Eye piece advise for 300p

[Don Pensack]

4 hours ago, bomberbaz said:

Sorry @Don Pensack surely if you add height to the focuser you are then having to wind the focuser in further to compensate or did I misunderstand what you meant?

Would pushing pushing your primary mirror up 5mm not be another option assuming that is there is enough travel!

Steve

The new 2" to 1.25" adapter would be SHORTER than the one currently used.   You are shortening the focuser thereby, not adding height.

So you misunderstood what I meant.

Pushing the mirror up 5mm wouldn't be enough unless the focuser only protruded 5mm inside the UTA, and the spike says it sticks in more than that.

My adapter switch would likely make a 15mm different or more.

[Don Pensack]

I see you used the term "back focus" to indicate "out focus".

Back focus is a photography term and it means gaining additional focus room outside the focuser, i.e. back focus.

It implies in focus of the focuser.  Sorry for my confusion.

In that case, there are a couple solutions:

1) add an extension tube to the focuser.  These pull the eyepiece out of the focuser by at least the length of the eyepiece's barrel, so the focuser would need to move in at least that far.

2) use only the 2" adapter for the focuser (the tall one provided by the manufacturer) and add a standard 2" to 1.25" adapter to that and do not use the 1.25" adapter that came with the scope again.

This would raise the eyepiece and cause you to lower the focuser.

 

However, to the point of the large extraneous spike in the image.  It is obviously not caused by the focuser, so what else protrudes into the inside diameter of the tube?

Edited June 16, 2020 by Don Pensack

[bomberbaz]

12 minutes ago, Don Pensack said:

The new 2" to 1.25" adapter would be SHORTER than the one currently used.   You are shortening the focuser thereby, not adding height.

So you misunderstood what I meant.

Pushing the mirror up 5mm wouldn't be enough unless the focuser only protruded 5mm inside the UTA, and the spike says it sticks in more than that.

My adapter switch would likely make a 15mm different or more.

Just checked the pictures and I see what you mean Don, should have checked beforehand, sorry bud.

Steve

[djpaul]

Ive only had my 300p for a couple of weeks so not sure if this info helps but i bought a baader 47mm click lock for my 300p. 

My main eyepieces used so far are 26mm nagler and 17 mm and 10mm  ethos .

I have the stock focuser and when out fully its 50mm.

So the baader makes it almost 100mm 

Which leaves me with sufficient back focus if ever needed.

 

[Geoff Barnes]

Barry, is that big spike visible to your eye or only when you use your camera, could it be a camera artifact?

[Ricochet]

1 hour ago, Don Pensack said:

However, to the point of the large extraneous spike in the image.  It is obviously not caused by the focuser, so what else protrudes into the inside diameter of the tube?

I have a vague recollection of reading that a secondary mirror that is too small with improperly blackened edges can produce such a spike. If that is true, and the focuser has to be extended further than "normal" then the first thing I would check is that the trusses are properly extended. Secondly I would check that the secondary is properly centred under the focuser as having a bevel on one side of the secondary clipping the light cone instinctively feels more like something that might create an additional pair of spikes. 

There is also a general mess of mini spikes that I suspect could be cleaned up by masking the primary edge and a weird, wide singular spike that perhaps is just  lens flare in the camera used to take the photographs. 

[niallk]

18 hours ago, John said:

Personally I don't find filters make a big difference to the Cat's Eye or Blinking planetary nebulae. They can make the central star in those nebulae harder to see though !

The Veil Nebula is becoming better and better placed now and that's where the O-III will really earn it's keep.

 

Yes an O-III is astounding on the Veil!

I have found the O-III helpful to try to discern some structure at 340x, cutting light from the very bright central star.  To me it looks like two ellipses at right angles to eachother, within the overall larger elongated shape.  I've never seen the 'splash shaped' much larger outer shell except in images!

Below is a very crude sketch on the phone.  The outer ellipse drawn marks out a diffuse bright area filled with green to my eye at the EP.  The two inner ones show edges I catch fleetingly - not obvious to me, and some nights are better than others.  I don't recall being able to see them without the O-III, but maybe i just didn't get a good enough dark & transparent night!  Will try again soon i hope

[bomberbaz]

27 minutes ago, niallk said:

Yes an O-III is astounding on the Veil!

I have found the O-III helpful to try to discern some structure at 340x, cutting light from the very bright central star.  To me it looks like two ellipses at right angles to eachother, within the overall larger elongated shape.  I've never seen the 'splash shaped' much larger outer shell except in images!

Below is a very crude sketch on the phone.  The outer ellipse drawn marks out a diffuse bright area filled with green to my eye at the EP.  The two inner ones show edges I catch fleetingly - not obvious to me, and some nights are better than others.  I don't recall being able to see them without the O-III, but maybe i just didn't get a good enough dark & transparent night!  Will try again soon i hope

looking forwar to trying this out when my new dob arrives, don't think my 10" orion will cut the magnfication or detail like your describing. Might try it if condtions ever allow though. 

[niallk]

7 hours ago, niallk said:

Yes an O-III is astounding on the Veil!

I have found the O-III helpful to try to discern some structure at 340x, cutting light from the very bright central star.  To me it looks like two ellipses at right angles to eachother, within the overall larger elongated shape.  I've never seen the 'splash shaped' much larger outer shell except in images!

Below is a very crude sketch on the phone.  The outer ellipse drawn marks out a diffuse bright area filled with green to my eye at the EP.  The two inner ones show edges I catch fleetingly - not obvious to me, and some nights are better than others.  I don't recall being able to see them without the O-III, but maybe i just didn't get a good enough dark & transparent night!  Will try again soon i hope

I think these are the regions I am detecting with the O-III: interested if anyone else sees them with/without a filter.  Its a wonderful target.

Apologies for the crude drawing on top of the beautiful Hubble image:

[John]

Guess what my first target is going to be when I next have the 12 inch dob out ? - the Cats Eye with the Lumicon O-III filter

[Don Pensack]

40 minutes ago, John said:

Guess what my first target is going to be when I next have the 12 inch dob out ? - the Cats Eye with the Lumicon O-III filter

Just be aware that if you use magnifications above about 15x/inch of aperture, your best view will be without the filter.

The contrast enhancement at high powers is very minor, and the dimming of the nebula more important when the magnification is large.

My best view of the Catseye has been at 493x in the 12.5" but without a filter.

[niallk]

1 hour ago, John said:

Guess what my first target is going to be when I next have the 12 inch dob out ? - the Cats Eye with the Lumicon O-III filter

And i'll be trying again sans-filter!! 😂 

Interesting comments too @Don Pensack thanks!

[John]

57 minutes ago, Don Pensack said:

Just be aware that if you use magnifications above about 15x/inch of aperture, your best view will be without the filter.

The contrast enhancement at high powers is very minor, and the dimming of the nebula more important when the magnification is large.

My best view of the Catseye has been at 493x in the 12.5" but without a filter.

Up to now I have not used a filter on this target either. Generally I prefer not to use filters unless they are going to make a sigiificant difference. But it is fun to try new things out

 

[Barry-W-Fenner]

Hi all.
Thanks for all the sound advice provided, it's appreciated.

My astrozap light shield is due tomorrow so I look forward to fitting it and seeing the difference.

I have also been reading another thread about collomating a 300p and the short cheshire eye piece came highly recommended. I have ordered one as I don't fully trust my laser.

I had a brief session with my 200p last night and had a look at Arcturus, it looked very similar to my 300p images, just much smaller. As expected the 4 defraction spikes were present but the  main difference was there was no big point of light running through the star. Next Time I get the 300p out I am going to let it cool longer. It is also possible that it could have been an artifact from the camera,  I will have a look to see if it is there with the naked eye.

I also checked the focuser position on the 200p and the tube is roughly about 1cm further in the tube than what my 300p would be, based on that I'm  guessing there is nothing wrong with the way the 300p is focusing? I look forward to trying out the above to see what difference it makes!

Im liking the pics of the cats eye above, I'm predominantly getting the central star and the oval shaped nebula running from 9 to 3 o, clock, and also some of the  nebula at 12 o'clock. I haven't seen any of the larger outer ring yet though . Perhaps when the scope is fully tuned and darker sky's return?

 

Thanks again all.

 

Baz

 

Edited June 17, 2020 by Barry-W-Fenner

[John]

I have some telephone cables that run across my garden. Occasionally I've noticed a new bright diffraction spike on a star only to find that one of those dratted cables has strayed close to the field of view

 

[Louis D]

21 minutes ago, John said:

I have some telephone cables that run across my garden. Occasionally I've noticed a new bright diffraction spike on a star only to find that one of those dratted cables has strayed close to the field of view

 

Thankfully, we have buried utilities in our neighborhood, so that's never been an issue for me.  On the other hand, we'll never get gigabit fiber optic internet because it would mean tearing up everyone's backyards to install it.  So, we're stuck with twisted pair DSL and coax cable internet.

[Barry-W-Fenner]

A little update for you all.

I set up the 300p last night with the intention of getting some observing in. The Scope was out cooling from about 8pm. I fitted my AstroZap light shield and collimated with my laser as I am still waiting for my short Cheshire eye piece to arrive. 

I set up in a different position in the garden today and had a look at Vega. Again it looked very good as previously. A bright white circular image, The 4 defraction spikes were visible as was the same line going through the center of the star. I unfocused until Vega was a doughnut and noticed that the washing line was just creeping across the unfocused image! Needless to say the washing line is now laying on the grass and I need to go sort that out shortly 🙂 However when focused on Vega, No extra line going across! Thanks you @John for putting that one into my head!

I let Vega drift across the FOV and it was stunning, Until I got to about the last 3rd of the way across. Then small lines of light started to appear from the edge of the star which I assume would be from the scope/eye piece combo?

By 10.30pm still only Vega & Arcturus visible! The wind had picked up, Clouds started rolling in and I was falling asleep while waiting for darkness! Its been a very busy week with work so I ended up packing up and hitting the sack. Not an ideal session but certainly good to learn a couple of things about the scope.

I have flocked behind the secondary mirror, Put my Dual speed focuser on along with the right angle finder and the scope is now getting to how I want it. I am wondering if it is worth flocking the bottom half of the tube or just leaving?

I havent had a huge amount of viewing time with this scope yet, However the time I have had at the eye piece I have been very impressed with the results so far, Even with a couple of niggles to resolve. The scope it self is of very nice quality, I am particularly impressed with the az bearing that comes with this scope, It really does glide freely and I would quite like to purchase the roller bearing kit for my 200p!

If the weather is good I might try to get up at 1-2am for some views of Jupiter & Saturn!

 

Thanks all.

Baz

Edited June 19, 2020 by Barry-W-Fenner

[John]

The washing line might have been enough. Veiwing a star when it is  near a hard edge such as a roof roof ridge can do the same.

[ian2]

Hi, did you pick up any eyepieces, and if so how are they performing? I’ve got the same scope!

[Barry-W-Fenner]

On 10/07/2020 at 19:00, ian2 said:

Hi, did you pick up any eyepieces, and if so how are they performing? I’ve got the same scope!

Hi Ian.

I haven't purchased any new eye pieces yet. I am  quite interested in picking up one in the Morpheus range at some point. I am quite pleased that I decided to hold off for the time being to get some experience with my current eye pieces. Unfortunately that hasn't happened as the weather has been so poor over the last month.

Regards

baz

 

[Louis D]

Any idea what focal length(s) you're leaning toward?

[Ricochet]

If it was my decision I would start with the 12.5mm. Start with/spend the most on an eyepiece that will give an exit pupil in the 2-2.5mm range and then work from there.

[Guest]

13 hours ago, Barry-W-Fenner said:

Hi Ian.

I haven't purchased any new eye pieces yet. I am  quite interested in picking up one in the Morpheus range at some point. I am quite pleased that I decided to hold off for the time being to get some experience with my current eye pieces. Unfortunately that hasn't happened as the weather has been so poor over the last month.

Regards

baz

 

No kidding, it's been bloody awful up here! Do those range of eyepieces change shape? 🤔🤣

[Barry-W-Fenner]

12 minutes ago, merlin100 said:

No kidding, it's been bloody awful up here! Do those range of eyepieces change shape? 🤔🤣

Yeah seriously poor viewing recently. It was nice to get out and have a look at The gas giants and a few bits at 3am this morning. No joy with the comet for me though. My NE is the worst area for me, All house roof and trees in that direction..

I left the scope outside and managed a look at the moon at 6am as well. It was very clear and showed some excellent detail against a clear blue sky!

If someone could invent a morphing eye piece they would sell like hot cakes! All focal lengths in one! 🙂

Baz

[bomberbaz]

1 hour ago, Barry-W-Fenner said:

Yeah seriously poor viewing recently. It was nice to get out and have a look at The gas giants and a few bits at 3am this morning. No joy with the comet for me though. My NE is the worst area for me, All house roof and trees in that direction..

I left the scope outside and managed a look at the moon at 6am as well. It was very clear and showed some excellent detail against a clear blue sky!

If someone could invent a morphing eye piece they would sell like hot cakes! All focal lengths in one! 🙂

Baz

Hey Baz, how's it going.

Just a quick one re NeoWise. It is currently becoming visible slightly to the NW and moves accross to the NE later on passing North at around 1pm.

You will only see it if you can get a view that gives you the bottom 10 degrees of altitude. For me this means looking from a bedroom window to gain the height above my neighbours roofs which thankfully are on a slight gradient below me so gains me a couple of feet and allows me to see it throughout the night. Hope that makes sense.