John

Try a good O-III on the Owl or the Veil and the difference over a UHC is quite noticable.

The Nikon NAV HW's cost around £980 each I believe. The ES 92's cost £379 each. £600 quid per eyepiece is quite a difference I didn't mention the Ethos equivilents in this thread because I thought that their price tag would cause a stir. I'm glad that the NAV HW's are so good

Can secondary adjustments be made with these scopes and those like them ?

Limestone or granite ?

It is odd when metric and imperial are mixed but I'm as guilty of that as anybody I refer to 1.25 inch or 2 inch eyepieces and then give their focal lengths in mm and also to my scopes apertures in inches but their focal lengths in mm I'm going to use cubits and palms from now on

It was a Baader UHC-S filter that 1st showed me the Veil Nebula, with a 100mm refractor. That was around 10 years ago so I think the UHC-S was quite a new product back then. I got it because I read (from Baader) that it was designed to have a more generous band pass so would be suitable for smaller aperture scopes. As I moved up in aperture from 100mm I found that "proper" UHC's and O-III's were more effective than the UHC-S. Which is sort of what I expected. Nothing wrong with the UHC-S though. It is good quality and does what it is designed to do.

Are there any baffles that will need re-positioning John ? Actually, thinking of it, what are the baffling arrangements of the scope ?

I use one of these with my 12 inch F/5.3: Cheap, simple and it works.

Hi, The 2.3mm gives 174x magnification with the 70mm Travelscope. The scope is designed as a portable low to medium power instrument. 100x is probably about as far as you can push it really.

When I visited the Herschel Museum in Bath (highly reccommended by the way) I was struck at the really short focal length eyepieces that the Herschel's used when observing. Apparently over 6,000x magnification on some occasions I came across this old paper, held by the RAS, on this topic by W H Steavenson for any that might be interested: http://articles.adsabs.harvard.edu//full/1924MNRAS..84..607S/0000607.000.html

Perhaps we need an "extreme observing techniques" thread

Worth bearing in mind that when looking for the really faint and elusive stuff, ANY light near your eyes (red or otherwise) will impair your ability to detect it. When I was looking for the Horsehead Nebula I needed to be dark adapted to a higher level than I have done before. I isolated myself from every form of light that I could for about an hour before try for the Horsehead and also observed faint objects to "limber up" as my eye got adapted. I turned my finder reticules off and just used the optical finder as well. Extreme challenges need extreme methods !

It took me a long time to realise that there are some occasions when using very high power is a useful "tool" for certain tasks. For example, I had observed Uranus and Neptune in the past at 200x or so, enough to see them as disks. I read somewhere that it was possible to see some of their moons with my scope but very high magnifications would help tease these tiny points of light out of the background sky. Using 300x - 400x has helped me to see Neptune's moon Triton and Titania and Oberon. I would still like to see Umbriel and Ariel and also Phobos and Deimos at Mars The views of the planets themselves are not (usually) augmented by such high magnifications of course. While they may not be the the most used tools in the tool kit, very high power eyepieces do have their uses.

No. I guess there is some coma visible at the field edges with my F/5.3 dob and the very wide angle eyepieces but I've not noticed it so far. Astigmatism from the eyepiece bothers me much more. 100 degree eyepieces are not something that everybody gets on with to be honest with you, regardless of how well they perform. Quite a lot of folks prefer the 68/70 degree apparent field, some are very happy with 40/50 degrees. At least we have the choice these days

With regard to DSO's in other galaxies, the huge star forming region of nebulosity, NGC 604, in Messier 33 is reasonably straightforward to observe even with moderate aperture scopes.

I don't image either - apart from the odd phone at the eyepiece shot. The shorter refractors will show some false colour (CA) and the longer ones less, or practically none in the case of the 80mm F/15. The shorter refractors are good for low to medium power deep sky type observing but not so good and lunar and planetary observing. I've owned the 127mm F/9.3 and the 152mm F/8 achromats (by Meade and Bresser now) and, personally, I prefer those to the shorter ones. The longer ones are harder to mount steadily though. If you are considering as wide a range of specifications as you seem to be, it might be worth starting a new thread to kick around the options. This one is about the ScopeTech 80mm F/15 of course

You won't see that when the scope is properly focused on an astronomical target. You need a 1.25" adapter for 1.25" eyepieces and the 2" adapter for 2" eyepieces. Don't put both adapters in the scope at once - they need to be used separately.

That's a pretty broad range of options when you include the 80mm F/15 in with them ! Is the desire simply to try a refractor or do you have a specific aim in mind ?

That looks OK to me. Quite a few mounts still just have one large locking screw and a smaller security screw so two large ones is a step up.

True ! My T-Rex alt-az is still on a steel tripod and is working splendidly

What, no wood ??????

A good, low cost, wide field eyepiece is the Maxvision 24mm. It has a 68 degree apparent field of view which means that it shows as much sky as a 1.25 inch eyepiece can and with enough magnification to keep the background sky reasonably dark. There are other eyepieces with a similar spec and also good performance but the Maxvision is one that you might find within your budget. They are out of production now so you will need to find a used one but they are well corrected eyepieces for their price which is more than can be said of some of the low cost wide field eyepieces.

A few times a year to society outreach events but not this year so far, for obvious reasons. I do most of my viewing from my back garden which is not too bad for light pollution although there is some.

Actually I wrap it in an old childs sleeping bag that was my daughters when she was a lot younger. I don't use a seat belt on it though - it neatly fits between the end of the boot and the rear of the passenger seat of the car so it's not going anywhere.