Ove the moon over the moon! And questions: Removing the primary, and R.A: Consistency

[ambrishnat]

I have recently bought a telescope. I initially took it out twice, and was over the moon over the moon, but have since been confined to bed rest for a week or two. I'd thought I'd use the time to sort out some of the details of my scope, such as ordering some decent eyepieces, collimation and setting circles.

I've tried to sort out the setting circles, but one thing I can't understand is how this works if stars maintain constant ra/dec values, yet move across the sky. Once R.A is calibrated, after a only a short amount of time, won't it need to be calibrated again in order to find stars via their ra/dec coordinates?

My other question is on collimation. A cheshire collimator arrived for me in the post the other day, and I soon discovered that there was no centre marker on my primary mirror. I want to remove the primary so I can put a marker on it, but I'm not really sure how. Should I take it out the top or the back of the tube? Do I just remove the locking and adjustment screws, and drop it out the bottom? It's a skywatcher 114mm reflector.

I really was blown away by the moon! I had a look at Jupiter too, and although I could make out the weather lines, I hadn't collimated and was only using the not-so-great eyepieces that came with it (25mm, 10mm and 2x barlow). The other day I ordered three vixen npl's, 6mm, 10mm and 15mm (and was surprised to find each of these cheaper than the cheshire collimator! Why is that?).

Thanks,

Andrew

[nightfisher]

dont worry about the setting circles, not many people use them, if you remove primary from the bottom, make a paper template the diameter of the mirror, then fold in half twice, forming a sort of triangle, nip of the corner open up place over mirror and mark with a permanent marker pen

[ambrishnat]

Actually, I just read an interesting skywatcher collimation tutorial, downloaded from their website. It had no mention of any mark in the middle of the primary, and all that was needed was a collimation cap. It's instructions were to adjust according to the reflection of the secondary in the primary. Does that sound feasible?

And when I say "over the moon over the moon", I am not repeating the phrase for effect. I literally mean that it is the moon that I am over the moon about. And please forgive me for explaining that if you got it, I just realized that there's potential to sound camp. Although if I did that probably wouldn't be too far from the truth about how I felt seeing the moon for the first time so close.

[todd8137]

makes life a little easier with a spot but with that size of scope you should be ok

[asteria]

I think whole process is easier with a centre spot as you have a reference point on the primary. Otherwise it's difficult to judge just where you are in relation to the centre. With short focal length reflectors this is quite important.

[Dob]

I have recently bought a telescope. I initially took it out twice, and was over the moon over the moon, but have since been confined to bed rest for a week or two. I'd thought I'd use the time to sort out some of the details of my scope, such as ordering some decent eyepieces, collimation and setting circles.

I've tried to sort out the setting circles, but one thing I can't understand is how this works if stars maintain constant ra/dec values, yet move across the sky. Once R.A is calibrated, after a only a short amount of time, won't it need to be calibrated again in order to find stars via their ra/dec coordinates?

My other question is on collimation. A cheshire collimator arrived for me in the post the other day, and I soon discovered that there was no centre marker on my primary mirror. I want to remove the primary so I can put a marker on it, but I'm not really sure how. Should I take it out the top or the back of the tube? Do I just remove the locking and adjustment screws, and drop it out the bottom? It's a skywatcher 114mm reflector.

I really was blown away by the moon! I had a look at Jupiter too, and although I could make out the weather lines, I hadn't collimated and was only using the not-so-great eyepieces that came with it (25mm, 10mm and 2x barlow). The other day I ordered three vixen npl's, 6mm, 10mm and 15mm (and was surprised to find each of these cheaper than the cheshire collimator! Why is that?).

Thanks,

Andrew

No, you dont need to remove locking and collimation screws.

There should be some screws or something thats holding primary mirror and its housing.

[Pauly]

And please forgive me for explaining that if you got it, I just realized that there's potential to sound camp. Although if I did that probably wouldn't be too far from the truth about how I felt seeing the moon for the first time so close.

:D:D That made me chuckle.

[assasincz]

I too have a Sky Watcher 114 reflector. It is actually easy to remove the primary, the housing of it is attached to the tube with three bolts. After removing them, you simply pull the entire mirror cell of the tube. Now I have made a centre mark on the primary from a 2x2mm square of black electrical tape. It makes collimation easier, no doubt, but I have soon found out that it was not neccessary, as the optical centre of the primare does not correspond with the geometrical centre of it, after I did a star collimation (you should take a look at that, it is very easy and precise, take a look at this thread http://stargazerslounge.com/discussions-scopes-whole-setups/156446-celestron-collimation-114-eq.html I write on how to do it).