amaury

You get more mag, at almost the same TFOV, with noticeable more eye relief.  Diminishing returns is something very common in the hobby to be honest. Whether the price difference is justifiable is totally your call. For most people it would be hard to justify. 

7 hours ago, Louis D said:

Without tracking, you'll be having to keep pushing the scope, letting it settle, and then allowing the planet image to drift across the imager.  Doable, but you'll tire of the process fairly quickly.  An equatorial platform will allow tracking for up to an hour before resetting it.

I have the same telescope, and as Louis D said, it is doable to record planets with a dob, but it's not by any means the right tool for the job. 

16 hours ago, wibblefish said:

Since I got my telescope back in Nov last year I have been enjoying the sights on the regular basis (when the cloud permits!) but at the moment I find myself in a bit of an ebb with it due to either unfavorable conditions or to little dark (yesterday didn't get anywhere near proper dark nights till 11pm). I am also restricted to only really having Friday / Saturday nights to play with at the moment and due to small kids and work during the week means I don't want to be up super late! 

What does everyone else do in these lighter months, are you staying up later to do the odd hour around midnight or up early in mornings? 

I find myself in a similar position nowadays. I started studying at night two weeks ago. I work during the day. That means I only really have time to stay up late on weekends.

The moon, and doubles are my main targets. I got to say I was never a big fan of doubles. A zoom makes it much more satisfying. 

I just got a planisphere this morning. Thanks a lot @Richard_B

This is a really nice-to-have item for visual observation and not messing my dark adaption using the phone app. 

22 hours ago, Richard_B said:

Do you still need a planishere? I realised I had a second older one (2000 I think - not sure if they go out of date as such) - you are more than welcome to it to see how you get on with it before stumping up the money on a new one. It's not the larger 12" version but works ok. PM me you address if you want it and I'll send it down.

Richard

Thanks Richard, I don't necessarily need one, it's a nice-to-have sort of thing really.

I think the stars move very slowly over decades but for the most part, the sky it's mostly the same as it was 20 years ago I think. For planets it's different story I guess.

I also use a couple of apps that are quite handy, they mess with your dark adaption, however.

This is my first upgrade for my 8" f6 Dob after quite a bit of research and insight from you guys.

A rebranded Explore Scientific 82 24mm from Opticstar (first class dealers as John said, highly recommended). 

13 hours ago, Barry-W-Fenner said:

Hi Amaury

https://www.firstlightoptics.com/adapters/baader-2-inch-click-lock-cl-extension-47mm.html

I have just purchased one of these for my 300p. The overall length is identical to the standard 2" skywatcher extension. I have fitted this along with a 1.25 to 2" click lock adapter. It works very well.

Hi Baz, 

It's good to hear from you.

The click-lock systems is lovely yes. The one you point at is the extension bit only.

I want to change the 2" focuser fitting/adapter as well (the M54 connection)

I might get this one plus the extender you mention. 

https://www.firstlightoptics.com/adapters/astro-essentials-2-inch-compression-ring-adapter-for-sky-watcher-newtonians-and-72ed-refractor-m54.html

Going fully click-lock makes the fitting plus the 37mm extension 10mm too long, I am not sure if I'll need those 10mm of in-travel focus. 

Sorry to revive this thread but I am about to do something very similar with the Baader Click-lock system.

I have a SW Skyliner 200p, same focuser fitting and adapters. (11mm and 47mm respectively of optical length)

That is an effective optical length of 58mm for any adapter. 

I am planning to change the fitting with the baader click-lock, the one below.

https://www.firstlightoptics.com/adapters/baader-2-clicklock-m54-clamp.html

That alone has a 30mm of optical length, I am guessing that is too short to the "stock" optical length. I'll be missing 27mm of back-travel in my 2" eyepieces. 

Baader also sells a 2" 37mm extension

https://www.firstlightoptics.com/adapters/baader-2-clicklock-clamp-37mm-extension.html

On 27/08/2020 at 18:10, Rob_UK_SE said:

I found that I needed a 2” replacement tube with a 35mm optical path

Somewhat close to this.

That brings the total optical length to 67mm for my 2" EPs, that means I'll be missing around 9mm of in-travel. Is this ok? or should I disregard the click-lock system completely?

I only do visual. 

Thanks in advance

On 12/04/2021 at 13:52, johninderby said:

My suggestion would be a second hand Explore Scientific focal extender. Will give better views than one of the barlows you mention. Second hand you should be able to pick one up for about 100 quid.

https://www.firstlightoptics.com/barlows/explore-scientific-2x-barlow-focal-extender-2.html

Or the same thing under the Opticstar brand.

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Telescopes-Opticstar.asp?p=0_10_5_1_8_56

potentially another re-branded ES 2X 2" focal extender? @johninderby @KP82 @Stu1smartcookie even cheaper. 

https://www.altairastro.com/altair-lightwave-2x-2-inch-flat-field-apo-tele-extender-barlow-2833-p.asp

I had been saving globular cluster for clearer nights. Last night was probably the clearest night I've had in the last month or so.

I had never attempted one before. Literally last night was my first time ever with globular clusters.

I drive my 8" Dob half for 30min to get to a Bortle 4 area, just for context. I am a total beginner too.

I took my time. I started NW with the double clusters near Cassiopeia. I love that one. Moved W to Auriga, M36, M37, M38, very beginners friendly and a lovely sight. Spent a good time in M35 in Gemini (although the waxing moon was too close).  

I always go to the Beehive too, easy to find, and still a lovely view. M67 always gives me some trouble, I find it tricky to find, I did eventually find it. That was my last stop in SW before jumping to Arcturus in the east. This is going to sound very silly but my heart was pumping like crazy. 

My expectations were mixed. M3 is apparently one of the brightest globular clusters in the night sky (top 3 I read somewhere), however, Turn Left at Orion warned me: "M3 is as faint as a sixth-magnitude star". Anyway, I thought it was going to be easy to find. How wrong I was.

I don't know how many times I scanned the Arcturus-Cor Caroli, and the Muphrid-Cor Caroli sections expecting to come across a "super bright/compact/ grainy" ball of light. 

As posted in that simulated view by @mdstuart, and going back to the topic of this thread, M3 looks rather dim, I could see a lot of graininess for sure. That's how I would describe "how does M3 look like?" from a beginners perspective that the only thing I had seen before was the moon and open clusters. 

1 hour ago, johninderby said:

And Opticstar are a first class dealer as well. Really look after their customers..👍🏻👍🏻👍🏻. 

I can tell you this regarding your comment. 

I contacted several companies, some in Europe too (they seem to have better stock), and the guys from Opticstar were the most responsive ones by a long shot. 

Just ordered the XL 82 24mm with them. 

15 minutes ago, johninderby said:

Made in the same factory and can have any brand name the buyer chooses. Many eyepieces and other items are the same but sold under several brands. Sometime the buyer may have different rubber moldings made to make them look a bit different.

Thanks John, just wanted to make sure, it just seemed too good to be true. ES are already good value EP in terms of performance per dollar, and on top of that you can get a cheaper re-branded version with the same performance.

10 minutes ago, Shimrod said:

The prices seem to roughly match what the corresponding ES eyepieces were selling for before the recent prices rises - and I have found a couple of older threads suggesting Opticstar and ES pricing has been more or less the same in the past. It might be worth picking some up while they are in stock, as newer stock may also come with a price rise!

Plus this, price is pre-rise. Made it a no-brainer for me considering the current circumstances with price and availability.

On 12/04/2021 at 13:52, johninderby said:

My suggestion would be a second hand Explore Scientific focal extender. Will give better views than one of the barlows you mention. Second hand you should be able to pick one up for about 100 quid.

https://www.firstlightoptics.com/barlows/explore-scientific-2x-barlow-focal-extender-2.html

Or the same thing under the Opticstar brand.

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Telescopes-Opticstar.asp?p=0_10_5_1_8_56

I reckoned I better digress here instead of creating a new whole discussion. 

Is it just literally an Explore Scientific re-brand? or is there a catch?

Browsing around I noticed that Opticstar also has a re-branded ES82 lineup that is 40quid cheaper than the actual Explore Scientific one, and they actually have stock.

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Telescopes-Opticstar.asp?p=0_10_5_1_8_322

Is it just literally a name change? I reckon if the eyepiece is made in the same factory in China, there will be zero optical perfomance difference and the is no "catch" other than a "name".  

Is it something like the ES/Maxvision case?

On 13/04/2021 at 22:31, Louis D said:

It's still quite comfortable to use with eyeglasses.  In use, it feels more like the 18mm of eye relief that my Pentax XWs and 14mm Morpheus have.

@Louis D, Do you think the same can be achieved with an ES82 24mm? the specs say it has 17.5mm of eye relief, in practice Don mentioned it has more like 14mm of effective eye relief. Haven't read any comments about folding the eyecups in the ES82 eyepieces. 

1 hour ago, Second Time Around said:

At night, like many others, I find I need about 0.25 dioptres extra spherical correction and about 0.50 extra cylinder correction (the latter is called night myopia).  I have special astronomy glasses as a result.  Even with 0.5 dioptres of astigmatism you're likely to notice it at exit pupils above about 4mm.   With an extra 0.25 correction you'll notice it at exit pupils above about 3mm.  See https://www.televue.com/engine/TV3b_page.asp?id=54&Tab=_Choose

This link is to the Televue Dioptrx, that is a way to correct astigmatism without wearing glasses.  A Dioptrx fits onto the top of many Televue eyepieces.  However, like with glasses, you need more eyelief to be able to see all the field of view.  How much depends on the shape of your eye sockets (and if wearing glasses their style makes a big difference). 

For many of us that means eye relief of 20mm+.  So this precludes all of the 100 degree FOV eyepieces on the market - the Ethos for example has only 15mm.  My view is that if I can't see all of the FOV anyway the extra cost isn't justified.

Some other non-Televue eyepieces also accept a Dioptrx, although sometimes an O ring is needed.  They need a top diameter of about 41-44mm. Those that do of 22-30mm focal length include:

Pentax XW: all I'm told

Explore Scientific 68 degree: 24mm and 28mm

APM Ultra Flat Field (and copies): 24mm (but not the 30mm)

Omegon Redline SWA 70 degree: 22mm.  This is an inexpensive hidden gem that many rate as very nearly as good as the 22mm Nagler and with more eye relief.  I sold mine only because it's a 2 inch eyepiece rather than a 1.25.

By the way, I prefer a Dioptrx because they have better coatings than even my expensive glasses.  Additionally, the angle of my astigmatism varies between prescriptions and a Dioptrx enables me to compensate for that.

Thanks Steve. Very useful information as usual.

That chart from televue is handy. Another reason for me to maybe stay around the 4mm exit pupil or maybe observe with my right eye which doesn't have any cylinder correction (I tend to observe with me left eye for some reason, the one with -0.5 Cyl)

I've read good things about that Omegon (and re-brands), I'll keep it in mind.

The APM Ultra Flat Field 30mm have been reported to be eyeglasses-friendly when the eyecup is folded down. Still not anywhere near the 22mm of eye relief they state in the specs. 

5 hours ago, Deadlake said:

ETA for delivery of EP’s from KUO is end of April.

Where did you buy from @Deadlake? Astrograph?

On 02/04/2021 at 17:04, Deadlake said:

The Zoom is designed to offer a nice wide flat field with a low focal ratio scope. Very low in fact. The idea being we can use them on the APO Binoculars which are F5.5. If it delivers then it means we could have a Zoom to replace the otherwise very good (as good as a TV EP) UFF range from 15mm down, and that also has a wider field of view.

Expectations are high on this one. I'll be patient instead of buying the Morpheus line up from 12.5mm down.

8 hours ago, Stu said:

My apologies, was just attempting to contribute to the conversation.

That is appreciated Stu. I am learning a lot from you guys. 

8 hours ago, jetstream said:

24" f4.1- it gives big magnification at nice bright exit pupils.

Wow!! that is a beast of a telescope! I'd be happier with darker skies with my 8" f6. 

8 hours ago, jetstream said:

"perceived contrast"

It's that "perceived contrast" that have made mid/hig power with ultra mega wide field of views (20mm/100afov for example) very appealing. 

Thanks @Stu, as @johninderby said, using exit pupil alone or any variable alone is an over simplification of a very complex subject such as the visibility of a given astronomical object. 

It's a never ending balancing act of many variables. I guess that explains why people have many eyepieces 😅  

The general consensus seems to be that the 20mm is more useful in most instances. Something tells me I'll buy both 😆

You guys have any insight about the ES82 24mm? it seems to be a happy middle, a quick search tells me it's apparently the weakest of the ES82 family. 

8 hours ago, Deadlake said:

Its a trade off between contrast with the 20mm and exit pupil with the 30 mm for filter usage

Yes and no.

For extended objects, contrast is independent of exit pupil. 

Magnification can make you see more detail due to the increased resolution so it seems that contrast improved, it is actually still the same contrast (for extended objects).

That's is the real benefit of observing the same TFOV but with a higher magnification. 

There is this good article that explains it better than I do.

https://medium.com/@phpdevster/how-telescope-aperture-affects-your-view-24507147d7fc

What you are really giving up with the 20mm/100deg EP is eye relief. I believe there isn't a single 20mm/100deg eyepiece that is eyeglasses-friendly. On the other hand, the APM UFF 30mm has superb eye relief.

1 hour ago, Stu said:

It’s well worth checking it out carefully

I'll do my homework with this. 

1 hour ago, Deadlake said:

Astrograph have a shipment in at the end of April, pending APM's large shipment to come in from KUO. I'm waiting on some APM EP's which I got before the price rise. As far as performance goes, when I purchased I discussed with another SGL user who has both the E21 and the APM 20 XWA, he told me skip the E21, the APM is sharper in the middle, weighs half as much and only losses out to the E21 with a small amount of astigmatism at the edge which you would notice unless under SQM > 21.8 skies. So I did, also got the APM 30 UFF as will show more contrast on darker skies.  Hope that helps.

It helps yes. The thing is that with my scope (8" 1200mm f/6 Dob), the APM 20 gives me 1.67deg TFOV, that makes the APM 30 UFF redundant as it almost overlaps in terms of TFOV (1.75 TFOV for the UFF).

The one thing I would be giving up with the 20/100 is eye relief (15mm). I only have very small corrections (-0.5 Sph and -0.5 Cyl) so I think I can do visual observing without glasses. Maybe I am wrong here and I am being too optimistic. 

42 minutes ago, John said:

eyepieces of this specification offer something very useful in terms of exit pupil / true field / magnification

I totally understand that usefulness now. I just never considered  ~20mm / 100 degree eyepieces because of the massive price premium of those specs. I was aiming more towards 24mm/82 deg or 30mm/70 because they have an equivalent TFOV in my scope, better eye relief, and better prices, at the expense of more exit pupil (which wouldn't be an issue in truly dark skies, but it doesn't get better than bortle 4 for me).   

6 hours ago, Louis D said:

so higher power and wider field of view eyepieces are more useful

I'll pay the premium for usefulness. Thanks Louis.

10 hours ago, Stu said:

The APM 20mm XWA is 100 degree and has an excellent reputation as being pretty close to a 21mm Ethos for a lot less money. Worth a look.

Thanks Stu, looks a like a bargain compared to a 21mm ethos or a ES100.  

I reckon I have to consider import fees when buying from Europe now. Is it any different than importing something from the US? 

I can get a similar TFOV with an ES82 24mm, a bit better eye relief and a tad cheaper than the APM 20mm

11 minutes ago, Rob_UK_SE said:

If it helps, I purchased a Pentax XW 30mm about a year ago, but have fairly recently sold it and purchased the cheaper APM 30mm ultra flat (which I consider even better). It was highly recommended at the time, but I secured a good deal on the XW... I wish I’d followed the advice on here and gone for the APM from the start!   

In comparison with the formidable 31mm Tele Vue Nagler, the 31mm has a considerable pincushion distortion, whereas the 30mm APM UFF is much more comfortable when scanning through the Milky Way etc.

The Baader Morpheus would work well alongside your future APM too.

I have read many good things about the APM too, that it punches above its weight, but never thought it would be better than a Pentax XW. Those are premium EPs as far as I know. The Baader Morpheus will be the 12.5mm (aiming for the "sweet spot" of 2mm exit pupil) Thank you all for your insight. It is appreciated indeed.

2 hours ago, Rob_UK_SE said:

Hello amaury,

I most frequently observe from our garden which benefits from Bortle 4 skies. For low power views of large objects (m81 and m82 together, the Pleiades, m31, the Veil, Double Cluster etc.)  I can only echo John’s comments that I too prefer using a 21mm eyepiece. This results in an exit pupil of 4.2mm. I also have a 30mm, but find the contrast is less effective from home when compared to the 21mm. By contrast (excluding the terrible pun), when I travel to darker skies I find the larger exit pupil useful, but it is subtle to my eyes at least. The darker skies have a much more dramatic effect (comparing the 21mm at home vs away). I have recently ordered a new scope so it will be interesting to see the impact of the new focal ratio on these eyepieces as I am going from f5 to f4.6.

I think if I was observing in a Bortle 6 area I would probably be aiming for approximately a 3mm exit pupil as my low power option (16mm or 17mm).

Just to complicate matters further, it’s also worth considering the impact of an eyepiece’s light transmission, scatter and the quality of the coatings as they all play a part in the quality of views and contrast achieved too.

Rob

Thanks Rob. (that was a funny pun tho'). I certainly understand there will be better contrast with the 21mm EP in bortle 4/5 skies. The thing is the balancing act between price/TFOV/Exit Pupil etc. Those 21mm with 100 AFOV EPs have a really steep price, as much as I would love to have one of those, I don't want to spend 80% of my budget on a single piece. I'll keep them in mind for a future investment for sure.