John

Some double stars and the moon with my 70mm F/6 ED this evening. Seeing not so great through. Moon was behind the house later so it was worth at least trying for some brighter DSO's. Despite the paltry aperture, I did manage to see M 65 and M 66 of the Leo Triplet group. NGC 3628 was not visible though, perhaps unsurprisingly given the small scope. As Meatloaf sang in 1977, "Two out of three, ain't bad" 🙂

13 minutes ago, IB20 said:

Here’s one for the diary. The next Mercury transit is due 13th November 2032! Almost certainly going to be a cloudy day! 🙃

 

The last one that I saw was on a pretty cloudy day as well. I got lucky with a few breaks in the clouds to snap some photos:

The Myriad has a somewhat more chunky eye cup design than the APM 100's.

4 minutes ago, Alan White said:

Well I found a member of my Astro club that owns a n22 t4 and had a look at it.

Then through it and with my glasses on, I cannot see the whole field stop without moving my lenses about.

Ho hum, time to ponder again.

Was that even with the top section of the eyepiece in the lowest position Alan ?

10 minutes ago, LukeTheNuke said:

It looks lovely! I've never owned a William Optics telescope, alas.

I like the idea of a big frac, and I was trying to persuade myself towards the Skywatcher ED150 just yesterday. But I think I am probably sticking at 120 mm as my biggest frac. I figure, it already feels fairly big to me, and not going higher gives me a good excuse for getting the Edge 8 SCT out.

I keep trying to talk myself into various new scopes, but I think it's just a dob larger than 10 inches where I have a proper gap. Of course, the Frac Fraternity may have different priorities to me!

I'm currently feeling that my 130mm F/9.2 is as large a refractor as I want to deal with. Like you, from time to time I look at 150's but, having tried some in the past, I'd probably go for a different design if I want to get more aperture again.

Impressive looking scope for an impressive price !

I sometimes wonder if these whopping refractors are designed to attract the crowds at astro shows, as much as anything else 🙄

I've not owned or used the 24mm ES 82 but I have owned the 22mm T4 and 20mm T5 Naglers. They were both excellent eyepieces although, personally, I found the 22mm Nagler more comfortable to use (more eye relief and a larger eye lens) and more immersive. I have read of a number of folks moving from a ~20mm / 100 degree eyepiece to the 22mm Nagler and being happy with the switch.

I went the other way but I guess the time might come when I reverse that move 🤔

There are other ~20mm ~80ish degree alternatives now as well such as the Stellalyra 20mm / 80:

https://www.firstlightoptics.com/stellalyra-eyepieces/stellalyra-20mm-2-80-ler-uwa-eyepiece.html

I've not used one of those though.

On 14/03/2024 at 08:34, Nicola Fletcher said:

That’s absolutely brilliant 😂 talk about confusing members of the public - ‘Where do I look?’ Is a valid question! 

 

I’m glad you think that @dweller25. I had a hard time choosing between the two. I read everything online that I could and went for the 180. Cool-down time and mounting requirements were my biggest concerns. I got a clear plastic box for the scope and I just put it outside a few hours before use. I really like the fan on the front of it too and will get one for it. In the end, it would be ideal to try these scopes before you buy one but unfortunately I don’t have any neighbours that have both a 180’ and 210! 🙄

Thats a good solution to cool down.

And I already have the clear plastic box ......... 🤔

Just a quick look at the moon and a few double stars with my 3 inch F/16 refractor this evening. My first look at the moon with this scope - as I hoped, the slow focal ratio resulted in no false colour visible at all around the lunar limb. Craters along the terminator were filled with jet black shadows. Very sharp views at 171x. As I gazed at the lunar surface, I thought of an 11 year old Patrick Moore getting his first glimpses of the moon with his newly acquired 3 inch refractor back in 1934. He must have been mesmerised by the views 🙂

1 hour ago, mikeDnight said:

 I think I've achieved many of my desires as regards visual astro but the pup us one I'd like to tick off. It would however only be a tick as it isn't something that would wow me. The largest aperture I've used for this list is 6 inches, while the smallest 4 inches.

 Things I've wanted to see and achieved are:

Halley's comet,

Colour in the Orion Nebula (pearl green),

Veil nebula along with cirrus nebula,

Alpine Valley central rill,

Spokes in Saturn's B ring,

Streaks in Saturn's A ring,

Encke minima,

Encke gap,

Vortex within Jupiter's Great red spot,

White oval's on Jupiter, 

Festoons, garlands, and barges on Jupiter, 

Clouds on Venus,

Albedo detail on Mercury,

Albedo features and polar cap fracture on Mars.

Olympus Mons,

Detail on Uranus.

IC434, the notch of the horse head, and the Flame nebula,

Nebulosity enmeshing the Pleiades,

Spiral structure and bridging arm of M51,

Dark divide in M82, 

Spiral structure in M81, 

Bright spiral arm in M33, 

Dark dust lanes in M31. 

Veins in M1, 

The success list is seemingly endless, but I would like to see Halley's return, as well as Hale Bopp. I doubt I'll make it to the first as I'm already a bit long in the tooth, and I know I won't make it to the latter unless someone invents an everlasting life pill. May be the central star in M57 would be an achievable goal before I pop off, but I reckon I'll need at least a 7" and top class seeing to catch that!

 

Thats an impressive list Mike and it shows what can be done with perseverance and some skill.

I think it's good to list these things, even if we have achieved them ourselves, so that others, perhaps new to the hobby, can be aware what is possible with amateur equipment.

I can recall quite a few instances during my first couple of decades of observing when I learned that something amazing could actually be seen by an amateur with a modest telescope by reading about it in a book, magazine or more lately on a forum. What I thought was beyond the grasp of the amateur, was actually within my grasp, if I was prepared to push for it 🙂

I did a little testing and measurement of 1.25 inch diagonals, mirror vs prism, for @wookie1965 / Paul. 

After that, the cloud cover allowed a look at Iota Leonis with my Tak 100mm, and that was about it !

On 12/04/2024 at 19:29, wookie1965 said:

Probably about 2/3mm 5mm at most hopefully. 

I've been doing some measuring for you Paul.

I'm using my Tak FC100 so the focuser position at focus is not the same as your Vixen but the difference between using the 2 diagonal types should be the same. 

1st photo shows the 1.25 mirror diagonal (similar to your current one) with the Svbony 3-8 zoom at 3mm which is the setting that needs the most inwards focus. The eyepiece is at sharp focus on a star in Leo.

2nd photo shows the exactly same as above but using the Celestron 1.25 prism diagonal. You can see the additional in-focus gain that the prism gives which I measured at 15mm.

Hope that helps reassure you 🙂

10 minutes ago, quasar117 said:

...Should I see an airy disk both inside and outside of focus? As yesterday I could only see it when racking the focuser in.

If the seeing is not too good, the pattern of diffraction rings around the airy disk will not be well defined on one side of sharp focus as it is on the other. 

This test needs to be done at quite high magnification - around 200x for a 4 inch scope is good.

This is what a decent 4 inch refractor star test should look like under very good seeing conditions:

Under less than good seeing conditions, the image on one side of focus may well look "mushy" rather than showing well defined diffraction rings. You might still get a nice in focus image though.

Polaris is a good test star. 

9 minutes ago, TiffsAndAstro said:

Do you know roughly what it would be at F5 for context?

Well, I believe that it is 4.8mm at F/6 so I guess F/5 will be somewhere in between - say around 3mm ?

There are formulae that can calculate it accurately but I don't recall them offhand.

I'm very sad to hear of this.

Professor Morison gave a talk on double star observing at my Astro Society a few years ago which I found very interesting indeed and I've used the notes he handed out as prompts for observing targets since then.

I also enjoyed his thoughts on optics and other things he posted on his website. 

A big loss to astronomy.

My experience is to get a scope out and see how it looks at the eyepiece rather than to rely too much on forecasts and models.

Very often I've had a good session against the predictions, which I would have missed out on if I'd not bothered to setup.

Of course there are quite a few occasions when the opposite is true but there you go ! 😉

As @Steve Ward posted earlier, if you wait for optimum conditions, your gear could gather a lot of dust and cobwebs in between uses🙄

55 minutes ago, groberts said:

Thanks Michael - how do you arrive at numbers quoted?

Graham

 

Divide the focal length of the scope by the focal length of the eyepiece.

58 minutes ago, groberts said:

Thanks - without wishing to be flippant, budget is not the issue here it's getting a couple of eyepieces will really transform my viewing with the Starfield. IMO I'm sure that FOV and eye relief are a problem for me, so want to make sure whatever road I go down this time those issues are dealt with.

As a matter of interest, is there a zoom eyepiece that might do the trick, thus provide greater flexibility?

Graham 

The only zooms that I have owned / used that offer a wide field of view and image quality that really does match or exceed excellent fixed focal lengths are the APM 7.7mm - 15.4mm super zoom:

APM Telescopes. APM Super Zoom Eyepiece 7.7mm to 15.4mm with 1.25" connector and filter thread (apm-telescopes.net)

and the Leica ASPH 8.9mm - 17.8mm zoom used with an adapter:

APM Telescopes. Leica Zoom eyepiece Vario 8.9 - 17.8 mm ASPH. - 1.25" (apm-telescopes.net)

The Svbony 3-8mm zoom offers great optical performance but may not be regarded as having a wide angle of view at 56 degrees.

Brass 'n sunshine plus an active photosphere. A nice combination 😁

My favourite is probably the 13mm but the very best performer of the ones I have is the 6mm - I have a quandary 🤔

(I opted for the 13mm in the poll)

I have the 21, 13, 8, 6 and 4.7 in the series and really like them all, of course 🙂

The "why" for the 13mm is based on it's versatility in my old 12 inch F/5.3 dob where it seemed to be able to deliver so well over a wide range of target types. 

I've also owned the 17mm and 3.7mm in the past and liked those as well but the focal lengths were not ones I used much.

Just the dear old 10mm to go, which is reputedly one of the best Ethos, so I'll have to try one, one day 🙂

Last night I could see the moon and just the brightest constellation stars through a thin but annoying cloud layer, so I didn't bother observing. It was Astro Society night anyway so I got my fill of astro fodder that way. Interesting talk about the Andromeda Galaxy being visually "warped" at it's extremities - something to look out for if I get a really dark, transparent night later this year when M31 is high in the sky.

Edit: posted in wrong section. Sorry.

Not sure about the image train issue but the challenge with an F/4 newtonian is that the "sweet spot" for accurate collimation has got really small at that focal ratio - around 1.4mm, so collimation has to be that much more precise to achieve diffraction limited performance. 

20 minutes ago, vlaiv said:

To me it looks like draw tube of focuser is closer 0.965" than 1.25"?

Also, having trouble figuring out how the scope attaches to dovetail or how it's mounted to the mount itself.

And yes - no CW bar or counterweights for that matter

 

I agree that it looks like a .965" focuser.

I think the optical tube is just resting on the mount head. There seems to be a short black screw projecting from the lower side of the optical tube resting against the dovetail bar in the mount clamp. Maybe some "Blu tack" was used to stop it rolling off during the photo shoot !

No self respecting astronomer wears a rucksack when observing either 😁

24 minutes ago, Captain Scarlet said:

You must be harsh with yourself about those to confidently declare a positive, in my opinion.....

Very true. If I have any doubts at all and if I have not been able to repeat an observation at least twice, I don't put it down as having been achieved.