First time out - so many questions!

[wolfytom]

Having picked up my new (to me) Orion (UK) 250 on Sunday and added Orion (US) Sirius 10 and 25mm plossls yesterday, last night I got to put it all to work for the first time.

I had an absolutely fantastic night. Saturn, Orion nebula and the Pleiades kept me entertained for hours despite my fumbling about, tripping over and generally idiotic behaviour. I’m just glad it was dark!

Anyway, I have a few (thousand) questions…

• How do I make sure the finder correlates to the scope itself? Currently, it seems way out.
  
• Why is the best place for focus at the very end of each moving part of the crayford? The lens, for example, is barely nipped onto by the screw – if I don’t put it there, I can’t focus at all but it doesn’t feel very safe.
  
• How on earth do I get the thing to track? I gave up last night and used the manual controls. When I switched the motors on, the target seemed to disappear twice as quick. (Did I put the scope on back to front? Can you even do that?)
  
• There seemed to be a fair bit of wobble and movement whenever I focussed. Is that normal? The scope, which has a single-speed Crayford, is on an EQ-5 mount on a pier on a muddy lawn.
  
• How do you use the polar finder, which is reticulated, when you can’t see the reticulations at night?
  

It will be very obvious by now that I am very, very new to this!

[vulcan]

It's good that you had such a good first light. I can answer a couple of your questions.

To align your finderscope you just center an object in your telescope view and then adjust the screws on the finder until the same object is centered in the crosshairs. You can do this in the daytime on any suitable distant object like a television aerial or church spire.

It is possible to get riticule illuminating LEDs for EQ5s. Sorry, I don't have a URL but one was posted a few days ago here.

[wolfytom]

Thanks Vulcan - I'll have a google.

I used to live in Christchurch - went to the Grange. (That probably explains why I couldn't work out how to use a finder!)

[wolfytom]

Just a bump to see if I can get some help with the remaining questions....

Why is the best place for focus at the very end of each moving part of the crayford? The lens, for example, is barely nipped onto by the screw – if I don’t put it there, I can’t focus at all but it doesn’t feel very safe.

How on earth do I get the thing to track? I gave up last night and used the manual controls. When I switched the motors on, the target seemed to disappear twice as quick.

There seemed to be a fair bit of wobble and movement whenever I focussed. Is that normal? The scope, which has a single-speed Crayford focusser, is on an EQ-5 mount on a pier on a muddy lawn.

Thanks very much

Andy:confused:

[John]

I have a 10" F/4.8 Orion Optics but it's not EQ mounted. I can talk about the issues with the single speed crayford though.

Mine needs a 40mm extension tube to bring eyepieces to focus - eyepieces can then be fully inserted and bought to focus - I use a 2" extension with a 2" - 1.25" adapter for the smaller format eyepieces.

The Crayford is not the best I've used. There are 2 hex screws underneath which will need to be gently tightened to get rid of the wobble. This will mean that the focus movement will become tighter but I've not found any way around that, so far.

[The Bat]

Sounds like you might need some sort of extension tube to resolve your focusing issue.

Tracking - not sure what mount you have but make sure the tracking is set to Northern hemisphere. If it's set to Southern it will go the other way and objects will therefore zoom out of the field of view quicker.

Focusing often introduces wobble, which is why imagers prefer to use electric focusers so that they don't have to touch the telescope.

Regarding your reticule problem, I shine a red light torch across (not straight down) the opening of my polar axis - it illuminates enough to see the cross hairs but is still dim enough for Polaris to shine through.

Sounds like a good first night otherwise.

Rachel

[brianb]

Mine needs a 40mm extension tube to bring eyepieces to focus - eyepieces can then be fully inserted and bought to focus - I use a 2" extension with a 2" - 1.25" adapter for the smaller format eyepieces.

They're made like that deliberately so that SLR type cameras can come to focus. IMO there should have been a extension tube supplied ... you certainly don't want the eyepiece hanging on by its fingernails!

[x6gas]

How do you use the polar finder, which is reticulated, when you can’t see the reticulations at night?

I struggle with this myself and it's harder (for me at least) in darker skies as there is even less contrast.

For me it's important to have good dark adjusted vision (and since this is usually the first thing you are doing that's not a given).

It is also really useful to have a good idea of where the reticule is so getting used to it in daylight helped.

Finally, you can obiously see the reticule when it obscures a star so hopefully by doing the above you can get Polaris to intersect some part of the reticule and adjust from there.

I don't find this particularly easy but then I've got pretty poor eyesight!

[wolfytom]

Brilliant! Thanks everyone - invaluable help as always.

I'll get the extension tube and a red light torch to go with the barlow I'm after.

I've had a fantastic time over the last 3 nights.

Saturn and its moons, Pleiades and the Orion nebula just simply blow me away.

Andromeda is spoiled by light pollution but I'm heading into the wilds of Cheshire this weekend to find dark skies.

I just need to read up on the drives now - I'm currently using the manual controls and boy does Saturn motor through a 10mm ep!

[John]

Try the scope on M13 in Hercules. 10" of aperture really makes the brighter globular clusters look good