John

Good news on the views !

Some of the brightest galaxies will be visible with the scope. In particular you should seek out Messier 81 and 82 in Ursa Major and Messier 31 in Andromeda. They will just look like faint smudges of light but they are galaxies. Low magnification is what is needed for these and a dark night with no moonlight in the sky and, if possible, away from other forms of lighting as well.

23 hours ago, heliumstar said:

If all is well with the scope otherwise why not just arrange for them to send you a new focuser?

Then the owner has to fit it, check that the optical axis lines up with the objective, and adjust the focuser tension to suit. If all is not well with the scope then, the supplier can always point the finger at the focuser not quite being installed correctly.

I think it is better to allow the suppler to supply a complete new unit and take responsibility for the overall quality and operation of what is supplied.

7 minutes ago, markclaire50 said:

Thanks John. I've not given up with the mak, but I'm not sure it'll pick out the F star, looking at Olly's post above! ??

What can I say ?

I get E &F consistently with my ED120 refractor, E consistently with my 100 / 102 refractors and F on really good nights with those smaller instruments. My observing experience is probably less than Olly's and my skies undoubtedly worse.

But thats just me with my eye from my back yard in a semi-urban environment

"Your mileage may vary" as they say

Lifetime scope ? - we have all been there, several times !

You already have a great scope so you can hone your skills on that (ie: E & F Trapezium) so the next one you get, you will really hit the ground running, so to speak !

Good luck in finding the one for you

You already have a Skywatcher 127mm mak-cassegrain don't you ?

I worry a bit when I see scope decisions based on the achivement (or not) of a very specific observational challenge.

Ten members here could say that they can easily see E & F Trapezium with a certain scope, then you get one, and can't make them out. I'm not sure where that has got you ?

Have you got enough finder shoes there on the ED120 Paul ? 

Eyepieces, diagonals etc come in 3 sizes generally. We are talking about the diameter of the chrome barrels with these sizes:

.965 inch - the older type scopes. Not used these days and new accessories in this fitting are not available.

1.25 inch - very common fitting these days and the vast majoority of scopes take this size.

2.0 inch - another common size these days for wide angles of view at low to medium magnifications.

Your scope will be either .965 inch or 1.25 inch fitting.

To try and get the scope to focus without a diagonal, put the 25mm eyepiece in the focuser tube and extend the focuser tube as far out as it will come by turning the focuser wheels. You might also be able to create an extension tube from the part with the 2x Barlow printed on it combined with the chrome part of the tube with the lens in it - the black part with the lens in would need to be removed and should unscrew from the chrome section. Try the extension tube you have now created between the eyepiece and the focuser tube and then move the focuser inwards and outwards to see if you can get focus. All this could be done with a distant target (a km away or more) in daylight rather than waiting for a clear night.

The scope may need a diagonal prism / mirror in place to reach focus. This picture below is of the scope in the link that Dweller25 posted earlier in this thread and you can see the diagonal in place and the amount of chrome drawtube that is showing. Without a diagonal in place the focuser would need to be racked out quite a bit further to get an eyepiece on it's own to reach focus.

Mr Spock must have better eyes than I have !

I'd never call seeing the Pup star an "easy spot" in any scope that I've seen it in. There are some very experienced double star observers with large scopes who have failed to see Sirus B so I don't think it ever falls into the "easy" category, from the UK at least.

I had the Pup in view (to my eye) with my 12" dob last year at a Society star party but none of my club member colleagues (some experienced observers) could see it at all

Mind you, they did not have the Vulcan eyesight

I'm not against the 9.25 SCT's though - they can be superb scopes if you get a good one.

37 minutes ago, parallaxerr said:

Well I'm going to phone them in a bit, could well be FCD-100, who knows. Avoiding the question sends out mixed messages though.

It really doesn't matter I suppose, provided the views are good, just nice to know.

FCD-100 is pretty close to FPL-53 in terms of it's specs. FCD-1 is pretty much the same as FPL-53. I believe the FCD glasses are by Hoya while the FPL's are Ohara glasses.

As I mentioned in my earlier post, there is quite a price difference in the cost of the glass blanks between these types which is usually reflected in the cost of the scope. The last figures that I saw (2017) showed FPL-51 costing 11x as much as Schott BK-7 crown glass and FPL-53 18x as much as BK-7. I reckon there is a similar difference with FCD-100 and FCD-1. Such cost differences will have to find their way into the retail price I would think.

What annoys some manufacturers and retailers I think is that all the talk is of the glass type in the ED element but the mating element(s) glass type, the figure and polish of the optical surfaces, the coatings used and the objective cell design and quality all contribute significantly to the end performance of the objective and yet are rarely discussed.

4 hours ago, markclaire50 said:

Thanks John. Pretty certain 7-10" will be aperture I go for. But it's the specific type of scope I'm ruminating over. Newt, mak or sct. Won't be a frac. 

If you get a 7-10" frac be sure to post lots of pictures

More seriously though, much above 130mm and I would be looking at a high spec newtonian I think - something like an F/6 with top quality mirrors and a relatively small central obstruction. Mak-newtonians are good as well - very "frac like" images

I have a 12" OO F/5.3 with a 21% central obstruction and a good quality primary in it. It can show really superb planetary images when the seeing is good. When the seeing is average to fair (ie: more often !) it still does well but my 120mm and 130mm refractors get mighty close despite the big aperture difference.

A lot of what can be seen through a scope is about the seeing conditions and the experience of the observer in teasing out the detail. When you identify the factors that contribute to the quality of the image your observe, the scope and eyepiece are lower down the list in terms of impact, generally.

Look at what one of our members here can see with just 3.9 inches of aperture:

I think the part marked 2x barlow lens screws onto the threads top of the chrome part of the tube to the upper right of the picture to create a complete barlow lens which the looks a bit like this:

"... features on ganymede ..."

When you say features I assume you mean the very subtle albedo changes that it is possible, under superb seeing conditions, to detect when using a really good 8 inch or larger aperture scope ?

Many scopes are capable of showing the 4 brightest Jovian moons as disks but seeing brightness variations on those disks ....... well thats a different level of observation

Hello and welcome to the forum.

The scope you have inherited is a newtonian. If you could post an image of it we can give you more info on the model and it's age and specification and recommend some eyepieces.

The stars look like points of light even when magnified hundreds of times with a telescope. You never see them any bigger. A telescope does help you to see fainter stars than you can with your eyes. Some stars are double or triple through the scope. Some cluster together. There are lots of things a scope can show you that our eyes cannot see.

If your scope has a 10 inch main mirror then it is a very capable instrument

3 hours ago, BGazing said:

Astronomik have narrowed their bands a couple of years ago. I have their new OIII and it is superb.

I also have DGM NPB and it is good on nebulas, but I honestly did not compare it with Astronomik. It has some ghosting on the stars, for those who are concerned. 

I believe Astronomik are now making Tele Vue's new range of narrowband and line filters, which are also starting to get some great feedback. Much better than the previous versions of the Tele Vue Bandmate O-III and UHC I understand.

You are quite right - you do need to make sure that the finder scope (the little one) is pointing in exactly the same place as the main scope is. This can be done in daylight using a distant target such as a chimney pot or telegraph pole - something a few miles away preferrably. Nowhere near the Sun of course - never look at that with any sort of optical aid.

Viewing from inside the house is not ideal because of the stray light around and also the heat from the house and window glass distoring the view. Outside is where the best views are to be had but you do need to wrap up warm at this time of year.

Posting some photos of what you have will help to identify any thing that is missing.

I really liked the AZ-4 that I had but even on a 2 inch steel tubed tripod (CG5) the ED120 was too much for the mount apart from low to medium magnifications. Funny how mounts have a sort of watershed loading in terms of tube length and weight - just tip over that and things just don't seem so stable any more. I could see a 150 mak-cassegain being find on the AZ-4 though - short tube.

1 hour ago, david_taurus83 said:

Thanks for the advice on the alt az mounts. Looks like the AZ4 is the one to go for. The steel tripod is a no brainer. Just need to stretch my own budget now. Seems 100mm F7 is the the one to go for. I messaged AA yesterday to see if they can confirm the type of glass used in the Starwave 102ED

Are you interested in the ED102 Ascent model or the ED102-R ? - the latter states FPL-53 in the blurb.

The diagonal would look a bit like the one pictured below. The 2x Barlow lens should have a glass element in the bottom end of it. If you have 2 eyepieces with different focal lengths (eg: 20mm and 12mm or similar) then you can get started. The diagonal would make viewing through the scope at the sky easier though (less back / neck breaking !).

The offset device is an erecting prism for terrestrial viewing. It turns the image that the scope produces into the orientation that our eyes see.

I would do everybody a favour and destroy the sun filter. One more of these dangerous devices less is a good thing.

Does it come with a diagonal prism / mirror (goes in between the end of the scope and the eyepiece) ?

This will make viewing through the scope at the sky somewhat more comfortable.

The Stellarvue ED102 is an older model I think. The 102ED Access has replaced it and I think they changed the glass in that one.

If the glass type is not mentioned assume FPL-51 or a Chinese equivalent. The price would indiate that too. FPL-53 (or equivilent) objectives are quite a bit more expensive due to the cost of the ED glass blanks.

Mike has confirmed my feelings on the differences between the AZ-5 and the AZ-4. The latter will hold more and hold it steadier IMHO. No slow motion controls though. Skytee 2 is a much more heavier duty mount again - mine holds my 130mm F/9.2 triplet refractor pretty well and that scope would completely swamp an AZ-4.