Spider Vanes and Secondary Mirror Appear in image.

[Torutro]

Hi,

I've been an amateur stargazer for a long time, and I recently bought my first (proper) telescope - the Celestron AstroMaster 130EQ - to develop it further.

However, when I look through the eyepiece, the spider vanes and secondary mirror shadow square appear above the image. After numerous days of trawling over other message boards and forums, I understood that this must be a focusing issue. Even after adjusting the focus by large margins, the spider vanes still appear over the image and warp it. 

I managed to find a forum board, that shared the exact issues, but did not provide a means of resolving it. The guy talks about his issues with Venus, but mine are with Jupiter and Mars. Here's the link:

https://astronomy.stackexchange.com/questions/19826/mirror-telescope-blocked-sight

The only time the image does not show the spider vanes is when it loses focus and is reduced to a single point, like in the bottom image of the link.

Any ideas on how to resolve this? Forgive my novice-level use of vocabulary, I've only had the telescope for a week.

 

Edit: For some reason, the issue doesn't appear for the moon, which is crystal clear and fully visible. Anybody have a reasoning for this?

 

Edited November 23, 2020 by Torutro

[AstroNebulee]

Hi

What eyepiece were you using at the time, if you have the spider vanes and secondary showing in your field of view that means your out of focus and need to focus in tighter. I think the moon will always look good without the vanes showing as its a much larger object to view. 

Edited November 23, 2020 by LeeHore7

[Torutro]

I was using the 20mm erect image eyepiece as well as the 10mm that came with the telescope. I'd focused to the max and minimum, but the spider vanes still appeared. 

 

Edited November 23, 2020 by Torutro

[Stu]

4 hours ago, Torutro said:

Hi,

I've been an amateur stargazer for a long time, and I recently bought my first (proper) telescope - the Celestron AstroMaster 130EQ - to develop it further.

However, when I look through the eyepiece, the spider vanes and secondary mirror shadow square appear above the image. After numerous days of trawling over other message boards and forums, I understood that this must be a focusing issue. Even after adjusting the focus by large margins, the spider vanes still appear over the image and warp it. 

I managed to find a forum board, that shared the exact issues, but did not provide a means of resolving it. The guy talks about his issues with Venus, but mine are with Jupiter and Mars. Here's the link:

https://astronomy.stackexchange.com/questions/19826/mirror-telescope-blocked-sight

The only time the image does not show the spider vanes is when it loses focus and is reduced to a single point, like in the bottom image of the link.

Any ideas on how to resolve this? Forgive my novice-level use of vocabulary, I've only had the telescope for a week.

 

Edit: For some reason, the issue doesn't appear for the moon, which is crystal clear and fully visible. Anybody have a reasoning for this?

 

Toruto, the bottom image in the link is the one that IS in focus, the others are other of focus. Objects are at their smallest when in focus; stars are point like, and planets show a small disk. Planets are small, so need a lot of magnification to see properly, somewhere above x100 to x150 would be a starting point; Jupiter can often look best at x180 but it depends on the conditions. Mars generally needs more, over x200 if the skies can take it.

I would try focusing on the Moon with the 10mm then panning the scope across to Mars as it should be essentially the same focus point, perhaps just a minor tweak needed.

[Torutro]

1 hour ago, Stu said:

Toruto, the bottom image in the link is the one that IS in focus, the others are other of focus. Objects are at their smallest when in focus; stars are point like, and planets show a small disk. Planets are small, so need a lot of magnification to see properly, somewhere above x100 to x150 would be a starting point; Jupiter can often look best at x180 but it depends on the conditions. Mars generally needs more, over x200 if the skies can take it.

I would try focusing on the Moon with the 10mm then panning the scope across to Mars as it should be essentially the same focus point, perhaps just a minor tweak needed.

Thank you so much for the advice!

I’ll give it another go, but the issue is that even with the 10mm eyepiece Mars appears in black and white hidden behind the spider vanes.

I might invest is some more powerful eyepieces, but according to the instruction manual, I should be able to see Mars and Jupiter without needing an additional eyepiece, so I was a fair bit confused as to why they were appearing just as points.

[KP82]

If you reached the end of the travel on the focuser but your view was still out of focus, try add an 1.25" extension tube between your eyepiece and the eyepiece holder. I'm still a little surprised the stock eyepieces shipped with the Celestron 130EQ couldn't reach focus on their own.

[markse68]

I suspect that what you’re seeing is the diffraction spikes from the spider vanes- they’re kinda inevitable with a newt on bright subjects. Sirius last night was producing razor sharp laser beams that spanned the whole fov in mine. The other issue is magnification. Mars is pretty small even at quite high magnification. Your scope is 650mm focal length I think so your 10mm ep will give you 65x magnification. I was observing Mars last night and the best view before i lost contrast was 200x and even then the disk is quite small in the eyepiece. but big enough to see some detail. You might try a 2x barlow to get a bigger disk but your scope is never going to produce a big image of Mars. Sounds like your focusing is fine if you get good views of the moon 👍 

[Torutro]

53 minutes ago, markse68 said:

I suspect that what you’re seeing is the diffraction spikes from the spider vanes- they’re kinda inevitable with a newt on bright subjects. Sirius last night was producing razor sharp laser beams that spanned the whole fov in mine. The other issue is magnification. Mars is pretty small even at quite high magnification. Your scope is 650mm focal length I think so your 10mm ep will give you 65x magnification. I was observing Mars last night and the best view before i lost contrast was 200x and even then the disk is quite small in the eyepiece. but big enough to see some detail. You might try a 2x barlow to get a bigger disk but your scope is never going to produce a big image of Mars. Sounds like your focusing is fine if you get good views of the moon 👍 

Thanks!

What you're saying makes a lot of sense now that I understand more about what's happening. On Celestron's official site, it says the highest useful magnification for this telescope is 307x, if I wanted to reach this, how is it achieved? Hopefully it'll help with the image.

Once again, please forgive my lack of proper terminology and understanding. I need to get a hold of a glossary specifically for astronomy. 😄

[markse68]

Ah that old chestnut- manufacturers do tend to say things like that but it’s not really true. Theoretically yes you can expect to get up to 50x per inch of aperture of your scope but in reality lots of other factors mess that up- most notably atmospheric seeing or the wobbly lensing effect of atmospheric turbulence. Last night was very good for me here- seeing was excellent but still i could only usefully magnify Mars to 200x with my scope which is a fair bit bigger than yours. To reach that sort of magnification you’d need a 2mm eyepiece (focal length of scope / focal length of ep) which is pretty specialised and would be expensive and unlikely to give you pleasing views of anything really except splitting double stars. You could try a cheap enough 2x barlow or a 5mm ep to give you double the magnification you have now and maybe on a good night you can go higher power with a 3x barlow or more but I think you need to be aware of the limitations of your scope- there’s an excellent thread here on managing expectations

 

 

But it’s not all bad- there’s loads to see in the night sky without high power magnification and arguably some of the most beautiful sights don’t need much power at all and actually  benefit from a low power wide field of view which your scope should give you

Mark

edit: just to add, I’ve read that the 10mm eps that get packaged with scopes like yours aren’t very good so barlowing it might not be such a good idea. Others can recommend decent reasonably priced upgrade eps but i’ve read BST starguiders are pretty decent for the money. I recently bought a Celestron 114mm scope- it’s classified as a starter scope. It is a smaller aperture but longer effective focal length than yours at 1000mm but I was pleasantly surprised by the view it gave of Mars with a decent 5mm ep. It was still a small disk but nice rosy colour and clearly visible (not much detail though) contrasting darker markings. Still higher magnification than a 5mm would give you but a new eyepiece would likely help 

Mark

Edited November 23, 2020 by markse68

[Torutro]

Thank you so much for all the help!

I'll do some hunting on extensions and lenses and hopefully resolve the issue of the spider vanes and the magnification. 

Once again, thanks!

Torutro

 

[Ricochet]

5 hours ago, Torutro said:

Thank you so much for all the help!

I'll do some hunting on extensions and lenses and hopefully resolve the issue of the spider vanes and the magnification. 

Once again, thanks!

Torutro

 

Re-read what @Stu has already said above, he has given you the correct answer. When observing astronomical objects you always turn the focuser to make the image smaller. If you are in focus then you should see a very small disk. If this is not the case then either you need to observe more carefully to notice, or if you have not aligned your finder scope with the telescope you may not be looking at Mars, but a nearby star.