John

I assume that your Celestron C-102 F/9.8 is one of the more recent, chinese made ones ? Back in the 1980's / 1990's Vixen used to make them for Celestron and they were exactly the same as the 102M Vixen's, apart from the gloss black colour scheme.

I've used the 3 that Don lists above. I still have a Baader Hyperion 8-24mm. Their prices vary considerably as do their specifications - between £200 (Baader) and £750 (Leica). Their performance is more or less in line with their pricing. The Baader (IMHO) gets close to good fixed focal length eyepieces in performance but looses out in terms of FoV at the long focal length end. The APM performed pretty much as well as Pentax XW's I felt but, in my scopes, had to be used as a 2 inch eyepiece due to the inwards focuser travel needed in 1.25 inch mode. The Leica is really good optically, a touch better than most fixed focal length eyepieces and is often combined with the Baader VIP barlow to give shorter focal lengths. I find the Baader useful to have in the eyepiece case and it's good for travel and outreach. The APM I had on loan and the Leica I tried for a few months but for some reason I didn't take to it in the long term Others find it essential though. That's my short and sweet summary of those from my contact with them. Others may well have a lot more to say on them 🙂

Visually, it's tough: "....Really, it's like trying to see a little bit of nothing with a little bit of less than nothing resting over it....." Jeremy Perez, 2006 Edit: Unless you are using EAA of course 🙂

I'm sorry that I'm a bit late to this. I had a 40mm Aero ED for a while and thought it a very good eyepiece. Best corrected of the Aero ED's that I've used. I have not compared it with a Vixen LVW 42mm though. Although the exit pupil is rather over-sized in the scope, I was pleasantly surprised how well corrected across the FoV the Aero ED 40mm was when I tried it in my F/5.3 12 inch dobsonian. I would probably want to "try before I buy" in my scopes, especially the faster ones, before jumping ship to the Vixen, just to see that there are some actual benefits. If you decide to move the 40mm Aero ED on, I'd certainly be interested in owning another one 🙂

For all but the larger DSO's it may well be all you need in a 102mm F/7 refractor. A true field of around 1.8 degrees will fit most things in 🙂

Not at all. Probably very sensible. Most of these very tough observing challenges result in a very marginal glimpse of something exceedingly indistinct. You do sometimes wonder why you bother 🙄

I've replied to your PM Paul. For the eyepieces I think what you need is a 36.4mm - 31.7mm push fit adapter, like this:

Personally I find it satisfying to see that thin dark line between the airy disks. I'm not doing "science" though - it's just for fun 😁

Yes, I thought that. Observing the "Pup" star is not really like resolving or splitting other double stars. The scattered light that surrounds Sirius A (diffraction rings, just scatter or a mixture of both) usually extends beyond the 11 arc seconds that separates it from Sirius B so the challenge is to spot that dim speck of light glimmering though that halo. There have been nights of exceptional seeing when the Sirius A halo is tighter but mostly it's a slightly different game from splitting the usual challenging pair.

Capital "P" Mr Speck Spock ? 🙂

First birds we saw after travelling a few thousand miles from the UK to Vancouver was a flock of Canade Geese 🙂 And it's not as if we don't have quite a few of them over here ! Hope you had a great solar session 🙂

Here's a good springtime challenge - spot the quasar 3C 273 in the "bowl" of Virgo. It's only going to appear as a very faint point of light but it's one of these targets that becomes a bit special when you know a little about it. 3C 273 is visually the brightest quasar in the sky. It lies around 2.4 billion light years from us so for some it may just be the most distant object that they have ever observed. The host galaxy is thought to also be the home to a massive black hole. The trick is to identify which faint speck of light is the quasar. Astronomy Now magazine put a good piece on this target on their website back in spring 2019, and it includes finder charts and other useful and interesting information: Seek out 3C 273, the brightest optical quasar, in the spring sky – Astronomy Now I have seen 3C 273 with my 12 inch dobsonian back in 2021 but currently my largest aperture scope is 130mm so I will have to see if I can tease it out of the sky with that. I will wait for a darkish night I think !

I had to boost up the magnification to around 100x to see any trace of it with direct vision Steve. The trouble is that the surface brightness is faint with this one.

I've never managed to see the Encke Gap / Division as far as I'm aware. The best views I ever had of Saturn were with my 12 inch dob when the planet was relatively high in the sky and on one or two nights of the very best seeing I managed to detect what I think was the Encke Minima but never a convincing sighting of the gap itself. With Saturn being so low from here over recent seasons, such fine detail has been even harder to detect I feel. What were your equipment, planet location and seeing condition circumstances when you spotted the minima ?

No problem. The imager is an Italian astronomer called Vincenzo della Vecchia. The equipment used was a CFF 30 cm Cassegrain and the QHY5III-200M (I assume the last is the camera ?). The image appeared in this CN thread and there is some discussion in it on the settings etc used which might make more sense to you than they do to me ! Zeta Cancri split - Double Star Observing - Cloudy Nights

I'm drawing my interesting session tonight with the Vixen ED102SS to a close with some galaxies and planetary nebulae. The transparency is not the best and the scope just a 4 incher but what the heck 🙂 I got a few galaxies in Leo. I often find NGC 2903 near the Lion's muzzle a good one with the smaller apertures. Quite easy to find as well. The Leo triplet was visible with the Hamburger (NGC 3628) being the hardest to pick out, as usual with a small scope. I picked up the Eskimo Nebula in Gemini then the Cats Eye Nebula in Draco. Moving to Ursa Major, finding the well known galactic pair of M51 and NGC 5195 looking like two dim eyes looking back at me, I then moved to Merak, popped in an O-III filter and saw the Owl Nebula (M97) looking quite bright as it was practically overhead. Removing the filter I was pleased to find that I could still see the Owl Neb but also, faintly, M108, the Surfboard Galaxy in the same field of view. It's been a good session with my old Vixen (24 years old I reckon). A very versatile scope as it proves itself to be time and time again 😀

Stu - I saw those fine lines with my 102mm from time to time as well. At least I thought I did, or might have. I wasn't sure if it was my eye playing tricks though - maybe joining up the two notches ? More observations needed ! 🙂

Thanks but the image is not mine (I don't image). I'll see if I can find who did though and let you know 🙂 I would imagine that imaging close double stars is a fairly specialised business and pretty tricky !

You will often see Tegmine / Zeta Cancri named as a target in observing reports around this time of the year. It is a fine triple star and also presents an interesting challenge for the 4-5 inch aperture scope. The close pair currently has a separation (source: Stelle Doppie database) of 1.098 arc seconds. The 3rd member of the group is separated from this pair by around 6 arc seconds, so relatively easy to split from the close pair. The close pair are of magnitude 5.3 and magnitude 6.25 respectively. The challenge for the 4 inch scope is that the Dawes resolution limit for that aperture is 1.14 arc seconds. The, perhaps more realistic, Rayleigh limit for a 4 inch scope is 1.36 arc seconds. So theoretically a 4 inch scope cannot show the close Tegmine pair as clearly split, whichever limit you choose to apply. These figures apply to stars of equal brightness I believe. What a good 4 inch scope can do however is to show this close pair as resolved. I am using the definition illustrated below by David Knisely: Tonight my 102mm F/6.5 refractor clearly showed the tight Tegmine pair as a resolved or notched pair of apparently touching airy disks. I take this to mean that the scope is performing to the Dawes limit under the fairly steady seeing conditions. When I observed Tegmine a few nights back with my 120mm F/7.5 refractor I could see that elusive sliver of black between the airy disks - the pair was split and the additional aperture was doing it's job. I have seen reports of the close Tegmine pair being split with a 4 inch aperture scope. I guess a sharper eyed observer than me, observing under excellent conditions might be able to see the pair as split. Or maybe the terms resolved pair and split pair were being used differently 🤔 Anyway, I've never been able to quite see a clear split with this pair with either my 3.9 or 4 inch refractors but I was quite happy with my resolved / notched pairing with the 4 inch refractor this evening. The scope is doing it's very best, especially when the slightly uneven brightness of the close Tegmine pair is taken into account🙂 Incidentally, I found 221x magnification the optimum for this target tonight. I tried more but the definition of the close pair didn't get any cleaner. Lower magnifications made seeing the "notch" effect harder. Another interesting factoid is that the name Tegmine is derived from the latin Tegmens, which means Crab's Shell, which is apt of course 🙂

Sorry, I should not have been so vague 😔 It's the Takahashi FC100-DL. An F/9 doublet with a fluorite element. Hope that helps 🙂

I managed to spot NGC 2419, the "Intergalactic Wanderer" globular cluster with my 102mm refractor tonight. It's pretty faint, small and indistinct to be honest so a larger scope will give a much better view. It's integrated brightness is given at mag 9 or 10 but the surface brightness is more like 12 so tough for a 4 inch scope I find. I needed around 100x magnification to be able to see it (vaguely) with direct vision. Less than that and it's only really apparent using averted vision. Transparency is mediocre here tonight. It's not a large object - a hazy patch really, about 6 arc minutes in apparent diameter. I "hopped" to it from Castor (see maps below). I passed the pair of Jishui and 70 Geminorum to reach a triangle of stars. NGC 2419 is a little above the top star of the triangle and on the end of a little curving line of 3 stars. The maps below are RACI finder orientated. The close map is the view with a 9x50 finder, approx. Fun challenge with a 4 inch scope 🙂 According to Wikipedia, if NGC 2419 is one of the brightest and largest globular clusters in our galaxy but it's a long, long, long way off. Still considered to be within our galaxy though, despite the rather romantic nickname 🙄

I got this tonight with my 102mm refractor. Thought I'd do a separate report on it: https://stargazerslounge.com/topic/419842-ngc-2419-the-intergallactic-wanderer/

A doublet.

Just managed to get a scope on 12P Pons-Brooks by standing in a flower bed right at the furthest end of the garden ! Nice looking comet - quite a bright nucleus now. No obvious tail with the 102mm refractor although averted vision / imagination suggested a direction that it might lie in. I'll be interested to see the images taken tonight to see if my eye was playing tricks on me 🙂

I have a 4 inch apo that goes to 300x, shows E & F Trap and Sirius B, conditions allowing. It's made by a company beginning with "T" 🙂 20 years or so ago I probably could not have achieved that much with the scope though - I guess my skills and experience have improved a little over time !