John

ED = Extra low Dispersion glass. One element or more of this more expensive glass. It's also used in ED doublet refractors and triplet apochromat refractors. You will see much discussion of the various ED glass types when refractors are discussed !

Sounds like you have got the relationship between barrel size and max field of view size correct as well

If you want wide fields and long eyepiece focal lengths then the 2 inch format is the way to go.

Because they have a 60 degree apparent field of view, the field stop (the ring inside the eyepiece that defines the field of view) would need to be larger than the inside diameter of the 1.25 inch barrel to maintain that beyond 25mm focal length. In other words, longer focal length BST Starguiders would need to be 2 inch format eyepieces. There are other eyepieces that already occupy that niche such as the Panaviews and the Aero ED's.

A 30mm in the 1.25 inch fitting, such as the Vixen NPL 30mm for example, would have an apparent field of view of around 50 degrees (limited by the inside barrel diameter again) so it would not show much, if any, more sky than a 25mm with a 60 degree apparent field of view. Hope that makes sense !

Personally I would buy the package - that is what I did when I bought my Tak FC-100DL. You get the tube clamp, finder and finder base then all of which match the scope.

I know that £300 seems expensive but that is the world of Takahashi accessories

Unless you already have them, you will also need a diagonal of suitable quality plus a dovetail bar to suit whatever mount you are going to use.

21 minutes ago, Martin13 said:

Thank you Mike really good info there. I will see if I can find the Takahashi you mention. I have a Delios 10mm eyepiece on loan at the moment with a view to buy it.

Here you go:

https://www.firstlightoptics.com/takahashi-fc-100-series-refractor-telescopes/tak_tfk10310.html

Very few in private hands as yet so the used market will be somewhat bleak I would think.

Tough question to answer. As an observer I think it might be Jupiter for me. Always something going on there and the details change as you observe.

20 minutes ago, JOC said:

I was scanning the thread titles and saw Eyepiece 101 and thought, 'my word someone's bank balance has been hit hard!!!'

William Optics did actually have a 9mm 101 degree eyepiece:

That extra 1 degree makes all the difference !

Can we keep buying and selling to the classifieds section please ?

Thanks

Also bear in mind that buying from the USA or Canada (or elsewhere outside the EU) will attract import duty and handling costs which adds around 20%-25% to the price for the buyer.

50 minutes ago, Marvin Jenkins said:

Just wanted to ask an open question to all of the above. As yet I have not got past A to D. Halfway through this thread I notice that #chiltonstar said that a good night exposes the F star an excellent night the E star.

This seems to be echoed by further posts. Don’t want to sound obvious but why is the alphabetical E star harder to see than F? Surely someone looked through a telescope back in the day and said “look a fifth star in the trapezium” the E star!!!

Why are they out of order to the views recorded on this forum? Surely if it is A B C D star then the next easiest is E followed by F not the other way round.

Marvin

 

E is easier to see than F I find. The distances between the E & F stars and their partners A and C is pretty much the same (4.5 arc seconds and 4.6 arc seconds) but C is somewhat brighter than A and thus the C - F pair is a more uneven brightness pair and therefore harder to split.

Uneven brightness between components of a binary system makes them harder to split even if the separation between is relatively unchallenging. Sirius A and B being the most extreme example.

Observing them at the altitudes they reach in the UK also adds to the challenge of course.

3 hours ago, Captain Magenta said:

this caught my eye a couple of weeks ago ...

Superb - I can vouch for the quality of the LZOS optics - absolutely top notch 

I've been quite happy with my cheap plastic cheshire for the past few years. Perhaps I've been kidding myself

The distinctive lines of a Vixen classic and the Nagler zoom of course !

I don't find the F/7.5 focal ratio of the ED120 too hard on eyepieces. I still like to use well corrected ones but they also get used in other scopes with faster focal ratios.

The Morpheus would be excellent in the 120 I reckon although I've not yet had the pleasure of using one of those

The 120mm ED doublets can handle quite a bit of magnification so some choices in short focal length eyepieces would be very useful in due course.

35 minutes ago, Piero said:

Not sure what some members above meant by star testing in this thread. Do they mean "checking" or "collimating" with a star test? ....

 

In my case, I use the star test to check that the collimation is good following adjustments that I might have made using a cheshire eyepiece. I agree that trying to actually collimate using a star test can be a trying process.

There is another clear patch passing over now but I've given up and bought the scope and mount inside now. Didn't really get a clear run at much tonight. Might pop out with binoculars later.

Great thread folks !

The 10mm BCO is a superb DSO eyepiece.

I'm also glad that I'm not the only person not to be bowled over 100% by the Leica zoom. It's a great eyepiece, no doubt particularly for a zoom but didn't make me feel that I wanted to part with my XW and Ethos collection.

Too many clouds about here to have a long enjoyable session unfortunately. Just a few doubles plus Venus with my 100mm refractor in short bursts between the cloud cover for me. better than nothing though

I guess the comet is Panstarrs Mark - how was it tonight ?

Great stuff Baz !!!!

I've been in and out several times tonight due to clouds blowing over and light rain. Bit frustrating but I did do some observing at least.

Now you have seen E & F they will be that much easier the next time around, as long as the seeing is decent.

Cloud cover again and light rain. Scope back in greenhouse. Me back in house for coffee

I was just starting to enjoy myself as well !

Quite nice just now so I have the 100mm Tak out. A big chunk of cloud came over about 30 mins ago and I thought that was the end of the fun but its cleared again now so I'm glad I kept the scope cool in the greenhouse

I'm getting E & F Trapezium intermittently with my Tak 100 refractor this evening. The Pentax XW 7mm (129x) is showing them more clearly than my shorter focal length eyepieces. E shows more often than F but now and then both pop into view together. Must be those little moments of steadier seeing 

Good choice. 171x is medium to high power with your 200P. Room for a shorter focal length in your set as well but that can come in due course

2 hours ago, R.frankish said:

Yer I just got barlow lens and 14mm eyepiece that I seen ppl saying was good but I was just trying it out and couldn't focus good enough just hoping I was looking at something to close 

I think this is being covered in your other thread on your eyepiece issue:

The closest focus distance of newtonians can be as much as 100 metres away. Racking the focuser right out and pulling the eyepiece partially out of the focus tube might enable you to reach focus. The instrument was designed to view objects a lot further away of course 

These are excellent images - thanks for posting them

Same here - the nice weather earlier has been replaced by quite thick clouds now

I was asking for trouble by starting this thread, wasn't I ?

I supposed to be helping with an outreach event on Thursday evening, which looks the best bet currently.

The flooding in some parts of the country looks awful