What eyepieces for F/4 scope?

[Major]

Thank you for heads up about laser collimator Charic!

I have just made collimator cap from top cap of my Barlow and tried collimation, but to my surprise the primary mirror came out and is attached to the bottom of the scope. So far the only way of adjusting it was applying some pressure (very delicate) before tightening screws back. Now it all seems straight, but will need more time after work tomorrow, just to make sure it's all good.

[John]

Sounds like you undid the 3 screws around the edge of the bottom part of the scope. This is what holds the mirror cell (the bottom part of the scope) into the tube - as you now know !

The collimation screws for the primary mirror are usually on the bottom end of the scope but sometimes hidden behind a circular plate which Skywatcher use on some models to keep dust off the mirror and mirror cell. However, I seem to recall that this model does not have collimation screws for the primary mirror - collimation adjustments are made only to the secondary mirror I think.

My advice right now is to get the mirror cell that holds the mirror back onto the scope tube ASAP and then not to try adjusting the collimation for the time being. Collimating an F/4 newtonian is quite a delicate business and it's easy to get things out of alignment rather than to make them slightly better aligned.

 

 

 

 

[Major]

That's exactly what I did John. I've misplaced user manual somewhere, so to avoid any damage I've put everything back together as soon as I realised I won't do anything. On the positive note - cleaning primary mirror will be as easy as it can get .

Now I managed some daytime test of the Vixen. I'm confused a bit cause stock 10mm seems to be sharper. Not a lot and I have to look for few seconds to notice, but still it is noticeable. What is even more noticeable is that 10mm has wider area in the middle that stays sharp. All is even more visible with stock Barlow. So now my questions are

Is this normal? I mean, after all Vixen gives me 50x magnification, 10mm - 40x, does it have any impact on overall sharpness?
Is it possible that something is wrong with glass inside? Eyepiece looks fine to me, but have to ask.
I know Heritage is a fast scope, but would Vixen perform better on slower scopes?

Thanks in advance.
Tom

[Timebandit]

Hello. I have a high a vixen NLV and in my fast acting scope I was not overly impressed with the overall views. But when it was placed in a slower scope then it performs very nicely. To my knowledge I don't think the vixen are recommended for scopes at F/4 , and that's why I suggested televues. Televues are tested down to F/4 so IMO I have not had any problems with televues in fast scopes to F/4.

I think you had some collimation issues. Do make sure your collimation is set up and accurate as this will have an effect on the view you get through the eyepiece. If in doubt you can always do a star test to double check.

I hope the above helps☺

[Major]

It does indeed, thank you.

To be sure will find user manual and do it as it should be done, then will get back with results.

As to the eyepieces, will see how far can I push mrs on Friday, birthday is coming . Shown her plossl 8mm for under 100 and she didn't say no, so fingers crossed .

 

[Charic]

I can't find a user manual? but there is a sponsor video of the product  https://www.youtube.com/watch?v=u-JjxAFsEIU but at no time does it show the base cap removal, so I cant see whats available to you from within inside, regarding adjusters for collimation, but will agree with John , that it may not be the case, that you only need to align the secondary, with the primary fixed?

[Major]

@Charic

I couldn't find online manual as well, but luckily had printed version, still can't find it though and there is a possibility that mrs has already packed it...

Looks like John might be right as after removal there was absolutely no adjusters at all - mirror is fixed to the plastic bottom, I would guess with some sort of glue. If that's the case, I will wait with collimation till next week, after move will do it without rush.

[Timebandit]

1 hour ago, Major said:

It does indeed, thank you.

To be sure will find user manual and do it as it should be done, then will get back with results.

As to the eyepieces, will see how far can I push mrs on Friday, birthday is coming . Shown her plossl 8mm for under 100 and she didn't say no, so fingers crossed .

 

 

Hi Major. It might be worth looking out for a second hand one. As they do come up from time to time. I recently got myself a second hand televues 8mm plossl at very sensible money from a fellow SGL member. And even though televues IMO are very good and are tested to my knowledge to F/4 ,since the recent price hike they have become very expensive and overpriced IMO. As i said try to look for a second hand one on here or possibly ABS, or maybe a wanted add.

I hope the above is helpfull☺

[Charic]

Yes, no rush, that's the key.
If when you look down the focuser, you can see that the secondary mirror appears circular, and equidistant from the circle of view that is formed by the edge of the focuser tube, you should be good to go. Then given some time for the scope to cool, line up on the North celestial pole, Polaris ( as it won't drift out of view) then whilst looking at the Star through an eyepiece, de-focus the Star in either direction? Your looking for a blurred image of the Star, but in-fact you should see a series of concentric rings / bands of light from the Star. If this all appears concentric, you scope is good, its collimated, If not, then take your time, and micro adjustments are all that's required, but unless you have dropped the scope somewhere, it should be ok, from leaving its box!

[Major]

Wow, once again thank you. @Timebandit for heads up and @Charic for detailed instructions!

Will do this test as soon as sky is clear. It was nice when I was at work, but now all I can see is thick layer of clouds and it doesn't look like anything will change tonight...

[Major]

Just a little update

I couldn't help but wonder, how would Sky Watcher UWA Planetary perform in my scope. Still cheap EP, but curiosity was growing since 6 am, so straight affter work I rushed to RVL to get one .



My initial thoughts after daytime test are very positive. EP is much more comfortable to use than little Vixen and has an eye cup, regarding sharpness I can't complain at all, it's the sharpest bit of kit I currently have.

That's it for now, I halt all spending on astro gear! At least till my birthday 

Edit:

Just checked cloud cover forecast... That deffo is the saddest part...



Edit 2

I have spotted Deneb not long ago, only had few minutes window, but saw tiny patch of clear sky. Did the star test and scope does require collimation.

[John]

The SWA planetary will feel more comfortable than a plossl because the latter design has short eyerelief (around 80% of the focal length) wheras the former has quite a bit more and a larger eye lens and field of view as well. All factors that add to viewing comfort.

I've never read that the Vixen NPL's are corrected to work down to F/4 but I have read that they use a similar optical "tweak" to the lens curvature that the Tele Vue plossls do. I compared the 30mm Vixen NPL to a Tele Vue 32mm plossl and the TV was indeed slightly better but there is also a price difference of  £90 between the two so I thought the Vixen did pretty well for it's cost.

Just a little word of warning - eyepieces that work excellently at F/4 are great but an F/4 newtonian produces it's own abberration called coma which will be apparent towards the outer part of the field of view (it's always the outer part isn't it ! )

It should not be too much of an issue with 50 degree field eyepieces but well corrected wide angles will show it - you can't win can you ?!

 

[Major]

Not really .Once again thank you for another bit of valuable info @John.

Speaking of comfort... Is it worth to upgrade finder on my scope? That red dot is just nasty - searching for some objects directly above me makes me go mad. Something light, conventional, with reticle, angled would be perfect...

[Timebandit]

9 minutes ago, Major said:

Not really .Once again thank you for another bit of valuable info @John.

Speaking of comfort... Is it worth to upgrade finder on my scope? That red dot is just nasty - searching for some objects directly above me makes me go mad. Something light, conventional, with reticle, angled would be perfect...

 

Hi. Get a telrad.they are just great, use mine all the time. Quick efficient and sensible money?

Or just a standard 90% angled one ,makes so much easier when approaching zenith. Or be greedy like me and have both.?

Hope the above helps☺

[Major]

3 minutes ago, Timebandit said:

 

Hi. Get a telrad.they are just great, use mine all the time. Quick efficient and sensible money?

 

Hope the above helps☺

Which Telrad do you have in mind @Timebandit? From what I see these look like stock finder that I have...

[Charic]

Will a Telrad fit comfortably on the little H100 and  i find it works better if your behind it, rather than just twisting your neck to peer through it! 

I stopped using my Telrad, but soon bought another?  but  have never used it since!  even though  its a permanent fixture to the scope. 

If you had a wide angle eyepiece, that would be just  good. I have the Panaview 70° afov, which helps, but to be honest now, I much prefer the dtaight through 9x50 scope, viewed through keeping both eyes open! works a treat, even searching overhead at my zenith.

[John]

Angled illuminated reticule finders are a little thin on the ground. You can get a 90 degree mirror / dew shield attachement as an add on for the above mentioned Telrad. Or there is always this from Tele Vue (at great expense it has to be said !):

http://www.telescopehouse.com/accessories/finderscopes/starbeams-set-televue.html

Here is the Telrad and (separate link) it's 90 degree / dew shield add-on:

http://www.telescopehouse.com/accessories/finderscopes/telrad-red-dot-finder.html

http://www.telescopehouse.com/accessories/finderscopes/telrad-dew-shield-with-mirror-for-90-deg-viewing.html

The Telrad projects 3 rings apparently against the sky rather than the single dot. Because the rings are a known apparent diameter this helps with star hopping. It's a big device to fit on a small scopes tube though, IMHO

I think I'd probably go for a Rigel Quikfinder on a small scope (it projects 2 rings but otherwise is similar to a Telrad):

https://www.firstlightoptics.com/finders/rigel-quikfinder-compact-reflex-sight.html

I use a Rigel unit on my 12" dob together with a 9x50 right angled optical finder and the combination works really well.

Actually in all honesty I'd probably make to with the supplied red dot finder and save my £'s for a larger scope in due course

 

 

 

[Charic]

Another issue with the Telrad for some folk like me, when you look through the Telrad, the image is not magnified, you see the real thing, with three concentric circles as described by John, and on the telrad site.
The problem I have, is that there is about 9 rings all overlapped?  which is an issue unless I wear my prescription glasses. Although you don't actually focus on the screen, you look through it to infinity ( and beyond.sorry Buzz!)  the  reticule appears to be projected onto the sky around your target. I cant focus on a Star and see the rings clearly, unless I wear my glasses. This may not affect everyone, but affects my use. From a darker site whereby its possible to not see the 9x50's reticule against the black sky, then the Telrad would suffice, the only reason to keep it at present.

I have said in several threads on SGL, my weather here has been total pants this year, yet I still  need to go out, to one specific site I have in mind ( no lights for miles) just to fully assess my needs and requirements from the kit I posses already?
I should be favouring my Delos at present,  but no?,  should I flock the scope for to help better the contrast and alleviate some of the light pollution, not sure! should I fit Bob's knobs, who knows?, should I keep this Telrad,  it hardly gets used,  and folk will buy them, when they become available , and should I drive some distance to collect the 300P that I desire, and will it better the present scope from the exact same site/conditions, it should do? 

The tests should  stop my impulse buying though I need two more Revelation Astros to complete my Plössl set,excluding the 40mm. If the Delos stay Ill get the next three longer focal lengths, If not there's cash there to complete some other purchases? 

[Timebandit]

7 minutes ago, Charic said:

Another issue with the Telrad for some folk like me, when you look through the Telrad, the image is not magnified, you see the real thing, with three concentric circles as described by John, and on the telrad site.
The problem I have, is that there is about 9 rings all overlapped?    

The tests should  stop my impulse buying though I need two more Revelation Astros to complete my Plössl set,excluding the 40mm. If the Delos stay Ill get the next three longer focal lengths, If not there's cash there to complete some other purchases? 

 

 9 rings overlapped?   I think Charic you must be having to many whiskey or vodka shots to warm you up on these cold observation nights ??

 

And as for eyepieces, The trouble is I think you have not found a eyepiece range that you are completely satisfied by the sounds of things? Ever that or like me a bit of a collectionist? but at least that way you find out if something works for you first hand and if not move on. Saying that I am starting to get some nice eyepieces that work for me IMO so trying certainly works for me☺

[Major]

7 minutes ago, Charic said:

Will a Telrad fit comfortably on the little H100 and  i find it works better if your behind it, rather than just twisting your neck to peer through it! 

I stopped using my Telrad, but soon bought another?  but  have never used it since!  even though  its a permanent fixture to the scope. 

If you had a wide angle eyepiece, that would be just  good. I have the Panaview 70° afov, which helps, but to be honest now, I much prefer the dtaight through 9x50 scope, viewed through keeping both eyes open! works a treat, even searching overhead at my zenith.

That's exactly what is so annoying - all the neck twisting and strange positions while using finder. B
 

15 minutes ago, John said:

Angled illuminated reticule finders are a little thin on the ground. You can get a 90 degree mirror / dew shield attachement as an add on for the above mentioned Telrad. Or there is always this from Tele Vue (at great expense it has to be said !):

http://www.telescopehouse.com/accessories/finderscopes/starbeams-set-televue.html

Here is the Telrad and (separate link) it's 90 degree / dew shield add-on:

http://www.telescopehouse.com/accessories/finderscopes/telrad-red-dot-finder.html

http://www.telescopehouse.com/accessories/finderscopes/telrad-dew-shield-with-mirror-for-90-deg-viewing.html

The Telrad projects 3 rings apparently against the sky rather than the single dot. Becuase the rings are a known apparent diameter this helps with star hopping. It's a big device to fit on a small scopes tube though.

I think I'd probably go for a Rigel Quikfinder on a small scope (it projects 2 rings but otherwise is similar to a Telrad):

https://www.firstlightoptics.com/finders/rigel-quikfinder-compact-reflex-sight.html

Actually in all honesty I'd probably make to with the supplied red dot finder and save my £'s for a larger scope in due course

Thank you for all links. That finder from TV looks the part indeed, but last option sounds very sensible too.... Guess I will try and just get used to red dot I have now, instead of upgrading 100P.
 

6 minutes ago, Charic said:

Another issue with the Telrad for some folk like me, when you look through the Telrad, the image is not magnified

(...)

The tests should  stop my impulse buying though I need two more Revelation Astros to complete my Plössl set,excluding the 40mm. If the Delos stay Ill get the next three longer focal lengths, If not there's cash there to complete some other purchases? 

I don't wear glasses (still can read plate from 20 meters...), but lack of magnification is also very valid point.

However, last paragraph of your post seems to sum me up perfectly... Eyepieces, finder, later maybe focuser (it's not the smoothest, I swear I need a new one! ), could have as well waited and get 200P. It's not that I am not happy with what I have, cause I am but some things could be improved . On the other side I would risk a guess that as soon as I get bigger scope, 100P will only be used by my daughter and only useful bits of kit will be eyepieces (I hope).
 

3 minutes ago, Timebandit said:

 

 9 rings overlapped?   I think Charic you must be having to many whiskey or vodka shots to warm you up on these cold observation nights ??

 

And as for eyepieces, The trouble is I think you have not found a eyepiece range that you are completely satisfied by the sounds of things? Ever that or like me a bit of a collectionist? but at least that way you find out if something works for you first hand and if not move on. Saying that I am starting to get some nice eyepieces that work for me IMO so trying certainly works for me☺

That would not work too well, I mean after all alcohol is cooling you even more ...

I don't think I found the ideal EPs yet, but let's face it - only ones I had contact with are stock, one Vixen and one SW (which after daytime test I think I like), not really many to have favourites ....

[Charic]

21 minutes ago, Timebandit said:

And as for eyepieces, The trouble is I think you have not found a eyepiece range that you are completely satisfied by the sounds of things? 

Lol........You may have missed one  or two of my posts  regarding eyepieces! and although Whisky is not my tipple of Choice, I have discovered  that the  Glenfidich  Solera 15Yr Malt does warms you up on a cold -7 and below, in my neck of the woods? 

To be honest Timebandit, the first ever eyepiece I purchased was the 8mm Starguider. simply stunning for the value as a first upgrade, and the views are just perfect for my needs on an f/6 scope.
That said I always wanted a Plössl set, and tried the 8mm TV. Not for me, eye-relief too tight. But hey! what about these Revelation Astros. They leave my Televue and Meades standing ( through my eyes at least, under my light polluted garden) but Guru John has guided me somewhat in a few PMs, and their is more testing to do? The delos, well TeleVue has always been in the back of my mind,  as the best there is, from written reports and advertising? but since owning my first one the 8mm, why do I not see £300 worth of improvement, its just not there ( my eyes alone) , and I have always said from the start why do  you need a premium eyepiece of such high value when my £49  EP does the same. It dont make sense? I have sufficient funds to have bought  the Televue Plössl's right from the Start, as for some reason< its fixed in my mindset that I needed a Plössl set. The 8mm failed my expectation, precluded buying the full set, so ventured around to buy some Meades, but now  I have two, almost complete eyepiece sets and very, very  happy with both sets, The Starguiders and the Revelations. I still may try the 8mm TV again, in the future, but why when a £9 Revelation? does just as well! The Starguiders are unfinished, to my mindset, as I cant own a 6mm!  That would just make me happier and the set complete, to match my f/6 scope! The Delos  EP's were purchased just to try them for comparison against the Starguiders ( not sure my good friend would send me  any more TeleVues in the post to trial? how trusting is that, amazing, will always be thankful for the gesture GD! )  and also  last Christmas,  I'd  hoped of obtaining a 300P Classic, whereby the TV's would be more than  capable (so I'm informed) should the Starguiders fail on such a fast scope, but  the EP's came first,  very cheap too. I know their RRP and second hand prices are easily £200 but I  paid far less, and wont pay any more. In-fact money has been  ready for the next one,  for some time now, but through a chance viewing on Astroboot, I have secured some new Binoculars, again just to trial them? They should better my Revelations in some respects although they are the same  15x70's, its inside what matters? and if they dont impress, or show any major change in whats already achievable from the present 15x70s under the same conditions, I know the new new bins will sell well, as folk are keen to own them?

As you quite rightly suggest, its personal  and very subjective, and can create some interesting feedback, when we get excited! as to what is right for us, but  every eyepiece will give  different results,  being telescope and focal length dependent, and each user will see or not their greatness or faults in the chosen eyepiece. Like I said, I just wanted to test and learn, why the TV Delos were so well regarded, and since owning them and studying the technical aspects, they were not only produced to equal their Ethos EP's but to enhance the user friendliness of any Plössl eyepiece, buy giving the user 72° afov and 20mm eye-relief. And I have the optin to continue using the telescope with or whithout my prescription glasses, or invest (to test) in a 1.0 Dioptre Dioptrx lense, to see if that improves the overall image, contrasrt, sharpness ect for these old eyes! and if they do, like I said, the rest of the Delos may be required, but then what for my beloved Starguiders? it will be a sad day!
I wanted a very cheap system that does the job, the Starguiders are my No1 choice, having tested the 8mm TV, my Meades against my first revelation, I have settled on my Revelation Astro [GSO] Plössl's as my second choice of recommended eyepieces for this type/size Skyliner.  the results are brilliant. The images  of Jupiter still remains small,  in the 60° but that's image scale, down to my scope, one reason to get me the 300P! Phew!

[Charic]

1 hour ago, Major said:

.......On the other side I would risk a guess that as soon as I get bigger scope, 100P will only be used by my daughter and only useful bits of kit will be eyepieces (I hope).

That would be perfect if your daughter could use the 100P or maybe some 7x50 Binoculars, With them she could see large swathes of the Sky, and once she knows what a Satellite looks like, she could follow them EVERY night as long as there's no clouds in the way. The binoculars will just show so much many more Stars that the eyes just cannot see, and the Moon will look good too. Teach her( how old?) to hold them steady or better still, rest/mount/balance them for a crystal sharp rock steady image(  the image may be  better view than  view from the 100P?)

As an upgrade to the 100P the 200P will blow your sock off, then when you look again, you'll lose the other! and  if/when aperture fever kicks in again (more expense!) then a 250P or higher may be warranted.

Cheaper than a  premium eyepiece alone?  the 200P offers a lot for your money.

https://www.firstlightoptics.com/beginner-telescopes/skywatcher-skyliner-200p-dobsonian.html

This one sits on the floor, and from a seated position, yes you still have to twist your neck a little to get onto the eyepiece, but you can get a corrected vision finder-scope, that many folk recommend. I have never tried one myself.

[Major]

Of course I will let her use the scope as much as she likes (within common sense of course). She seems to be very interested in space in general and I really don't want to kill it. Now she's 7 yo, so would manage some light binos but if not, I still have two or three photo tripods that she could use. When I was gazing with binos, she was a bit too small to hold steady 16x50, but getting her some smaller/lighter stuff could work perfectly.

That is exactly the scope I am looking at from quite long time now. And I will have it in near future .

PS. No idea why I took second part of of Timebandit's post as addressed to me....

[Charic]

The younger generation have wider pupils, so matching a Binocular to the pupil size allows for better light transmission and a brighter image. 7x50s should be light enough for her to hand hold. Lay her in a duvet or sleeping bag with you nearby, She'll keep warm and interested, and if partially reclined on a sunbed, or lounger, she can hold and rest the binoculars over her eyes without too much of an issue. If your both in the same scenario, looking up at the sky, use the 'Clock' method for identifying objects quickly?  If you should see a Shooting Star, to your right, just shout 3 oclock, and she should look in that general direction, to see the remains/last few seconds of the meteors trail?

[Major]

Some good ideas here, will test them as soon as I can, thank you.