Eye piece advise for 300p

[Barry-W-Fenner]

Evening all.

After touching on this topic in my other thread, I though it might be wise to ask this question officially in the correct place 🙂

First I will give a quick low down, I managed to get some time at the eye piece last night with the 300p from about 10pm to 12.30am Despite not having the ideal equipment for this scope, conditions being very misty with intermittent cloud and of course no astro darkness, I was totally amazed at the views provided. 

My collection of BST's are in this scope more miss than hit unfortunately. To my eye the lower powers of the larger focal length along with the  high powers of the 5 & 3.2mm all gave less than ideal views.

However the mid range powers provided by the 8,12 & 15mm were surprisingly good inspire of them only really providing a clear image over approx 2/3rd of the FOV. Without  going into to much detail here Vega & Arcturus were both beautiful spheres of white & soft Orange light. with the 8mm - x187

The cats eye Nebula was simply jaw dropping. I am used to seeing this as a Green oval shape but in the 300p with the 15mm providing x100 mag I could see the actual green structure with various layers to the nebula, The central star was also constant. I was so impressed with this I dragged the wife out for a look 🙂

I am now looking to purchase an eye piece more suited for this scope and am looking at one of the Baader Morpheus range thanks to the advise provide by members on here. I will only be able to purchase one and for the moment this will have to cover my asto needs. As this eye piece is going to be my workhorse I would like to find a middle ground fora combination of viewing planetary nebula, Globs, Planets and stars. Being that I had some very enjoyable viewing between x187 down to x100 I was hoping for some advise on what FL Morpheus to buy.  I am thinking along the lines of either the 9mm to give x166 but also the 12.5mm which will give x120 and might be better suited to all round viewing?

I would appreciate any advise from experienced members with these FL in a 12" dob please.

Its worth bearing in mind I have 3no BST eye piece in the range that performed admirably that I can use for the time being. I also have the 30mm Aero ED for low power wide field which I am hoping to use tonight.

Thanks all.

 

Regards

Barry

 

[John]

I'm sure others will give you good advice Barry - I don't use the Morpheus eyepieces but they do seem to have quickly gathered a lot of fans.

I think you are right that the middle focal lengths are the best ones in the BST Starguider range.

I'm glad you are impressed with the views through your 300P. Wait until you see Messier 13 at around 150x !!!

 

[bomberbaz]

Glad you enjoying the scope Baz. TBH I thought the 3.5 & 5 would have done better than you say, however you may find this was down to the not so good skies and the fact you would be really pushing the magnification at x300 & x430 under poor conditions

I know I signposted the morpheus to you although as I said back then it was based on reviews I had read and price and not personal experience.

I do agree that getting a eyepiece in the middle ground will serve you well first and either 14 or 12.5 are the ones I would consider.

I look forward to reading a review if/when you do eventually get one.

Steve

[Don Pensack]

Barry,

There will be coma visible in this instrument as long as you don't use a coma corrector, so NO eyepiece will be perfect to the edge.

I assume this is a SkyWatcher Flex-Tube dob with a 1500mm focal length, as such, f/5.

Normally, a complete set of eyepieces for the scope might be 60x/120x/180x/240x/300x

That would be focal lengths of 25mm, 12.5mm, 8mm, 6mm, and 5mm.  Your current set lacks only a 6mm, so the jump from 8mm to 5mm is a big one.

That is not set in stone.  A more minimalist set might be 21mm, 11mm, 7mm, 5mm.  A more maximalist set 30mm, 25mm, 20mm, 15mm, 12.5mm, 10mm, 7.5mm, 5mm, 3.5mm

You have all the eyepieces you need, though there are eyepieces with wider fields and sharper image quality in the outer field (taking into account that coma will make stars in the outer field distorted

so no eyepiece will be perfect).

With that aperture, it is unlikely you would want or need more than one eyepiece to yield a magnification under 100x.  Likewise, if you need eyepieces above 300x, it's just as desirable to 

get there by adding a Barlow lens to a lower power.

Any eyepiece shorter than 7-8mm will be limited by the seeing conditions, so whether you get sharp stars won't likely be determined by the eyepiece.

Any eyepiece longer than 15mm is also less likely to be used except for the largest of objects, and, even then, you'll likely go higher to investigate details more.

"Planetary" eyepieces will be 7-8mm and shorter.

Highest visual acuity and best overall views will be eyepieces from 10mm to 15mm (2-3mm exit pupils).

Low powers will be 12.5mm and longer eyepieces.

It looks like you don't need long eye relief for glasses, so just about everything will work.

 

I have a 12.5"(31.8cm), but the focal length is 22% longer than yours, so my eyepieces are a little different.

I have a "maximalist" set of 30, 22, 17.5, 14, 12.5, 11, 10, 8, 6, 4.7, 3.7mm focal lengths.  I would note that the seeing conditions at my normal sites are very good, so 300x is always usable and sharp.

Note also that some of the magnifications are a bit close together, so I tend to break the focal lengths down into "sets"--one for poor seeing, and one for good seeing.  So it's really more like a set of 5 and a set of 6.

And, truth be known, I sometimes spend the entire night using only 2 focal lengths--especially if all my targets are small and faint.  So it's normal you might have a night when you use only the medium powers (120-240x on your scope),

and another night mostly lower powers (50-120x).  It will depend on the seeing, and the targets, as to which focal length is best.

 

P.S. The Catseye nebula will be incredible in your scope with > 200x, or a shorter focal length than 7.5mm.  The amount of detail will be leaps and bounds above what can be seen at 100x.

If looking at the Morpheus, I recommend the 12.5mm for starters.  I think you will use it a lot and it hits a point of high visual acuity (2.5mm exit pupil)

 

[Louis D]

I have the 9mm Morpheus and find it to be nearly the equal of my 10mm Delos, just with a wider AFOV.

The 14mm is nice, but has some field curvature and astigmatism in the last 15% of the field.

My understanding is that the 12.5mm, which I don't have, is somewhere in between performance wise.

 

[bomberbaz]

See below the simulator for the 12.5mm morpheus. Frames M51 very nicely and gives you 10x magnification per inch. I think it's a very good starting point as Don says.

Since chatting with one of the members on here ref; viewing galaxies I have done further research on viewing them and it seems 10X magnification per inch of aperture or there abouts gets mentioned a lot.

[John]

12-13mm is a nice general purpose focal length for a quality widefield eyepiece. I think that is why 13mm was the focal length that the first Nagler came out in and years later the first Ethos as well.

 

[Barry-W-Fenner]

Thank you all for the informative advise, I really appreciate it. I will read over these comments again tonight to refresh my mind and reply 🙂

I am quite keen on the 12.5mm Morpheus now going by the above!

 

Baz

[John]

The trouble is Baz, you get a sort of "domino effect" when you get one particularly nice eyepiece in your collection ........ it's a slippery slope

[Barry-W-Fenner]

26 minutes ago, John said:

The trouble is Baz, you get a sort of "domino effect" when you get one particularly nice eyepiece in your collection ........ it's a slippery slope

This is very true John, Look what happened to me with the BST range 🙂

On a "positive" note though I dont think I am going to be in a position to purchase another high end eye piece after this initial one for quite some time. That is why I am trying to find a middle ground and get a FL that will me quite versatile. However I do understand that there is no one size fits all in this game. hence why I am asking this advise. 

Long term I am going to do my best to purchase 3-4 high end eye pieces and stick with them, As you have mentioned though this is a very slippery slope 🙂

Thanks

Baz

 

[Barry-W-Fenner]

Hi all.

I have been having a think today and am unsure if i should go for the 9mm or 12mm Morpheus.

As pointed out above the 12.5 will give around x120 or x10 per inch of aperture which is a nice benchmark for Galaxy hunting apparently.  (I wouldn't know because i am useless at hunting galaxy's down 🙂 ) My preferred objects to view are Planets,Planetary Nebula, Glob & open clusters. These seem to be where I am getting the most viewing enjoyment. I also enjoy double star viewing. With that in mind would I be better off with the 9mm as it would give x166 magnification and hopefully show some great detail in these targets at a medium power.

 

On the subject of double stars. I attempted the double,double in Lyra with the 3 BST eye pieces that work ok in the 300p - I could not split them at x150 or x100 they were clear but the split would just turn into two oval shaped points when i focused on them.

I assume this is an example of the BST'S not being ideal for a 300p as i can split the double double with these eye pieces in the 200p

 

Thank you

[bomberbaz]

may be worth just hanging fire baz and using the bst's until you find out where your niche is going to be for the time being.

You might end up with a kind of buyers remorse otherwise. 

[Barry-W-Fenner]

28 minutes ago, bomberbaz said:

may be worth just hanging fire baz and using the bst's until you find out where your niche is going to be for the time being.

You might end up with a kind of buyers remorse otherwise. 

Thanks Steve,

I am hoping to get out tonight again to give the bst range another try, As you mentioned above the high powers may perform better under improved sky conditions. I may also find that more of the range also perform well in the right conditions 🙂 

 

[Ricochet]

1 hour ago, Barry-W-Fenner said:

I assume this is an example of the BST'S not being ideal for a 300p as i can split the double double with these eye pieces in the 200p

Along with the poor image quality that you saw through the 5mm Starguider, which is one of the best two in my opinion, I think this is more likely a sign that the atmospheric conditions were not very good. Try again on another occasion and see if the same issue still occurs. If you have the double star you are trying to split right in the centre of view then you can probably discount any issue with an eyepiece.

[JOC]

19 hours ago, Barry-W-Fenner said:

Vega & Arcturus were both beautiful spheres of white & soft Orange light

Spheres of light - I was under the impression that most stars except Sol only gave points of light - were you in focus?

[Barry-W-Fenner]

18 minutes ago, JOC said:

Spheres of light - I was under the impression that most stars except Sol only gave points of light - were you in focus?

I believe so, I did note to myself that these two stars were the only ones which had this appearance. In my limited experience I put that down to them both being larger and brighter than than most other stars visible.  In the grand scheme of things anyway 🙂

All other stars did show as a points of light some looked ok and others not so. After taking on board the opinions on here I put this down to very poor skies rather than the eye pieces themselves.  Having said that, Even on a poor night i have never seen the Cats Eye look so good, It blew me away.

I am looking forward to another session testing the scope in hopefully better conditions.

It might also be worth mentioning that I haven't received my AstroZap Dew/Light Shield yet as they are on an extended lead time. I will be interested to see if this also helps with contrast and viewing.

Baz

[Guest]

Don't be so keen to divest yourself of the BST collection you have just yet, Barry.😉

[John]

The double double would be an easy split when the conditions are half decent.

Shows that they were not and probably accounts for the mediocre views with the 5mm BST Starguider as well.

The difference between your 200mm F/5.9 and the 300mm F/4.9 should not result in a "cliff edge" drop in the BST Starguiders performance. It will be more subtle than that and only really discernable in the outer 20% of the field of view really.

While eyepieces such as the Morpheus are a bit better you are into the law of diminishing returns from the Starguiders upwards I think. The big step is from the stock EP's to the Starguiders.

 

[Sky-searcher]

5 hours ago, Barry-W-Fenner said:

This is very true John, Look what happened to me with the BST range 🙂

On a "positive" note though I dont think I am going to be in a position to purchase another high end eye piece after this initial one for quite some time. That is why I am trying to find a middle ground and get a FL that will me quite versatile. However I do understand that there is no one size fits all in this game. hence why I am asking this advise. 

Long term I am going to do my best to purchase 3-4 high end eye pieces and stick with them, As you have mentioned though this is a very slippery slope 🙂

Thanks

Baz

 

As John mentioned it is a slippery slope. I purchased a used Morpheus 14mm for a great price as I liked the look of them & wanted to try it out. I was hooked as soon as I used it. I have so far ended up with a 9 & 6.5 also ( bought used). They are a fantastic eyepiece & will add to the set as I can, but don’t come up for sale used very often. I did see a set of 5 Morpheus for sale on ABS today, ad price a bit wrong ( says £45000, think it supposed to be £450 ). If it’s correct that’s a good price for them. 

[Barry-W-Fenner]

1 hour ago, John said:

The double double would be an easy split when the conditions are half decent.

Shows that they were not and probably accounts for the mediocre views with the 5mm BST Starguider as well.

The difference between your 200mm F/5.9 and the 300mm F/4.9 should not result in a "cliff edge" drop in the BST Starguiders performance. It will be more subtle than that and only really discernable in the outer 20% of the field of view really.

While eyepieces such as the Morpheus are a bit better you are into the law of diminishing returns from the Starguiders upwards I think. The big step is from the stock EP's to the Starguiders.

 

That's quite reassuring to hear John. I didn't really know how much the BST range would be affected by an F/4.9. I also didn't realise  how poor the viewing conditions had become until my neighbors  security lights came on and I could see the mist and moisture in the air. I was having to much fun viewing The Cats Eye 🙂 Hopefully tonight stays clear and I can see what the scope/eye piece combo is capable of! 

 

Baz

[Sky-searcher]

18 minutes ago, Barry-W-Fenner said:

That's quite reassuring to hear John. I didn't really know how much the BST range would be affected by an F/4.9. I also didn't realise  how poor the viewing conditions had become until my neighbors  security lights came on and I could see the mist and moisture in the air. I was having to much fun viewing The Cats Eye 🙂 Hopefully tonight stays clear and I can see what the scope/eye piece combo is capable of! 

 

Baz

Barry, I would persevere with the Starguider’s at present & not rush into buying anything yet. John is right in saying there isn’t a big jump between BST’s & the likes of Morpheus eyepieces like there is from stock to BST’s. I also have several Starguider eyepieces & can vouch for that. It shows how good they are for the money. Thanks Andy 

[niallk]

The Cat's Eye is a treat 8-9mm and 12-13mm should be good choices, and pushing the mag higher can be worth it too.

I was going to ask if you have an O-III filter?  With a 300mm mirror it could be a good call for planetary nebs.

[Barry-W-Fenner]

17 hours ago, JOC said:

Spheres of light - I was under the impression that most stars except Sol only gave points of light - were you in focus?

Morning Andy,

For reference this is what Arcturus & Vega look like at focus for me.

[JOC]

46 minutes ago, Barry-W-Fenner said:

For reference this is what Arcturus & Vega look like at focus for me.

Well not that I know huge amounts about these things, but they wouldn't look like that in my beginners system I'd see points of light, OK, bright points of light, but points of light nonetheless.  Those pictures have got more in common with something like Venus or another brighter planet (though it is bright even for saturn and not the right shape, even out of focus, for rings around a disc), but even then you shouldn't be seeing the diffraction spikes.  If you have no more travel left in the focusser to get pin-points of light have you got any necessary adapters etc. in place?  Have you perhaps upped the magnification too much and got to the point when all you are seeing is a hazey blob, or did you have dew on the mirror?  If that's what you are seeing, even in my experience as a rank amateur, that doesn't look correct to me.   Perhaps someone more experienced will be along to comment.  NB.  Andy is someone different 😉

 

NNB.  I too would stick with the BST's if you have them, your scope is somewhat similar to mine and the BST's should be ideal once you get the focussing sorted,

Edited June 16, 2020 by JOC

[Barry-W-Fenner]

28 minutes ago, JOC said:

Well not that I know huge amounts about these things, but they wouldn't look like that in my beginners system I'd see points of light, OK, bright points of light, but points of light nonetheless.  Those pictures have got more in common with something like Venus or another brighter planet (though it is bright even for saturn and not the right shape, even out of focus, for rings around a disc), but even then you shouldn't be seeing the diffraction spikes.  If you have no more travel left in the focusser to get pin-points of light have you got any necessary adapters etc. in place?  Have you perhaps upped the magnification too much and got to the point when all you are seeing is a hazey blob, or did you have dew on the mirror?  If that's what you are seeing, even in my experience as a rank amateur, that doesn't look correct to me.   Perhaps someone more experienced will be along to comment.  NB.  Andy is someone different 😉

 

NNB.  I too would stick with the BST's if you have them, your scope is somewhat similar to mine and the BST's should be ideal once you get the focussing sorted,

Thanks JOC.  I did think these stars were showing more like planets. Being inexperienced I assumed that it was down to the scope resolving them larger. I did note that all the smaller stars were producing more of a point of light but they are giving off a small spike on one side, If that makes sense.

I also did note that to gain "focus" I am using a large amount of back focus, It is not totally maxed out but not far off. Please see attached pic. I am using the 1.25 adapter for my BST Eye pieces and also the 2" adapter for my 30mm - I do feel like something is wrong to be honest. But having said that, I have enjoyed some great views of the Cats Eye?

Magnification wise these pics were taken last night with my 8mm BST x187 Mag. It was also dry last night so no dew forming on the mirrors.

One thing that might be a factor, When the scope arrive I swapped over the standard focuser to my Sky watcher Duel-speed model. on the standard focuser was the white spacer that can be seen in the pic between the tube and focuser. I put this on the back of my duel speed and reattached as I thought it would be requirement on the 300p. Perhaps I dont need this spacer with the duel speed model?

 

Sorry for the mistaken identity! Thanks for your input JOC, Its greatly appreciated.

Barry