"Planetary" wide-field EP for an f/5 dob?

[cajen2]

I can often smuggle in a new EP under the nose of SWMBO but an EQ platform may be a trifle trickier! 😁

[cajen2]

1 minute ago, Highburymark said:

Sure - astrograph.net

Ah, not .com, then! Thanks Mark.

[Ricochet]

8 hours ago, cajen2 said:

Nobody has told me, but is the Williams Optics version exactly the same as the APM?

I think the problem is that we need someone to test them side by side to determine if there is any difference in reality. The design of the lenses internally is the same but when the APM line was announced it was claimed that the lens coatings are better. Coatings and stray light control make a big difference in performance so if they are better it would be worth paying the extra in my opinion. Are they actually better in practice? I don't know. You should also note that the eyecup has been changed in the APM version, which may make the eyepiece more or less comfortable to use. 

However, for planetary viewing I personally prefer to use binoviewers. This necessitates using smaller eyepieces so that you can comfortably get both eyes positioned over the eye lenses. Usually you will need a barlow or gpc to be able to bring the focus point within the range of your focuser travel, which means that long focal length pairs of eyepieces that aren't necessarily well corrected at your telescope's focal ratio will actually be fine. Sticking with the APM brand, the UFF range (60°-65°) are often used for this. 

[vagk]

You should also consider buying Pentax XW 5 or/and 7 version... One of the best options in my opinion.

Edited December 25, 2021 by vagk

[Deadlake]

On 23/12/2021 at 21:17, Don Pensack said:

Then the equivalent APM XWA in 4.7mm (labeled 5mm) and 3.5mm, both 110°.

I have this EP and it’s very comfortable to use and wonderfully sharp. Great for framing either the moon or Jovian system.

[Deadlake]

7 hours ago, Ricochet said:

I think the problem is that we need someone to test them side by side to determine if there is any difference in reality. The design of the lenses internally is the same but when the APM line was announced it was claimed that the lens coatings are better. Coatings and stray light control make a big difference in performance so if they are better it would be worth paying the extra in my opinion. Are they actually better in practice? I don't know. You should also note that the eyecup has been changed in the APM version, which may make the eyepiece more or less comfortable to use. 

However, for planetary viewing I personally prefer to use binoviewers. This necessitates using smaller eyepieces so that you can comfortably get both eyes positioned over the eye lenses. Usually you will need a barlow or gpc to be able to bring the focus point within the range of your focuser travel, which means that long focal length pairs of eyepieces that aren't necessarily well corrected at your telescope's focal ratio will actually be fine. Sticking with the APM brand, the UFF range (60°-65°) are often used for this. 

Stellarvue do a clone of the APM range which I found out after I purchased have baffles on the bottom casing that stop’s stray light. This reportedly helps when viewing the planets. You would need to order from the US as no EU vendors.

[Louis D]

18 hours ago, cajen2 said:

Nobody has told me, but is the Williams Optics version exactly the same as the APM?

Optically the same, ergonomically different.  The WO has a broad, twist up eye cup whereas the APM and Stellarvue have tapered tops culminating in a traditional flip up-down eye cup.

Edited December 25, 2021 by Louis D

[RT65CB-SWL]

Keep a watch for the TeleVue Radian, (the predecessor of the DeLite). Although I only have the 6mm, it does give planets the ‘Wow!’ factor.

The reason I chose the Radian when they were released, was the ‘Instajust’ feature and was within my budget at the time of purchase.

If you do source a second hand Radian, it should include… or ask if it includes the ‘pupil guide’ which is shown above.

TV Pupil Guide Instructions.pdf

Edited December 25, 2021 by Philip R

[John]

My choices are the Ethos SX 4.7mm and the Pentax XW 5mm for my 12 inch f/5.3 dob. I'm lucky enough to have both.

I understand that a number of brands 110 degree 5mm / 4.7mms carry the same optics as the APMs. Pick the version with the ergonomics and price that suits you best.

If you go for a Pentax XW you will loose nothing in optical quality to an Ethos IMHO, just in AFoV.

 

[scarp15]

Perhaps Delos 4.5mm and maybe 3.5mm. 72 degree apparent field of view, 20mm eye relief. Both do occasionally come available used and you could perhaps request for one in the listings. 

[cajen2]

8 minutes ago, scarp15 said:

Perhaps Delos 4.5mm and maybe 3.5mm. 72 degree apparent field of view, 20mm eye relief. Both do occasionally come available used and you could perhaps request for one in the listings. 

Good thought, though I don't often see a Delos come up in the classified.....and it'd probably be snapped up PDQ!

[cajen2]

There's a Nagler 3.5mm......but I think that's too low a f/l for me.

Edited December 26, 2021 by cajen2

[scarp15]

9 hours ago, cajen2 said:

Good thought, though I don't often see a Delos come up in the classified.....and it'd probably be snapped up PDQ!

Include Ebay, I have a 3.5mm Delos and 18.2 DeLite through this means.

[cajen2]

I tried that. There's only stuff imported from the USA, with £30-odd postage plus unknown duty.

[John]

13 hours ago, cajen2 said:

There's a Nagler 3.5mm......but I think that's too low a f/l for me.

I use to have the Nagler 3.5 and 2.5mm. Didn't use the 2.5mm much. I have the 3.5mm Pentax XW now and that get some use even with my 12 inch F/5.3 dob. Very often used with my refractors.

[cajen2]

You don't think it'd push an f/5 150mm Newt a bit too far, John?

[Don Pensack]

On 25/12/2021 at 08:01, Deadlake said:

Stellarvue do a clone of the APM range which I found out after I purchased have baffles on the bottom casing that stop’s stray light. This reportedly helps when viewing the planets. You would need to order from the US as no EU vendors.

Both the APM and Stellarvue have the same baffle in the 2" adapter.  The difference is that the bottom barrel of the eyepiece is stainless steel on the Stellarvue and aluminum on the APM.

[Deadlake]

5 hours ago, Don Pensack said:

Both the APM and Stellarvue have the same baffle in the 2" adapter.  The difference is that the bottom barrel of the eyepiece is stainless steel on the Stellarvue and aluminum on the APM.

My mistake in this quote I thought you mean’t there was an additional baffle:

https://www.cloudynights.com/topic/744418-apm-110º-35-47-compared-to-ethos-sx-110º-37-47/page-2#entry10723203

[Don Pensack]

3 hours ago, Deadlake said:

My mistake in this quote I thought you meant there was an additional baffle:

https://www.cloudynights.com/topic/744418-apm-110º-35-47-compared-to-ethos-sx-110º-37-47/page-2#entry10723203

I look in the APM and see the same thing.  There are probably multiple baffles along the length, and a field stop somewhere above the field lens and a focal plane even higher in the eyepiece.

The extra baffle in the 2" adapter is probably a good thing.  It made a *slight* difference in the TeleVue Apollo 11, and lower baffles were built into the Vixen HRs and a few other eyepieces I've seen.

So, whether APM or Stellarvue, I would use the 2" adapter if it has a lower baffle in it, or at least experiment to see if the baffle in the 2" adapter makes any difference at all.

In the post to which you link, I was comparing the Ethos SX to the Stellarvue.

[cajen2]

Well, Jupiter and Saturn are not in ideal positions any more, so I have a little time before Mars needs investigating....

I think my choice will be between the Morpheus 4.5mm and the WO/APM 5mm, probably decided by availability!

As usual, you've all been extremely helpful - it's much appreciated.

Edited January 9, 2022 by cajen2

[Guest]

I have noticed you have said out of the budget range a few times.  I ran across these a while back and think maybe I will add a couple to my eyepieces later.

https://www.telescope.com/mobileEnsemble/Accessories/Telescope-Eyepieces/Orion-LHD-80-Degree-Lanthanum-Ultra-Wide-1252-Eyepieces/pc/3/sc/47/268.uts

 

[John]

I had a Nirvana 4mm for a while and found that to be a pretty good high power / wide field eyepiece.

 

[cajen2]

Well, I've finally decided. I really wanted the Morpheus 4.5mm, but none of my trusted sites had any in stock. In fact, one of them contacted the suppliers and was told that Baader are now quoting June for the next supply!😥

So I've pulled the trigger on a Pentax 5mm from Flo (now at the normal price, of course!). I'm very happy with my 14mm, so can't go wrong. I just wish the FOV was slightly wider....

[Don Pensack]

4 hours ago, cajen2 said:

Well, I've finally decided. I really wanted the Morpheus 4.5mm, but none of my trusted sites had any in stock. In fact, one of them contacted the suppliers and was told that Baader are now quoting June for the next supply!😥

So I've pulled the trigger on a Pentax 5mm from Flo (now at the normal price, of course!). I'm very happy with my 14mm, so can't go wrong. I just wish the FOV was slightly wider....

You could add the 4.7mm APM XWA (they call it 5mm).  It's a different enough experience from the Pentax that they might have different uses.  But 110° is plenty wide if wider is what you want.

And less costly than the TeleVue Nagler T6 in 5mm.  With such a small exit pupil, you probably won't need glasses, so extra long eye relief isn't critical.

[cajen2]

11 minutes ago, Don Pensack said:

You could add the 4.7mm APM XWA (they call it 5mm).  It's a different enough experience from the Pentax that they might have different uses.  But 110° is plenty wide if wider is what you want.

And less costly than the TeleVue Nagler T6 in 5mm.  With such a small exit pupil, you probably won't need glasses, so extra long eye relief isn't critical.

Yes, indeed; the APM was one of the EPs I'd considered. Again, availability from trusted suppliers was the issue. Not the sort of outlay I'd like to make on eBay, for example!

I've ordered the Pentax now, and I think two EPs at those f/l and prices would just be self-indulgent!😉

Edited January 13, 2022 by cajen2