Don Pensack

On 28/03/2020 at 08:33, JOC said:

So probably as many folks have done I've coverted a full set of eye-pieces.  I've seen those beautiful and extortionantly priced boxes of green and black that many own and wished for similar, but I could never justify that amount of expense for what little observing I actually get to do.  However, from the eclectic assortment of cheaper EP's that I accumulated from SGL classifieds I realised I much preferred an EP with plenty of eye relief and a wider field of view.  I then got a chance on the SGL classifeds board to buy a Baader Morpheus 14mm at a good price.  What a difference - this really seemed to be a great thing and on the moon it was terrific.  I wanted more - the trouble was they were mostly upwards of £190 a pop sometimes clearing the £200 mark depending on the seller - I couldn't afford them.  Then a second one popped up on SGL classifieds (I forget which now) - sod it, it was around the same price as the first one - ouch went the bank balance, and again and again and again!  Of course the more I got the more I wanted to complete the collection and thanks to SGL classifeds I am finally there - it took a while, but I now own the whole collection for a fraction of what I could have got them for new.  Bro had a really nice old metal flight case, so I've sprung for pluckable foam and here is my 'best' collection of EP's - it rather ruins the look to add the Pentax XW 5mm, but I know that's also rather nice glass so it does belong there I think.  The only thing is the Morpheus stops at 17.5mm and that rather misses on the wider field views of the sky, but for the sake of my bank balance that's probably a good thing and I have some lesser EP's that do serve in that capacity.  

I do think I am very lucky - it isn't a box of classic green and black, but I'm rather chuffed with it.

Try a 30mm APM UltraFlat field eyepiece to round out the set.

Then your training will be complete.

For low power, a 30mm APM UltraFlat Field eyepiece is a winner.

It's lighter and smaller and as sharp as the 31mm Nagler and 30mm Pentax XW, with which it competes.  And compatible with glasses.

The next one needed is something like the 17.5 Morpheus.  Wider, which befits a higher power, and also compatible with glasses.

If you don't need glasses, the TeleVue Nagler Type 6 eyepieces could round out the higher powers (down to a 3.5mm eyepiece).

The APM 100s are a good value, too, and the shortest focal lengths are the best-corrected, I've found.

It makes sense to go wider in apparent field as the magnification goes up, to keep the field from shrinking too much.

Especially in an undriven dob, where things can go whizzing through the field and a wider eyepiece gives you more time between nudges.

Russ, though the Morpheus can be used as 2" eyepieces, you should think of them as 1.25", because if used as 2", they require an enormous amount of out-travel at the focuser.

They are closer to parfocal with a lot of other eyepieces if used as 1.25".  There is no harm in using them that way.  All the eyepieces I've mentioned except the 30mm APM can be used as 1.25" eyepieces.

On 30/03/2020 at 04:55, Ciaran Meier said:

Hello folks

Been observing from home lately given current curtailments.  LP eliminates all but the brightest stars and make DSO hunting a tad tricky.  Has anyone any experience on boosting contrast on these objects.  I know there's no miracle fix for this but it would be nice to tease out a bit more detail if possible. 

Current setup:

8 inch F6 newt.

6mm EP.  1mm exit pupil. x200

12mm EP. 2mm exit pupil.  X100

25mm EP.  4.2mm exit pupil.  X48

Any advice much appreciated. 

Ciaran. 

The primary thing to do in an urban LP environment is use a bit higher powers than normally used at a dark site.  Yes, this will dim the object as well as the background, but the larger size and darker background will make most extended objects a bit easier to see.  For any star or star cluster (open, globular), higher power yields improved contrast and allows you to see fainter stars.

Many if not most beginners use too low a magnification for most objects and that's OK in dark skies, even though they'd see more at higher power.

With most DSOs (not the largest objects) observed in an urban setting, you probably shouldn't go lower in power to view them than 0.5D in millimeters, i.e. a 10" scope at 127x, or a 6" scope at 76x.

The lower powers can be quite nice, but not particularly when the skies are light-polluted.

I seem to recall some early Questars, Bushnells, and even a Celestron with threaded-in eyepieces.

But I haven't seen one since the '80s.

Just posted the 2020 Eyepiece Buyer's Guide

https://www.cloudynights.com/topic/700069-2020-eyepieces-buyers-guide/

Enjoy.

On 27/03/2020 at 12:57, Paul73 said:

Thanks Don

So I focus using the Paracorr rather than the focuser? Sorry about the blindingly basic question, but I’ve only ever found the need for one with wide wide angle eyepieces which i’ve only owned at the long end of things.

I’m sure that I’ve got an in travel adapter from when I had a set of Delos back when there were a few more ££ available for Astro gear.

Paul

 

Sorry, just saw your question.  The Paracorr's top is not smooth enough to be used for fine focusing.  What you do is focus with it (after setting the Paracorr with an eyepiece that you know the setting for and focusing the scope) when you insert eyepiece B just to find out what the proper setting is for eyepiece B.  Write it down.  Next time, before inserting that eyepiece, dial the top to the setting you discovered, then insert the eyepiece.  It'll be really close to focus and only a tiny touch up of the fine focus knob will be necessary to achieve pinpoint focus.  Even with knowing the settings for every eyepiece in your collection, you will still need about a 1mm range of focus in your focuser.

As for figuring out what eyepiece to start with, if you own a Paracorr 1, you should not use a 31mm Nagler, or 21mm or 17mm Ethos or a 20mm ES 100° as your starter eyepiece, as these do not have optimum settings in the range of the tunable top.

Use another eyepiece you know the setting for.  The eyepieces I mention will all use Setting 5 (all the way down on the Paracorr 1 ), but that setting is still a tad short of optimum.  Because they are not at the optimum position relative to the CC lens, if you focused using the tunable top on another eyepiece, it, too, would be at the wrong position for optimum correction.

So, an 8mm Delos uses the Paracorr 1.25" included adapter and the 14mm and 17.3mm use the in-travel adapter to make them parfocal with the 12mm and shorter Delos, all of which are parfocal.

1 hour ago, Paul73 said:

Hi Guys

I’m looking to fill the midrange hole in my eyepiece lineup. Something in the 13 to 15mm range would fit the bill. It will be used primarily in my f4 16” Dob to bring out the detail in galaxies. I’m a big fan of the Delos range having used them happily without the need for a Paracorr. But I’m wavering.... these APM wide wide eyepieces seem to get some good press...

My other eyepieces are an ES 82° 24mm (with a Paracorr)and an 8mm Delos (not with a Paracorr). I have a set of TV Plossls but they are way to narrow for this scope. I don’t want to be fiddling around with Paracorr settings when changing eyepieces. 

So APM 13mm 100° or Delos 14mm 72°?

Thoughts?

Paul

 

The visibility of coma is apparent field related, i.e. you WILL see significant coma in a 13mm 100°, whereas it will be substantially less in a 72° field eyepiece.

I don't really understand why you don't use the Paracorr for all your eyepieces as it not only eliminates coma but also slightly flattens the field.

The 13 APM has a small amount of induced astigmatism at f/5 which will be worse at f/4.  The Delos will have a far better edge, where star images are concerned.

As for not fiddling around with Paracorr settings, perhaps you aren't aware you needn't do that.  The Paracorr will parfocalize all eyepieces, i.e. simply insert eyepiece B after eyepiece A

is properly set in the Paracorr, and focus eyepiece B using the Paracorr's top.  The setting that results in focus is the setting for that eyepiece.  That's no more complicated

than moving the focuser.  Even if you insert a 1.25" adapter, the process is the same.  You may still need to fine focus with the focuser, but a half millimeter of focus travel is about all you'll need.

The 14mm Delos, however, will need the TeleVue In-travel adapter (AIT) to be parfocal with the 8mm Delos when the 8mm Delos is used with the Paracorr adapter.

6 hours ago, mikeDnight said:

Yes, I'm most definitely more of a Pantax fan than Televue. But like many things in this hobby, it really boils down to personal preferences and where our comfort zone lies.  Last night for example, I spent an hour and a half just sweeping around aimlessly. I was using my 17.5mm Morpheus for the first hour, but found as I tired, I struggled to keep my eye on axis, which caused blackout. I also became very aware after prolonged use, that i had to roll my eye around to see the full field. That's not so bad initially, but after an hour, it becomes tiresome and uncomfortable. After swapping the Morpheus for my 25mm Parks Gold and 18mm Celestron Ultima, the slightly narrower true field became much more comfortable to observe with (no eye rolling), and M81 & 82 would still both fit nicely into the field of view. Now I'm in yet another quandary - do I keep the 17.5mm Morpheus or sell it to free up funds???? 

Add the additional eyeguard extender.  That will solve your problem.

From hours in the field:

Mars: Contrast Booster stupendous--simply the best Mars filter out there.

Jupiter--Moon and Sky glow filter better, though CB helps a little.  Best is no filter and high power.

Saturn--Yellow #12 or #15 enhances shadow details in rings.  Otherwise, like Jupiter--high powers with no filter is best. M&SG not much help at all.

21 hours ago, Sunshine said:

Well, about 250 CAD i guess, i think my next eyepiece will need to have better eye relief, i am tired of touching eyeball to glass as i do with my ES 14mm 82 degree.

Some possibilities compatible with glasses:

Baader: Hyperions, Morpheuses

Explore Scientific: 30x82, 28-40x68, 12-17x92, 26-40x62, 30-40x52

TeleVue: Delites, Deloses, 32-55 Plössl, Apollo 11, 27-41 Panoptics, 22-31 Naglers, 17 Nagler marginal (a bit tight)

Olivon (BST or Barsta): 70° Series, 58° series (marginal--a bit tight)

Pentax: XWs, XFs

APM: 12.5x84, 24x65, 30x70

Vixen: 2.5-25 SLV

There are others, but that gives you some choices.

8 hours ago, John said:

I tend to prefer more magnification than 40x as well - hence the value of my Ethos 21. 43x and 2.3 degrees of true field with my ED120.

Sometimes it is nice to go lower though and I do enjoy the "context" views

 

Since you can have an exit pupil larger than your pupil in a refractor (it only sacrifices some light, but the magnification is really low), I've tried a 55mm Plössl in my 4" refractor and got to 13x and a field of 3.7°.

It's not quite large enough a field for using the scope itself as a finder (my finder is 8x and a 6° field), and the magnification is barely more than my finder, albeit with a significant jump in aperture.

"Context" views for objects like the Pleiades or M31 do require massive fields of view.  My best view of those objects with context is something that yields ~10-20x and a 4.5° field, like a 31mm Nagler in a TeleVue NP101 refractor.

I've regretted selling mine for several years.

On 14/03/2020 at 21:53, Sunshine said:

My 18mm APM eyepiece yields 44x in my 115mm Eon refractor, I am aware this is purely subjective but, should I bother buying a 24mm or 30mm lets say?. How often do you use powers in the 25x range? and, what would I be missing out on at such low magnifications?

For me, yes, 44x is low enough as a low power.  I don't need for my refractor to duplicate a binoculars power or field size.

IF you seek a really wide field and really low power, then perhaps it makes sense, but I really see very little reason even then to have a magnification below about 5X/inch (5mm exit pupil)

That would be a 23mm eyepiece.  Yes, the image is brighter at low power, but star clusters will be poorly resolved, and galaxies really small so unless you really enjoy the "context" view,  I wouldn't bother.

The largest eyepiece I use with my 4" refractor is an 18.2mm yielding 39x.  My most-used eyepiece is an 11mm (65x) or a 7mm (102x).

On 09/03/2020 at 13:51, Littleguy80 said:

I’ve never been a fan of coloured filters for planetary observing. I just prefer a more natural look. I like the Baader Neodymium for Jupiter. I also have the Baader Contrast Booster but there does add some false colour. However, I find myself contemplating a #47 Violet filter to try and see some cloud details on Venus. Has anyone else tried this? Are there other coloured filters that really stand out? I read some very positive comments on magenta for Mars. 

I used a #30 magenta on Mars for a while, but a friend suggested the Baader Contrast Booster.  it is simply the most amazing Mars filter I've ever used, and I've had about 9 other specialized Mars filters over the years, including the TeleVue Mars A and Mars B, the TeleVue Planetary filter, the Orion Mars filter and the Sirius Optics Mars filter, a #23a, a #25, a #21, and the #30 magenta.  None gave the incredible images of the CB.  If you have one, try it on Mars.  You'll be amazed.

On 26/02/2020 at 13:34, JTEC said:

I thought that the Televues were made by Astronomik and essentially identical to the Astronomiks, Televue claiming to select to meet their own supposedly uncompromising standards.  Certainly the recent TV OIII filter I have is excellent and very tight. That said, and I’ve not put it to the test, but I bet you’d be pushed to notice any difference between the straight Astronomiks and the ones made by Astronomik for Televue.

Except the UHC.  Astronomik's UHC filter passes the H-α wavelength at a high percentage, whereas TeleVue's Nebustar II (their version of the UHC) has no red transmission at all.

Star images in the Astronomik have a bit of red tint to them, where the stars in the TeleVue are the usual blue green seen in a filter lacking red transmission.

The current Lumicon Gen.3 UHC has the same profile as the TeleVue, while the DGM admits a much broader patch of red than the Astronomik.

The 11mm was the poorest selling Nagler, maybe the same as the 2.5mm (also discontinued).

Everyone who bought the 13mm skipped to the 9mm as the next size.

The Apollo 11 eyepiece was designed to commemorate the moon landing of the LEM of the Apollo 11 mission.

So of course it had to be 11mm.  It almost missed the 50th anniversary year because of some changes after the prototypes.

The Nagler wasn't discontinued because of the Apollo 11 eyepiece, but because of sales.

And if TeleVue came out with a long eye relief line of T7 Naglers, I'd suggest they skip 11mm.😀

My astigmatism has gotten worse over the years.  At first, no visible astigmatism at 6mm exit pupil, then 4mm, then 2mm.

But the eyepieces I use under the 2mm exit pupil are so good, I don't intend to part with them until forced to do so by Mother Nature.

You can plan for getting worse, I suppose, and just get only eyepieces compatible with glasses all the way down to the smallest focal length.

I can see that, but I'd hate to give up 100-120° fields, especially at high power in an undriven dob.

Though it's excellent, I'll never get my investment back.  Only my heirs will appreciate it, perhaps.

But in the meantime, I have something that brings back a lot of memories and yields pretty darn good images in my scope in a form I can use my glasses with.

I compared it to the 12.5 Morpheus, 10 Ethos and a couple of others.  If you don't need glasses at that focal length, my advice is for the 10 Ethos.

And if you don't need the large field, the 10 Delos.  There just aren't any long eye relief ultrawide 10-11mm focal length eyepieces that can bring back memories like this one does.

It's ridiculously expensive, and, in a few years, you may be able to buy a used one for less.

On 27/02/2020 at 04:25, heliumstar said:

So, astigmatism got a little worse and I got new prescription for glasses. I am thinking of going full 20mm+ eye relief with all eyepieces and just wear glasses when observing.

So far I found Pentax XW (had them and they are great but oh my the size), Baader Morpheus (size is again an issue but great eyepieces) and TV Delite.

Is there anything out there in the range of 15-5mm with small form factor and eye relief ok with glasses that I am missing?

Baader Hyperion, Baader Morpheus, Explore Scientific 92° series, Explore Scientific 28,34,40 x 68°, ES 26,32, 40 x 62°, ES 30, 40 x 52°, TeleVue Nagler 31, Delos eyepieces, Delite eyepieces, Nagler 22,

Olivon 70° series, Olivon 58° series, Vixen SLV, Pentax XW, APM UFF in 24mm and 30mm

Boiling it down to the 5-15mm range, 2 Hyperions, 4 Morpheus, 7 Delos, 8 Delites, 3 Olivon 70, 6 Olivon 58s, 5 Pentax XW, 2 Pentax XF, 8 Vixen SLV = 45 eyepieces in your range,

and that's not all of them, merely the ones I can remember off the top of my head.

But, bear in mind you may not need glasses below a certain exit pupil.  I use glasses from 11mm up and no glasses for 10mm down.  You may not require glasses for your shortest focal lengths.

Here is a site with tests of many filters.

You can also overlay any filter graphs on top of one another.

https://searchlight.semrock.com/?sid=a08a1af9-84ee-49d2-959d-153d7e7c0eb8#

daylight review:

https://www.cloudynights.com/topic/687544-televue-apollo-11-reviews-here/?p=9867782

Nighttime review:

https://www.cloudynights.com/topic/687544-televue-apollo-11-reviews-here/?p=10009894

There are other reviews in that same thread.

Piero,

I did not check the Paracorr setting for the 30mm APM UFF eyepiece because you find its setting the same way you find the setting using the ES HRCC:

You use an eyepiece, any eyepiece, that you know the Paracorr setting for, insert the eyepiece, dial in the correct setting, focus the scope and lock the focuser

(figuratively, i.e. don't move it).  Insert the new eyepiece and focus using the tunable top.  The setting that results is the correct setting for that eyepiece.

So since I had been using a TeleVue eyepiece prior to using the 30mm APM, i simply inserted the eyepiece and focused with the tunable top.

I didn't even bother to look at what the setting was since coma correction was perfect and stars at the edge were tiny pinpoints.

Every time someone asks me what the Paracorr setting is for eyepiece X, I just ask if they have one eyepiece they know the correct setting for.

If they do, they know the setting for every eyepiece because the tunable top parfocalizes all eyepieces that focus within the range of the tunable tops adjustment (0.7").

Just focus using the tunable top.  Now, that won't give you extremely fine focus, which is why you still need to have a millimeter travel in the focuser.

Re: a comparison of distortion characteristics between the 30mm APM UFF and the 30mm Pentax XW:

The XW has a very small amount of positive angular magnification distortion, so is like most astronomical eyepieces.

The APM UFF has a very small amount of negative angular magnification distortion, so is a little more unusual (far from unique).

Both, however, have been designed to control AMD tightly, so both show pincushion rectilinear distortion in daylight use.

It's obvious both were designed for astronomy use, as opposed to daytime use in spotting scopes.

On 20/12/2019 at 12:53, Louis D said:

I'm good with my 30mm APM UFF at 30mm.  I've found at least one comparison that liked it better than the XW except in comfort.  Since I find the UFF comfortable enough, I'll stick with it.

 

+1 for the 30mm APM UFF in my f/5 scope.  I have to use glasses at this exit pupil, but correction is excellent and glasses were usable with the eyecup folded down.

It was just a little sharper and had slightly better contrast than the 30mm XW in the outer 10° of field.  I rated it equal to the 31mm Nagler except for apparent field.

It is NOT compatible with a TeleVue DioptRx, so if you need astigmatism correction, you'll need to use glasses or contacts.

On 15/01/2020 at 15:01, SimM said:

I'm looking for some help with getting a balanced set of useful eyepieces... for me it's the most difficult thing to manage.

I realise that there is a lot to know about eyepieces. I'm confused by some of the terms like back focus, AFOV, field stops, vignetting and differences between 1 1/4" and 2" eyepieces/diagonals when considering what eyepieces to get.

I have a new equatorial mount and an existing F3.5 10" newtonian (lots of coma) with an EdgeHD 800 OTA.

My collection of 1 1/4" low grade eyepieces are not very exciting and aligned more to the newtonian scope requires me to give eyepiece selection some thought. Originally I was going to put the newtonian on the mount (requires some work) and replace my eyepieces with a view to eventually being able to use them with a 2" diagonal. Later I planned to buy the EdgeHD 800. However the difficulty of selecting eyepieces and my interest in the SCT has lead to buy the SCT and consider buying eyepieces for the SCT now that will also be useable on the newtonian.

I wear glasses and have astigmatism and my previous dislike of small exit pupils e.g. 4mm eyepieces attracts me to some Baader Hyperian eyepieces - they mostly have 20mm eye relief.

The complete range is 5/8/10/13/17/21/24mm, so approximately 400x, 250x, 200x, 150x, 120x, 100x and 85x magnification.

In the UK I can't see myself reaching for the 5mm 400x as seeing conditions good enough to use it would be very rare... I'm drawn to combinations of:

1. 8/13/17/24mm e.g. 250x, 150x, 120x and 85x
2. 8/13/21/24mm e.g. 250x, 150x, 100x and 85x
3. 10/17/24 e.g. 250x, 120x and 85x

I can see value in everything except the 5mm - can this one really be useful e.g. detail on moon or splitting stars in all but best conditions?

Some of the terms like back focus or actual focal length being longer or F/10 really being F/10.5 mean nothing to me.

If the field stops are less than 1 1/4" (28mm is 28.5mm) is there any value gained by switching to a 2" diagonal for the same lens (probably not) and only a benefit for longer/ultra wide eyepieces?

Is vignetting in an eyepiece likely with any of these with a 1 1'4" diagonal?

A 2" diagonal is a lot bigger and the light path is longer, but for the OTA and an eyepiece, the focal length is somehow increased for reasons I don't understand.

I can see value in all the eyepieces except for the 5mm but having all of them becomes either costly or requires too much swapping, so 3-4 as a starter set would be preferable?

Later I will add a 2" diagonal and some longer/wider eyepieces.

Simon

Read this:  https://www.handprint.com/ASTRO/ae1.html

And the 4 parts that follow.  You will understand a lot more than the basics by you reach part 3 or 4.

Paul,

It's about what you'd expect:

Wide field, Well-corrected at the edge, cheap---pick any two.

Well corrected widefields at f/5:

TeleVue Nagler 31mm--grade A

TeleVue 35mm Panoptic  grade A- (slight field curvature)

Pentax XW 30mm  grade B+ (slight field curvature and slight astigmatism)

Explore Scientific 30mm 82°  Grade B (a bit more astigmatism)

APM UFF 30mm Grade B- (even more astigmatism)

Most other 30-35,, eyepieces with wide fields fall in the Grade C and below category at f/5, like the 31mm and 36mm Hyperions.

That being said, if you don't mind a bit of astigmatism mixed with the natural coma of an f/5 scope, many eyepieces would work as "finder" eyepieces. but if you are serious about creating a low power view with sharp stars from side to side, first get a coma corrector for the scope, then look to invest a bit of money for the eyepiece.  Narrow fields?--you have a lot of good choices.