Focussing Problem

[skir]

I got a couple of hours of clear sky tonight so it was time to get the scope out for the first time. Everything went together ok. Tried to align the finder scope but where I am currently we're on top of a hill and surrounded by other houses so I couldn't get onto anything more than about 100 metres away. I was unable to focus with a 32mm ep, but figured this was down to the lack of distance.

Did a quick align which in fact the goto didn't move at all so I must have got it lined up pretty well off the compass and eyeballing it.

I followed this up with a two star align to get things more precise. This was a little entertaining as it was giving me different stars to align on but I didn't know where the majority of these were. A bit of head scratching and I remembered I had a copy of star map on an iPad. This came to the rescue.

But first question. Has anyone got some good tips for dealing with stuff being upside down compared to what you actually see? I was having real problems aligning to stars because of this as a/ everything was upside down in the finder and b/ through the finder I could see a lot more stars than by eyeballing alone which I found very confusing.

However the biggest issue, besides the manual for the hc being completely out of date was not being able to focus. I mean I just couldn't get close at all. I gave up on viewing anything and used the session just to work my way round the sky a bit and play with the alignment routine.

I did a quick check of Collimaton outside and then again when I brought the scope back in and that seems all ok. I tried using the fine focusser and normal focusser but neither made any difference.

I have a focusser that will take a 2" inch ep and this then has a adapter fitted into it to take a 1.25" ep. Am I missing an extension or something here that as causing the inability to focus?

[Cornelius Varley]

I believe you only need the 1.25" adapter screwed into the lower part . If you put the 1.25 adapter into the 2" adapter the eyepiece will be too far away from the focal point of the telescope.

[gkec]

I use a red dot finder as well as a normal optical finder. So if can't see the target in the optical viewfinder or I am unsure of which star I am looking at I have the red dot to fall back on. I didn't attach the red dot tonight and wished I had.

As for focussing what is the scope?

[skir]

The 2 inch part is actually part of the focusser tube it doesn't appear to be removeable though.

[skir]

I use a red dot finder as well as a normal optical finder. So if can't see the target in the optical viewfinder or I am unsure of which star I am looking at I have the red dot to fall back on. I didn't attach the red dot tonight and wished I had.

As for focussing what is the scope?

So the red dot type actually puts a dot on the star you're looking at? Sorry, I've never seen one working before.

Scope is an Altair astro f5 8" newt.

[Scooot]

Skir re being upside down, I think I saw you discussing Sky a safari, if you get the App you can flip the sky so it's the same way around as your view through the eye piece.

[skir]

Skir re being upside down, I think I saw you discussing Sky a safari, if you get the App you can flip the sky so it's the same way around as your view through the eye piece.

Ah that's good to know then, another good reason for buying it I think. But I really need to work out this focussing problem as I cannot see anything through an 8 or a 32mm ep. I did think of pointing the scope at the moon to give me something large to focus on but sadly the clouds rolled in so that was a non-starter. However I don't think it would have made any difference tbh.

[gkec]

So the red dot type actually puts a dot on the star you're looking at? Sorry, I've never seen one working before.

Scope is an Altair astro f5 8" newt.

In effect yes. There is a transparent screen that the laser projects onto and you can see the stars through. So you can aim it like a big gun! You have to align it at the start of your observing session like you do the finder scope. But it is easier to align the the scope.

[skir]

Just wondering if it would be worth pulling the eyepiece up and out of the focusser slightly to see if I can the attain focus?

[cosmojaydee]

I don't know much about your scope but I had a similar issue when I first used a scope. The EP that you are using is a 2" ? , there should be a tube extension with a 1.25" adapter attached, remove the 1.25" adapter and you are left with the tube extension , place this in the draw tube ( fucuser) and then your EP into the extension tube

[Pappy Nick]

I had trouble focussing a couple of nights ago - it turned out to be just a bad case of dew/condensation on everything - objective lens, eyepieces, even the plastic accessory tray was wet !!!

[Rwetherell]

Skir - I have had exactly the same issue with my 8" SW. I had a 2" to 1.25" adaptor in the end of the focuser and couldn't get to focus. There isn't enough backwards travel on the focuser and the only way i could get to focus was to partly remove the ep from the focuser.

I checked my collimation and it was fine and unfortunately having asked on here previously nobody has yet been able to come up with a satisfactory answer...

Richard

[skir]

I don't know much about your scope but I had a similar issue when I first used a scope. The EP that you are using is a 2" ? , there should be a tube extension with a 1.25" adapter attached, remove the 1.25" adapter and you are left with the tube extension , place this in the draw tube ( fucuser) and then your EP into the extension tube

it is a 2" focuser. To explain the setup:-

I have the draw tube which then has a 2" to 1.25" adapter and then the eyepiece. The scope was second hand and no extension tube came with it. Is this missing tube what is causing the problem?

[skir]

Skir - I have had exactly the same issue with my 8" SW. I had a 2" to 1.25" adaptor in the end of the focuser and couldn't get to focus. There isn't enough backwards travel on the focuser and the only way i could get to focus was to partly remove the ep from the focuser.

I checked my collimation and it was fine and unfortunately having asked on here previously nobody has yet been able to come up with a satisfactory answer...

Richard

would you have to buy a different focuser then? Do I actually need an extension tube because I don't have one? By backward travel I guess you mean going away from the scope? Sorry for the daft questions!

[skir]

Well I've tried with the 32mm EP. I have disconnected the EP from the draw tube and pulled it away from the focuser. Once it is about 2-3 inches from the end of the focuser it seems to gain focus at least in that I can see the end of the focussing tube and a very small image in the centre of the hole.

Can someone offer some help here? I'm a bit lost.

[cosmojaydee]

These came with the scope I have.

(A) is an extension tube, I have to use with a 2" EP to get focus as this increases backward travel(away from the OT).

( is the 1.25" adapter which can either be

1) be placed into the extension tube

so you would get focuser, extension tube,1.25 adapter

2) be placed directly into the focuser

so you would have , focuser , 1.25" adapter

[cosmojaydee]

The smiley is supposed to read B

[dephelis]

I followed this up with a two star align to get things more precise. This was a little entertaining as it was giving me different stars to align on but I didn't know where the majority of these were. A bit of head scratching and I remembered I had a copy of star map on an iPad. This came to the rescue.

But first question. Has anyone got some good tips for dealing with stuff being upside down compared to what you actually see? I was having real problems aligning to stars because of this as a/ everything was upside down in the finder and b/ through the finder I could see a lot more stars than by eyeballing alone which I found very confusing.

If you have the StarMap app, you can add your telescope, eyepiece and finder scope details to it and have it display everything according to the orientation of your field of view.

For example I have my finderscope set up as up/down reversed and my views through my Mak's diagonal up/down normal and left/right reversed. You can then also use the find function to draw a line from a bright starting star to your target which will be visible in the StarMaps ocular view.

[skir]

These came with the scope I have.

(A) is an extension tube, I have to use with a 2" EP to get focus as this increases backward travel(away from the OT).

( is the 1.25" adapter which can either be

1) be placed into the extension tube

so you would get focuser, extension tube,1.25 adapter

2) be placed directly into the focuser

so you would have , focuser , 1.25" adapter

well I've got the 1.25" adapter going directly into the focuser which going by what you're saying should work. Or do I need an extension which I don't have?

[cosmojaydee]

well I've got the 1.25" adapter going directly into the focuser which going by what you're saying should work. Or do I need an extension which I don't have?

If you still can't get focus then probably

[skir]

If you have the StarMap app, you can add your telescope, eyepiece and finder scope details to it and have it display everything according to the orientation of your field of view.

For example I have my finderscope set up as up/down reversed and my views through my Mak's diagonal up/down normal and left/right reversed. You can then also use the find function to draw a line from a bright starting star to your target which will be visible in the StarMaps ocular view.

I've just got the free version of star map which I guess wouldn't do all of that, but I plan on getting a paid for copy of sky safari which I guess might have the same functionality? I can see how useful this could be.

[dephelis]

I've just got the free version of star map which I guess wouldn't do all of that, but I plan on getting a paid for copy of sky safari which I guess might have the same functionality? I can see how useful this could be.

As far as I can tell, from the SkySafari feature lists, none of the SkySafari apps include that functionality. You do need the Pro version of StarMap for it though. You might want to do a comparison between the two apps.

http://www.star-map.fr/features/

http://www.southernstars.com/products/skysafari/versions.html

IIRC StarMap pro can use SkySafari's SkyFi system also.

Not a huge difference between SkySafari Plus and StarMap Pro as far as I can see.

[skir]

Cheers for that I'll take a good look at them both then before making a decision.

The main issue at the moment though is the inability to focus, I need to solve that before anything else as I can't see anything currently.

[dephelis]

Cheers for that I'll take a good look at them both then before making a decision.

The main issue at the moment though is the inability to focus, I need to solve that before anything else as I can't see anything currently.

Bare with me on this suggestion, as this actually happened with me when I first got my 150P.

Is the focus tube moving when you turn the focus knobs? If not, undo the focuser lock screw which is located on the opposite side of the focus assembly to the altair text.

[dephelis]

Bare with me on this suggestion, as this actually happened with me when I first got my 150P.

Is the focus tube moving when you turn the focus knobs? If not, undo the focuser lock screw which is located on the opposite side of the focus assembly to the altair text.

Gah, I've got the flu and was't suggesting you get naked! I did of course mean to write "Bear with me"!