John

Just be aware that the Baader UHC-S (if that is what you have in mind) is really a broadband filter. It has a much wider band pass width than other UHC's. I think a "conventional" UHC such as the Orion Ultrablock or Astronomik UHC would be a better choice. I find an O-III pretty effective with my 100mm and 102mm refractors.

Thanks both. The scopes that I would use it with are F/9 and F/9.2 refractors. A flourite doublet and a triplet. The ED120 is F/7.5 but inward focus will be an issue with that one - I only have around 30mm when at focus. The F/9 and F/9.2 are binoviewer friendly (not that I use one) without a barlow so I am hoping that I can just pop the ADC on and use it with those without a barlow or other adaptation ?

I'm so sorry - that was a typo (which I have now corrected). Since I HAVE been using Gorilla tape the mount has been firmly held to the scope. Sorry for the confusion ! My finder clips firmly into it's bracket so I have not needed any additional fastening there.

Still easy to pick up with 11x70 binoculars tonight but I could not get it with the naked eye. Maybe when it's completely dark ? Seems like an old friend now even though it's slowly fading.

I'd go for a UHC personally and add an O-III in due course. I've tried a few CLS / Skyglow / broadband filters and found them rather innefective to be honest with you.

Strange - I don't find that I need any ties on mine not that I'm using the Gorilla double sided tape

A barlow isn't mandatory is it ?

One of our members owned one of those I seem to recall but I can't recall who it was

That sounds like the effect of varying seeing / transparency as you were observing and also you "getting your eye in" so to speak. Occasionally you get a piece of optimum atmosphere over you and the detail pops teasingly into view then you blink and it's gone again. Observing for a period of time gives you more chance of catching these moments. These face on spiral galaxies are usually a lot larger than we can see visually but we might get the occasional glimpse of what our scopes can do if take somewhere truly dark and transparent. Seeing them is one thing, seeing some spiral form in them another and seeing the full extent of their structure something else again. How do you know what you are seeing and are not seeing ? - I guess that is down to reading the reports of others using similar equipment and practice, practice, practice. Personally I like to be able to repeat an observation of a challenging object at least once before being sure what I've seen. Sometimes the subsequent attempts convince me that I didn't see it the first time and sometimes I get the warm glow of confirmation. It's those little fleeting moments (and this goes for planetary detail as well) that keeps us "in the game" I reckon The Horsehead Nebula is probably the most challenging target that I have observed. I guess I'd been preparing and practicing that for a few years before I was finally convinced that I had managed to see it. One of the least impressive objects I've ever observed but still mighty satisfying Nice sketches - I'm sure they were both accurate at moments during your session

On a practical note, how much inwards focuser travel do the ZWO and Altair ADC's eat up ? I've seen a figure of 57mm for the ZWO but that sounds a lot to me Thanks

The Vixen Porta Mini has slow motion controls and the centre of gravity of the scope in a better place: https://www.teleskop-express.de/shop/product_info.php/language/en/info/p2933_Vixen-MINI-PORTA---Azimutal-Mount-with-tripod---friction-control---slow-movement.html

Congratulations. Pretty decent 2 inch eyepiece. Quite light as well. I have the 30mm and the 40mm in that series.

Vote with your wallet Alan ! There are other good options out there.

Yes, lots of them, but you need to know exactly where to point the scope to find them. A good star chart is essential and also making sure that the finder scope is aligned as accurately as possible with the main scope.

I'm finding something similar with my 7.2mm - 21.5mm zoom + Baader 2.25x combination, especially with my refractors. I have not quite reached the point where my top end 1.25" eyepiece collection gets the chop but, you never know .........

Having invested several £thousand in planetary scopes a few years back I guess it would seem churlish not to try a device for £100 or so at some point

I fell into the trap of commenting on the options that the OP is considering There are other very good options of course

So it's use an ADC or don't bother then ? As per the title of this thread - it appears that they are essential for good (serious ?) planetary observing even when the planets are significantly higher in the sky than they are now.

TV have changed the design of their undercuts in the past few years. They have chamfered the lower cutaway edge to reduce the chances of it snagging as the eyepiece is removed.

SGL is a little bit older than that. Helen and I joined around the same time, about 14 years ago. I think the forum had been around for a year or so before that. The earliest member that I can find joined in June 2005. I joined in November of that year. I think back then FLO was pretty much a one-person business working from their house ? I ought to say that I've been a member of the other forum mentioned above for a similar length of time.

Optically they are both exactly the same, it is just the mount that is different. The aluminum legs do the EQ3-2 mount no favours when trying to handle the long tube of the 150PL. The dobsonian mount is much steadier and the eyepiece and finder of the scope remain in an accessible position at all times. The equatorial mount can have motor drives fitted or even a GOTO system but the EQ5 mount on steel tripod legs would be the minimum that I would consider for the 1200mm focal length tube assembly.

My highest power eyepiece is actually 2mm - one end of the 4mm - 2mm zoom. I use that very infrequently with any of my scopes. I suppose I could use my 2.25x barlow lens on it and have a 1.77mm - 0.88mm zoom but somehow I doubt it would be of much use

I've chosen eyepiece but I am a self confessed occularholic

My most used high power eyepieces are in the 6mm - 3.5mm range. My scopes range in aperture from 90mm to 300mm and in focal length from 630mm to 1590mm so the range of powers that the above eyepieces give is wide - from 100x - 450x. I find that I use 200x - 300x surprisingly often. I use high powers on planets, the moon, double stars, planetary nebula and sometimes to tease out faint point source targets such as supernovae. I find having a range of high power eyepiece options is helpful because the magnification that works the best varies due to seeing conditions as well as the needs of the different targets. With your Skymax 127mm I could see that both the eyepieces that you are considering would prove useful.

If FPL-53 glass has been used for the ED element the chances are that a suitable glass has been selected for the 2nd element as well. FPL-53 glass is very expensive - there would be little point in using an unsuitable element to mate with it. It is the combination of the two suitable glass types that controls the CA levels rather than just the ED element.