Dipper. Polaris is not the brightest star in the sky and may even appear dim, depending

upon your sky conditions.

Prior to re-collimating the primary mirror, locate the collimation screws on the rear of the telescope tube.

The rear cell (shown in Figure 7-1) has three large thumbscrews which are used for collimation and three

small thumbscrews which are used to lock the mirror in place. The collimation screws tilt the primary

mirror. You will start by loosening the small locking screws a few turns each. Normally, motions on the

order of an

turn will make a difference, with approximately a

turn being the maximum required

for the large collimation screws. Turn one collimation screw at a time and with a collimation tool or

eyepiece see how the collimation is affected (see the following paragraph below). It will take some

experimenting but you will eventually get the centering you desire.

Secondary

Mirror

Primary

Mirror

Mirror Clip

Report abuse

Libble takes abuse of its services very seriously. We're committed to dealing with such abuse according to the laws in your country of residence. When you submit a report, we'll investigate it and take the appropriate action. We'll get back to you only if we require additional details or have more information to share.

Product:

Forumrules

To achieve meaningful questions, we apply the following rules:

First, read the manual;
Check if your question has been asked previously;
Try to ask your question as clearly as possible;
Did you already try to solve the problem? Please mention this;
Is your problem solved by a visitor then let him/her know in this forum;
To give a response to a question or answer, do not use this form but click on the button 'reply to this question';
Your question will be posted here and emailed to our subscribers. Therefore, avoid filling in personal details.

new questions and answers
new manuals

You will receive an email to register for one or both of the options.

Get your user manual by e-mail

Enter your email address to receive the manual of Celestron AstroMaster 90 EQ in the language / languages: English as an attachment in your email.

The manual is 10 mb in size.

You will receive the manual in your email within minutes. If you have not received an email, then probably have entered the wrong email address or your mailbox is too full. In addition, it may be that your ISP may have a maximum size for emails to receive.

Others manual(s) of Celestron AstroMaster 90 EQ

Celestron AstroMaster 90 EQ User Manual - German - 32 pages

The manual is sent by email. Check your email

If you have not received an email with the manual within fifteen minutes, it may be that you have a entered a wrong email address or that your ISP has set a maximum size to receive email that is smaller than the size of the manual.

The email address you have provided is not correct.

Please check the email address and correct it.

Your question is posted on this page

Would you like to receive an email when new answers and questions are posted? Please enter your email address.

Info

Celestron AstroMaster 90 EQ Manual

Product: