John

The focus point of the 17.3 and 14mm Delos suited me because it is much closer to where my Pentax XW's reach focus so they play together quite nicely

I've never needed to use a Paracorr so I don't know how it affects that. It looks as if the TV "In-Travel" adapter would make all the Delos eyepieces par focal:

http://www.televue.com/engine/TV3b_page.asp?id=23&Tab=_intrav

If my main field of interest was the deep sky I would go for a reflector every time. I can't afford, house or handle the sort of aperture in refractors that I can in reflectors.

12" in reflector:

12 inch refractor:

I believe these are accurate and independently measured:

24mm - 42°

20mm - 49°

16mm - 52°

12mm - 58°

8mm - 70°

So good and bad news, so to speak !

3 hours ago, PaulB said:

Thanks Steve.

I have already done that. If I remove the centre dust cap I can increase the focal length from F5 to F10.

When it arrived, thank you FLO. It said on the box. "May Contain Clouds" and they weren't kidding 😆

Actually the focal length stays the same. The focal ratio changes because of the reduction in aperture. If you reduce the aperture to 16mm you will get to F/30.

Apologies if you already knew that

If you buy a complete set of Delos it's worth noting that the 17.3mm and the 14mm reach focus at a point that is about 8mm further inwards than the rest of the range.

Nice report - thanks

Really fascinating objects, globular clusters.

Here is another one, when you are next observing in the vicinity of Lynx:

They both look great and work excellently too I'll bet

I love wooden tripods. Really finishes off a scope setup well and they are really effective too

A good alternative to the TV 40mm plossl might be the Vixen 40mm NPL. I believe the NPL's use a figuring approach to the lenses that are similar to the TV Plossls. The 30mm NPL is certainly very nice for it's price.

The Skytee II might be OK. Depends how fussy you are about stability.

On the double stars I think the 127mm triplet will be better than your current scopes. On the deep sky, the 7mm over your 120mm F/5 will make a slight difference but the scope will be a lot heavier, longer and will take longer to cool down than the 120mm achromat.

If you go for the triplet 127, make sure you have a good returns policy. If the collimation is knocked out of whack in transit it's a specialist job in sorting it out.

What mount do you have in mind ?

These 5 inch triplets are quite heavy and long scopes - they need stout mounts.

If you need to buy another mount as well, it would well skew the equation somewhat.

Maybe a candidate for triple layer boxes like Takahashi use ?

27 minutes ago, Geoff Barnes said:

A bit of a dilemma for you @John, where on earth will you put your next scope without upsetting your better half? 🤔

I can put a strong shelf in above the refractors and fit an 8-11 inch SCT or mak-cassegrain in there

It's called "scope corner" already so might as well go for broke !

1 hour ago, Paz said:

..I like all the refractors having finders and diagonals loaded and ready to go, I bet that saves a lot of hassle.

I keep the finders off the dob though - too much chance of whacking something on the way out of the french windows.

59 minutes ago, Simon Dunsmore said:

2 hours ago, John said:

.....Wouldn't want to drag that dob into a field though....

Fortunately it's not too heavy lifted in two sections. 10kg for the base and 16kg for the tube. I've taken it to star parties quite a few times.

You look very well organised there Simon

My scopes, mounts and eyepieces all live in a corner of the dining room. I just lift the scope or scopes that I'm going to use out through the french windows and onto the patio where I observe from.

Magnification limits are theoretical assuming perfect optics and perfect seeing conditions. Real world conditions mean that somewhat lower magnificiations are much more useful.

Much astronomical observing is actually done at low or medium magnifications.

17 minutes ago, Sunnydays said:

Isn’t 18mm eye relief pretty good? That’s what the zoom i was looking at listed it as? (Apertura 9mm - 27mm Zoom Eyepiece - ZOOM927), The Baader is 12-15mm which is still really good right?

If the eyepiece actually has that, 18mm is generous eye relief.

Often the actual usable eye relief is rather less though. The eye cup design and eye lens recess can eat into the eye relief.

If the seeing conditions are not so good, globular cluster resolution suffers as well.

I have an RACI 9x50 Celestron finder but I don't notice that it is stopped down. It performs very similarly to my Skywatcher and Orion 9x50 RACI's.

There is a light baffle fitted inside the tube just in front of where the diagonal attaches but that looks as if it would allow the full light cone from the objective through.

Congratulations on the 5mm XW John. Like @Timebandit I have owned one for many years and find it an extremely well made and high performing eyepiece. It is my favourite lunar eyepiece with my 12 inch dob

I too have ended up with a "short set" of XW's

My 12 inch dob has the same Celestron RACI illuminated finder that you have alongside a Rigel Quikfinder. I've also owned a few Telrads and they are very good as well. The Baader Skysufer III is a competent single dot finder but having the defined field circular reticules that the Rigel and Telrad has is a great help with star hopping.

1 hour ago, Barry-W-Fenner said:

Right now I get it. Thanks Ricochet. I do have a 2" adapter the same length that I can use. I thought that with the baader clicklock I would be doing away with adapters and attaching directly to the focus tube. However that is not the case....

 

Looks like my earlier post DID apply to your focuser after all.

You do need the 2 inch adapter because the focuser drawtube is a bit over 2 inches in diameter so you can't put the Baader adapter straight into it.

1 minute ago, markse68 said:

like i said John, i don’t have this issue with my other xws so no- not generally but yes perhaps for the 7 when looking at Jupiter 😉

Another reason why cherry picking from ranges is better than going for the "complete set"

I had the 12mm and the 17mm ES 92's for a while. The ergonomics and eye relief of the 12 just didn't work for me but the 17mm, after some practice, I am getting used to and I know like. The 12mm went to a new home and its still a superb eyepiece. Just not for me

I've avoided the 14mm and 20mm XW's up to now because of the reported field curvature but it might be that they are absolute gems for me if I do try them one day

Only one way to find out ......

3 minutes ago, markse68 said:

well my 7mm ortho didn’t have this issue 😉 Nice to have the extra fov and er though for sure.

So orthos might be better choices for you than wide fields with long eye relief and large curved optical elements ?