After two sessions with stock 200P - eyepiece upgrade advice?

[vlaiv]

Cross "flares" or diffraction spikes are feature of reflecting telescope that has spider support of secondary mirror. It has nothing to do with eyepiece.

Take your 25mm eyepiece and point a scope to very bright star - you should be able to see it as well. You can also see it in images like this one:

Just look around internet for astro images - and you will find images with stars that have cross shape.

Outer field in Panaview can suffer from what is called coma as well - this is related again to telescope design and nothing to do with eyepiece (but wide field long focal length eyepieces make it more visible). It looks like this:

Main fault of the eyepiece will be "seagull" like star shapes at the edges, a bit like this:

Or combined with above coma - more like this (wings come from astigmatism and tail from coma):

[Louis D]

4 hours ago, Deisler said:

I spent 30 mins or so, trying to find Andromeda galaxy - to my disappointment I did not manage to see it. But I did see a faint 'galaxy' near there - I suspect it was M110 but it could be M32 I am not so sure.

You more than likely found M31's core.  As can be seen below, if you can see M32 and/or M110, you can see M31 as much brighter and bigger than either in the same field of view.  From my own observing from my light polluted backyard, all I can see is the core of M31 (the pure white part below) and the cores of M32 and M110 as slightly larger than stellar light patches.  If you don't know what to look for and where to look for them, M32 and M110 can be easily overlooked in light polluted skies at lower powers.  Try increasing the power on that faint galaxy you found to see if you can resolve its companions as non-stellar.

[jetstream]

5 hours ago, Deisler said:

I spent 30 mins or so, trying to find Andromeda galaxy - to my disappointment I did not manage to see it

You most likely did see it- trying more magnification on M31 could help. Also what do you collimate with?

[Deisler]

10 hours ago, vlaiv said:

Cross "flares" or diffraction spikes are feature of reflecting telescope that has spider support of secondary mirror. It has nothing to do with eyepiece.

Take your 25mm eyepiece and point a scope to very bright star - you should be able to see it as well. You can also see it in images like this one:

Just look around internet for astro images - and you will find images with stars that have cross shape.

Outer field in Panaview can suffer from what is called coma as well - this is related again to telescope design and nothing to do with eyepiece (but wide field long focal length eyepieces make it more visible). It looks like this:

Main fault of the eyepiece will be "seagull" like star shapes at the edges, a bit like this:

Or combined with above coma - more like this (wings come from astigmatism and tail from coma):

Thank you. Certainly interesting stuff for me to learn.

I did find 'seagull' pattern at the edge of the view - it did not bother me that much as I don't really look for them.

Did not notice Coma - I will try to see if I can find them. 

 

Is there a way to mitigate the 'diffraction spikes' as I found them distract my view a lot, particularly for those dim stars next to a very bright one?

[Deisler]

6 hours ago, Louis D said:

You more than likely found M31's core.  As can be seen below, if you can see M32 and/or M110, you can see M31 as much brighter and bigger than either in the same field of view.  From my own observing from my light polluted backyard, all I can see is the core of M31 (the pure white part below) and the cores of M32 and M110 as slightly larger than stellar light patches.  If you don't know what to look for and where to look for them, M32 and M110 can be easily overlooked in light polluted skies at lower powers.  Try increasing the power on that faint galaxy you found to see if you can resolve its companions as non-stellar.

I can only see one faint 'galaxy'-like object at the direction of andromeda galaxy. I tried to search for others but no success.

Because of the relatively small size of the object I saw (it was oval-shaped), I thought it was M32 or M110, as I expected M31 to be much bigger than that. But having seen your post made me realise what I saw was indeed M31, perhaps only the core of it. 

I did try to use my stock 10mm to see it, but the image becomes really poor. Will try with BST EP when they arrive.

 

[John]

 

16 minutes ago, Deisler said:

Thank you. Certainly interesting stuff for me to learn.

I did find 'seagull' pattern at the edge of the view - it did not bother me that much as I don't really look for them.

Did not notice Coma - I will try to see if I can find them. 

 

Is there a way to mitigate the 'diffraction spikes' as I found them distract my view a lot, particularly for those dim stars next to a very bright one?

Coma won't be very obvious in an F/6 newtonian. I hardly notice it with my F/5.3 and that is when using 100 degree eyepieces.

Diffraction spikes around beighter point sources are caused by the vanes holding the secondary support in place. It is possible to reduce their visual impact by replacing the 4 straight vane design with a curved vane design but that is quite an operation to carry out even if you can source suitable replacement vanes.

Even with curved vanes diffraction is still there but it is spread over the field of view:

M110 is much fainter than M31. M32 is more of a small fuzzy star. M31 looks like a brightish oval patch of light. Seeing the dust lane structure is not at all easy - you need really dark skies to pick out that.

 

[Stu]

11 minutes ago, Deisler said:

Is there a way to mitigate the 'diffraction spikes' as I found them distract my view a lot, particularly for those dim stars next to a very bright one?

Not easily unfortunately. You would need to change the secondary support to a curved vane version of some description. This does not eliminate the diffraction, but rather smears it around so it is much less noticeable.

Some info here.

http://www.destinycomp.com/Curved Vane Telescope Spider Review.htm

[Deisler]

5 hours ago, jetstream said:

You most likely did see it- trying more magnification on M31 could help. Also what do you collimate with?

This was the pic I took with my phone when I collimated it a week ago. Checked last night - it remained the same.

I did it with the red Cheshire EP.

[Deisler]

@John @Stu

Wow you guys are so knowledgable! Very interesting.

I guess that is a no-go for me  

 

[jetstream]

4 hours ago, Deisler said:

This was the pic I took with my phone when I collimated it a week ago. Checked last night - it remained the same.

I might humbly suggest that your collimation doesn't seem right, it is an iterative process, back and forth from sec alignment to primary etc. I collimate with everything from a cheap effective Celestron Cheshire to more expensive tools.

Part of your eyepiece issues may be related to collimation.

[jetstream]

At f6 it should look something more like this

[Deisler]

6 hours ago, jetstream said:

At f6 it should look something more like this

Yes. I will try to re-do the collimation over the next week. Clear Outside APP shows I will have no clear skies over the next 10 days so I will have plenty of time playing with my P200 inside!

[bingevader]

7 hours ago, jetstream said:

I might humbly suggest that your collimation doesn't seem right, it is an iterative process, back and forth from sec alignment to primary etc. I collimate with everything from a cheap effective Celestron Cheshire to more expensive tools.

Part of your eyepiece issues may be related to collimation.

I would have to concur!

From what you said about the 10mm stock eyepiece and now the Panaview, I feel there is something else going on, that is not just the fault of the EP.

Seeing conditions may play a part, arguably neither of these EPs are by any means top class, but they shouldn't disappoint.