John

"... for DSO, which makes up 95% of my observing... "

Is this balance likely to change ?

If not, going for an ED for 5% of your viewing interests might mean accepting aperture compromises to DSO viewing. With your desire to upgrade the focuser and continue to use the AZ-4 mount, it's a tricky balancing act

William Optics used to market a 110mm F/5.95 FPL-51 ED doublet which might have fitted the requirements and it sells, when it comes up, for £500-£600.

17 minutes ago, parallaxerr said:

.. though many argue that the better colour correction and figure of the glass would negate it.

 

It would for planetary / lunar/ double star viewing but not really for observing DSO's.

Thanks Louis - Glenn it was

I used to have the 24.5mm and 18mm Series 1 SPEERS-WALER's (many years ago) and they were great in the slower scopes I had then (F/10) but they did require a lot of inwards focuser movement to reach focus. When I got my F/6.5 Vixen ED refractor though they showed quite a lot of edge field astigmatism which was not to my taste at all so I let them go. From reports I read back then, the longer focal lengths in that series were the weakest and the field correction improved a lot in the 10mm and shorter focal lengths. The zoom was considered a bit of a "Nagler killer". They were bulky eyepieces (tall) but not as heavy as you would expect them to be.

I'd be interested to try the series II and III SW's and see how they developed over the years.

I believe Greg Speers used optics sourced from Japan, Taiwan and China as the years progressed but many of the Antares products were assembled in Canada. They did have some issues with dust between the optics on new products a few times. I think that may have put off some potential dealers for their products ?

2 hours ago, Paul73 said:

Some great work there. For the rest of us, who don’t have the requisite skills, there are alternatives to Feathertouch products. I consider the Moonlite unit on the side of my Dob to be really pretty good. But, I can’t help thinking that I could make some improvements ??.

 

I like the Moonlite focusers (I have 3 of them currently) but I now have a Feathertouch on my 130mm triplet and thats in another league again to be fair to it. The engineering and design quality is really superb on the FT. I can see why there is a cost associated with this sort of quality.

Great stuff Neil despite not (quite) getting it.

I reckon mag 14.7 is the faintest point source that I've seen with my 12" dob so you are doing well to get close to that with your 10". Sounds like you will get it next time out !

It's great fun to try and see these immensely distant objects I think

I think all the filters mentioned are quality items but they just do things slightly differently so it's up to personal preferences which are preferred perhaps.

I tried a couple of low cost UHC filters recently that worked up to a point but the better quality brands seem much more effective. I think the cheaper ones have more generous band pass widths and perhaps lower overall % peak pass rates which hold them back.

There is obviously more to making a good filter than there might seem initially.

I've done the same comparison and, overall, preferred the NBP. Yes there was a red tint to stars but I thought that the DGM NBP bought out a little more structure in nebulae than the Astronomik UHC did with my scopes / eye / skies and it's the nebulosity that I use such a filter to see.

I recently asked about the Astronomik UHC again (it's been a while since I owned one) on another forum and it got a bit of a rasberry from the folks there, which surprised me because Astronomik make good filters, if a little "wide" for some tastes.

Filter preferences are pretty personal though so I've no doubt that opinions will vary as is often the case !

I'd love to try another Astronomik O-III though. That one was all the deep sky filter that I needed for quite a while.

For a GOTO scope like the C8 SE I tend to agree with the above and the basic RDF supplied does the job.

I don't use GOTO so finding is an important business for me. My preference is a RACI optical finder mounted alongside a Rigel Quikfinder (similar to a Telrad). For really detailed star hopping a low power / wide angle eyepiece adds the final touch:

Not normal at all. The Rigel circles look like this:

You need to view them against a really dark background to see them (they are fine when seen against a dark sky) and your eye needs to be a few inches behind the finder window.

Maybe the window on your Rigel has got scratched ?

The 7.2-21.5 zoom is pretty good quality and may well be from the same source as the 9mm-27mm that is the subject of this thread.

A similar post on the Coudynights forum got no feedback either, which suggests that these might not be a good seller !

https://www.cloudynights.com/topic/540173-9-27mm-zoom-eyepiece/

Here are mine. I'm down to two cases now

A Powermate, TeleXtender or Focal Extender (Tele Vue, Meade and ES products) move the focus point either not at all or very little.

Nice sequence

I wonder what happened to the vulture ?

I have compared the 1.25" 2x ES Telextender with a 1.25" 2.5x Powermate and the difference was very slight indeed to be honest. I guess it's the same as is being found quite often these days ES have got within a few % of the Tele Vue equivalent performance for quite a lot less money.

While I've not used the 2 inch ES Telextenders I can't see any reason why they would not mirror this situation.

You can't mix ES products with TV in the eyepiece case though - they squabble when you close the lid !

This thread is in danger of becoming an elaborate discourse on the topic of diagonals which might not actually be of much practical help to the original poster

I think Moonshanes post hits the nail on the head with regard to the original question:

48 minutes ago, PGM said:

I wonder if any Tak FC-100D owners could help me with yet another focusing problem. Previously I could not bring any eyepiece to focus, but @mikeDnight told me to remove the #81 adaptor and that solved it completely. Now I purchased a barlow (Celestron X-Cel ED Barlow 2x) and I can't achieve focus. I've tried with and without the #81 adaptor.
Any suggestions?

Usually with a barlow in place, you need to find a bit more inwards focuser travel to reach focus. Is that your problem - lack of enough inwards focuser movement ?

The X-Cel ED barlow goes betwen the diagonal and the eyepiece I believe - is that where you are putting yours ?

Edit: could you post a photo of the focuser end of your scope as you have been using it so that we can double check on the componants. The Tak diagrams are all well and good but it's not all that clear which adapter is which.

They are excatly the same telescope under different brandings. The manufacturer is GSO (Guan Sheng Optical). I think the accessories supplied at the same as well. Flip a coin to decide perhaps ?

In the UK these were marketed under the "Revelation" branding. Good scopes. Similar in performance to the Skywatcher dobsonians. Meade dobs (the Lightbridges) are also made by GSO and will contain the same optics as the ones that you are looking at.

Nice choices Alan

I've yet to use a DeLite. A few tempting ones popped up for sale during the Xmas period but I resisted.

I had a 3mm Radian for a while and that was good but I expect the Delite of that focal length would exceed it by some margin being a later design using newer glass types and coatings.

Currently I use a 2-4mm TV Nagler zoom or a Pentax XW 3.5mm to cover that FL and they seem pretty good to me but there is always room for a little more improvement I'm sure

I ran an Ethos SX 3.7mm alongside the Pentax 3.5mm for several months but eventually concluded that the XW was just a touch sharper and scatter free. So my Ethos SX's (I had the 4.7 too) went to other homes as well.

11 hours ago, anachristina said:

....  Anyway here are a couple of photos I tried taking by putting the camera of my phone directly above my 20mm erecting eyepiece. That’s a fair representation of what I see when I peek through the eyepiece... when I took this I was in our living room with bright lights on, and I was trying to look outside the window...

What were you trying to view through the window and how far away was it ?

16 minutes ago, anachristina said:

PeterCPC thanks a lot!! I was actually able to set up my 127EQ a couple of times now but when I look through it I see nothing... I was thinking maybe it’s about the telescope not being collimated so I tried using Celestron collimating eyepiece but to no success.

If you can see nothing it's not the collimation, it's something else. Collimation improves the view in terms of resolution and sharpness but even an uncollimated scope will show reasonably good images of the stars, planets, the moon etc.

Perhaps you could give us more details of what you have been trying to view, the accessories you are using with the scope at the time and the results. We will then hopefully be able to diagonse the problem

I'm pleased that there are positive SW ED150 experiences being had Chris - the scope deserves some good news given the rather uncertain start it had (not yours, which was fine from the off of course).

I'm hoping to have another one to try out for the forum sometime next year

1 hour ago, JeremyS said:

Is that a display case for all your astro kit behind you, John? ?

 

Unfortunately not - I have to make do with aluminum cases. Moy other half seems to have crammed the cabinets with bric-a-brac !

Nice little telextender from Uncle Al

It's the same as the Skywatcher Explorer 200P - made by the same manufacturer.

I wonder if the mirror cell is moving around rather than the primary mirror itself ?

I've owned a couple with this design and they hold their collimation well usually. I generally collimate with the scope at around a 45 degree angle.